From 507fc5cf256bd4d1749a6109ef45c8462dd82185 Mon Sep 17 00:00:00 2001
From: Matthew Hughes <34972397+matthewhughes934@users.noreply.github.com>
Date: Thu, 27 Oct 2022 19:25:34 +0100
Subject: [PATCH 001/231] Add type inference for `dict.keys` membership
 (#13372)

Closes #13360
---
 mypy/checker.py                |  2 ++
 test-data/unit/pythoneval.test | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/mypy/checker.py b/mypy/checker.py
index 31177795e5e51..d66bf764b517b 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -6656,6 +6656,8 @@ def builtin_item_type(tp: Type) -> Type | None:
             "builtins.dict",
             "builtins.set",
             "builtins.frozenset",
+            "_collections_abc.dict_keys",
+            "typing.KeysView",
         ]:
             if not tp.args:
                 # TODO: fix tuple in lib-stub/builtins.pyi (it should be generic).
diff --git a/test-data/unit/pythoneval.test b/test-data/unit/pythoneval.test
index 59ab586b17e63..692f62bf64547 100644
--- a/test-data/unit/pythoneval.test
+++ b/test-data/unit/pythoneval.test
@@ -1636,3 +1636,27 @@ foo("")
 foo(list(""))
 foo(list((list(""), "")))
 [out]
+
+[case testNarrowTypeForDictKeys]
+# flags: --strict-optional
+from typing import Dict, KeysView, Optional
+
+d: Dict[str, int]
+key: Optional[str]
+if key in d.keys():
+    reveal_type(key)
+else:
+    reveal_type(key)
+
+kv: KeysView[str]
+k: Optional[str]
+if k in kv:
+    reveal_type(k)
+else:
+    reveal_type(k)
+
+[out]
+_testNarrowTypeForDictKeys.py:7: note: Revealed type is "builtins.str"
+_testNarrowTypeForDictKeys.py:9: note: Revealed type is "Union[builtins.str, None]"
+_testNarrowTypeForDictKeys.py:14: note: Revealed type is "builtins.str"
+_testNarrowTypeForDictKeys.py:16: note: Revealed type is "Union[builtins.str, None]"

From 2d70ac0b33b448d5ef51c0856571068dd0754af6 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 27 Oct 2022 15:04:28 -0700
Subject: [PATCH 002/231] Add hidden options to disable bytes promotion
 (#13952)

It might be useful to run mypy_primer without promotions in typeshed.
This would give us more confidence in changes stemming from
https://github.com/python/typeshed/issues/9001
---
 mypy/main.py                    |  6 ++++++
 mypy/options.py                 | 16 +++++++++++++---
 mypy/semanal_classprop.py       |  4 ++++
 test-data/unit/check-flags.test | 15 +++++++++++++++
 4 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/mypy/main.py b/mypy/main.py
index 360a8ed1df17e..405596c209919 100644
--- a/mypy/main.py
+++ b/mypy/main.py
@@ -1121,6 +1121,12 @@ def add_invertible_flag(
     parser.add_argument(
         "--enable-incomplete-features", action="store_true", help=argparse.SUPPRESS
     )
+    parser.add_argument(
+        "--disable-bytearray-promotion", action="store_true", help=argparse.SUPPRESS
+    )
+    parser.add_argument(
+        "--disable-memoryview-promotion", action="store_true", help=argparse.SUPPRESS
+    )
 
     # options specifying code to check
     code_group = parser.add_argument_group(
diff --git a/mypy/options.py b/mypy/options.py
index b89ad97708c17..3a08ff9455ee7 100644
--- a/mypy/options.py
+++ b/mypy/options.py
@@ -56,9 +56,16 @@ class BuildType:
     "warn_unused_ignores",
 }
 
-OPTIONS_AFFECTING_CACHE: Final = (PER_MODULE_OPTIONS | {"platform", "bazel", "plugins"}) - {
-    "debug_cache"
-}
+OPTIONS_AFFECTING_CACHE: Final = (
+    PER_MODULE_OPTIONS
+    | {
+        "platform",
+        "bazel",
+        "plugins",
+        "disable_bytearray_promotion",
+        "disable_memoryview_promotion",
+    }
+) - {"debug_cache"}
 
 # Features that are currently incomplete/experimental
 TYPE_VAR_TUPLE: Final = "TypeVarTuple"
@@ -329,6 +336,9 @@ def __init__(self) -> None:
         # Deprecated reverse version of the above, do not use.
         self.enable_recursive_aliases = False
 
+        self.disable_bytearray_promotion = False
+        self.disable_memoryview_promotion = False
+
     # To avoid breaking plugin compatibility, keep providing new_semantic_analyzer
     @property
     def new_semantic_analyzer(self) -> bool:
diff --git a/mypy/semanal_classprop.py b/mypy/semanal_classprop.py
index b5a702592144d..5d21babcc597d 100644
--- a/mypy/semanal_classprop.py
+++ b/mypy/semanal_classprop.py
@@ -165,6 +165,10 @@ def add_type_promotion(
     if not promote_targets:
         if defn.fullname in TYPE_PROMOTIONS:
             target_sym = module_names.get(TYPE_PROMOTIONS[defn.fullname])
+            if defn.fullname == "builtins.bytearray" and options.disable_bytearray_promotion:
+                target_sym = None
+            elif defn.fullname == "builtins.memoryview" and options.disable_memoryview_promotion:
+                target_sym = None
             # With test stubs, the target may not exist.
             if target_sym:
                 target_info = target_sym.node
diff --git a/test-data/unit/check-flags.test b/test-data/unit/check-flags.test
index 03c2d1f38b822..5a075dd6efef8 100644
--- a/test-data/unit/check-flags.test
+++ b/test-data/unit/check-flags.test
@@ -2128,3 +2128,18 @@ Ts = TypeVarTuple("Ts")  # E: "TypeVarTuple" support is experimental, use --enab
 from typing_extensions import TypeVarTuple
 Ts = TypeVarTuple("Ts")  # OK
 [builtins fixtures/tuple.pyi]
+
+
+[case testDisableBytearrayPromotion]
+# flags: --disable-bytearray-promotion
+def f(x: bytes) -> None: ...
+f(bytearray(b"asdf"))  # E: Argument 1 to "f" has incompatible type "bytearray"; expected "bytes"
+f(memoryview(b"asdf"))
+[builtins fixtures/primitives.pyi]
+
+[case testDisableMemoryviewPromotion]
+# flags: --disable-memoryview-promotion
+def f(x: bytes) -> None: ...
+f(bytearray(b"asdf"))
+f(memoryview(b"asdf"))  # E: Argument 1 to "f" has incompatible type "memoryview"; expected "bytes"
+[builtins fixtures/primitives.pyi]

From 5319fa34a8004c1568bb6f032a07b8b14cc95bed Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sat, 29 Oct 2022 12:47:21 -0700
Subject: [PATCH 003/231] Revert sum literal integer change (#13961)

This is allegedly causing large performance problems, see 13821

typeshed/8231 had zero hits on mypy_primer, so it's not the worst thing
to undo. Patching this in typeshed also feels weird, since there's a
more general soundness issue. If a typevar has a bound or constraint, we
might not want to solve it to a Literal.

If we can confirm the performance regression or fix the unsoundness
within mypy, I might pursue upstreaming this in typeshed.

(Reminder: add this to the sync_typeshed script once merged)
---
 mypy/typeshed/stdlib/builtins.pyi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index ed60a7c018e76..d3b3f677b370c 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -1569,11 +1569,11 @@ _SupportsSumNoDefaultT = TypeVar("_SupportsSumNoDefaultT", bound=_SupportsSumWit
 # Instead, we special-case the most common examples of this: bool and literal integers.
 if sys.version_info >= (3, 8):
     @overload
-    def sum(__iterable: Iterable[bool | _LiteralInteger], start: int = ...) -> int: ...  # type: ignore[misc]
+    def sum(__iterable: Iterable[bool], start: int = ...) -> int: ...  # type: ignore[misc]
 
 else:
     @overload
-    def sum(__iterable: Iterable[bool | _LiteralInteger], __start: int = ...) -> int: ...  # type: ignore[misc]
+    def sum(__iterable: Iterable[bool], __start: int = ...) -> int: ...  # type: ignore[misc]
 
 @overload
 def sum(__iterable: Iterable[_SupportsSumNoDefaultT]) -> _SupportsSumNoDefaultT | Literal[0]: ...

From 40d04a5af0b658ae5ef6181c7f3d89a984fe3547 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sat, 29 Oct 2022 13:05:49 -0700
Subject: [PATCH 004/231] Revert sum literal changes on an ongoing basis
 (#13962)

Makes sure we continue to cherry pick
https://github.com/python/mypy/pull/13961
---
 misc/sync-typeshed.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/misc/sync-typeshed.py b/misc/sync-typeshed.py
index c6856f86744a7..743a2934e0c3c 100644
--- a/misc/sync-typeshed.py
+++ b/misc/sync-typeshed.py
@@ -184,8 +184,10 @@ def main() -> None:
     subprocess.run(["git", "commit", "-m", message], check=True)
     print("Created typeshed sync commit.")
 
-    # Currently just LiteralString reverts
-    commits_to_cherry_pick = ["780534b13722b7b0422178c049a1cbbf4ea4255b"]
+    commits_to_cherry_pick = [
+        "780534b13722b7b0422178c049a1cbbf4ea4255b",  # LiteralString reverts
+        "5319fa34a8004c1568bb6f032a07b8b14cc95bed",  # sum reverts
+    ]
     for commit in commits_to_cherry_pick:
         subprocess.run(["git", "cherry-pick", commit], check=True)
         print(f"Cherry-picked {commit}.")

From 41c160231bb53cb9895044506c2b08aba692922b Mon Sep 17 00:00:00 2001
From: Nikita Sobolev <mail@sobolevn.me>
Date: Mon, 31 Oct 2022 02:35:52 +0300
Subject: [PATCH 005/231] Warn on invalid `*args` and `**kwargs` with
 `ParamSpec` (#13892)

Closes #13890
---
 mypy/semanal.py                               |  61 ++++++++++
 .../unit/check-parameter-specification.test   | 113 ++++++++++++++++++
 2 files changed, 174 insertions(+)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index b37c9b2a5c77b..b8f708b22a924 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -69,6 +69,8 @@
 from mypy.nodes import (
     ARG_NAMED,
     ARG_POS,
+    ARG_STAR,
+    ARG_STAR2,
     CONTRAVARIANT,
     COVARIANT,
     GDEF,
@@ -843,6 +845,7 @@ def analyze_func_def(self, defn: FuncDef) -> None:
                 defn.type = result
                 self.add_type_alias_deps(analyzer.aliases_used)
                 self.check_function_signature(defn)
+                self.check_paramspec_definition(defn)
                 if isinstance(defn, FuncDef):
                     assert isinstance(defn.type, CallableType)
                     defn.type = set_callable_name(defn.type, defn)
@@ -1282,6 +1285,64 @@ def check_function_signature(self, fdef: FuncItem) -> None:
         elif len(sig.arg_types) > len(fdef.arguments):
             self.fail("Type signature has too many arguments", fdef, blocker=True)
 
+    def check_paramspec_definition(self, defn: FuncDef) -> None:
+        func = defn.type
+        assert isinstance(func, CallableType)
+
+        if not any(isinstance(var, ParamSpecType) for var in func.variables):
+            return  # Function does not have param spec variables
+
+        args = func.var_arg()
+        kwargs = func.kw_arg()
+        if args is None and kwargs is None:
+            return  # Looks like this function does not have starred args
+
+        args_defn_type = None
+        kwargs_defn_type = None
+        for arg_def, arg_kind in zip(defn.arguments, defn.arg_kinds):
+            if arg_kind == ARG_STAR:
+                args_defn_type = arg_def.type_annotation
+            elif arg_kind == ARG_STAR2:
+                kwargs_defn_type = arg_def.type_annotation
+
+        # This may happen on invalid `ParamSpec` args / kwargs definition,
+        # type analyzer sets types of arguments to `Any`, but keeps
+        # definition types as `UnboundType` for now.
+        if not (
+            (isinstance(args_defn_type, UnboundType) and args_defn_type.name.endswith(".args"))
+            or (
+                isinstance(kwargs_defn_type, UnboundType)
+                and kwargs_defn_type.name.endswith(".kwargs")
+            )
+        ):
+            # Looks like both `*args` and `**kwargs` are not `ParamSpec`
+            # It might be something else, skipping.
+            return
+
+        args_type = args.typ if args is not None else None
+        kwargs_type = kwargs.typ if kwargs is not None else None
+
+        if (
+            not isinstance(args_type, ParamSpecType)
+            or not isinstance(kwargs_type, ParamSpecType)
+            or args_type.name != kwargs_type.name
+        ):
+            if isinstance(args_defn_type, UnboundType) and args_defn_type.name.endswith(".args"):
+                param_name = args_defn_type.name.split(".")[0]
+            elif isinstance(kwargs_defn_type, UnboundType) and kwargs_defn_type.name.endswith(
+                ".kwargs"
+            ):
+                param_name = kwargs_defn_type.name.split(".")[0]
+            else:
+                # Fallback for cases that probably should not ever happen:
+                param_name = "P"
+
+            self.fail(
+                f'ParamSpec must have "*args" typed as "{param_name}.args" and "**kwargs" typed as "{param_name}.kwargs"',
+                func,
+                code=codes.VALID_TYPE,
+            )
+
     def visit_decorator(self, dec: Decorator) -> None:
         self.statement = dec
         # TODO: better don't modify them at all.
diff --git a/test-data/unit/check-parameter-specification.test b/test-data/unit/check-parameter-specification.test
index 6af596fc1febd..6f488f108153c 100644
--- a/test-data/unit/check-parameter-specification.test
+++ b/test-data/unit/check-parameter-specification.test
@@ -1166,3 +1166,116 @@ def func3(callback: Callable[P1, str]) -> Callable[P1, str]:
         return "foo"
     return inner
 [builtins fixtures/paramspec.pyi]
+
+
+[case testInvalidParamSpecDefinitionsWithArgsKwargs]
+from typing import Callable, ParamSpec
+
+P = ParamSpec('P')
+
+def c1(f: Callable[P, int], *args: P.args, **kwargs: P.kwargs) -> int: ...
+def c2(f: Callable[P, int]) -> int: ...
+def c3(f: Callable[P, int], *args, **kwargs) -> int: ...
+
+# It is ok to define,
+def c4(f: Callable[P, int], *args: int, **kwargs: str) -> int:
+    # but not ok to call:
+    f(*args, **kwargs)  # E: Argument 1 has incompatible type "*Tuple[int, ...]"; expected "P.args" \
+                        # E: Argument 2 has incompatible type "**Dict[str, str]"; expected "P.kwargs"
+    return 1
+
+def f1(f: Callable[P, int], *args, **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f2(f: Callable[P, int], *args: P.args, **kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f3(f: Callable[P, int], *args: P.args) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f4(f: Callable[P, int], **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+
+# Error message test:
+P1 = ParamSpec('P1')
+
+def m1(f: Callable[P1, int], *a, **k: P1.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+[builtins fixtures/paramspec.pyi]
+
+
+[case testInvalidParamSpecAndConcatenateDefinitionsWithArgsKwargs]
+from typing import Callable, ParamSpec
+from typing_extensions import Concatenate
+
+P = ParamSpec('P')
+
+def c1(f: Callable[Concatenate[int, P], int], *args: P.args, **kwargs: P.kwargs) -> int: ...
+def c2(f: Callable[Concatenate[int, P], int]) -> int: ...
+def c3(f: Callable[Concatenate[int, P], int], *args, **kwargs) -> int: ...
+
+# It is ok to define,
+def c4(f: Callable[Concatenate[int, P], int], *args: int, **kwargs: str) -> int:
+    # but not ok to call:
+    f(1, *args, **kwargs)  # E: Argument 2 has incompatible type "*Tuple[int, ...]"; expected "P.args" \
+                           # E: Argument 3 has incompatible type "**Dict[str, str]"; expected "P.kwargs"
+    return 1
+
+def f1(f: Callable[Concatenate[int, P], int], *args, **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f2(f: Callable[Concatenate[int, P], int], *args: P.args, **kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f3(f: Callable[Concatenate[int, P], int], *args: P.args) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f4(f: Callable[Concatenate[int, P], int], **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+[builtins fixtures/paramspec.pyi]
+
+
+[case testValidParamSpecInsideGenericWithoutArgsAndKwargs]
+from typing import Callable, ParamSpec, Generic
+from typing_extensions import Concatenate
+
+P = ParamSpec('P')
+
+class Some(Generic[P]): ...
+
+def create(s: Some[P], *args: int): ...
+def update(s: Some[P], **kwargs: int): ...
+def delete(s: Some[P]): ...
+
+def from_callable1(c: Callable[P, int], *args: int, **kwargs: int) -> Some[P]: ...
+def from_callable2(c: Callable[P, int], **kwargs: int) -> Some[P]: ...
+def from_callable3(c: Callable[P, int], *args: int) -> Some[P]: ...
+
+def from_extra1(c: Callable[Concatenate[int, P], int], *args: int, **kwargs: int) -> Some[P]: ...
+def from_extra2(c: Callable[Concatenate[int, P], int], **kwargs: int) -> Some[P]: ...
+def from_extra3(c: Callable[Concatenate[int, P], int], *args: int) -> Some[P]: ...
+[builtins fixtures/paramspec.pyi]
+
+
+[case testUnboundParamSpec]
+from typing import Callable, ParamSpec
+
+P1 = ParamSpec('P1')
+P2 = ParamSpec('P2')
+
+def f0(f: Callable[P1, int], *args: P1.args, **kwargs: P2.kwargs): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+
+def f1(*args: P1.args): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+def f2(**kwargs: P1.kwargs): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+def f3(*args: P1.args, **kwargs: int): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+def f4(*args: int, **kwargs: P1.kwargs): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+
+# Error message is based on the `args` definition:
+def f5(*args: P2.args, **kwargs: P1.kwargs): ...  # E: ParamSpec must have "*args" typed as "P2.args" and "**kwargs" typed as "P2.kwargs"
+def f6(*args: P1.args, **kwargs: P2.kwargs): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+
+# Multiple `ParamSpec` variables can be found, they should not affect error message:
+P3 = ParamSpec('P3')
+
+def f7(first: Callable[P3, int], *args: P1.args, **kwargs: P2.kwargs): ...  # E: ParamSpec must have "*args" typed as "P1.args" and "**kwargs" typed as "P1.kwargs"
+def f8(first: Callable[P3, int], *args: P2.args, **kwargs: P1.kwargs): ...  # E: ParamSpec must have "*args" typed as "P2.args" and "**kwargs" typed as "P2.kwargs"
+[builtins fixtures/paramspec.pyi]
+
+
+[case testArgsKwargsWithoutParamSpecVar]
+from typing import Generic, Callable, ParamSpec
+
+P = ParamSpec('P')
+
+# This must be allowed:
+class Some(Generic[P]):
+    def call(self, *args: P.args, **kwargs: P.kwargs): ...
+
+# TODO: this probably should be reported.
+def call(*args: P.args, **kwargs: P.kwargs): ...
+[builtins fixtures/paramspec.pyi]

From 758f43c5d27eda339fd340a7b68bce59b3684254 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Mon, 31 Oct 2022 00:52:27 -0700
Subject: [PATCH 006/231] Add another invalid ParamSpec test case (#13968)

Don't think there's a test case corresponding to the issue in #13966
---
 test-data/unit/check-parameter-specification.test | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test-data/unit/check-parameter-specification.test b/test-data/unit/check-parameter-specification.test
index 6f488f108153c..329985c4f75bf 100644
--- a/test-data/unit/check-parameter-specification.test
+++ b/test-data/unit/check-parameter-specification.test
@@ -1188,6 +1188,7 @@ def f1(f: Callable[P, int], *args, **kwargs: P.kwargs) -> int: ...  # E: ParamSp
 def f2(f: Callable[P, int], *args: P.args, **kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
 def f3(f: Callable[P, int], *args: P.args) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
 def f4(f: Callable[P, int], **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f5(f: Callable[P, int], *args: P.args, extra_keyword_arg: int, **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
 
 # Error message test:
 P1 = ParamSpec('P1')
@@ -1217,6 +1218,7 @@ def f1(f: Callable[Concatenate[int, P], int], *args, **kwargs: P.kwargs) -> int:
 def f2(f: Callable[Concatenate[int, P], int], *args: P.args, **kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
 def f3(f: Callable[Concatenate[int, P], int], *args: P.args) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
 def f4(f: Callable[Concatenate[int, P], int], **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
+def f5(f: Callable[Concatenate[int, P], int], *args: P.args, extra_keyword_arg: int, **kwargs: P.kwargs) -> int: ...  # E: ParamSpec must have "*args" typed as "P.args" and "**kwargs" typed as "P.kwargs"
 [builtins fixtures/paramspec.pyi]
 
 

From 7569d88d0d650be73070c2536ddc3746d61237dd Mon Sep 17 00:00:00 2001
From: Michael Lee <michael.lee.0x2a@gmail.com>
Date: Mon, 31 Oct 2022 07:24:42 -0700
Subject: [PATCH 007/231] Fix crash with malformed TypedDicts and
 disllow-any-expr (#13963)

Fixes #13066

During the semanal phase, mypy opts to ignore and skip processing any
malformed or illegal statements inside of a TypedDict class definition,
such as method definitions.

Skipping semanal analysis on these statements can cause any number of
odd downstream problems: the type-checking phase assumes that all
semanal-only semantic constructs (e.g. FakeInfo) have been purged by
this point, and so can crash at any point once this precondition has
been violated.

This diff opts to solve this problem by filtering down the list of
statements so we keep only the ones we know are legal within a TypedDict
definition.

The other possible solution to this problem is to modify mypy so we skip
checking TypedDict class bodies entirely during type checking and
fine-grained deps analysis. Doing this would also let address #10007 and
supersede my other diff #13732.

I decided against doing this for now because:

1. I wasn't sure if this was actually safe, especially in the
fine-grained deps phase and for mypyc.
2. I think no matter what, the semanal phase should not leak
semanal-only types: relaxing this postcondition would make it harder to
reason about mypy. So, we'd probably want to make this change regardless
of what we do in the later phases.
---
 mypy/semanal_typeddict.py           | 32 +++++++++++++++++++++--------
 test-data/unit/check-typeddict.test | 13 ++++++++++++
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/mypy/semanal_typeddict.py b/mypy/semanal_typeddict.py
index fd6b1bbd2bbf2..b864c2a306159 100644
--- a/mypy/semanal_typeddict.py
+++ b/mypy/semanal_typeddict.py
@@ -23,6 +23,7 @@
     NameExpr,
     PassStmt,
     RefExpr,
+    Statement,
     StrExpr,
     TempNode,
     TupleExpr,
@@ -93,7 +94,7 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
             and defn.base_type_exprs[0].fullname in TPDICT_NAMES
         ):
             # Building a new TypedDict
-            fields, types, required_keys = self.analyze_typeddict_classdef_fields(defn)
+            fields, types, statements, required_keys = self.analyze_typeddict_classdef_fields(defn)
             if fields is None:
                 return True, None  # Defer
             info = self.build_typeddict_typeinfo(
@@ -102,6 +103,7 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
             defn.analyzed = TypedDictExpr(info)
             defn.analyzed.line = defn.line
             defn.analyzed.column = defn.column
+            defn.defs.body = statements
             return True, info
 
         # Extending/merging existing TypedDicts
@@ -139,7 +141,12 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
         # Iterate over bases in reverse order so that leftmost base class' keys take precedence
         for base in reversed(typeddict_bases):
             self.add_keys_and_types_from_base(base, keys, types, required_keys, defn)
-        new_keys, new_types, new_required_keys = self.analyze_typeddict_classdef_fields(defn, keys)
+        (
+            new_keys,
+            new_types,
+            new_statements,
+            new_required_keys,
+        ) = self.analyze_typeddict_classdef_fields(defn, keys)
         if new_keys is None:
             return True, None  # Defer
         keys.extend(new_keys)
@@ -151,6 +158,7 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> tuple[bool, TypeInfo | N
         defn.analyzed = TypedDictExpr(info)
         defn.analyzed.line = defn.line
         defn.analyzed.column = defn.column
+        defn.defs.body = new_statements
         return True, info
 
     def add_keys_and_types_from_base(
@@ -250,7 +258,7 @@ def map_items_to_base(
 
     def analyze_typeddict_classdef_fields(
         self, defn: ClassDef, oldfields: list[str] | None = None
-    ) -> tuple[list[str] | None, list[Type], set[str]]:
+    ) -> tuple[list[str] | None, list[Type], list[Statement], set[str]]:
         """Analyze fields defined in a TypedDict class definition.
 
         This doesn't consider inherited fields (if any). Also consider totality,
@@ -259,17 +267,22 @@ def analyze_typeddict_classdef_fields(
         Return tuple with these items:
          * List of keys (or None if found an incomplete reference --> deferral)
          * List of types for each key
+         * List of statements from defn.defs.body that are legally allowed to be a
+           part of a TypedDict definition
          * Set of required keys
         """
         fields: list[str] = []
         types: list[Type] = []
+        statements: list[Statement] = []
         for stmt in defn.defs.body:
             if not isinstance(stmt, AssignmentStmt):
-                # Still allow pass or ... (for empty TypedDict's).
-                if not isinstance(stmt, PassStmt) and not (
+                # Still allow pass or ... (for empty TypedDict's) and docstrings
+                if isinstance(stmt, PassStmt) or (
                     isinstance(stmt, ExpressionStmt)
                     and isinstance(stmt.expr, (EllipsisExpr, StrExpr))
                 ):
+                    statements.append(stmt)
+                else:
                     self.fail(TPDICT_CLASS_ERROR, stmt)
             elif len(stmt.lvalues) > 1 or not isinstance(stmt.lvalues[0], NameExpr):
                 # An assignment, but an invalid one.
@@ -281,8 +294,9 @@ def analyze_typeddict_classdef_fields(
                 if name in fields:
                     self.fail(f'Duplicate TypedDict key "{name}"', stmt)
                     continue
-                # Append name and type in this case...
+                # Append stmt, name, and type in this case...
                 fields.append(name)
+                statements.append(stmt)
                 if stmt.type is None:
                     types.append(AnyType(TypeOfAny.unannotated))
                 else:
@@ -293,9 +307,9 @@ def analyze_typeddict_classdef_fields(
                         and not self.api.is_func_scope(),
                     )
                     if analyzed is None:
-                        return None, [], set()  # Need to defer
+                        return None, [], [], set()  # Need to defer
                     types.append(analyzed)
-                # ...despite possible minor failures that allow further analyzis.
+                # ...despite possible minor failures that allow further analysis.
                 if stmt.type is None or hasattr(stmt, "new_syntax") and not stmt.new_syntax:
                     self.fail(TPDICT_CLASS_ERROR, stmt)
                 elif not isinstance(stmt.rvalue, TempNode):
@@ -317,7 +331,7 @@ def analyze_typeddict_classdef_fields(
             t.item if isinstance(t, RequiredType) else t for t in types
         ]
 
-        return fields, types, required_keys
+        return fields, types, statements, required_keys
 
     def check_typeddict(
         self, node: Expression, var_name: str | None, is_func_scope: bool
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index 4c68b7b692ff8..796f2f547528c 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -221,6 +221,19 @@ reveal_type(d)  # N: Revealed type is "TypedDict('__main__.D', {'y': builtins.in
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
 
+[case testCannotCreateTypedDictWithDecoratedFunction]
+# flags: --disallow-any-expr
+# https://github.com/python/mypy/issues/13066
+from typing import TypedDict
+class D(TypedDict):
+    @classmethod  # E: Invalid statement in TypedDict definition; expected "field_name: field_type"
+    def m(self) -> D:
+        pass
+d = D()
+reveal_type(d)  # N: Revealed type is "TypedDict('__main__.D', {})"
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
 [case testTypedDictWithClassmethodAlternativeConstructorDoesNotCrash]
 # https://github.com/python/mypy/issues/5653
 from typing import TypedDict

From 8c691242d6326dc9e1c8521e18fd13eaf15a3b49 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Mon, 31 Oct 2022 09:52:09 -0700
Subject: [PATCH 008/231] Preserve (some) implicitly exported types (#13967)

Fixes some of #13965, fixes #12749

We also need to modify attribute access logic (this is the TODO in the
PR), which is a little trickier. But cases like #13933 convinced me it's
worth making this change, even before I get around to figuring that out.
---
 mypy/semanal.py                   | 28 ++++++++++++++++++++--------
 test-data/unit/check-flags.test   | 13 +++++++++----
 test-data/unit/check-modules.test |  2 +-
 3 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index b8f708b22a924..3a2caab41d3a8 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -2303,10 +2303,20 @@ def visit_import_from(self, imp: ImportFrom) -> None:
                     )
                     continue
 
-            if node and not node.module_hidden:
+            if node:
                 self.process_imported_symbol(
                     node, module_id, id, imported_id, fullname, module_public, context=imp
                 )
+                if node.module_hidden:
+                    self.report_missing_module_attribute(
+                        module_id,
+                        id,
+                        imported_id,
+                        module_public=module_public,
+                        module_hidden=not module_public,
+                        context=imp,
+                        add_unknown_imported_symbol=False,
+                    )
             elif module and not missing_submodule:
                 # Target module exists but the imported name is missing or hidden.
                 self.report_missing_module_attribute(
@@ -2394,6 +2404,7 @@ def report_missing_module_attribute(
         module_public: bool,
         module_hidden: bool,
         context: Node,
+        add_unknown_imported_symbol: bool = True,
     ) -> None:
         # Missing attribute.
         if self.is_incomplete_namespace(import_id):
@@ -2418,13 +2429,14 @@ def report_missing_module_attribute(
                     suggestion = f"; maybe {pretty_seq(matches, 'or')}?"
                     message += f"{suggestion}"
         self.fail(message, context, code=codes.ATTR_DEFINED)
-        self.add_unknown_imported_symbol(
-            imported_id,
-            context,
-            target_name=None,
-            module_public=module_public,
-            module_hidden=not module_public,
-        )
+        if add_unknown_imported_symbol:
+            self.add_unknown_imported_symbol(
+                imported_id,
+                context,
+                target_name=None,
+                module_public=module_public,
+                module_hidden=not module_public,
+            )
 
         if import_id == "typing":
             # The user probably has a missing definition in a test fixture. Let's verify.
diff --git a/test-data/unit/check-flags.test b/test-data/unit/check-flags.test
index 5a075dd6efef8..33723b7fee768 100644
--- a/test-data/unit/check-flags.test
+++ b/test-data/unit/check-flags.test
@@ -1606,14 +1606,19 @@ strict_equality = false
 
 
 [case testNoImplicitReexport]
-# flags: --no-implicit-reexport
-from other_module_2 import a
+# flags: --no-implicit-reexport --show-error-codes
+from other_module_2 import a  # E: Module "other_module_2" does not explicitly export attribute "a"  [attr-defined]
+reveal_type(a)  # N: Revealed type is "builtins.int"
+
+import other_module_2
+# TODO: this should also reveal builtins.int, see #13965
+reveal_type(other_module_2.a)  # E: "object" does not explicitly export attribute "a"  [attr-defined] \
+                               # N: Revealed type is "Any"
+
 [file other_module_1.py]
 a = 5
 [file other_module_2.py]
 from other_module_1 import a
-[out]
-main:2: error: Module "other_module_2" does not explicitly export attribute "a"
 
 [case testNoImplicitReexportRespectsAll]
 # flags: --no-implicit-reexport
diff --git a/test-data/unit/check-modules.test b/test-data/unit/check-modules.test
index a8eced3959e5f..0b64daaf5abe2 100644
--- a/test-data/unit/check-modules.test
+++ b/test-data/unit/check-modules.test
@@ -1794,7 +1794,7 @@ from stub import C
 c = C()
 reveal_type(c.x)  # N: Revealed type is "builtins.int"
 it: Iterable[int]
-reveal_type(it)  # N: Revealed type is "Any"
+reveal_type(it)  # N: Revealed type is "typing.Iterable[builtins.int]"
 
 [file stub.pyi]
 from typing import Iterable

From 55d0adf17a15ddbd0a8e9fb9d27f848117522a17 Mon Sep 17 00:00:00 2001
From: Valentin Stanciu <250871+svalentin@users.noreply.github.com>
Date: Tue, 1 Nov 2022 12:32:44 +0200
Subject: [PATCH 009/231] Update version on master for next release (#13974)

Next release is 1.0 so also update the comments.
NOTE: Should we go with 1.0 or 1.0.0? I chose 1.0.0 to make it clear
that we can have minor revisions 3 numbers deep. i.e. x.y.z
---
 mypy/version.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mypy/version.py b/mypy/version.py
index 837206834e385..b125385f9b433 100644
--- a/mypy/version.py
+++ b/mypy/version.py
@@ -5,10 +5,10 @@
 from mypy import git
 
 # Base version.
-# - Release versions have the form "0.NNN".
-# - Dev versions have the form "0.NNN+dev" (PLUS sign to conform to PEP 440).
-# - For 1.0 we'll switch back to 1.2.3 form.
-__version__ = "0.990+dev"
+# - Release versions have the form "1.2.3".
+# - Dev versions have the form "1.2.3+dev" (PLUS sign to conform to PEP 440).
+# - Before 1.0 we had the form "0.NNN".
+__version__ = "1.0.0+dev"
 base_version = __version__
 
 mypy_dir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))

From 32c26f208732097c0fcc3d4cf0fb2cd9fbd1a99b Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Tue, 1 Nov 2022 13:20:59 +0000
Subject: [PATCH 010/231] Typeshed branch 'master' was renamed to 'main'
 (#13980)

There aren't really any big changes required over on mypy's side (I was
worried there would be more breakage, but I think mypy should be fine).
Cf. https://github.com/python/typeshed/issues/8956.
---
 misc/sync-typeshed.py | 2 +-
 mypy/checker.py       | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/misc/sync-typeshed.py b/misc/sync-typeshed.py
index 743a2934e0c3c..878ffaa23bfbb 100644
--- a/misc/sync-typeshed.py
+++ b/misc/sync-typeshed.py
@@ -134,7 +134,7 @@ def main() -> None:
     parser.add_argument(
         "--commit",
         default=None,
-        help="Typeshed commit (default to latest master if using a repository clone)",
+        help="Typeshed commit (default to latest main if using a repository clone)",
     )
     parser.add_argument(
         "--typeshed-dir",
diff --git a/mypy/checker.py b/mypy/checker.py
index d66bf764b517b..a23c03b2b09a4 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -4580,7 +4580,7 @@ def visit_with_stmt(self, s: WithStmt) -> None:
             # exceptions or not. We determine this using a heuristic based on the
             # return type of the __exit__ method -- see the discussion in
             # https://github.com/python/mypy/issues/7214 and the section about context managers
-            # in https://github.com/python/typeshed/blob/master/CONTRIBUTING.md#conventions
+            # in https://github.com/python/typeshed/blob/main/CONTRIBUTING.md#conventions
             # for more details.
 
             exit_ret_type = get_proper_type(exit_ret_type)

From fed90caa47e61ccaa4b9aac44f2d7545bcf1a955 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Tue, 1 Nov 2022 18:32:47 +0000
Subject: [PATCH 011/231] ipc: Remove some typeshed-related TODOs (#13982)

As per the TODO comments, this PR removes some unnecessary `assert`s in
`mypy/ipc.py`. When these `assert`s were added in #6148, typeshed wasn't
able to use `Literal` types yet. However, nowadays, typeshed has precise
`Literal` overloads for `_winapi.WriteFile` and
`_winapi.ConnectNamedType`, meaning mypy is able to precisely infer the
return type of these function calls without the need for the `assert`s
in `mypy/ipc.py`:
https://github.com/python/typeshed/blob/main/stdlib/_winapi.pyi.
---
 mypy/ipc.py | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/mypy/ipc.py b/mypy/ipc.py
index d52769bdb2b1a..f07616df0fd0a 100644
--- a/mypy/ipc.py
+++ b/mypy/ipc.py
@@ -89,9 +89,6 @@ def write(self, data: bytes) -> None:
         if sys.platform == "win32":
             try:
                 ov, err = _winapi.WriteFile(self.connection, data, overlapped=True)
-                # TODO: remove once typeshed supports Literal types
-                assert isinstance(ov, _winapi.Overlapped)
-                assert isinstance(err, int)
                 try:
                     if err == _winapi.ERROR_IO_PENDING:
                         timeout = int(self.timeout * 1000) if self.timeout else _winapi.INFINITE
@@ -217,8 +214,6 @@ def __enter__(self) -> IPCServer:
             # client never connects, though this can be "solved" by killing the server
             try:
                 ov = _winapi.ConnectNamedPipe(self.connection, overlapped=True)
-                # TODO: remove once typeshed supports Literal types
-                assert isinstance(ov, _winapi.Overlapped)
             except OSError as e:
                 # Don't raise if the client already exists, or the client already connected
                 if e.winerror not in (_winapi.ERROR_PIPE_CONNECTED, _winapi.ERROR_NO_DATA):

From 8b825472a02f0a30419c02e285ba931107a42959 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Tue, 1 Nov 2022 19:58:45 +0000
Subject: [PATCH 012/231] checker.py: Remove unneeded `cast()` (#13984)

---
 mypy/checker.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index a23c03b2b09a4..71e2be3d73834 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -7,7 +7,6 @@
 from contextlib import contextmanager, nullcontext
 from typing import (
     AbstractSet,
-    Any,
     Callable,
     Dict,
     Generic,
@@ -3453,8 +3452,7 @@ def check_multi_assignment_from_union(
                 assert declared_type is not None
                 clean_items.append((type, declared_type))
 
-            # TODO: fix signature of zip() in typeshed.
-            types, declared_types = cast(Any, zip)(*clean_items)
+            types, declared_types = zip(*clean_items)
             self.binder.assign_type(
                 expr,
                 make_simplified_union(list(types)),

From 0457d33609ef8dd7d7e32ff18dd39da3e4ecc3fc Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Wed, 2 Nov 2022 21:06:33 -0700
Subject: [PATCH 013/231] Make TryStar not crash (#13991)

---
 mypy/fastparse.py                   | 22 ++++++++++++++++++++++
 mypy/test/helpers.py                |  8 +++++++-
 mypy/test/testcheck.py              |  2 ++
 test-data/unit/check-python311.test |  6 ++++++
 4 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 test-data/unit/check-python311.test

diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index a5c51c72934e4..0d42ef53f4566 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -212,6 +212,10 @@ def ast3_parse(
         MatchAs = Any
         MatchOr = Any
         AstNode = Union[ast3.expr, ast3.stmt, ast3.ExceptHandler]
+    if sys.version_info >= (3, 11):
+        TryStar = ast3.TryStar
+    else:
+        TryStar = Any
 except ImportError:
     try:
         from typed_ast import ast35  # type: ignore[attr-defined]  # noqa: F401
@@ -1249,6 +1253,24 @@ def visit_Try(self, n: ast3.Try) -> TryStmt:
         )
         return self.set_line(node, n)
 
+    def visit_TryStar(self, n: TryStar) -> TryStmt:
+        # TODO: we treat TryStar exactly like Try, which makes mypy not crash. See #12840
+        vs = [
+            self.set_line(NameExpr(h.name), h) if h.name is not None else None for h in n.handlers
+        ]
+        types = [self.visit(h.type) for h in n.handlers]
+        handlers = [self.as_required_block(h.body, h.lineno) for h in n.handlers]
+
+        node = TryStmt(
+            self.as_required_block(n.body, n.lineno),
+            vs,
+            types,
+            handlers,
+            self.as_block(n.orelse, n.lineno),
+            self.as_block(n.finalbody, n.lineno),
+        )
+        return self.set_line(node, n)
+
     # Assert(expr test, expr? msg)
     def visit_Assert(self, n: ast3.Assert) -> AssertStmt:
         node = AssertStmt(self.visit(n.test), self.visit(n.msg))
diff --git a/mypy/test/helpers.py b/mypy/test/helpers.py
index 8bee8073bd16c..145027404ff79 100644
--- a/mypy/test/helpers.py
+++ b/mypy/test/helpers.py
@@ -282,8 +282,14 @@ def num_skipped_suffix_lines(a1: list[str], a2: list[str]) -> int:
 
 
 def testfile_pyversion(path: str) -> tuple[int, int]:
-    if path.endswith("python310.test"):
+    if path.endswith("python311.test"):
+        return 3, 11
+    elif path.endswith("python310.test"):
         return 3, 10
+    elif path.endswith("python39.test"):
+        return 3, 9
+    elif path.endswith("python38.test"):
+        return 3, 8
     else:
         return defaults.PYTHON3_VERSION
 
diff --git a/mypy/test/testcheck.py b/mypy/test/testcheck.py
index 442e25b54ff22..4fe2ee6393c0b 100644
--- a/mypy/test/testcheck.py
+++ b/mypy/test/testcheck.py
@@ -44,6 +44,8 @@
     typecheck_files.remove("check-python39.test")
 if sys.version_info < (3, 10):
     typecheck_files.remove("check-python310.test")
+if sys.version_info < (3, 11):
+    typecheck_files.remove("check-python311.test")
 
 # Special tests for platforms with case-insensitive filesystems.
 if sys.platform not in ("darwin", "win32"):
diff --git a/test-data/unit/check-python311.test b/test-data/unit/check-python311.test
new file mode 100644
index 0000000000000..b98bccc9059d7
--- /dev/null
+++ b/test-data/unit/check-python311.test
@@ -0,0 +1,6 @@
+[case testTryStarDoesNotCrash]
+try:
+    pass
+except* Exception as e:
+    reveal_type(e)  # N: Revealed type is "builtins.Exception"
+[builtins fixtures/exception.pyi]

From a4da89e0543ee0d213b30216c9e15a5d00fcd578 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Wed, 2 Nov 2022 22:10:17 -0700
Subject: [PATCH 014/231] Better story for import redefinitions (#13969)

This changes our importing logic to be more consistent and to treat
import statements more like assignments.

Fixes #13803, fixes #13914, fixes half of #12965, probably fixes #12574

The primary motivation for this is when typing modules as protocols, as
in #13803. But it turns out we already allowed redefinition with "from"
imports, so this also seems like a nice consistency win.

We move shared logic from visit_import_all and visit_import_from (via
process_imported_symbol) into add_imported_symbol. We then reuse it in
visit_import.

To simplify stuff, we inline the code from add_module_symbol into
visit_import. Then we copy over logic from add_symbol, because MypyFile
is not a SymbolTableNode, but this isn't the worst thing ever.

Finally, we now need to check non-from import statements like
assignments, which was a thing we weren't doing earlier.
---
 mypy/checker.py                       |  4 +-
 mypy/semanal.py                       | 84 +++++++++++++--------------
 test-data/unit/check-classes.test     |  3 +-
 test-data/unit/check-incremental.test |  5 +-
 test-data/unit/check-modules.test     | 19 ++++++
 test-data/unit/check-protocols.test   | 56 ++++++++++++++++++
 test-data/unit/check-redefine.test    |  2 +-
 7 files changed, 119 insertions(+), 54 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 71e2be3d73834..8973ade98228b 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -2527,8 +2527,8 @@ def visit_import_from(self, node: ImportFrom) -> None:
     def visit_import_all(self, node: ImportAll) -> None:
         self.check_import(node)
 
-    def visit_import(self, s: Import) -> None:
-        pass
+    def visit_import(self, node: Import) -> None:
+        self.check_import(node)
 
     def check_import(self, node: ImportBase) -> None:
         for assign in node.assignments:
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 3a2caab41d3a8..77555648ba7eb 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -2235,13 +2235,33 @@ def visit_import(self, i: Import) -> None:
                 base_id = id.split(".")[0]
                 imported_id = base_id
                 module_public = use_implicit_reexport
-            self.add_module_symbol(
-                base_id,
-                imported_id,
-                context=i,
-                module_public=module_public,
-                module_hidden=not module_public,
-            )
+
+            if base_id in self.modules:
+                node = self.modules[base_id]
+                if self.is_func_scope():
+                    kind = LDEF
+                elif self.type is not None:
+                    kind = MDEF
+                else:
+                    kind = GDEF
+                symbol = SymbolTableNode(
+                    kind, node, module_public=module_public, module_hidden=not module_public
+                )
+                self.add_imported_symbol(
+                    imported_id,
+                    symbol,
+                    context=i,
+                    module_public=module_public,
+                    module_hidden=not module_public,
+                )
+            else:
+                self.add_unknown_imported_symbol(
+                    imported_id,
+                    context=i,
+                    target_name=base_id,
+                    module_public=module_public,
+                    module_hidden=not module_public,
+                )
 
     def visit_import_from(self, imp: ImportFrom) -> None:
         self.statement = imp
@@ -2377,19 +2397,6 @@ def process_imported_symbol(
                     module_hidden=module_hidden,
                     becomes_typeinfo=True,
                 )
-        existing_symbol = self.globals.get(imported_id)
-        if (
-            existing_symbol
-            and not isinstance(existing_symbol.node, PlaceholderNode)
-            and not isinstance(node.node, PlaceholderNode)
-        ):
-            # Import can redefine a variable. They get special treatment.
-            if self.process_import_over_existing_name(imported_id, existing_symbol, node, context):
-                return
-        if existing_symbol and isinstance(node.node, PlaceholderNode):
-            # Imports are special, some redefinitions are allowed, so wait until
-            # we know what is the new symbol node.
-            return
         # NOTE: we take the original node even for final `Var`s. This is to support
         # a common pattern when constants are re-exported (same applies to import *).
         self.add_imported_symbol(
@@ -2507,14 +2514,9 @@ def visit_import_all(self, i: ImportAll) -> None:
                     if isinstance(node.node, MypyFile):
                         # Star import of submodule from a package, add it as a dependency.
                         self.imports.add(node.node.fullname)
-                    existing_symbol = self.lookup_current_scope(name)
-                    if existing_symbol and not isinstance(node.node, PlaceholderNode):
-                        # Import can redefine a variable. They get special treatment.
-                        if self.process_import_over_existing_name(name, existing_symbol, node, i):
-                            continue
                     # `from x import *` always reexports symbols
                     self.add_imported_symbol(
-                        name, node, i, module_public=True, module_hidden=False
+                        name, node, context=i, module_public=True, module_hidden=False
                     )
 
         else:
@@ -5589,24 +5591,6 @@ def add_local(self, node: Var | FuncDef | OverloadedFuncDef, context: Context) -
         node._fullname = name
         self.add_symbol(name, node, context)
 
-    def add_module_symbol(
-        self, id: str, as_id: str, context: Context, module_public: bool, module_hidden: bool
-    ) -> None:
-        """Add symbol that is a reference to a module object."""
-        if id in self.modules:
-            node = self.modules[id]
-            self.add_symbol(
-                as_id, node, context, module_public=module_public, module_hidden=module_hidden
-            )
-        else:
-            self.add_unknown_imported_symbol(
-                as_id,
-                context,
-                target_name=id,
-                module_public=module_public,
-                module_hidden=module_hidden,
-            )
-
     def _get_node_for_class_scoped_import(
         self, name: str, symbol_node: SymbolNode | None, context: Context
     ) -> SymbolNode | None:
@@ -5653,13 +5637,23 @@ def add_imported_symbol(
         self,
         name: str,
         node: SymbolTableNode,
-        context: Context,
+        context: ImportBase,
         module_public: bool,
         module_hidden: bool,
     ) -> None:
         """Add an alias to an existing symbol through import."""
         assert not module_hidden or not module_public
 
+        existing_symbol = self.lookup_current_scope(name)
+        if (
+            existing_symbol
+            and not isinstance(existing_symbol.node, PlaceholderNode)
+            and not isinstance(node.node, PlaceholderNode)
+        ):
+            # Import can redefine a variable. They get special treatment.
+            if self.process_import_over_existing_name(name, existing_symbol, node, context):
+                return
+
         symbol_node: SymbolNode | None = node.node
 
         if self.is_class_scope():
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index b16387f194d41..4ed44c90f275c 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -7414,8 +7414,7 @@ class Foo:
     def meth1(self, a: str) -> str: ...  # E: Name "meth1" already defined on line 5
 
     def meth2(self, a: str) -> str: ...
-    from mod1 import meth2  # E: Unsupported class scoped import \
-                            # E: Name "meth2" already defined on line 8
+    from mod1 import meth2  # E: Incompatible import of "meth2" (imported name has type "Callable[[int], int]", local name has type "Callable[[Foo, str], str]")
 
 class Bar:
     from mod1 import foo  # E: Unsupported class scoped import
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index d4e6779403b41..3ec0ed2c63f58 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -1025,10 +1025,7 @@ import a.b
 
 [file a/b.py]
 
-[rechecked b]
-[stale]
-[out2]
-tmp/b.py:4: error: Name "a" already defined on line 3
+[stale b]
 
 [case testIncrementalSilentImportsAndImportsInClass]
 # flags: --ignore-missing-imports
diff --git a/test-data/unit/check-modules.test b/test-data/unit/check-modules.test
index 0b64daaf5abe2..b3267f66653d8 100644
--- a/test-data/unit/check-modules.test
+++ b/test-data/unit/check-modules.test
@@ -651,10 +651,29 @@ try:
     from m import f, g # E: Incompatible import of "g" (imported name has type "Callable[[Any, Any], Any]", local name has type "Callable[[Any], Any]")
 except:
     pass
+
+import m as f  # E: Incompatible import of "f" (imported name has type "object", local name has type "Callable[[Any], Any]")
+
 [file m.py]
 def f(x): pass
 def g(x, y): pass
 
+[case testRedefineTypeViaImport]
+from typing import Type
+import mod
+
+X: Type[mod.A]
+Y: Type[mod.B]
+from mod import B as X
+from mod import A as Y  # E: Incompatible import of "Y" (imported name has type "Type[A]", local name has type "Type[B]")
+
+import mod as X  # E: Incompatible import of "X" (imported name has type "object", local name has type "Type[A]")
+
+[file mod.py]
+class A: ...
+class B(A): ...
+
+
 [case testImportVariableAndAssignNone]
 try:
     from m import x
diff --git a/test-data/unit/check-protocols.test b/test-data/unit/check-protocols.test
index 8cdfd2a3e0d92..113b2000fc227 100644
--- a/test-data/unit/check-protocols.test
+++ b/test-data/unit/check-protocols.test
@@ -3787,3 +3787,59 @@ from typing_extensions import Final
 
 a: Final = 1
 [builtins fixtures/module.pyi]
+
+
+[case testModuleAsProtocolRedefinitionTopLevel]
+from typing import Protocol
+
+class P(Protocol):
+    def f(self) -> str: ...
+
+cond: bool
+t: P
+if cond:
+    import mod1 as t
+else:
+    import mod2 as t
+
+import badmod as t  # E: Incompatible import of "t" (imported name has type Module, local name has type "P")
+
+[file mod1.py]
+def f() -> str: ...
+
+[file mod2.py]
+def f() -> str: ...
+
+[file badmod.py]
+def nothing() -> int: ...
+[builtins fixtures/module.pyi]
+
+[case testModuleAsProtocolRedefinitionImportFrom]
+from typing import Protocol
+
+class P(Protocol):
+    def f(self) -> str: ...
+
+cond: bool
+t: P
+if cond:
+    from package import mod1 as t
+else:
+    from package import mod2 as t
+
+from package import badmod as t  # E: Incompatible import of "t" (imported name has type Module, local name has type "P")
+
+package: int = 10
+
+import package.mod1 as t
+import package.mod1  # E: Incompatible import of "package" (imported name has type Module, local name has type "int")
+
+[file package/mod1.py]
+def f() -> str: ...
+
+[file package/mod2.py]
+def f() -> str: ...
+
+[file package/badmod.py]
+def nothing() -> int: ...
+[builtins fixtures/module.pyi]
diff --git a/test-data/unit/check-redefine.test b/test-data/unit/check-redefine.test
index e73f715c9ec0f..e3f1b976d4e98 100644
--- a/test-data/unit/check-redefine.test
+++ b/test-data/unit/check-redefine.test
@@ -285,7 +285,7 @@ def f() -> None:
     import typing as m
     m = 1 # E: Incompatible types in assignment (expression has type "int", variable has type Module)
     n = 1
-    import typing as n # E: Name "n" already defined on line 5
+    import typing as n  # E: Incompatible import of "n" (imported name has type Module, local name has type "int")
 [builtins fixtures/module.pyi]
 
 [case testRedefineLocalWithTypeAnnotation]

From 77a92b598bbfa129613d16e17b5e00ad7af9d1ab Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 3 Nov 2022 05:53:00 -0700
Subject: [PATCH 015/231] [mypyc] allow use of enum.Enum (#13995)

Fixes https://github.com/mypyc/mypyc/issues/896
---
 mypyc/irbuild/classdef.py        |  6 +++++-
 mypyc/test-data/run-classes.test | 10 ++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index 2c412253ec713..905747fed5543 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -482,7 +482,11 @@ def populate_non_ext_bases(builder: IRBuilder, cdef: ClassDef) -> Value:
                 name = "_NamedTuple"
             base = builder.get_module_attr("typing", name, cdef.line)
         else:
-            base = builder.load_global_str(cls.name, cdef.line)
+            cls_module = cls.fullname.rsplit(".", 1)[0]
+            if cls_module == builder.current_module:
+                base = builder.load_global_str(cls.name, cdef.line)
+            else:
+                base = builder.load_module_attr_by_fullname(cls.fullname, cdef.line)
         bases.append(base)
         if cls.fullname in MAGIC_TYPED_DICT_CLASSES:
             # The remaining base classes are synthesized by mypy and should be ignored.
diff --git a/mypyc/test-data/run-classes.test b/mypyc/test-data/run-classes.test
index d505bda2d7055..177bae0cc8956 100644
--- a/mypyc/test-data/run-classes.test
+++ b/mypyc/test-data/run-classes.test
@@ -263,6 +263,16 @@ class TestEnum(Enum):
 
 assert TestEnum.test() == 3
 
+import enum
+
+class Pokemon(enum.Enum):
+    magikarp = 1
+    squirtle = 2
+    slowbro = 3
+
+assert Pokemon.magikarp.value == 1
+assert Pokemon.squirtle.name == 'squirtle'
+
 [file other.py]
 # Force a multi-module test to make sure we can compile multi-file with
 # non-extension classes

From 451ae0e4600af848b02390495e4317b997d51032 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 3 Nov 2022 05:54:25 -0700
Subject: [PATCH 016/231] [mypyc] fix for typeshed changes to Collection
 (#13994)

---
 mypyc/irbuild/classdef.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index 905747fed5543..34fc1fd766b00 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -451,6 +451,7 @@ def populate_non_ext_bases(builder: IRBuilder, cdef: ClassDef) -> Value:
             "typing.Collection",
             "typing.Reversible",
             "typing.Container",
+            "typing.Sized",
         ):
             # HAX: Synthesized base classes added by mypy don't exist at runtime, so skip them.
             #      This could break if they were added explicitly, though...

From bc78eb56eb93f75be749c02860ccecbf66022a6f Mon Sep 17 00:00:00 2001
From: dosisod <39638017+dosisod@users.noreply.github.com>
Date: Thu, 3 Nov 2022 05:55:16 -0700
Subject: [PATCH 017/231] Fix Mypyc not compiling on Arch Linux (#13978)

Closes https://github.com/mypyc/mypyc/issues/956

This was originally a part of #13953, see
https://github.com/python/mypy/pull/13953#discussion_r1007593391
---
 mypyc/build.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mypyc/build.py b/mypyc/build.py
index 4f40a6cd08659..a9aa16f5dfee3 100644
--- a/mypyc/build.py
+++ b/mypyc/build.py
@@ -534,6 +534,10 @@ def mypycify(
             "-Wno-unused-command-line-argument",
             "-Wno-unknown-warning-option",
             "-Wno-unused-but-set-variable",
+            "-Wno-ignored-optimization-argument",
+            # Disables C Preprocessor (cpp) warnings
+            # See https://github.com/mypyc/mypyc/issues/956
+            "-Wno-cpp",
         ]
     elif compiler.compiler_type == "msvc":
         # msvc doesn't have levels, '/O2' is full and '/Od' is disable

From 11a040d418b95d1956e90b734ac3e832e119090d Mon Sep 17 00:00:00 2001
From: dosisod <39638017+dosisod@users.noreply.github.com>
Date: Thu, 3 Nov 2022 16:34:59 -0700
Subject: [PATCH 018/231] Add `__match_args__` to node types (#13330)

Closes #13243.

For the most part, in order to determine which fields where worth
pattern matching against, I looked at what was being displayed in the
`StrConv` class (defined in `mypy/strconv.py`). I might've missed some
fields, but for the most part all of the important ones are there.

In addition, to make pattern matching feel more natural, I re-arranged
the fields to better align with how they look in the source code. For
example, when matching against `OpExpr`, you would do:

```python
match o:
    case OpExpr(IntExpr(1), "+", IntExpr(2)):
        pass
```

instead of:

```python
match o:
    case OpExpr("+", IntExpr(1), IntExpr(2)):
        pass
```
---
 mypy/nodes.py             | 136 ++++++++++++++++++++++++++++++++++++++
 mypyc/irbuild/classdef.py |   2 +-
 mypyc/irbuild/prepare.py  |   6 +-
 3 files changed, 142 insertions(+), 2 deletions(-)

diff --git a/mypy/nodes.py b/mypy/nodes.py
index 7334d91143467..9221ec48aa61b 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -298,6 +298,8 @@ class MypyFile(SymbolNode):
         "future_import_flags",
     )
 
+    __match_args__ = ("name", "path", "defs")
+
     # Fully qualified module name
     _fullname: Bogus[str]
     # Path to the file (empty string if not known)
@@ -433,6 +435,8 @@ class Import(ImportBase):
 
     __slots__ = ("ids",)
 
+    __match_args__ = ("ids",)
+
     ids: list[tuple[str, str | None]]  # (module id, as id)
 
     def __init__(self, ids: list[tuple[str, str | None]]) -> None:
@@ -448,6 +452,8 @@ class ImportFrom(ImportBase):
 
     __slots__ = ("id", "names", "relative")
 
+    __match_args__ = ("id", "names", "relative")
+
     id: str
     relative: int
     names: list[tuple[str, str | None]]  # Tuples (name, as name)
@@ -467,6 +473,8 @@ class ImportAll(ImportBase):
 
     __slots__ = ("id", "relative", "imported_names")
 
+    __match_args__ = ("id", "relative")
+
     id: str
     relative: int
     # NOTE: Only filled and used by old semantic analyzer.
@@ -652,6 +660,8 @@ class Argument(Node):
 
     __slots__ = ("variable", "type_annotation", "initializer", "kind", "pos_only")
 
+    __match_args__ = ("variable", "type_annotation", "initializer", "kind", "pos_only")
+
     def __init__(
         self,
         variable: Var,
@@ -790,6 +800,8 @@ class FuncDef(FuncItem, SymbolNode, Statement):
         "is_mypy_only",
     )
 
+    __match_args__ = ("name", "arguments", "type", "body")
+
     # Note that all __init__ args must have default values
     def __init__(
         self,
@@ -880,6 +892,8 @@ class Decorator(SymbolNode, Statement):
 
     __slots__ = ("func", "decorators", "original_decorators", "var", "is_overload")
 
+    __match_args__ = ("decorators", "var", "func")
+
     func: FuncDef  # Decorated function
     decorators: list[Expression]  # Decorators (may be empty)
     # Some decorators are removed by semanal, keep the original here.
@@ -991,6 +1005,8 @@ class Var(SymbolNode):
         "invalid_partial_type",
     )
 
+    __match_args__ = ("name", "type", "final_value")
+
     def __init__(self, name: str, type: mypy.types.Type | None = None) -> None:
         super().__init__()
         self._name = name  # Name without module prefix
@@ -1099,6 +1115,8 @@ class ClassDef(Statement):
         "deco_line",
     )
 
+    __match_args__ = ("name", "defs")
+
     name: str  # Name of the class without module prefix
     fullname: Bogus[str]  # Fully qualified name of the class
     defs: Block
@@ -1176,6 +1194,8 @@ class GlobalDecl(Statement):
 
     __slots__ = ("names",)
 
+    __match_args__ = ("names",)
+
     names: list[str]
 
     def __init__(self, names: list[str]) -> None:
@@ -1191,6 +1211,8 @@ class NonlocalDecl(Statement):
 
     __slots__ = ("names",)
 
+    __match_args__ = ("names",)
+
     names: list[str]
 
     def __init__(self, names: list[str]) -> None:
@@ -1204,6 +1226,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class Block(Statement):
     __slots__ = ("body", "is_unreachable")
 
+    __match_args__ = ("body", "is_unreachable")
+
     def __init__(self, body: list[Statement]) -> None:
         super().__init__()
         self.body = body
@@ -1226,6 +1250,8 @@ class ExpressionStmt(Statement):
 
     __slots__ = ("expr",)
 
+    __match_args__ = ("expr",)
+
     expr: Expression
 
     def __init__(self, expr: Expression) -> None:
@@ -1258,6 +1284,8 @@ class AssignmentStmt(Statement):
         "invalid_recursive_alias",
     )
 
+    __match_args__ = ("lvalues", "rvalues", "type")
+
     lvalues: list[Lvalue]
     # This is a TempNode if and only if no rvalue (x: t).
     rvalue: Expression
@@ -1306,6 +1334,8 @@ class OperatorAssignmentStmt(Statement):
 
     __slots__ = ("op", "lvalue", "rvalue")
 
+    __match_args__ = ("lvalue", "op", "rvalue")
+
     op: str  # TODO: Enum?
     lvalue: Lvalue
     rvalue: Expression
@@ -1323,6 +1353,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class WhileStmt(Statement):
     __slots__ = ("expr", "body", "else_body")
 
+    __match_args__ = ("expr", "body", "else_body")
+
     expr: Expression
     body: Block
     else_body: Block | None
@@ -1350,6 +1382,8 @@ class ForStmt(Statement):
         "is_async",
     )
 
+    __match_args__ = ("index", "index_type", "expr", "body", "else_body")
+
     # Index variables
     index: Lvalue
     # Type given by type comments for index, can be None
@@ -1392,6 +1426,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class ReturnStmt(Statement):
     __slots__ = ("expr",)
 
+    __match_args__ = ("expr",)
+
     expr: Expression | None
 
     def __init__(self, expr: Expression | None) -> None:
@@ -1405,6 +1441,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class AssertStmt(Statement):
     __slots__ = ("expr", "msg")
 
+    __match_args__ = ("expr", "msg")
+
     expr: Expression
     msg: Expression | None
 
@@ -1420,6 +1458,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class DelStmt(Statement):
     __slots__ = ("expr",)
 
+    __match_args__ = ("expr",)
+
     expr: Lvalue
 
     def __init__(self, expr: Lvalue) -> None:
@@ -1454,6 +1494,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class IfStmt(Statement):
     __slots__ = ("expr", "body", "else_body")
 
+    __match_args__ = ("expr", "body", "else_body")
+
     expr: list[Expression]
     body: list[Block]
     else_body: Block | None
@@ -1471,6 +1513,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class RaiseStmt(Statement):
     __slots__ = ("expr", "from_expr")
 
+    __match_args__ = ("expr", "from_expr")
+
     # Plain 'raise' is a valid statement.
     expr: Expression | None
     from_expr: Expression | None
@@ -1487,6 +1531,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class TryStmt(Statement):
     __slots__ = ("body", "types", "vars", "handlers", "else_body", "finally_body")
 
+    __match_args__ = ("body", "types", "vars", "handlers", "else_body", "finally_body")
+
     body: Block  # Try body
     # Plain 'except:' also possible
     types: list[Expression | None]  # Except type expressions
@@ -1519,6 +1565,8 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 class WithStmt(Statement):
     __slots__ = ("expr", "target", "unanalyzed_type", "analyzed_types", "body", "is_async")
 
+    __match_args__ = ("expr", "target", "body")
+
     expr: list[Expression]
     target: list[Lvalue | None]
     # Type given by type comments for target, can be None
@@ -1548,6 +1596,10 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 
 
 class MatchStmt(Statement):
+    __slots__ = ("subject", "patterns", "guards", "bodies")
+
+    __match_args__ = ("subject", "patterns", "guards", "bodies")
+
     subject: Expression
     patterns: list[Pattern]
     guards: list[Expression | None]
@@ -1579,6 +1631,8 @@ class IntExpr(Expression):
 
     __slots__ = ("value",)
 
+    __match_args__ = ("value",)
+
     value: int  # 0 by default
 
     def __init__(self, value: int) -> None:
@@ -1600,6 +1654,8 @@ class StrExpr(Expression):
 
     __slots__ = ("value",)
 
+    __match_args__ = ("value",)
+
     value: str  # '' by default
 
     def __init__(self, value: str) -> None:
@@ -1615,6 +1671,8 @@ class BytesExpr(Expression):
 
     __slots__ = ("value",)
 
+    __match_args__ = ("value",)
+
     # Note: we deliberately do NOT use bytes here because it ends up
     # unnecessarily complicating a lot of the result logic. For example,
     # we'd have to worry about converting the bytes into a format we can
@@ -1639,6 +1697,8 @@ class FloatExpr(Expression):
 
     __slots__ = ("value",)
 
+    __match_args__ = ("value",)
+
     value: float  # 0.0 by default
 
     def __init__(self, value: float) -> None:
@@ -1654,6 +1714,8 @@ class ComplexExpr(Expression):
 
     __slots__ = ("value",)
 
+    __match_args__ = ("value",)
+
     value: complex
 
     def __init__(self, value: complex) -> None:
@@ -1678,6 +1740,8 @@ class StarExpr(Expression):
 
     __slots__ = ("expr", "valid")
 
+    __match_args__ = ("expr", "valid")
+
     expr: Expression
     valid: bool
 
@@ -1734,6 +1798,8 @@ class NameExpr(RefExpr):
 
     __slots__ = ("name", "is_special_form")
 
+    __match_args__ = ("name", "node")
+
     def __init__(self, name: str) -> None:
         super().__init__()
         self.name = name  # Name referred to (may be qualified)
@@ -1752,6 +1818,8 @@ class MemberExpr(RefExpr):
 
     __slots__ = ("expr", "name", "def_var")
 
+    __match_args__ = ("expr", "name", "node")
+
     def __init__(self, expr: Expression, name: str) -> None:
         super().__init__()
         self.expr = expr
@@ -1813,6 +1881,8 @@ class CallExpr(Expression):
 
     __slots__ = ("callee", "args", "arg_kinds", "arg_names", "analyzed")
 
+    __match_args__ = ("callee", "args", "arg_kinds", "arg_names")
+
     def __init__(
         self,
         callee: Expression,
@@ -1841,6 +1911,8 @@ def accept(self, visitor: ExpressionVisitor[T]) -> T:
 class YieldFromExpr(Expression):
     __slots__ = ("expr",)
 
+    __match_args__ = ("expr",)
+
     expr: Expression
 
     def __init__(self, expr: Expression) -> None:
@@ -1854,6 +1926,8 @@ def accept(self, visitor: ExpressionVisitor[T]) -> T:
 class YieldExpr(Expression):
     __slots__ = ("expr",)
 
+    __match_args__ = ("expr",)
+
     expr: Expression | None
 
     def __init__(self, expr: Expression | None) -> None:
@@ -1872,6 +1946,8 @@ class IndexExpr(Expression):
 
     __slots__ = ("base", "index", "method_type", "analyzed")
 
+    __match_args__ = ("base", "index")
+
     base: Expression
     index: Expression
     # Inferred __getitem__ method type
@@ -1896,6 +1972,8 @@ class UnaryExpr(Expression):
 
     __slots__ = ("op", "expr", "method_type")
 
+    __match_args__ = ("op", "expr")
+
     op: str  # TODO: Enum?
     expr: Expression
     # Inferred operator method type
@@ -1916,6 +1994,8 @@ class AssignmentExpr(Expression):
 
     __slots__ = ("target", "value")
 
+    __match_args__ = ("target", "value")
+
     def __init__(self, target: Expression, value: Expression) -> None:
         super().__init__()
         self.target = target
@@ -1931,6 +2011,8 @@ class OpExpr(Expression):
 
     __slots__ = ("op", "left", "right", "method_type", "right_always", "right_unreachable")
 
+    __match_args__ = ("left", "op", "right")
+
     op: str  # TODO: Enum?
     left: Expression
     right: Expression
@@ -1959,6 +2041,8 @@ class ComparisonExpr(Expression):
 
     __slots__ = ("operators", "operands", "method_types")
 
+    __match_args__ = ("operands", "operators")
+
     operators: list[str]
     operands: list[Expression]
     # Inferred type for the operator methods (when relevant; None for 'is').
@@ -1989,6 +2073,8 @@ class SliceExpr(Expression):
 
     __slots__ = ("begin_index", "end_index", "stride")
 
+    __match_args__ = ("begin_index", "end_index", "stride")
+
     begin_index: Expression | None
     end_index: Expression | None
     stride: Expression | None
@@ -2013,6 +2099,8 @@ class CastExpr(Expression):
 
     __slots__ = ("expr", "type")
 
+    __match_args__ = ("expr", "type")
+
     expr: Expression
     type: mypy.types.Type
 
@@ -2030,6 +2118,8 @@ class AssertTypeExpr(Expression):
 
     __slots__ = ("expr", "type")
 
+    __match_args__ = ("expr", "type")
+
     expr: Expression
     type: mypy.types.Type
 
@@ -2047,6 +2137,8 @@ class RevealExpr(Expression):
 
     __slots__ = ("expr", "kind", "local_nodes")
 
+    __match_args__ = ("expr", "kind", "local_nodes")
+
     expr: Expression | None
     kind: int
     local_nodes: list[Var] | None
@@ -2068,6 +2160,8 @@ class SuperExpr(Expression):
 
     __slots__ = ("name", "info", "call")
 
+    __match_args__ = ("name", "call", "info")
+
     name: str
     info: TypeInfo | None  # Type that contains this super expression
     call: CallExpr  # The expression super(...)
@@ -2085,6 +2179,8 @@ def accept(self, visitor: ExpressionVisitor[T]) -> T:
 class LambdaExpr(FuncItem, Expression):
     """Lambda expression"""
 
+    __match_args__ = ("arguments", "arg_names", "arg_kinds", "body")
+
     @property
     def name(self) -> str:
         return "<lambda>"
@@ -2108,6 +2204,8 @@ class ListExpr(Expression):
 
     __slots__ = ("items",)
 
+    __match_args__ = ("items",)
+
     items: list[Expression]
 
     def __init__(self, items: list[Expression]) -> None:
@@ -2123,6 +2221,8 @@ class DictExpr(Expression):
 
     __slots__ = ("items",)
 
+    __match_args__ = ("items",)
+
     items: list[tuple[Expression | None, Expression]]
 
     def __init__(self, items: list[tuple[Expression | None, Expression]]) -> None:
@@ -2140,6 +2240,8 @@ class TupleExpr(Expression):
 
     __slots__ = ("items",)
 
+    __match_args__ = ("items",)
+
     items: list[Expression]
 
     def __init__(self, items: list[Expression]) -> None:
@@ -2155,6 +2257,8 @@ class SetExpr(Expression):
 
     __slots__ = ("items",)
 
+    __match_args__ = ("items",)
+
     items: list[Expression]
 
     def __init__(self, items: list[Expression]) -> None:
@@ -2170,6 +2274,8 @@ class GeneratorExpr(Expression):
 
     __slots__ = ("left_expr", "sequences", "condlists", "is_async", "indices")
 
+    __match_args__ = ("left_expr", "indices", "sequences", "condlists")
+
     left_expr: Expression
     sequences: list[Expression]
     condlists: list[list[Expression]]
@@ -2200,6 +2306,8 @@ class ListComprehension(Expression):
 
     __slots__ = ("generator",)
 
+    __match_args__ = ("generator",)
+
     generator: GeneratorExpr
 
     def __init__(self, generator: GeneratorExpr) -> None:
@@ -2215,6 +2323,8 @@ class SetComprehension(Expression):
 
     __slots__ = ("generator",)
 
+    __match_args__ = ("generator",)
+
     generator: GeneratorExpr
 
     def __init__(self, generator: GeneratorExpr) -> None:
@@ -2230,6 +2340,8 @@ class DictionaryComprehension(Expression):
 
     __slots__ = ("key", "value", "sequences", "condlists", "is_async", "indices")
 
+    __match_args__ = ("key", "value", "indices", "sequences", "condlists")
+
     key: Expression
     value: Expression
     sequences: list[Expression]
@@ -2263,6 +2375,8 @@ class ConditionalExpr(Expression):
 
     __slots__ = ("cond", "if_expr", "else_expr")
 
+    __match_args__ = ("if_expr", "cond", "else_expr")
+
     cond: Expression
     if_expr: Expression
     else_expr: Expression
@@ -2282,6 +2396,8 @@ class TypeApplication(Expression):
 
     __slots__ = ("expr", "types")
 
+    __match_args__ = ("expr", "types")
+
     expr: Expression
     types: list[mypy.types.Type]
 
@@ -2359,6 +2475,8 @@ class TypeVarExpr(TypeVarLikeExpr):
 
     __slots__ = ("values",)
 
+    __match_args__ = ("name", "values", "upper_bound")
+
     # Value restriction: only types in the list are valid as values. If the
     # list is empty, there is no restriction.
     values: list[mypy.types.Type]
@@ -2402,6 +2520,8 @@ def deserialize(cls, data: JsonDict) -> TypeVarExpr:
 class ParamSpecExpr(TypeVarLikeExpr):
     __slots__ = ()
 
+    __match_args__ = ("name", "upper_bound")
+
     def accept(self, visitor: ExpressionVisitor[T]) -> T:
         return visitor.visit_paramspec_expr(self)
 
@@ -2430,6 +2550,8 @@ class TypeVarTupleExpr(TypeVarLikeExpr):
 
     __slots__ = ()
 
+    __match_args__ = ("name", "upper_bound")
+
     def accept(self, visitor: ExpressionVisitor[T]) -> T:
         return visitor.visit_type_var_tuple_expr(self)
 
@@ -2458,6 +2580,8 @@ class TypeAliasExpr(Expression):
 
     __slots__ = ("type", "tvars", "no_args", "node")
 
+    __match_args__ = ("type", "tvars", "no_args", "node")
+
     # The target type.
     type: mypy.types.Type
     # Names of unbound type variables used to define the alias
@@ -2486,6 +2610,8 @@ class NamedTupleExpr(Expression):
 
     __slots__ = ("info", "is_typed")
 
+    __match_args__ = ("info",)
+
     # The class representation of this named tuple (its tuple_type attribute contains
     # the tuple item types)
     info: TypeInfo
@@ -2505,6 +2631,8 @@ class TypedDictExpr(Expression):
 
     __slots__ = ("info",)
 
+    __match_args__ = ("info",)
+
     # The class representation of this typed dict
     info: TypeInfo
 
@@ -2521,6 +2649,8 @@ class EnumCallExpr(Expression):
 
     __slots__ = ("info", "items", "values")
 
+    __match_args__ = ("info", "items", "values")
+
     # The class representation of this enumerated type
     info: TypeInfo
     # The item names (for debugging)
@@ -2557,6 +2687,8 @@ class NewTypeExpr(Expression):
 
     __slots__ = ("name", "old_type", "info")
 
+    __match_args__ = ("name", "old_type", "info")
+
     name: str
     # The base type (the second argument to NewType)
     old_type: mypy.types.Type | None
@@ -2580,6 +2712,8 @@ class AwaitExpr(Expression):
 
     __slots__ = ("expr",)
 
+    __match_args__ = ("expr",)
+
     expr: Expression
 
     def __init__(self, expr: Expression) -> None:
@@ -3283,6 +3417,8 @@ def f(x: B[T]) -> T: ...  # without T, Any would be used here
         "eager",
     )
 
+    __match_args__ = ("name", "target", "alias_tvars", "no_args")
+
     def __init__(
         self,
         target: mypy.types.Type,
diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index 34fc1fd766b00..4502c201a2e87 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -629,7 +629,7 @@ def find_attr_initializers(
                 and not isinstance(stmt.rvalue, TempNode)
             ):
                 name = stmt.lvalues[0].name
-                if name == "__slots__":
+                if name in ("__slots__", "__match_args__"):
                     continue
 
                 if name == "__deletable__":
diff --git a/mypyc/irbuild/prepare.py b/mypyc/irbuild/prepare.py
index 82162d1d0d0e5..dc153ea11561e 100644
--- a/mypyc/irbuild/prepare.py
+++ b/mypyc/irbuild/prepare.py
@@ -226,7 +226,11 @@ def prepare_class_def(
 
         if isinstance(node.node, Var):
             assert node.node.type, "Class member %s missing type" % name
-            if not node.node.is_classvar and name not in ("__slots__", "__deletable__"):
+            if not node.node.is_classvar and name not in (
+                "__slots__",
+                "__deletable__",
+                "__match_args__",
+            ):
                 ir.attributes[name] = mapper.type_to_rtype(node.node.type)
         elif isinstance(node.node, (FuncDef, Decorator)):
             prepare_method_def(ir, module_name, cdef, mapper, node.node)

From 428b1723285bcb44b74d4986105d631d41c25e97 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 4 Nov 2022 00:26:07 -0700
Subject: [PATCH 019/231] Clarify docs surrounding install-types (#14003)

See #13681

More clearly point out the speed cost and the alternative of installing
stub packages directly
---
 docs/source/running_mypy.rst | 46 ++++++++++++------------------------
 1 file changed, 15 insertions(+), 31 deletions(-)

diff --git a/docs/source/running_mypy.rst b/docs/source/running_mypy.rst
index a7eb3fc5e1e7e..264cec59749e7 100644
--- a/docs/source/running_mypy.rst
+++ b/docs/source/running_mypy.rst
@@ -322,34 +322,27 @@ the library, you will get a message like this:
     main.py:1: note: Hint: "python3 -m pip install types-PyYAML"
     main.py:1: note: (or run "mypy --install-types" to install all missing stub packages)
 
-You can resolve the issue by running the suggested pip command or
-commands. Alternatively, you can use :option:`--install-types <mypy
---install-types>` to install all known missing stubs:
+You can resolve the issue by running the suggested pip commands.
+If you're running mypy in CI, you can ensure the presence of any stub packages
+you need the same as you would any other test dependency, e.g. by adding them to
+the appropriate ``requirements.txt`` file.
 
-.. code-block:: text
-
-    mypy --install-types
-
-This installs any stub packages that were suggested in the previous
-mypy run. You can also use your normal mypy command line with the
-extra :option:`--install-types <mypy --install-types>` option to
-install missing stubs at the end of the run (if any were found).
-
-Use :option:`--install-types <mypy --install-types>` with
-:option:`--non-interactive <mypy --non-interactive>`  to install all suggested
-stub packages without asking for confirmation, *and* type check your
-code, in a single command:
+Alternatively, add the :option:`--install-types <mypy --install-types>`
+to your mypy command to install all known missing stubs:
 
 .. code-block:: text
 
-   mypy --install-types --non-interactive src/
+    mypy --install-types
 
-This can be useful in Continuous Integration jobs if you'd prefer not
-to manage stub packages manually. This is somewhat slower than
-explicitly installing stubs before running mypy, since it may type
-check your code twice -- the first time to find the missing stubs, and
+This is slower than explicitly installing stubs, since if effectively
+runs mypy twice -- the first time to find the missing stubs, and
 the second time to type check your code properly after mypy has
-installed the stubs.
+installed the stubs. It also can make controlling stub versions harder,
+resulting in less reproducible type checking.
+
+By default, :option:`--install-types <mypy --install-types>` shows a confirmation prompt.
+Use :option:`--non-interactive <mypy --non-interactive>` to install all suggested
+stub packages without asking for confirmation *and* type check your code:
 
 If you've already installed the relevant third-party libraries in an environment
 other than the one mypy is running in, you can use :option:`--python-executable
@@ -394,15 +387,6 @@ this error, try:
     you must run ``mypy ~/foo-project/src`` (or set the ``MYPYPATH`` to
     ``~/foo-project/src``.
 
-In some rare cases, you may get the "Cannot find implementation or library
-stub for module" error even when the module is installed in your system.
-This can happen when the module is both missing type hints and is installed
-on your system in an unconventional way.
-
-In this case, follow the steps above on how to handle
-:ref:`missing type hints in third party libraries <missing-type-hints-for-third-party-library>`.
-
-
 .. _finding-imports:
 
 How imports are found

From 796068d06a0ab171d22f7be555c28dfad57db433 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Fri, 4 Nov 2022 11:04:52 +0000
Subject: [PATCH 020/231] running_mypy.rst: Fix typo (#14004)

Introduced in #14003
---
 docs/source/running_mypy.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/source/running_mypy.rst b/docs/source/running_mypy.rst
index 264cec59749e7..3deaf26023fcf 100644
--- a/docs/source/running_mypy.rst
+++ b/docs/source/running_mypy.rst
@@ -334,7 +334,7 @@ to your mypy command to install all known missing stubs:
 
     mypy --install-types
 
-This is slower than explicitly installing stubs, since if effectively
+This is slower than explicitly installing stubs, since it effectively
 runs mypy twice -- the first time to find the missing stubs, and
 the second time to type check your code properly after mypy has
 installed the stubs. It also can make controlling stub versions harder,

From 331b170c5d0e55a11a78a7f60fad5a8a8b5d6f2c Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 4 Nov 2022 16:03:33 +0000
Subject: [PATCH 021/231] Fix crash on nested unions in recursive types
 (#14007)

Fixes #14000

This will introduce some minor perf penalty, but only for code that
actually uses recursive types.
---
 mypy/typeops.py                           |  4 ++--
 test-data/unit/check-recursive-types.test | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/mypy/typeops.py b/mypy/typeops.py
index 7eb1a67b46ea2..5b29dc71991b1 100644
--- a/mypy/typeops.py
+++ b/mypy/typeops.py
@@ -71,13 +71,13 @@ def is_recursive_pair(s: Type, t: Type) -> bool:
     """
     if isinstance(s, TypeAliasType) and s.is_recursive:
         return (
-            isinstance(get_proper_type(t), Instance)
+            isinstance(get_proper_type(t), (Instance, UnionType))
             or isinstance(t, TypeAliasType)
             and t.is_recursive
         )
     if isinstance(t, TypeAliasType) and t.is_recursive:
         return (
-            isinstance(get_proper_type(s), Instance)
+            isinstance(get_proper_type(s), (Instance, UnionType))
             or isinstance(s, TypeAliasType)
             and s.is_recursive
         )
diff --git a/test-data/unit/check-recursive-types.test b/test-data/unit/check-recursive-types.test
index a0875c60362cc..0d727b109658b 100644
--- a/test-data/unit/check-recursive-types.test
+++ b/test-data/unit/check-recursive-types.test
@@ -808,3 +808,21 @@ def test2() -> Tree2:
 def test3() -> Tree3:
     return 42  # E: Incompatible return value type (got "int", expected "Union[str, Tuple[Tree3, Tree3, Tree3]]")
 [builtins fixtures/tuple.pyi]
+
+[case testRecursiveDoubleUnionNoCrash]
+from typing import Tuple, Union, Callable, Sequence
+
+K = Union[int, Tuple[Union[int, K]]]
+L = Union[int, Callable[[], Union[int, L]]]
+M = Union[int, Sequence[Union[int, M]]]
+
+x: K
+x = x
+y: L
+y = y
+z: M
+z = z
+
+x = y  # E: Incompatible types in assignment (expression has type "L", variable has type "K")
+z = x  # OK
+[builtins fixtures/tuple.pyi]

From 807da2675bfdc7ec434f8d5677c13722a555e8da Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sat, 5 Nov 2022 18:51:59 -0700
Subject: [PATCH 022/231] Fix and optimise overload compatibility checking
 (#14018)

Discovered as part of #14017
---
 mypy/subtypes.py                   | 54 ++++++++++++---------------
 test-data/unit/check-classes.test  | 59 +++++++++++++++++++++++-------
 test-data/unit/check-selftype.test | 28 ++++++++++++++
 3 files changed, 96 insertions(+), 45 deletions(-)

diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 38fae16e70111..2724379ab8780 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -823,9 +823,8 @@ def visit_overloaded(self, left: Overloaded) -> bool:
             # Ensure each overload in the right side (the supertype) is accounted for.
             previous_match_left_index = -1
             matched_overloads = set()
-            possible_invalid_overloads = set()
 
-            for right_index, right_item in enumerate(right.items):
+            for right_item in right.items:
                 found_match = False
 
                 for left_index, left_item in enumerate(left.items):
@@ -834,43 +833,36 @@ def visit_overloaded(self, left: Overloaded) -> bool:
                     # Order matters: we need to make sure that the index of
                     # this item is at least the index of the previous one.
                     if subtype_match and previous_match_left_index <= left_index:
-                        if not found_match:
-                            # Update the index of the previous match.
-                            previous_match_left_index = left_index
-                            found_match = True
-                            matched_overloads.add(left_item)
-                            possible_invalid_overloads.discard(left_item)
+                        previous_match_left_index = left_index
+                        found_match = True
+                        matched_overloads.add(left_index)
+                        break
                     else:
                         # If this one overlaps with the supertype in any way, but it wasn't
                         # an exact match, then it's a potential error.
                         strict_concat = self.options.strict_concatenate if self.options else True
-                        if is_callable_compatible(
-                            left_item,
-                            right_item,
-                            is_compat=self._is_subtype,
-                            ignore_return=True,
-                            ignore_pos_arg_names=self.subtype_context.ignore_pos_arg_names,
-                            strict_concatenate=strict_concat,
-                        ) or is_callable_compatible(
-                            right_item,
-                            left_item,
-                            is_compat=self._is_subtype,
-                            ignore_return=True,
-                            ignore_pos_arg_names=self.subtype_context.ignore_pos_arg_names,
-                            strict_concatenate=strict_concat,
+                        if left_index not in matched_overloads and (
+                            is_callable_compatible(
+                                left_item,
+                                right_item,
+                                is_compat=self._is_subtype,
+                                ignore_return=True,
+                                ignore_pos_arg_names=self.subtype_context.ignore_pos_arg_names,
+                                strict_concatenate=strict_concat,
+                            )
+                            or is_callable_compatible(
+                                right_item,
+                                left_item,
+                                is_compat=self._is_subtype,
+                                ignore_return=True,
+                                ignore_pos_arg_names=self.subtype_context.ignore_pos_arg_names,
+                                strict_concatenate=strict_concat,
+                            )
                         ):
-                            # If this is an overload that's already been matched, there's no
-                            # problem.
-                            if left_item not in matched_overloads:
-                                possible_invalid_overloads.add(left_item)
+                            return False
 
                 if not found_match:
                     return False
-
-            if possible_invalid_overloads:
-                # There were potentially invalid overloads that were never matched to the
-                # supertype.
-                return False
             return True
         elif isinstance(right, UnboundType):
             return True
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index 4ed44c90f275c..42aaa68b5873f 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -3872,28 +3872,59 @@ class Super:
     def foo(self, a: C) -> C: pass
 
 class Sub(Super):
-    @overload  # Fail
+    @overload
     def foo(self, a: A) -> A: pass
     @overload
     def foo(self, a: B) -> C: pass  # Fail
     @overload
     def foo(self, a: C) -> C: pass
+
+class Sub2(Super):
+    @overload
+    def foo(self, a: B) -> C: pass  # Fail
+    @overload
+    def foo(self, a: A) -> A: pass
+    @overload
+    def foo(self, a: C) -> C: pass
+
+class Sub3(Super):
+    @overload
+    def foo(self, a: A) -> int: pass
+    @overload
+    def foo(self, a: A) -> A: pass
+    @overload
+    def foo(self, a: C) -> C: pass
 [builtins fixtures/classmethod.pyi]
 [out]
-tmp/foo.pyi:16: error: Signature of "foo" incompatible with supertype "Super"
-tmp/foo.pyi:16: note:      Superclass:
-tmp/foo.pyi:16: note:          @overload
-tmp/foo.pyi:16: note:          def foo(self, a: A) -> A
-tmp/foo.pyi:16: note:          @overload
-tmp/foo.pyi:16: note:          def foo(self, a: C) -> C
-tmp/foo.pyi:16: note:      Subclass:
-tmp/foo.pyi:16: note:          @overload
-tmp/foo.pyi:16: note:          def foo(self, a: A) -> A
-tmp/foo.pyi:16: note:          @overload
-tmp/foo.pyi:16: note:          def foo(self, a: B) -> C
-tmp/foo.pyi:16: note:          @overload
-tmp/foo.pyi:16: note:          def foo(self, a: C) -> C
 tmp/foo.pyi:19: error: Overloaded function signature 2 will never be matched: signature 1's parameter type(s) are the same or broader
+tmp/foo.pyi:24: error: Signature of "foo" incompatible with supertype "Super"
+tmp/foo.pyi:24: note:      Superclass:
+tmp/foo.pyi:24: note:          @overload
+tmp/foo.pyi:24: note:          def foo(self, a: A) -> A
+tmp/foo.pyi:24: note:          @overload
+tmp/foo.pyi:24: note:          def foo(self, a: C) -> C
+tmp/foo.pyi:24: note:      Subclass:
+tmp/foo.pyi:24: note:          @overload
+tmp/foo.pyi:24: note:          def foo(self, a: B) -> C
+tmp/foo.pyi:24: note:          @overload
+tmp/foo.pyi:24: note:          def foo(self, a: A) -> A
+tmp/foo.pyi:24: note:          @overload
+tmp/foo.pyi:24: note:          def foo(self, a: C) -> C
+tmp/foo.pyi:25: error: Overloaded function signatures 1 and 2 overlap with incompatible return types
+tmp/foo.pyi:32: error: Signature of "foo" incompatible with supertype "Super"
+tmp/foo.pyi:32: note:      Superclass:
+tmp/foo.pyi:32: note:          @overload
+tmp/foo.pyi:32: note:          def foo(self, a: A) -> A
+tmp/foo.pyi:32: note:          @overload
+tmp/foo.pyi:32: note:          def foo(self, a: C) -> C
+tmp/foo.pyi:32: note:      Subclass:
+tmp/foo.pyi:32: note:          @overload
+tmp/foo.pyi:32: note:          def foo(self, a: A) -> int
+tmp/foo.pyi:32: note:          @overload
+tmp/foo.pyi:32: note:          def foo(self, a: A) -> A
+tmp/foo.pyi:32: note:          @overload
+tmp/foo.pyi:32: note:          def foo(self, a: C) -> C
+tmp/foo.pyi:35: error: Overloaded function signature 2 will never be matched: signature 1's parameter type(s) are the same or broader
 
 [case testTypeTypeOverlapsWithObjectAndType]
 from foo import *
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index 506e8bfe8ab1c..bfb0eb5a4d894 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -128,6 +128,34 @@ reveal_type(cast(A, C()).copy())  # N: Revealed type is "__main__.A"
 
 [builtins fixtures/bool.pyi]
 
+[case testSelfTypeOverrideCompatibility]
+from typing import overload, TypeVar, Generic
+
+T = TypeVar("T")
+
+class A(Generic[T]):
+    @overload
+    def f(self: A[int]) -> int: ...
+    @overload
+    def f(self: A[str]) -> str: ...
+    def f(self): ...
+
+class B(A[T]):
+    @overload
+    def f(self: A[int]) -> int: ...
+    @overload
+    def f(self: A[str]) -> str: ...
+    def f(self): ...
+
+class B2(A[T]):
+    @overload
+    def f(self: A[int]) -> int: ...
+    @overload
+    def f(self: A[str]) -> str: ...
+    @overload
+    def f(self: A[bytes]) -> bytes: ...
+    def f(self): ...
+
 [case testSelfTypeSuper]
 from typing import TypeVar, cast
 

From e8de6d1fc5c908e738f69494de38ea191fb12e60 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 7 Nov 2022 10:34:35 +0000
Subject: [PATCH 023/231] Add support for exception groups and except* (#14020)

Ref #12840

It looks like from the point of view of type checking support is quite
easy. Mypyc support however requires some actual work, so I don't
include it in this PR.
---
 mypy/checker.py                       | 37 +++++++++++++++----
 mypy/fastparse.py                     |  2 +-
 mypy/message_registry.py              |  3 ++
 mypy/nodes.py                         |  7 ++--
 mypy/strconv.py                       |  2 ++
 mypy/treetransform.py                 |  4 ++-
 mypyc/irbuild/statement.py            |  2 ++
 test-data/unit/check-python311.test   | 51 +++++++++++++++++++++++++--
 test-data/unit/fixtures/exception.pyi | 11 ++++--
 9 files changed, 104 insertions(+), 15 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 8973ade98228b..5744a4ef4937c 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -4305,7 +4305,7 @@ def visit_try_without_finally(self, s: TryStmt, try_frame: bool) -> None:
                     with self.binder.frame_context(can_skip=True, fall_through=4):
                         typ = s.types[i]
                         if typ:
-                            t = self.check_except_handler_test(typ)
+                            t = self.check_except_handler_test(typ, s.is_star)
                             var = s.vars[i]
                             if var:
                                 # To support local variables, we make this a definition line,
@@ -4325,7 +4325,7 @@ def visit_try_without_finally(self, s: TryStmt, try_frame: bool) -> None:
             if s.else_body:
                 self.accept(s.else_body)
 
-    def check_except_handler_test(self, n: Expression) -> Type:
+    def check_except_handler_test(self, n: Expression, is_star: bool) -> Type:
         """Type check an exception handler test clause."""
         typ = self.expr_checker.accept(n)
 
@@ -4341,22 +4341,47 @@ def check_except_handler_test(self, n: Expression) -> Type:
                 item = ttype.items[0]
                 if not item.is_type_obj():
                     self.fail(message_registry.INVALID_EXCEPTION_TYPE, n)
-                    return AnyType(TypeOfAny.from_error)
-                exc_type = item.ret_type
+                    return self.default_exception_type(is_star)
+                exc_type = erase_typevars(item.ret_type)
             elif isinstance(ttype, TypeType):
                 exc_type = ttype.item
             else:
                 self.fail(message_registry.INVALID_EXCEPTION_TYPE, n)
-                return AnyType(TypeOfAny.from_error)
+                return self.default_exception_type(is_star)
 
             if not is_subtype(exc_type, self.named_type("builtins.BaseException")):
                 self.fail(message_registry.INVALID_EXCEPTION_TYPE, n)
-                return AnyType(TypeOfAny.from_error)
+                return self.default_exception_type(is_star)
 
             all_types.append(exc_type)
 
+        if is_star:
+            new_all_types: list[Type] = []
+            for typ in all_types:
+                if is_proper_subtype(typ, self.named_type("builtins.BaseExceptionGroup")):
+                    self.fail(message_registry.INVALID_EXCEPTION_GROUP, n)
+                    new_all_types.append(AnyType(TypeOfAny.from_error))
+                else:
+                    new_all_types.append(typ)
+            return self.wrap_exception_group(new_all_types)
         return make_simplified_union(all_types)
 
+    def default_exception_type(self, is_star: bool) -> Type:
+        """Exception type to return in case of a previous type error."""
+        any_type = AnyType(TypeOfAny.from_error)
+        if is_star:
+            return self.named_generic_type("builtins.ExceptionGroup", [any_type])
+        return any_type
+
+    def wrap_exception_group(self, types: Sequence[Type]) -> Type:
+        """Transform except* variable type into an appropriate exception group."""
+        arg = make_simplified_union(types)
+        if is_subtype(arg, self.named_type("builtins.Exception")):
+            base = "builtins.ExceptionGroup"
+        else:
+            base = "builtins.BaseExceptionGroup"
+        return self.named_generic_type(base, [arg])
+
     def get_types_from_except_handler(self, typ: Type, n: Expression) -> list[Type]:
         """Helper for check_except_handler_test to retrieve handler types."""
         typ = get_proper_type(typ)
diff --git a/mypy/fastparse.py b/mypy/fastparse.py
index 0d42ef53f4566..209ebb89f36b4 100644
--- a/mypy/fastparse.py
+++ b/mypy/fastparse.py
@@ -1254,7 +1254,6 @@ def visit_Try(self, n: ast3.Try) -> TryStmt:
         return self.set_line(node, n)
 
     def visit_TryStar(self, n: TryStar) -> TryStmt:
-        # TODO: we treat TryStar exactly like Try, which makes mypy not crash. See #12840
         vs = [
             self.set_line(NameExpr(h.name), h) if h.name is not None else None for h in n.handlers
         ]
@@ -1269,6 +1268,7 @@ def visit_TryStar(self, n: TryStar) -> TryStmt:
             self.as_block(n.orelse, n.lineno),
             self.as_block(n.finalbody, n.lineno),
         )
+        node.is_star = True
         return self.set_line(node, n)
 
     # Assert(expr test, expr? msg)
diff --git a/mypy/message_registry.py b/mypy/message_registry.py
index c84ce120dbda9..18acb2cd7a71f 100644
--- a/mypy/message_registry.py
+++ b/mypy/message_registry.py
@@ -44,6 +44,9 @@ def with_additional_msg(self, info: str) -> ErrorMessage:
 NO_RETURN_EXPECTED: Final = ErrorMessage("Return statement in function which does not return")
 INVALID_EXCEPTION: Final = ErrorMessage("Exception must be derived from BaseException")
 INVALID_EXCEPTION_TYPE: Final = ErrorMessage("Exception type must be derived from BaseException")
+INVALID_EXCEPTION_GROUP: Final = ErrorMessage(
+    "Exception type in except* cannot derive from BaseExceptionGroup"
+)
 RETURN_IN_ASYNC_GENERATOR: Final = ErrorMessage(
     '"return" with value in async generator is not allowed'
 )
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 9221ec48aa61b..0ea89611dc1ab 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -1529,9 +1529,9 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
 
 
 class TryStmt(Statement):
-    __slots__ = ("body", "types", "vars", "handlers", "else_body", "finally_body")
+    __slots__ = ("body", "types", "vars", "handlers", "else_body", "finally_body", "is_star")
 
-    __match_args__ = ("body", "types", "vars", "handlers", "else_body", "finally_body")
+    __match_args__ = ("body", "types", "vars", "handlers", "else_body", "finally_body", "is_star")
 
     body: Block  # Try body
     # Plain 'except:' also possible
@@ -1540,6 +1540,8 @@ class TryStmt(Statement):
     handlers: list[Block]  # Except bodies
     else_body: Block | None
     finally_body: Block | None
+    # Whether this is try ... except* (added in Python 3.11)
+    is_star: bool
 
     def __init__(
         self,
@@ -1557,6 +1559,7 @@ def __init__(
         self.handlers = handlers
         self.else_body = else_body
         self.finally_body = finally_body
+        self.is_star = False
 
     def accept(self, visitor: StatementVisitor[T]) -> T:
         return visitor.visit_try_stmt(self)
diff --git a/mypy/strconv.py b/mypy/strconv.py
index 1acf7699316cb..9b369618b88e4 100644
--- a/mypy/strconv.py
+++ b/mypy/strconv.py
@@ -276,6 +276,8 @@ def visit_del_stmt(self, o: mypy.nodes.DelStmt) -> str:
 
     def visit_try_stmt(self, o: mypy.nodes.TryStmt) -> str:
         a: list[Any] = [o.body]
+        if o.is_star:
+            a.append("*")
 
         for i in range(len(o.vars)):
             a.append(o.types[i])
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index d7f159d02a229..c863db6b3dd56 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -373,7 +373,7 @@ def visit_raise_stmt(self, node: RaiseStmt) -> RaiseStmt:
         return RaiseStmt(self.optional_expr(node.expr), self.optional_expr(node.from_expr))
 
     def visit_try_stmt(self, node: TryStmt) -> TryStmt:
-        return TryStmt(
+        new = TryStmt(
             self.block(node.body),
             self.optional_names(node.vars),
             self.optional_expressions(node.types),
@@ -381,6 +381,8 @@ def visit_try_stmt(self, node: TryStmt) -> TryStmt:
             self.optional_block(node.else_body),
             self.optional_block(node.finally_body),
         )
+        new.is_star = node.is_star
+        return new
 
     def visit_with_stmt(self, node: WithStmt) -> WithStmt:
         new = WithStmt(
diff --git a/mypyc/irbuild/statement.py b/mypyc/irbuild/statement.py
index 371a305e67b9e..a1d36c011aa1a 100644
--- a/mypyc/irbuild/statement.py
+++ b/mypyc/irbuild/statement.py
@@ -616,6 +616,8 @@ def transform_try_stmt(builder: IRBuilder, t: TryStmt) -> None:
     # constructs that we compile separately. When we have a
     # try/except/else/finally, we treat the try/except/else as the
     # body of a try/finally block.
+    if t.is_star:
+        builder.error("Exception groups and except* cannot be compiled yet", t.line)
     if t.finally_body:
 
         def transform_try_body() -> None:
diff --git a/test-data/unit/check-python311.test b/test-data/unit/check-python311.test
index b98bccc9059d7..9bf62b0c489d0 100644
--- a/test-data/unit/check-python311.test
+++ b/test-data/unit/check-python311.test
@@ -1,6 +1,53 @@
-[case testTryStarDoesNotCrash]
+[case testTryStarSimple]
 try:
     pass
 except* Exception as e:
-    reveal_type(e)  # N: Revealed type is "builtins.Exception"
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[builtins.Exception]"
+[builtins fixtures/exception.pyi]
+
+[case testTryStarMultiple]
+try:
+    pass
+except* Exception as e:
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[builtins.Exception]"
+except* RuntimeError as e:
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[builtins.RuntimeError]"
+[builtins fixtures/exception.pyi]
+
+[case testTryStarBase]
+try:
+    pass
+except* BaseException as e:
+    reveal_type(e)  # N: Revealed type is "builtins.BaseExceptionGroup[builtins.BaseException]"
+[builtins fixtures/exception.pyi]
+
+[case testTryStarTuple]
+class Custom(Exception): ...
+
+try:
+    pass
+except* (RuntimeError, Custom) as e:
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[Union[builtins.RuntimeError, __main__.Custom]]"
+[builtins fixtures/exception.pyi]
+
+[case testTryStarInvalidType]
+class Bad: ...
+try:
+    pass
+except* (RuntimeError, Bad) as e:  # E: Exception type must be derived from BaseException
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[Any]"
+[builtins fixtures/exception.pyi]
+
+[case testTryStarGroupInvalid]
+try:
+    pass
+except* ExceptionGroup as e:  # E: Exception type in except* cannot derive from BaseExceptionGroup
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[Any]"
+[builtins fixtures/exception.pyi]
+
+[case testTryStarGroupInvalidTuple]
+try:
+    pass
+except* (RuntimeError, ExceptionGroup) as e:  # E: Exception type in except* cannot derive from BaseExceptionGroup
+    reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[Union[builtins.RuntimeError, Any]]"
 [builtins fixtures/exception.pyi]
diff --git a/test-data/unit/fixtures/exception.pyi b/test-data/unit/fixtures/exception.pyi
index bf6d21c8716e9..1c88723e71918 100644
--- a/test-data/unit/fixtures/exception.pyi
+++ b/test-data/unit/fixtures/exception.pyi
@@ -1,3 +1,4 @@
+import sys
 from typing import Generic, TypeVar
 T = TypeVar('T')
 
@@ -5,7 +6,8 @@ class object:
     def __init__(self): pass
 
 class type: pass
-class tuple(Generic[T]): pass
+class tuple(Generic[T]):
+    def __ge__(self, other: object) -> bool: ...
 class function: pass
 class int: pass
 class str: pass
@@ -13,11 +15,14 @@ class unicode: pass
 class bool: pass
 class ellipsis: pass
 
-# Note: this is a slight simplification. In Python 2, the inheritance hierarchy
-# is actually Exception -> StandardError -> RuntimeError -> ...
 class BaseException:
     def __init__(self, *args: object) -> None: ...
 class Exception(BaseException): pass
 class RuntimeError(Exception): pass
 class NotImplementedError(RuntimeError): pass
 
+if sys.version_info >= (3, 11):
+    _BT_co = TypeVar("_BT_co", bound=BaseException, covariant=True)
+    _T_co = TypeVar("_T_co", bound=Exception, covariant=True)
+    class BaseExceptionGroup(BaseException, Generic[_BT_co]): ...
+    class ExceptionGroup(BaseExceptionGroup[_T_co], Exception): ...

From d2a3e667bf0bedb19a1e88baaf7f3ffebc12c74a Mon Sep 17 00:00:00 2001
From: Michael Lee <michael.lee.0x2a@gmail.com>
Date: Mon, 7 Nov 2022 05:28:37 -0800
Subject: [PATCH 024/231] Fix crash with PartialTypes and the enum plugin
 (#14021)

Fixes #12109.

The original issue reported that the bug had to do with the use of the
`--follow-imports=skip` flag. However, it turned out this was a red
herring after closer inspection: I was able to trigger a more minimal
repro both with and without this flag:

```python
from enum import Enum

class Foo(Enum):
    a = []  # E: Need type annotation for "a" (hint: "a: List[<type>] = ...")
    b = None

    def check(self) -> None:
        reveal_type(Foo.a.value)  # N: Revealed type is "<partial list[?]>"
        reveal_type(Foo.b.value)  # N: Revealed type is "<partial None>"
```

The first two `reveal_types` demonstrate the crux of the bug: the enum
plugin does not correctly handle and convert partial types into regular
types when inferring the type of the `.value` field.

This can then cause any number of downstream problems. For example,
suppose we modify `def check(...)` so it runs `reveal_type(self.value)`.
Doing this will trigger a crash in mypy because it makes the enum plugin
eventually try running `is_equivalent(...)` on the two partial types.
But `is_equivalent` does not support partial types, so we crash.

I opted to solve this problem by:

1. Making the enum plugin explicitly call the `fixup_partial_types`
function on all field types. This prevents the code from crashing.

2. Modifies mypy so that Final vars are never marked as being
PartialTypes. Without this, `reveal_type(Foo.b.value)` would report a
type of `Union[Any, None]` instead of just `None`. (Note that all enum
fields are implicitly final).
---
 mypy/checker.py                | 50 ++++++++++++++++------------------
 mypy/checkexpr.py              |  3 +-
 mypy/plugins/enums.py          |  3 +-
 mypy/typeops.py                | 15 ++++++++++
 test-data/unit/check-enum.test | 27 ++++++++++++++++++
 5 files changed, 70 insertions(+), 28 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 5744a4ef4937c..3ebc829daa0ea 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -159,6 +159,7 @@
     erase_to_bound,
     erase_to_union_or_bound,
     false_only,
+    fixup_partial_type,
     function_type,
     get_type_vars,
     is_literal_type_like,
@@ -2738,8 +2739,8 @@ def check_assignment(
                         # None initializers preserve the partial None type.
                         return
 
-                    if is_valid_inferred_type(rvalue_type):
-                        var = lvalue_type.var
+                    var = lvalue_type.var
+                    if is_valid_inferred_type(rvalue_type, is_lvalue_final=var.is_final):
                         partial_types = self.find_partial_types(var)
                         if partial_types is not None:
                             if not self.current_node_deferred:
@@ -3687,7 +3688,10 @@ def infer_variable_type(
         """Infer the type of initialized variables from initializer type."""
         if isinstance(init_type, DeletedType):
             self.msg.deleted_as_rvalue(init_type, context)
-        elif not is_valid_inferred_type(init_type) and not self.no_partial_types:
+        elif (
+            not is_valid_inferred_type(init_type, is_lvalue_final=name.is_final)
+            and not self.no_partial_types
+        ):
             # We cannot use the type of the initialization expression for full type
             # inference (it's not specific enough), but we might be able to give
             # partial type which will be made more specific later. A partial type
@@ -6114,7 +6118,7 @@ def enter_partial_types(
                         self.msg.need_annotation_for_var(var, context, self.options.python_version)
                         self.partial_reported.add(var)
                     if var.type:
-                        fixed = self.fixup_partial_type(var.type)
+                        fixed = fixup_partial_type(var.type)
                         var.invalid_partial_type = fixed != var.type
                         var.type = fixed
 
@@ -6145,20 +6149,7 @@ def handle_partial_var_type(
                 else:
                     # Defer the node -- we might get a better type in the outer scope
                     self.handle_cannot_determine_type(node.name, context)
-            return self.fixup_partial_type(typ)
-
-    def fixup_partial_type(self, typ: Type) -> Type:
-        """Convert a partial type that we couldn't resolve into something concrete.
-
-        This means, for None we make it Optional[Any], and for anything else we
-        fill in all of the type arguments with Any.
-        """
-        if not isinstance(typ, PartialType):
-            return typ
-        if typ.type is None:
-            return UnionType.make_union([AnyType(TypeOfAny.unannotated), NoneType()])
-        else:
-            return Instance(typ.type, [AnyType(TypeOfAny.unannotated)] * len(typ.type.type_vars))
+            return fixup_partial_type(typ)
 
     def is_defined_in_base_class(self, var: Var) -> bool:
         if var.info:
@@ -7006,20 +6997,27 @@ def infer_operator_assignment_method(typ: Type, operator: str) -> tuple[bool, st
     return False, method
 
 
-def is_valid_inferred_type(typ: Type) -> bool:
-    """Is an inferred type valid?
+def is_valid_inferred_type(typ: Type, is_lvalue_final: bool = False) -> bool:
+    """Is an inferred type valid and needs no further refinement?
 
-    Examples of invalid types include the None type or List[<uninhabited>].
+    Examples of invalid types include the None type (when we are not assigning
+    None to a final lvalue) or List[<uninhabited>].
 
     When not doing strict Optional checking, all types containing None are
     invalid.  When doing strict Optional checking, only None and types that are
     incompletely defined (i.e. contain UninhabitedType) are invalid.
     """
-    if isinstance(get_proper_type(typ), (NoneType, UninhabitedType)):
-        # With strict Optional checking, we *may* eventually infer NoneType when
-        # the initializer is None, but we only do that if we can't infer a
-        # specific Optional type.  This resolution happens in
-        # leave_partial_types when we pop a partial types scope.
+    proper_type = get_proper_type(typ)
+    if isinstance(proper_type, NoneType):
+        # If the lvalue is final, we may immediately infer NoneType when the
+        # initializer is None.
+        #
+        # If not, we want to defer making this decision. The final inferred
+        # type could either be NoneType or an Optional type, depending on
+        # the context. This resolution happens in leave_partial_types when
+        # we pop a partial types scope.
+        return is_lvalue_final
+    elif isinstance(proper_type, UninhabitedType):
         return False
     return not typ.accept(NothingSeeker())
 
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index ac16f9c9c8131..0c392ae755d7b 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -111,6 +111,7 @@
     custom_special_method,
     erase_to_union_or_bound,
     false_only,
+    fixup_partial_type,
     function_type,
     is_literal_type_like,
     make_simplified_union,
@@ -2925,7 +2926,7 @@ def find_partial_type_ref_fast_path(self, expr: Expression) -> Type | None:
         if isinstance(expr.node, Var):
             result = self.analyze_var_ref(expr.node, expr)
             if isinstance(result, PartialType) and result.type is not None:
-                self.chk.store_type(expr, self.chk.fixup_partial_type(result))
+                self.chk.store_type(expr, fixup_partial_type(result))
                 return result
         return None
 
diff --git a/mypy/plugins/enums.py b/mypy/plugins/enums.py
index 75b301252f068..1acf42d11ee6d 100644
--- a/mypy/plugins/enums.py
+++ b/mypy/plugins/enums.py
@@ -19,7 +19,7 @@
 from mypy.nodes import TypeInfo
 from mypy.semanal_enum import ENUM_BASES
 from mypy.subtypes import is_equivalent
-from mypy.typeops import make_simplified_union
+from mypy.typeops import fixup_partial_type, make_simplified_union
 from mypy.types import CallableType, Instance, LiteralType, ProperType, Type, get_proper_type
 
 ENUM_NAME_ACCESS: Final = {f"{prefix}.name" for prefix in ENUM_BASES} | {
@@ -77,6 +77,7 @@ def _infer_value_type_with_auto_fallback(
     """
     if proper_type is None:
         return None
+    proper_type = get_proper_type(fixup_partial_type(proper_type))
     if not (isinstance(proper_type, Instance) and proper_type.type.fullname == "enum.auto"):
         return proper_type
     assert isinstance(ctx.type, Instance), "An incorrect ctx.type was passed."
diff --git a/mypy/typeops.py b/mypy/typeops.py
index 5b29dc71991b1..9f224e02c0887 100644
--- a/mypy/typeops.py
+++ b/mypy/typeops.py
@@ -41,6 +41,7 @@
     Overloaded,
     Parameters,
     ParamSpecType,
+    PartialType,
     ProperType,
     TupleType,
     Type,
@@ -1016,3 +1017,17 @@ def try_getting_instance_fallback(typ: Type) -> Instance | None:
     elif isinstance(typ, TypeVarType):
         return try_getting_instance_fallback(typ.upper_bound)
     return None
+
+
+def fixup_partial_type(typ: Type) -> Type:
+    """Convert a partial type that we couldn't resolve into something concrete.
+
+    This means, for None we make it Optional[Any], and for anything else we
+    fill in all of the type arguments with Any.
+    """
+    if not isinstance(typ, PartialType):
+        return typ
+    if typ.type is None:
+        return UnionType.make_union([AnyType(TypeOfAny.unannotated), NoneType()])
+    else:
+        return Instance(typ.type, [AnyType(TypeOfAny.unannotated)] * len(typ.type.type_vars))
diff --git a/test-data/unit/check-enum.test b/test-data/unit/check-enum.test
index 039ddd1621cdb..db86434550993 100644
--- a/test-data/unit/check-enum.test
+++ b/test-data/unit/check-enum.test
@@ -2100,3 +2100,30 @@ class Some:
 class A(Some, Enum):
     __labels__ = {1: "1"}
 [builtins fixtures/dict.pyi]
+
+[case testEnumWithPartialTypes]
+from enum import Enum
+
+class Mixed(Enum):
+    a = []  # E: Need type annotation for "a" (hint: "a: List[<type>] = ...")
+    b = None
+
+    def check(self) -> None:
+        reveal_type(Mixed.a.value)  # N: Revealed type is "builtins.list[Any]"
+        reveal_type(Mixed.b.value)  # N: Revealed type is "None"
+
+        # Inferring Any here instead of a union seems to be a deliberate
+        # choice; see the testEnumValueInhomogenous case above.
+        reveal_type(self.value)  # N: Revealed type is "Any"
+
+        for field in Mixed:
+            reveal_type(field.value)  # N: Revealed type is "Any"
+            if field.value is None:
+                pass
+
+class AllPartialList(Enum):
+    a = []  # E: Need type annotation for "a" (hint: "a: List[<type>] = ...")
+    b = []  # E: Need type annotation for "b" (hint: "b: List[<type>] = ...")
+
+    def check(self) -> None:
+        reveal_type(self.value)  # N: Revealed type is "builtins.list[Any]"

From 39d35cdee1bd02a6fb071334273e1c1fb0893066 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 7 Nov 2022 15:38:41 +0000
Subject: [PATCH 025/231] Fix new style union syntax in type aliases (#14008)

Fix Python 3.10 `|` union syntax in type aliases, when one of
the operands is a type alias or a type with an overloaded `__init__`.

We can now infer `typing._SpecialForm` for type aliases in a runtime
context.

Also create a bunch of minimal test-only stubs for stdlib modules
to fix some test failures caused by the missing `typing._SpecialForm`
in the default test stubs. This is generally what we want in any case,
since using typeshed stubs with minimal builtins/typing stubs can
result in unpredictable behavior and slow tests.

Fixes #12368. Fixes #12005. Fixes #11426.
---
 mypy/checker.py                             |  8 ++--
 mypy/checkexpr.py                           |  7 ++-
 mypy/messages.py                            |  4 ++
 mypyc/test-data/run-async.test              |  3 ++
 test-data/unit/check-ctypes.test            | 13 ++++++
 test-data/unit/check-dataclasses.test       |  3 +-
 test-data/unit/check-generics.test          |  8 ++--
 test-data/unit/check-literal.test           |  5 +-
 test-data/unit/check-python310.test         | 16 +++++++
 test-data/unit/check-type-aliases.test      | 26 ++++++-----
 test-data/unit/fixtures/args.pyi            |  1 +
 test-data/unit/fixtures/type.pyi            |  1 +
 test-data/unit/fixtures/typing-full.pyi     |  2 +
 test-data/unit/fixtures/typing-medium.pyi   |  2 +
 test-data/unit/lib-stub/_decimal.pyi        |  4 ++
 test-data/unit/lib-stub/datetime.pyi        | 16 +++++++
 test-data/unit/lib-stub/decimal.pyi         |  3 ++
 test-data/unit/lib-stub/functools.pyi       | 35 ++++++++++++++
 test-data/unit/lib-stub/traceback.pyi       |  3 ++
 test-data/unit/lib-stub/unannotated_lib.pyi |  1 +
 test-data/unit/pythoneval.test              | 52 +++++++++++++++++++++
 21 files changed, 186 insertions(+), 27 deletions(-)
 create mode 100644 test-data/unit/lib-stub/_decimal.pyi
 create mode 100644 test-data/unit/lib-stub/datetime.pyi
 create mode 100644 test-data/unit/lib-stub/decimal.pyi
 create mode 100644 test-data/unit/lib-stub/functools.pyi
 create mode 100644 test-data/unit/lib-stub/traceback.pyi
 create mode 100644 test-data/unit/lib-stub/unannotated_lib.pyi

diff --git a/mypy/checker.py b/mypy/checker.py
index 3ebc829daa0ea..67d132afe2c7c 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -6048,11 +6048,11 @@ def lookup_qualified(self, name: str) -> SymbolTableNode:
             last = parts[-1]
             if last in n.names:
                 return n.names[last]
-            elif len(parts) == 2 and parts[0] == "builtins":
-                fullname = "builtins." + last
+            elif len(parts) == 2 and parts[0] in ("builtins", "typing"):
+                fullname = ".".join(parts)
                 if fullname in SUGGESTED_TEST_FIXTURES:
-                    suggestion = ", e.g. add '[builtins fixtures/{}]' to your test".format(
-                        SUGGESTED_TEST_FIXTURES[fullname]
+                    suggestion = ", e.g. add '[{} fixtures/{}]' to your test".format(
+                        parts[0], SUGGESTED_TEST_FIXTURES[fullname]
                     )
                 else:
                     suggestion = ""
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 0c392ae755d7b..a271fb876bf3c 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -3870,9 +3870,8 @@ class LongName(Generic[T]): ...
         else:
             if alias_definition:
                 return AnyType(TypeOfAny.special_form)
-            # This type is invalid in most runtime contexts, give it an 'object' type.
-            # TODO: Use typing._SpecialForm instead?
-            return self.named_type("builtins.object")
+            # The _SpecialForm type can be used in some runtime contexts (e.g. it may have __or__).
+            return self.named_type("typing._SpecialForm")
 
     def apply_type_arguments_to_callable(
         self, tp: Type, args: Sequence[Type], ctx: Context
@@ -4742,7 +4741,7 @@ def has_member(self, typ: Type, member: str) -> bool:
             typ = typ.fallback
         if isinstance(typ, Instance):
             return typ.type.has_readable_member(member)
-        if isinstance(typ, CallableType) and typ.is_type_obj():
+        if isinstance(typ, FunctionLike) and typ.is_type_obj():
             return typ.fallback.type.has_readable_member(member)
         elif isinstance(typ, AnyType):
             return True
diff --git a/mypy/messages.py b/mypy/messages.py
index 4e762faa0b325..e11ee9d0f7f29 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -132,6 +132,7 @@
     "builtins.isinstance": "isinstancelist.pyi",
     "builtins.property": "property.pyi",
     "builtins.classmethod": "classmethod.pyi",
+    "typing._SpecialForm": "typing-medium.pyi",
 }
 
 
@@ -2253,6 +2254,9 @@ def format_literal_value(typ: LiteralType) -> str:
             if itype.extra_attrs and itype.extra_attrs.mod_name and module_names:
                 return f"{base_str} {itype.extra_attrs.mod_name}"
             return base_str
+        if itype.type.fullname == "typing._SpecialForm":
+            # This is not a real type but used for some typing-related constructs.
+            return "<typing special form>"
         if verbosity >= 2 or (fullnames and itype.type.fullname in fullnames):
             base_str = itype.type.fullname
         else:
diff --git a/mypyc/test-data/run-async.test b/mypyc/test-data/run-async.test
index e664ed3bb55a0..85ad172d61dfd 100644
--- a/mypyc/test-data/run-async.test
+++ b/mypyc/test-data/run-async.test
@@ -13,6 +13,9 @@ async def g() -> int:
 async def f() -> int:
     return await g()
 
+[file asyncio/__init__.pyi]
+async def sleep(t: float) -> None: ...
+
 [typing fixtures/typing-full.pyi]
 
 [file driver.py]
diff --git a/test-data/unit/check-ctypes.test b/test-data/unit/check-ctypes.test
index 5a350256f8e96..beb1afd779c04 100644
--- a/test-data/unit/check-ctypes.test
+++ b/test-data/unit/check-ctypes.test
@@ -20,6 +20,7 @@ a[3] = b"bytes"  # E: No overload variant of "__setitem__" of "Array" matches ar
 for x in a:
     reveal_type(x)  # N: Revealed type is "builtins.int"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesArrayCustomElementType]
 import ctypes
@@ -52,6 +53,7 @@ myu: Union[ctypes.Array[ctypes.c_int], List[str]]
 for myi in myu:
     reveal_type(myi)  # N: Revealed type is "Union[builtins.int, builtins.str]"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesArrayUnionElementType]
 import ctypes
@@ -76,6 +78,7 @@ mya[3] = b"bytes"  # E: No overload variant of "__setitem__" of "Array" matches
 for myx in mya:
     reveal_type(myx)  # N: Revealed type is "Union[__main__.MyCInt, builtins.int]"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesCharArrayAttrs]
 import ctypes
@@ -84,6 +87,7 @@ ca = (ctypes.c_char * 4)(b'a', b'b', b'c', b'\x00')
 reveal_type(ca.value)  # N: Revealed type is "builtins.bytes"
 reveal_type(ca.raw)  # N: Revealed type is "builtins.bytes"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesCharPArrayDoesNotCrash]
 import ctypes
@@ -91,6 +95,7 @@ import ctypes
 # The following line used to crash with "Could not find builtin symbol 'NoneType'"
 ca = (ctypes.c_char_p * 0)()
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesWcharArrayAttrs]
 import ctypes
@@ -99,6 +104,7 @@ wca = (ctypes.c_wchar * 4)('a', 'b', 'c', '\x00')
 reveal_type(wca.value)  # N: Revealed type is "builtins.str"
 wca.raw  # E: Array attribute "raw" is only available with element type "c_char", not "c_wchar"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesCharUnionArrayAttrs]
 import ctypes
@@ -108,6 +114,7 @@ cua: ctypes.Array[Union[ctypes.c_char, ctypes.c_wchar]]
 reveal_type(cua.value)  # N: Revealed type is "Union[builtins.bytes, builtins.str]"
 cua.raw  # E: Array attribute "raw" is only available with element type "c_char", not "Union[c_char, c_wchar]"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesAnyUnionArrayAttrs]
 import ctypes
@@ -117,6 +124,7 @@ caa: ctypes.Array[Union[ctypes.c_char, Any]]
 reveal_type(caa.value)  # N: Revealed type is "Union[builtins.bytes, Any]"
 reveal_type(caa.raw)  # N: Revealed type is "builtins.bytes"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesOtherUnionArrayAttrs]
 import ctypes
@@ -126,6 +134,7 @@ cua: ctypes.Array[Union[ctypes.c_char, ctypes.c_int]]
 cua.value  # E: Array attribute "value" is only available with element type "c_char" or "c_wchar", not "Union[c_char, c_int]"
 cua.raw  # E: Array attribute "raw" is only available with element type "c_char", not "Union[c_char, c_int]"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesAnyArrayAttrs]
 import ctypes
@@ -134,6 +143,7 @@ aa: ctypes.Array[Any]
 reveal_type(aa.value)  # N: Revealed type is "Any"
 reveal_type(aa.raw)  # N: Revealed type is "builtins.bytes"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesOtherArrayAttrs]
 import ctypes
@@ -142,6 +152,7 @@ oa = (ctypes.c_int * 4)(1, 2, 3, 4)
 oa.value  # E: Array attribute "value" is only available with element type "c_char" or "c_wchar", not "c_int"
 oa.raw  # E: Array attribute "raw" is only available with element type "c_char", not "c_int"
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testCtypesArrayConstructorStarargs]
 import ctypes
@@ -154,6 +165,7 @@ reveal_type(intarr4(*int_values))  # N: Revealed type is "ctypes.Array[ctypes.c_
 reveal_type(intarr4(*c_int_values))  # N: Revealed type is "ctypes.Array[ctypes.c_int]"
 reveal_type(intarr6(1, ctypes.c_int(2), *int_values))  # N: Revealed type is "ctypes.Array[ctypes.c_int]"
 reveal_type(intarr6(1, ctypes.c_int(2), *c_int_values))  # N: Revealed type is "ctypes.Array[ctypes.c_int]"
+[typing fixtures/typing-medium.pyi]
 
 float_values = [1.0, 2.0, 3.0, 4.0]
 intarr4(*float_values) # E: Array constructor argument 1 of type "List[float]" is not convertible to the array element type "Iterable[c_int]"
@@ -167,3 +179,4 @@ x = {"a": 1, "b": 2}
 intarr4(**x)
 
 [builtins fixtures/floatdict.pyi]
+[typing fixtures/typing-medium.pyi]
diff --git a/test-data/unit/check-dataclasses.test b/test-data/unit/check-dataclasses.test
index 3ec4c60e69295..d4064124109bd 100644
--- a/test-data/unit/check-dataclasses.test
+++ b/test-data/unit/check-dataclasses.test
@@ -633,8 +633,9 @@ class Two:
 
 c = Two()
 x = c.S
-reveal_type(x)  # N: Revealed type is "builtins.object"
+reveal_type(x)  # N: Revealed type is "typing._SpecialForm"
 [builtins fixtures/dataclasses.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testDataclassOrdering]
 # flags: --python-version 3.7
diff --git a/test-data/unit/check-generics.test b/test-data/unit/check-generics.test
index b7d98a783a49e..7df52b60fc0bc 100644
--- a/test-data/unit/check-generics.test
+++ b/test-data/unit/check-generics.test
@@ -1049,20 +1049,20 @@ CA = Callable[[T], int]
 TA = Tuple[T, int]
 UA = Union[T, int]
 
-cs = CA + 1 # E: Unsupported left operand type for + ("object")
+cs = CA + 1 # E: Unsupported left operand type for + ("<typing special form>")
 reveal_type(cs) # N: Revealed type is "Any"
 
-ts = TA() # E: "object" not callable
+ts = TA() # E: "<typing special form>" not callable
 reveal_type(ts) # N: Revealed type is "Any"
 
-us = UA.x # E: "object" has no attribute "x"
+us = UA.x # E: "<typing special form>" has no attribute "x"
 reveal_type(us) # N: Revealed type is "Any"
 
 xx = CA[str] + 1  # E: Type application is only supported for generic classes
 yy = TA[str]()  # E: Type application is only supported for generic classes
 zz = UA[str].x  # E: Type application is only supported for generic classes
 [builtins fixtures/tuple.pyi]
-
+[typing fixtures/typing-medium.pyi]
 [out]
 
 [case testGenericTypeAliasesTypeVarBinding]
diff --git a/test-data/unit/check-literal.test b/test-data/unit/check-literal.test
index da8f1570a4f42..ef8c9095e58aa 100644
--- a/test-data/unit/check-literal.test
+++ b/test-data/unit/check-literal.test
@@ -1484,16 +1484,17 @@ Alias = Literal[3]
 
 isinstance(3, Literal[3])           # E: Cannot use isinstance() with Literal type
 isinstance(3, Alias)                # E: Cannot use isinstance() with Literal type \
-                                    # E: Argument 2 to "isinstance" has incompatible type "object"; expected "Union[type, Tuple[Any, ...]]"
+                                    # E: Argument 2 to "isinstance" has incompatible type "<typing special form>"; expected "Union[type, Tuple[Any, ...]]"
 isinstance(3, Renamed[3])           # E: Cannot use isinstance() with Literal type
 isinstance(3, indirect.Literal[3])  # E: Cannot use isinstance() with Literal type
 
 issubclass(int, Literal[3])           # E: Cannot use issubclass() with Literal type
 issubclass(int, Alias)                # E: Cannot use issubclass() with Literal type \
-                                      # E: Argument 2 to "issubclass" has incompatible type "object"; expected "Union[type, Tuple[Any, ...]]"
+                                      # E: Argument 2 to "issubclass" has incompatible type "<typing special form>"; expected "Union[type, Tuple[Any, ...]]"
 issubclass(int, Renamed[3])           # E: Cannot use issubclass() with Literal type
 issubclass(int, indirect.Literal[3])  # E: Cannot use issubclass() with Literal type
 [builtins fixtures/isinstancelist.pyi]
+[typing fixtures/typing-medium.pyi]
 [out]
 
 [case testLiteralErrorsWhenSubclassed]
diff --git a/test-data/unit/check-python310.test b/test-data/unit/check-python310.test
index 1548d5dadcfdc..3b90a910e943a 100644
--- a/test-data/unit/check-python310.test
+++ b/test-data/unit/check-python310.test
@@ -1788,3 +1788,19 @@ def f6(a: object) -> None:
         case _ if y is not None:  # E: Name "y" may be undefined
             pass
 [builtins fixtures/tuple.pyi]
+
+[case testTypeAliasWithNewUnionSyntaxAndNoneLeftOperand]
+from typing import overload
+class C:
+    @overload
+    def __init__(self) -> None: pass
+    @overload
+    def __init__(self, x: int) -> None: pass
+    def __init__(self, x=0):
+        pass
+
+class D: pass
+
+X = None | C
+Y = None | D
+[builtins fixtures/type.pyi]
diff --git a/test-data/unit/check-type-aliases.test b/test-data/unit/check-type-aliases.test
index 8dafc8f47a6ce..fab372976ab27 100644
--- a/test-data/unit/check-type-aliases.test
+++ b/test-data/unit/check-type-aliases.test
@@ -821,28 +821,28 @@ c = Child()
 
 reveal_type(NormalImplicit)   # N: Revealed type is "def () -> __main__.Foo"
 reveal_type(NormalExplicit)   # N: Revealed type is "def () -> __main__.Foo"
-reveal_type(SpecialImplicit)  # N: Revealed type is "builtins.object"
-reveal_type(SpecialExplicit)  # N: Revealed type is "builtins.object"
+reveal_type(SpecialImplicit)  # N: Revealed type is "typing._SpecialForm"
+reveal_type(SpecialExplicit)  # N: Revealed type is "typing._SpecialForm"
 
 reveal_type(Parent.NormalImplicit)   # N: Revealed type is "def () -> __main__.Foo"
 reveal_type(Parent.NormalExplicit)   # N: Revealed type is "def () -> __main__.Foo"
-reveal_type(Parent.SpecialImplicit)  # N: Revealed type is "builtins.object"
-reveal_type(Parent.SpecialExplicit)  # N: Revealed type is "builtins.object"
+reveal_type(Parent.SpecialImplicit)  # N: Revealed type is "typing._SpecialForm"
+reveal_type(Parent.SpecialExplicit)  # N: Revealed type is "typing._SpecialForm"
 
 reveal_type(Child.NormalImplicit)   # N: Revealed type is "def () -> __main__.Foo"
 reveal_type(Child.NormalExplicit)   # N: Revealed type is "def () -> __main__.Foo"
-reveal_type(Child.SpecialImplicit)  # N: Revealed type is "builtins.object"
-reveal_type(Child.SpecialExplicit)  # N: Revealed type is "builtins.object"
+reveal_type(Child.SpecialImplicit)  # N: Revealed type is "typing._SpecialForm"
+reveal_type(Child.SpecialExplicit)  # N: Revealed type is "typing._SpecialForm"
 
 reveal_type(p.NormalImplicit)   # N: Revealed type is "def () -> __main__.Foo"
 reveal_type(p.NormalExplicit)   # N: Revealed type is "def () -> __main__.Foo"
-reveal_type(p.SpecialImplicit)  # N: Revealed type is "builtins.object"
-reveal_type(p.SpecialExplicit)  # N: Revealed type is "builtins.object"
+reveal_type(p.SpecialImplicit)  # N: Revealed type is "typing._SpecialForm"
+reveal_type(p.SpecialExplicit)  # N: Revealed type is "typing._SpecialForm"
 
 reveal_type(c.NormalImplicit)   # N: Revealed type is "def () -> __main__.Foo"
 reveal_type(p.NormalExplicit)   # N: Revealed type is "def () -> __main__.Foo"
-reveal_type(c.SpecialImplicit)  # N: Revealed type is "builtins.object"
-reveal_type(c.SpecialExplicit)  # N: Revealed type is "builtins.object"
+reveal_type(c.SpecialImplicit)  # N: Revealed type is "typing._SpecialForm"
+reveal_type(c.SpecialExplicit)  # N: Revealed type is "typing._SpecialForm"
 
 # Use type aliases in a type alias context in a plausible way
 
@@ -895,6 +895,7 @@ reveal_type(weird_child_2)  # N: Revealed type is "def () -> Any"
 reveal_type(weird_child_3)  # N: Revealed type is "def () -> Any"
 reveal_type(weird_child_4)  # N: Revealed type is "def () -> Any"
 [builtins fixtures/tuple.pyi]
+[typing fixtures/typing-medium.pyi]
 
 [case testMalformedTypeAliasRuntimeReassignments]
 from typing import Union
@@ -927,8 +928,8 @@ SpecialExplicit = 4  # E: Cannot assign multiple types to name "SpecialExplicit"
 
 Parent.NormalImplicit = 4  # E: Incompatible types in assignment (expression has type "int", variable has type "Type[Foo]")
 Parent.NormalExplicit = 4  # E: Incompatible types in assignment (expression has type "int", variable has type "Type[Foo]")
-Parent.SpecialImplicit = 4
-Parent.SpecialExplicit = 4
+Parent.SpecialImplicit = 4  # E: Incompatible types in assignment (expression has type "int", variable has type "<typing special form>")
+Parent.SpecialExplicit = 4  # E: Incompatible types in assignment (expression has type "int", variable has type "<typing special form>")
 
 Child.NormalImplicit = 4  # E: Incompatible types in assignment (expression has type "int", variable has type "Type[Foo]")
 Child.NormalExplicit = 4  # E: Incompatible types in assignment (expression has type "int", variable has type "Type[Foo]")
@@ -945,3 +946,4 @@ c.NormalExplicit = 4  # E: Incompatible types in assignment (expression has type
 c.SpecialImplicit = 4
 c.SpecialExplicit = 4
 [builtins fixtures/tuple.pyi]
+[typing fixtures/typing-medium.pyi]
diff --git a/test-data/unit/fixtures/args.pyi b/test-data/unit/fixtures/args.pyi
index 8d0ecc00f4b6d..9985ccf848178 100644
--- a/test-data/unit/fixtures/args.pyi
+++ b/test-data/unit/fixtures/args.pyi
@@ -26,6 +26,7 @@ class list(Sequence[T], Generic[T]): pass
 
 class int:
     def __eq__(self, o: object) -> bool: pass
+class float: pass
 class str: pass
 class bytes: pass
 class bool: pass
diff --git a/test-data/unit/fixtures/type.pyi b/test-data/unit/fixtures/type.pyi
index 755b45ff0bb56..77feb41ba70be 100644
--- a/test-data/unit/fixtures/type.pyi
+++ b/test-data/unit/fixtures/type.pyi
@@ -13,6 +13,7 @@ class list(Generic[T]): pass
 class type(Generic[T]):
     __name__: str
     def __or__(self, other: Union[type, None]) -> type: pass
+    def __ror__(self, other: Union[type, None]) -> type: pass
     def mro(self) -> List['type']: pass
 
 class tuple(Generic[T]): pass
diff --git a/test-data/unit/fixtures/typing-full.pyi b/test-data/unit/fixtures/typing-full.pyi
index c406da986818f..04568f7c03f38 100644
--- a/test-data/unit/fixtures/typing-full.pyi
+++ b/test-data/unit/fixtures/typing-full.pyi
@@ -179,3 +179,5 @@ class _TypedDict(Mapping[str, object]):
     def pop(self, k: NoReturn, default: T = ...) -> object: ...
     def update(self: T, __m: T) -> None: ...
     def __delitem__(self, k: NoReturn) -> None: ...
+
+class _SpecialForm: pass
diff --git a/test-data/unit/fixtures/typing-medium.pyi b/test-data/unit/fixtures/typing-medium.pyi
index 568fe057c4cf4..863b0703989d0 100644
--- a/test-data/unit/fixtures/typing-medium.pyi
+++ b/test-data/unit/fixtures/typing-medium.pyi
@@ -68,4 +68,6 @@ class ContextManager(Generic[T]):
     # Use Any because not all the precise types are in the fixtures.
     def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> Any: pass
 
+class _SpecialForm: pass
+
 TYPE_CHECKING = 1
diff --git a/test-data/unit/lib-stub/_decimal.pyi b/test-data/unit/lib-stub/_decimal.pyi
new file mode 100644
index 0000000000000..2c2c5bff11f70
--- /dev/null
+++ b/test-data/unit/lib-stub/_decimal.pyi
@@ -0,0 +1,4 @@
+# Very simplified decimal stubs for use in tests
+
+class Decimal:
+    def __new__(cls, value: str = ...) -> Decimal: ...
diff --git a/test-data/unit/lib-stub/datetime.pyi b/test-data/unit/lib-stub/datetime.pyi
new file mode 100644
index 0000000000000..7d71682d051d1
--- /dev/null
+++ b/test-data/unit/lib-stub/datetime.pyi
@@ -0,0 +1,16 @@
+# Very simplified datetime stubs for use in tests
+
+class datetime:
+    def __new__(
+        cls,
+        year: int,
+        month: int,
+        day: int,
+        hour: int = ...,
+        minute: int = ...,
+        second: int = ...,
+        microsecond: int = ...,
+        *,
+        fold: int = ...,
+    ) -> datetime: ...
+    def __format__(self, __fmt: str) -> str: ...
diff --git a/test-data/unit/lib-stub/decimal.pyi b/test-data/unit/lib-stub/decimal.pyi
new file mode 100644
index 0000000000000..d2ab6eda9ff18
--- /dev/null
+++ b/test-data/unit/lib-stub/decimal.pyi
@@ -0,0 +1,3 @@
+# Very simplified decimal stubs for use in tests
+
+from _decimal import *
diff --git a/test-data/unit/lib-stub/functools.pyi b/test-data/unit/lib-stub/functools.pyi
new file mode 100644
index 0000000000000..9e62a14c2f344
--- /dev/null
+++ b/test-data/unit/lib-stub/functools.pyi
@@ -0,0 +1,35 @@
+from typing import Generic, TypeVar, Callable, Any, Mapping
+
+_T = TypeVar("_T")
+
+class _SingleDispatchCallable(Generic[_T]):
+    registry: Mapping[Any, Callable[..., _T]]
+    def dispatch(self, cls: Any) -> Callable[..., _T]: ...
+    # @fun.register(complex)
+    # def _(arg, verbose=False): ...
+    @overload
+    def register(self, cls: type[Any], func: None = ...) -> Callable[[Callable[..., _T]], Callable[..., _T]]: ...
+    # @fun.register
+    # def _(arg: int, verbose=False):
+    @overload
+    def register(self, cls: Callable[..., _T], func: None = ...) -> Callable[..., _T]: ...
+    # fun.register(int, lambda x: x)
+    @overload
+    def register(self, cls: type[Any], func: Callable[..., _T]) -> Callable[..., _T]: ...
+    def _clear_cache(self) -> None: ...
+    def __call__(__self, *args: Any, **kwargs: Any) -> _T: ...
+
+def singledispatch(func: Callable[..., _T]) -> _SingleDispatchCallable[_T]: ...
+
+def total_ordering(cls: type[_T]) -> type[_T]: ...
+
+class cached_property(Generic[_T]):
+    func: Callable[[Any], _T]
+    attrname: str | None
+    def __init__(self, func: Callable[[Any], _T]) -> None: ...
+    @overload
+    def __get__(self, instance: None, owner: type[Any] | None = ...) -> cached_property[_T]: ...
+    @overload
+    def __get__(self, instance: object, owner: type[Any] | None = ...) -> _T: ...
+    def __set_name__(self, owner: type[Any], name: str) -> None: ...
+    def __class_getitem__(cls, item: Any) -> Any: ...
diff --git a/test-data/unit/lib-stub/traceback.pyi b/test-data/unit/lib-stub/traceback.pyi
new file mode 100644
index 0000000000000..83c1891f80f5d
--- /dev/null
+++ b/test-data/unit/lib-stub/traceback.pyi
@@ -0,0 +1,3 @@
+# Very simplified traceback stubs for use in tests
+
+def print_tb(*args, **kwargs) -> None: ...
diff --git a/test-data/unit/lib-stub/unannotated_lib.pyi b/test-data/unit/lib-stub/unannotated_lib.pyi
new file mode 100644
index 0000000000000..90bfb6fa47d63
--- /dev/null
+++ b/test-data/unit/lib-stub/unannotated_lib.pyi
@@ -0,0 +1 @@
+def f(x): ...
diff --git a/test-data/unit/pythoneval.test b/test-data/unit/pythoneval.test
index 692f62bf64547..f6336b48ee7b0 100644
--- a/test-data/unit/pythoneval.test
+++ b/test-data/unit/pythoneval.test
@@ -1660,3 +1660,55 @@ _testNarrowTypeForDictKeys.py:7: note: Revealed type is "builtins.str"
 _testNarrowTypeForDictKeys.py:9: note: Revealed type is "Union[builtins.str, None]"
 _testNarrowTypeForDictKeys.py:14: note: Revealed type is "builtins.str"
 _testNarrowTypeForDictKeys.py:16: note: Revealed type is "Union[builtins.str, None]"
+
+[case testTypeAliasWithNewStyleUnion]
+# flags: --python-version 3.10
+from typing import Literal, Type, TypeAlias
+
+Foo = Literal[1, 2]
+reveal_type(Foo)
+Bar1 = Foo | Literal[3]
+Bar2 = Literal[3] | Foo
+Bar3 = Foo | Foo | Literal[3] | Foo
+
+U1 = int | str
+U2 = U1 | bytes
+U3 = bytes | U1
+
+Opt1 = None | int
+Opt2 = None | float
+Opt3 = int | None
+Opt4 = float | None
+
+A = Type[int] | str
+B: TypeAlias = Type[int] | str
+[out]
+_testTypeAliasWithNewStyleUnion.py:5: note: Revealed type is "typing._SpecialForm"
+
+[case testTypeAliasWithNewStyleUnionInStub]
+# flags: --python-version 3.7
+import m
+
+[file m.pyi]
+from typing import Type
+from typing_extensions import Literal, TypeAlias
+
+Foo = Literal[1, 2]
+reveal_type(Foo)
+Bar1 = Foo | Literal[3]
+Bar2 = Literal[3] | Foo
+Bar3 = Foo | Foo | Literal[3] | Foo
+
+U1 = int | str
+U2 = U1 | bytes
+U3 = bytes | U1
+
+Opt1 = None | int
+Opt2 = None | float
+Opt3 = int | None
+Opt4 = float | None
+
+A = Type[int] | str
+B: TypeAlias = Type[int] | str
+[out]
+m.pyi:5: note: Revealed type is "typing._SpecialForm"

From 7465abd3d2fe4211a8aaa9453b402fea60071561 Mon Sep 17 00:00:00 2001
From: Valentin Stanciu <250871+svalentin@users.noreply.github.com>
Date: Tue, 8 Nov 2022 15:22:56 +0200
Subject: [PATCH 026/231] Filter out wasm32 wheel in upload-pypi.py (#14035)

Tried to make it in a way such that we can add more rules for platforms
we want to filter out in the future.
Tested it with `python3 misc/upload-pypi.py --dry-run 0.990`
Fixes #14026
---
 misc/upload-pypi.py | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/misc/upload-pypi.py b/misc/upload-pypi.py
index be8da9e44f86b..e60ec3cca2079 100644
--- a/misc/upload-pypi.py
+++ b/misc/upload-pypi.py
@@ -29,6 +29,21 @@ def is_whl_or_tar(name: str) -> bool:
     return name.endswith(".tar.gz") or name.endswith(".whl")
 
 
+def item_ok_for_pypi(name: str) -> bool:
+    if not is_whl_or_tar(name):
+        return False
+
+    if name.endswith(".tar.gz"):
+        name = name[:-7]
+    if name.endswith(".whl"):
+        name = name[:-4]
+
+    if name.endswith("wasm32"):
+        return False
+
+    return True
+
+
 def get_release_for_tag(tag: str) -> dict[str, Any]:
     with urlopen(f"{BASE}/{REPO}/releases/tags/{tag}") as f:
         data = json.load(f)
@@ -75,7 +90,7 @@ def check_sdist(dist: Path, version: str) -> None:
 
 
 def spot_check_dist(dist: Path, version: str) -> None:
-    items = [item for item in dist.iterdir() if is_whl_or_tar(item.name)]
+    items = [item for item in dist.iterdir() if item_ok_for_pypi(item.name)]
     assert len(items) > 10
     assert all(version in item.name for item in items)
     assert any(item.name.endswith("py3-none-any.whl") for item in items)
@@ -93,7 +108,7 @@ def tmp_twine() -> Iterator[Path]:
 
 def upload_dist(dist: Path, dry_run: bool = True) -> None:
     with tmp_twine() as twine:
-        files = [item for item in dist.iterdir() if is_whl_or_tar(item.name)]
+        files = [item for item in dist.iterdir() if item_ok_for_pypi(item.name)]
         cmd: list[Any] = [twine, "upload"]
         cmd += files
         if dry_run:

From fa22a49ef1154285d4f251086f85cadf16e54cd9 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Tue, 8 Nov 2022 15:43:57 +0000
Subject: [PATCH 027/231] Fix crash on inference with recursive alias to
 recursive instance (#14038)

Fixes #14031

It turns out premature optimization is the root of all evil. (It turns
out this costs us less than 1% time on self-check).
---
 mypy/constraints.py                       |  3 ++-
 mypy/types.py                             |  6 ++++++
 test-data/unit/check-recursive-types.test | 11 +++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index 49b042d5baf05..2a641bf27ed57 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -177,8 +177,9 @@ def infer_constraints(template: Type, actual: Type, direction: int) -> list[Cons
         for (t, a) in reversed(TypeState.inferring)
     ):
         return []
-    if has_recursive_types(template):
+    if has_recursive_types(template) or isinstance(get_proper_type(template), Instance):
         # This case requires special care because it may cause infinite recursion.
+        # Note that we include Instances because the may be recursive as str(Sequence[str]).
         if not has_type_vars(template):
             # Return early on an empty branch.
             return []
diff --git a/mypy/types.py b/mypy/types.py
index e322cf02505ff..2f0feb703f6aa 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3240,6 +3240,12 @@ def __init__(self) -> None:
     def visit_type_var(self, t: TypeVarType) -> bool:
         return True
 
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> bool:
+        return True
+
+    def visit_param_spec(self, t: ParamSpecType) -> bool:
+        return True
+
 
 def has_type_vars(typ: Type) -> bool:
     """Check if a type contains any type variables (recursively)."""
diff --git a/test-data/unit/check-recursive-types.test b/test-data/unit/check-recursive-types.test
index 0d727b109658b..95b0918866f12 100644
--- a/test-data/unit/check-recursive-types.test
+++ b/test-data/unit/check-recursive-types.test
@@ -826,3 +826,14 @@ z = z
 x = y  # E: Incompatible types in assignment (expression has type "L", variable has type "K")
 z = x  # OK
 [builtins fixtures/tuple.pyi]
+
+[case testRecursiveInstanceInferenceNoCrash]
+from typing import Sequence, TypeVar, Union
+
+class C(Sequence[C]): ...
+
+T = TypeVar("T")
+def foo(x: T) -> C: ...
+
+Nested = Union[C, Sequence[Nested]]
+x: Nested = foo(42)

From dbcbb3f5c3ef791c98088da0bd1dfa6cbf51f301 Mon Sep 17 00:00:00 2001
From: dosisod <39638017+dosisod@users.noreply.github.com>
Date: Tue, 8 Nov 2022 17:57:39 -0800
Subject: [PATCH 028/231] [mypyc] Use tabs instead of spaces in emitted C code
 (#14016)

By using tabs instead of spaces for indentation in the emitted C code we
are able to reduce the file size by almost 9%:

| File | Size |
|------|------|
| `build/__native_74cdc94b2b24dafac2a2.c` (spaces) | 86.5MB |
| `build/__native_74cdc94b2b24dafac2a2.c` (tabs)   | 79.6MB |

For this particular file we save about 6.9MB, or 8.7%.

I checked, and this has no effect on the compilation speed, which is to
be expected. At the very least opening these auto generated files inside
an editor will be faster, even if the compilation isn't any faster.

I am interested in making mypy/mypyc faster, and this seemed like a
low-hanging fruit that could be beneficial.
---
 mypyc/codegen/emit.py          | 6 +++---
 mypyc/test/test_emit.py        | 2 +-
 mypyc/test/test_emitfunc.py    | 6 +++---
 mypyc/test/test_emitwrapper.py | 3 ++-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/mypyc/codegen/emit.py b/mypyc/codegen/emit.py
index 5d47636b4c1e0..15dece700a1e1 100644
--- a/mypyc/codegen/emit.py
+++ b/mypyc/codegen/emit.py
@@ -176,10 +176,10 @@ def __init__(
     # Low-level operations
 
     def indent(self) -> None:
-        self._indent += 4
+        self._indent += 1
 
     def dedent(self) -> None:
-        self._indent -= 4
+        self._indent -= 1
         assert self._indent >= 0
 
     def label(self, label: BasicBlock) -> str:
@@ -194,7 +194,7 @@ def attr(self, name: str) -> str:
     def emit_line(self, line: str = "") -> None:
         if line.startswith("}"):
             self.dedent()
-        self.fragments.append(self._indent * " " + line + "\n")
+        self.fragments.append(self._indent * "\t" + line + "\n")
         if line.endswith("{"):
             self.indent()
 
diff --git a/mypyc/test/test_emit.py b/mypyc/test/test_emit.py
index 7351cd7fb13ee..1b624a7a6cdb7 100644
--- a/mypyc/test/test_emit.py
+++ b/mypyc/test/test_emit.py
@@ -28,4 +28,4 @@ def test_emit_line(self) -> None:
         emitter.emit_line("a {")
         emitter.emit_line("f();")
         emitter.emit_line("}")
-        assert emitter.fragments == ["line;\n", "a {\n", "    f();\n", "}\n"]
+        assert emitter.fragments == ["line;\n", "a {\n", "\tf();\n", "}\n"]
diff --git a/mypyc/test/test_emitfunc.py b/mypyc/test/test_emitfunc.py
index d7dcf3be532b5..3b44f7e444c8e 100644
--- a/mypyc/test/test_emitfunc.py
+++ b/mypyc/test/test_emitfunc.py
@@ -833,7 +833,7 @@ def assert_emit(
 
         op.accept(visitor)
         frags = declarations.fragments + emitter.fragments
-        actual_lines = [line.strip(" ") for line in frags]
+        actual_lines = [line.strip(" \t") for line in frags]
         assert all(line.endswith("\n") for line in actual_lines)
         actual_lines = [line.rstrip("\n") for line in actual_lines]
         if not expected.strip():
@@ -900,7 +900,7 @@ def test_simple(self) -> None:
                 "    return cpy_r_arg;\n",
                 "}\n",
             ],
-            result,
+            [line.replace("\t", 4 * " ") for line in result],
             msg="Generated code invalid",
         )
 
@@ -927,6 +927,6 @@ def test_register(self) -> None:
                 "    CPy_Unreachable();\n",
                 "}\n",
             ],
-            result,
+            [line.replace("\t", 4 * " ") for line in result],
             msg="Generated code invalid",
         )
diff --git a/mypyc/test/test_emitwrapper.py b/mypyc/test/test_emitwrapper.py
index c4465656444c5..ec5adb4c6622c 100644
--- a/mypyc/test/test_emitwrapper.py
+++ b/mypyc/test/test_emitwrapper.py
@@ -56,5 +56,6 @@ def test_check_int(self) -> None:
         )
 
     def assert_lines(self, expected: list[str], actual: list[str]) -> None:
-        actual = [line.rstrip("\n") for line in actual]
+        actual = [line.rstrip("\n").replace(4 * " ", "\t") for line in actual]
+        expected = [line.replace(4 * " ", "\t") for line in expected]
         assert_string_arrays_equal(expected, actual, "Invalid output")

From 5cc14390337f28e6f90efaf0ad5c4b1d322a8638 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 10 Nov 2022 17:37:09 +0000
Subject: [PATCH 029/231] Don't ignore errors in files passed on the command
 line (#14060)

#13768 had a bug so that errors were sometimes silenced in files that
were under a directory in `sys.path`. `sys.path` sometimes includes the
current working directory, resulting in no errors reported at all. Fix it by
always reporting errors if a file was passed on the command line (unless
*explicitly* silenced).

When using import following errors can still be ignored, which is
questionable, but this didn't change recently so I'm not addressing it
here.

Fixes #14042.
---
 mypy/build.py               | 10 ++++--
 mypy/dmypy_server.py        | 14 ++++----
 mypy/modulefinder.py        |  8 +++--
 mypy/server/update.py       | 28 +++++++++++-----
 mypy/test/testcmdline.py    |  8 ++---
 test-data/unit/cmdline.test | 65 +++++++++++++++++++++++++++++++++++++
 6 files changed, 108 insertions(+), 25 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index 31851680ea825..27dc1141ce28b 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -1940,7 +1940,7 @@ def __init__(
                 raise
             if follow_imports == "silent":
                 self.ignore_all = True
-        elif path and is_silent_import_module(manager, path):
+        elif path and is_silent_import_module(manager, path) and not root_source:
             self.ignore_all = True
         self.path = path
         if path:
@@ -2629,7 +2629,7 @@ def find_module_and_diagnose(
                 else:
                     skipping_module(manager, caller_line, caller_state, id, result)
             raise ModuleNotFound
-        if is_silent_import_module(manager, result):
+        if is_silent_import_module(manager, result) and not root_source:
             follow_imports = "silent"
         return (result, follow_imports)
     else:
@@ -3024,7 +3024,11 @@ def load_graph(
     for bs in sources:
         try:
             st = State(
-                id=bs.module, path=bs.path, source=bs.text, manager=manager, root_source=True
+                id=bs.module,
+                path=bs.path,
+                source=bs.text,
+                manager=manager,
+                root_source=not bs.followed,
             )
         except ModuleNotFound:
             continue
diff --git a/mypy/dmypy_server.py b/mypy/dmypy_server.py
index 671999065e7d1..be2f4ab8d6182 100644
--- a/mypy/dmypy_server.py
+++ b/mypy/dmypy_server.py
@@ -592,7 +592,7 @@ def fine_grained_increment_follow_imports(self, sources: list[BuildSource]) -> l
         sources.extend(new_files)
 
         # Process changes directly reachable from roots.
-        messages = fine_grained_manager.update(changed, [])
+        messages = fine_grained_manager.update(changed, [], followed=True)
 
         # Follow deps from changed modules (still within graph).
         worklist = changed[:]
@@ -609,13 +609,13 @@ def fine_grained_increment_follow_imports(self, sources: list[BuildSource]) -> l
                 sources2, graph, seen, changed_paths
             )
             self.update_sources(new_files)
-            messages = fine_grained_manager.update(changed, [])
+            messages = fine_grained_manager.update(changed, [], followed=True)
             worklist.extend(changed)
 
         t2 = time.time()
 
         def refresh_file(module: str, path: str) -> list[str]:
-            return fine_grained_manager.update([(module, path)], [])
+            return fine_grained_manager.update([(module, path)], [], followed=True)
 
         for module_id, state in list(graph.items()):
             new_messages = refresh_suppressed_submodules(
@@ -632,10 +632,10 @@ def refresh_file(module: str, path: str) -> list[str]:
             new_unsuppressed = self.find_added_suppressed(graph, seen, manager.search_paths)
             if not new_unsuppressed:
                 break
-            new_files = [BuildSource(mod[1], mod[0]) for mod in new_unsuppressed]
+            new_files = [BuildSource(mod[1], mod[0], followed=True) for mod in new_unsuppressed]
             sources.extend(new_files)
             self.update_sources(new_files)
-            messages = fine_grained_manager.update(new_unsuppressed, [])
+            messages = fine_grained_manager.update(new_unsuppressed, [], followed=True)
 
             for module_id, path in new_unsuppressed:
                 new_messages = refresh_suppressed_submodules(
@@ -717,7 +717,7 @@ def find_reachable_changed_modules(
                 for dep in state.dependencies:
                     if dep not in seen:
                         seen.add(dep)
-                        worklist.append(BuildSource(graph[dep].path, graph[dep].id))
+                        worklist.append(BuildSource(graph[dep].path, graph[dep].id, followed=True))
         return changed, new_files
 
     def direct_imports(
@@ -725,7 +725,7 @@ def direct_imports(
     ) -> list[BuildSource]:
         """Return the direct imports of module not included in seen."""
         state = graph[module[0]]
-        return [BuildSource(graph[dep].path, dep) for dep in state.dependencies]
+        return [BuildSource(graph[dep].path, dep, followed=True) for dep in state.dependencies]
 
     def find_added_suppressed(
         self, graph: mypy.build.Graph, seen: set[str], search_paths: SearchPaths
diff --git a/mypy/modulefinder.py b/mypy/modulefinder.py
index 5d542b1549060..e64dba5ce29da 100644
--- a/mypy/modulefinder.py
+++ b/mypy/modulefinder.py
@@ -115,15 +115,19 @@ def __init__(
         module: str | None,
         text: str | None = None,
         base_dir: str | None = None,
+        followed: bool = False,
     ) -> None:
         self.path = path  # File where it's found (e.g. 'xxx/yyy/foo/bar.py')
         self.module = module or "__main__"  # Module name (e.g. 'foo.bar')
         self.text = text  # Source code, if initially supplied, else None
         self.base_dir = base_dir  # Directory where the package is rooted (e.g. 'xxx/yyy')
+        self.followed = followed  # Was this found by following imports?
 
     def __repr__(self) -> str:
-        return "BuildSource(path={!r}, module={!r}, has_text={}, base_dir={!r})".format(
-            self.path, self.module, self.text is not None, self.base_dir
+        return (
+            "BuildSource(path={!r}, module={!r}, has_text={}, base_dir={!r}, followed={})".format(
+                self.path, self.module, self.text is not None, self.base_dir, self.followed
+            )
         )
 
 
diff --git a/mypy/server/update.py b/mypy/server/update.py
index 686068a4aad00..a1f57b5a67467 100644
--- a/mypy/server/update.py
+++ b/mypy/server/update.py
@@ -203,7 +203,10 @@ def __init__(self, result: BuildResult) -> None:
         self.processed_targets: list[str] = []
 
     def update(
-        self, changed_modules: list[tuple[str, str]], removed_modules: list[tuple[str, str]]
+        self,
+        changed_modules: list[tuple[str, str]],
+        removed_modules: list[tuple[str, str]],
+        followed: bool = False,
     ) -> list[str]:
         """Update previous build result by processing changed modules.
 
@@ -219,6 +222,7 @@ def update(
                 Assume this is correct; it's not validated here.
             removed_modules: Modules that have been deleted since the previous update
                 or removed from the build.
+            followed: If True, the modules were found through following imports
 
         Returns:
             A list of errors.
@@ -256,7 +260,9 @@ def update(
             self.blocking_error = None
 
         while True:
-            result = self.update_one(changed_modules, initial_set, removed_set, blocking_error)
+            result = self.update_one(
+                changed_modules, initial_set, removed_set, blocking_error, followed
+            )
             changed_modules, (next_id, next_path), blocker_messages = result
 
             if blocker_messages is not None:
@@ -329,6 +335,7 @@ def update_one(
         initial_set: set[str],
         removed_set: set[str],
         blocking_error: str | None,
+        followed: bool,
     ) -> tuple[list[tuple[str, str]], tuple[str, str], list[str] | None]:
         """Process a module from the list of changed modules.
 
@@ -355,7 +362,7 @@ def update_one(
             )
             return changed_modules, (next_id, next_path), None
 
-        result = self.update_module(next_id, next_path, next_id in removed_set)
+        result = self.update_module(next_id, next_path, next_id in removed_set, followed)
         remaining, (next_id, next_path), blocker_messages = result
         changed_modules = [(id, path) for id, path in changed_modules if id != next_id]
         changed_modules = dedupe_modules(remaining + changed_modules)
@@ -368,7 +375,7 @@ def update_one(
         return changed_modules, (next_id, next_path), blocker_messages
 
     def update_module(
-        self, module: str, path: str, force_removed: bool
+        self, module: str, path: str, force_removed: bool, followed: bool
     ) -> tuple[list[tuple[str, str]], tuple[str, str], list[str] | None]:
         """Update a single modified module.
 
@@ -380,6 +387,7 @@ def update_module(
             path: File system path of the module
             force_removed: If True, consider module removed from the build even if path
                 exists (used for removing an existing file from the build)
+            followed: Was this found via import following?
 
         Returns:
             Tuple with these items:
@@ -417,7 +425,7 @@ def update_module(
         manager.errors.reset()
         self.processed_targets.append(module)
         result = update_module_isolated(
-            module, path, manager, previous_modules, graph, force_removed
+            module, path, manager, previous_modules, graph, force_removed, followed
         )
         if isinstance(result, BlockedUpdate):
             # Blocking error -- just give up
@@ -552,6 +560,7 @@ def update_module_isolated(
     previous_modules: dict[str, str],
     graph: Graph,
     force_removed: bool,
+    followed: bool,
 ) -> UpdateResult:
     """Build a new version of one changed module only.
 
@@ -575,7 +584,7 @@ def update_module_isolated(
         delete_module(module, path, graph, manager)
         return NormalUpdate(module, path, [], None)
 
-    sources = get_sources(manager.fscache, previous_modules, [(module, path)])
+    sources = get_sources(manager.fscache, previous_modules, [(module, path)], followed)
 
     if module in manager.missing_modules:
         manager.missing_modules.remove(module)
@@ -728,12 +737,15 @@ def get_module_to_path_map(graph: Graph) -> dict[str, str]:
 
 
 def get_sources(
-    fscache: FileSystemCache, modules: dict[str, str], changed_modules: list[tuple[str, str]]
+    fscache: FileSystemCache,
+    modules: dict[str, str],
+    changed_modules: list[tuple[str, str]],
+    followed: bool,
 ) -> list[BuildSource]:
     sources = []
     for id, path in changed_modules:
         if fscache.isfile(path):
-            sources.append(BuildSource(path, id, None))
+            sources.append(BuildSource(path, id, None, followed=followed))
     return sources
 
 
diff --git a/mypy/test/testcmdline.py b/mypy/test/testcmdline.py
index 268b6bab1ec25..2e8b0dc9a1cd5 100644
--- a/mypy/test/testcmdline.py
+++ b/mypy/test/testcmdline.py
@@ -69,12 +69,10 @@ def test_python_cmdline(testcase: DataDrivenTestCase, step: int) -> None:
     env["PYTHONPATH"] = PREFIX
     if os.path.isdir(extra_path):
         env["PYTHONPATH"] += os.pathsep + extra_path
+    cwd = os.path.join(test_temp_dir, custom_cwd or "")
+    args = [arg.replace("$CWD", os.path.abspath(cwd)) for arg in args]
     process = subprocess.Popen(
-        fixed + args,
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
-        cwd=os.path.join(test_temp_dir, custom_cwd or ""),
-        env=env,
+        fixed + args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=cwd, env=env
     )
     outb, errb = process.communicate()
     result = process.returncode
diff --git a/test-data/unit/cmdline.test b/test-data/unit/cmdline.test
index 2ea7f07da3bce..92b0af6942bc3 100644
--- a/test-data/unit/cmdline.test
+++ b/test-data/unit/cmdline.test
@@ -1505,3 +1505,68 @@ def f():
 [out]
 a.py:2: note: By default the bodies of untyped functions are not checked, consider using --check-untyped-defs
 == Return code: 0
+
+[case testCustomTypeshedDirFilePassedExplicitly]
+# cmd: mypy --custom-typeshed-dir dir m.py dir/stdlib/foo.pyi
+[file m.py]
+1()
+[file dir/stdlib/abc.pyi]
+1()  # Errors are not reported from typeshed by default
+[file dir/stdlib/builtins.pyi]
+class object: pass
+class str(object): pass
+class int(object): pass
+[file dir/stdlib/sys.pyi]
+[file dir/stdlib/types.pyi]
+[file dir/stdlib/typing.pyi]
+[file dir/stdlib/mypy_extensions.pyi]
+[file dir/stdlib/typing_extensions.pyi]
+[file dir/stdlib/foo.pyi]
+1()  # Errors are reported if the file was explicitly passed on the command line
+[file dir/stdlib/VERSIONS]
+[out]
+dir/stdlib/foo.pyi:1: error: "int" not callable
+m.py:1: error: "int" not callable
+
+[case testFileInPythonPathPassedExplicitly1]
+# cmd: mypy $CWD/pypath/foo.py
+[file pypath/foo.py]
+1()
+[out]
+pypath/foo.py:1: error: "int" not callable
+
+[case testFileInPythonPathPassedExplicitly2]
+# cmd: mypy pypath/foo.py
+[file pypath/foo.py]
+1()
+[out]
+pypath/foo.py:1: error: "int" not callable
+
+[case testFileInPythonPathPassedExplicitly3]
+# cmd: mypy -p foo
+# cwd: pypath
+[file pypath/foo/__init__.py]
+1()
+[file pypath/foo/m.py]
+1()
+[out]
+foo/m.py:1: error: "int" not callable
+foo/__init__.py:1: error: "int" not callable
+
+[case testFileInPythonPathPassedExplicitly4]
+# cmd: mypy -m foo
+# cwd: pypath
+[file pypath/foo.py]
+1()
+[out]
+foo.py:1: error: "int" not callable
+
+[case testFileInPythonPathPassedExplicitly5]
+# cmd: mypy -m foo.m
+# cwd: pypath
+[file pypath/foo/__init__.py]
+1()  # TODO: Maybe this should generate errors as well? But how would we decide?
+[file pypath/foo/m.py]
+1()
+[out]
+foo/m.py:1: error: "int" not callable

From b18281c857a3e089740b6c6c03ff52a529c1b0ba Mon Sep 17 00:00:00 2001
From: Nick Drozd <nicholasdrozd@gmail.com>
Date: Thu, 10 Nov 2022 14:20:38 -0600
Subject: [PATCH 030/231] Simplify boolean return logic in various places
 (#14012)

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 misc/fix_annotate.py             |  9 +++---
 mypy/build.py                    | 20 ++++++--------
 mypy/checker.py                  | 24 ++++++----------
 mypy/modulefinder.py             | 23 +++++++---------
 mypy/stubgen.py                  |  5 +---
 mypy/subtypes.py                 | 34 ++++++++---------------
 mypy/typeanal.py                 |  4 +--
 mypy/types.py                    | 47 ++++++++++++++++----------------
 mypyc/ir/class_ir.py             |  5 +---
 mypyc/irbuild/prebuildvisitor.py | 10 +++----
 mypyc/irbuild/prepare.py         | 23 ++++++++++------
 11 files changed, 86 insertions(+), 118 deletions(-)

diff --git a/misc/fix_annotate.py b/misc/fix_annotate.py
index b661a899924c0..7fffba8a85079 100644
--- a/misc/fix_annotate.py
+++ b/misc/fix_annotate.py
@@ -213,8 +213,7 @@ def has_return_exprs(self, node):
         results = {}
         if self.return_expr.match(node, results):
             return True
-        for child in node.children:
-            if child.type not in (syms.funcdef, syms.classdef):
-                if self.has_return_exprs(child):
-                    return True
-        return False
+        return any(
+            child.type not in (syms.funcdef, syms.classdef) and self.has_return_exprs(child)
+            for child in node.children
+        )
diff --git a/mypy/build.py b/mypy/build.py
index 27dc1141ce28b..62367c35915e7 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2728,11 +2728,8 @@ def in_partial_package(id: str, manager: BuildManager) -> bool:
             else:
                 parent_mod = parent_st.tree
         if parent_mod is not None:
-            if parent_mod.is_partial_stub_package:
-                return True
-            else:
-                # Bail out soon, complete subpackage found
-                return False
+            # Bail out soon, complete subpackage found
+            return parent_mod.is_partial_stub_package
         id = parent
     return False
 
@@ -3580,9 +3577,10 @@ def record_missing_stub_packages(cache_dir: str, missing_stub_packages: set[str]
 
 
 def is_silent_import_module(manager: BuildManager, path: str) -> bool:
-    if not manager.options.no_silence_site_packages:
-        for dir in manager.search_paths.package_path + manager.search_paths.typeshed_path:
-            if is_sub_path(path, dir):
-                # Silence errors in site-package dirs and typeshed
-                return True
-    return False
+    if manager.options.no_silence_site_packages:
+        return False
+    # Silence errors in site-package dirs and typeshed
+    return any(
+        is_sub_path(path, dir)
+        for dir in manager.search_paths.package_path + manager.search_paths.typeshed_path
+    )
diff --git a/mypy/checker.py b/mypy/checker.py
index 67d132afe2c7c..fef85d085496e 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -2292,9 +2292,7 @@ def is_final_enum_value(self, sym: SymbolTableNode) -> bool:
         ):
             return False
 
-        if self.is_stub or sym.node.has_explicit_value:
-            return True
-        return False
+        return self.is_stub or sym.node.has_explicit_value
 
     def check_enum_bases(self, defn: ClassDef) -> None:
         """
@@ -5978,10 +5976,7 @@ def store_type(self, node: Expression, typ: Type) -> None:
         self._type_maps[-1][node] = typ
 
     def has_type(self, node: Expression) -> bool:
-        for m in reversed(self._type_maps):
-            if node in m:
-                return True
-        return False
+        return any(node in m for m in reversed(self._type_maps))
 
     def lookup_type_or_none(self, node: Expression) -> Type | None:
         for m in reversed(self._type_maps):
@@ -6152,13 +6147,11 @@ def handle_partial_var_type(
             return fixup_partial_type(typ)
 
     def is_defined_in_base_class(self, var: Var) -> bool:
-        if var.info:
-            for base in var.info.mro[1:]:
-                if base.get(var.name) is not None:
-                    return True
-            if var.info.fallback_to_any:
-                return True
-        return False
+        if not var.info:
+            return False
+        return var.info.fallback_to_any or any(
+            base.get(var.name) is not None for base in var.info.mro[1:]
+        )
 
     def find_partial_types(self, var: Var) -> dict[Var, Context] | None:
         """Look for an active partial type scope containing variable.
@@ -6354,8 +6347,7 @@ def is_writable_attribute(self, node: Node) -> bool:
         elif isinstance(node, OverloadedFuncDef) and node.is_property:
             first_item = cast(Decorator, node.items[0])
             return first_item.var.is_settable_property
-        else:
-            return False
+        return False
 
     def get_isinstance_type(self, expr: Expression) -> list[TypeRange] | None:
         if isinstance(expr, OpExpr) and expr.op == "|":
diff --git a/mypy/modulefinder.py b/mypy/modulefinder.py
index e64dba5ce29da..b2abb4847705b 100644
--- a/mypy/modulefinder.py
+++ b/mypy/modulefinder.py
@@ -148,14 +148,11 @@ def __init__(self, sources: list[BuildSource]) -> None:
                 self.source_modules[source.module] = source.path or ""
 
     def is_source(self, file: MypyFile) -> bool:
-        if file.path and file.path in self.source_paths:
-            return True
-        elif file._fullname in self.source_modules:
-            return True
-        elif self.source_text_present:
-            return True
-        else:
-            return False
+        return (
+            (file.path and file.path in self.source_paths)
+            or file._fullname in self.source_modules
+            or self.source_text_present
+        )
 
 
 class FindModuleCache:
@@ -573,11 +570,11 @@ def _is_compatible_stub_package(self, stub_dir: str) -> bool:
         whether the stubs are compatible with Python 2 and 3.
         """
         metadata_fnam = os.path.join(stub_dir, "METADATA.toml")
-        if os.path.isfile(metadata_fnam):
-            with open(metadata_fnam, "rb") as f:
-                metadata = tomllib.load(f)
-            return bool(metadata.get("python3", True))
-        return True
+        if not os.path.isfile(metadata_fnam):
+            return True
+        with open(metadata_fnam, "rb") as f:
+            metadata = tomllib.load(f)
+        return bool(metadata.get("python3", True))
 
     def find_modules_recursive(self, module: str) -> list[BuildSource]:
         module_path = self.find_module(module)
diff --git a/mypy/stubgen.py b/mypy/stubgen.py
index fbae9ebaa2528..8c7e24504270e 100755
--- a/mypy/stubgen.py
+++ b/mypy/stubgen.py
@@ -1309,10 +1309,7 @@ def is_private_name(self, name: str, fullname: str | None = None) -> bool:
 
     def is_private_member(self, fullname: str) -> bool:
         parts = fullname.split(".")
-        for part in parts:
-            if self.is_private_name(part):
-                return True
-        return False
+        return any(self.is_private_name(part) for part in parts)
 
     def get_str_type_of_node(
         self, rvalue: Expression, can_infer_optional: bool = False, can_be_any: bool = True
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 2724379ab8780..9a4982f5b8ecb 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -429,22 +429,18 @@ def visit_erased_type(self, left: ErasedType) -> bool:
         # This may be encountered during type inference. The result probably doesn't
         # matter much.
         # TODO: it actually does matter, figure out more principled logic about this.
-        if self.subtype_context.keep_erased_types:
-            return False
-        return True
+        return not self.subtype_context.keep_erased_types
 
     def visit_deleted_type(self, left: DeletedType) -> bool:
         return True
 
     def visit_instance(self, left: Instance) -> bool:
         if left.type.fallback_to_any and not self.proper_subtype:
-            if isinstance(self.right, NoneType):
-                # NOTE: `None` is a *non-subclassable* singleton, therefore no class
-                # can by a subtype of it, even with an `Any` fallback.
-                # This special case is needed to treat descriptors in classes with
-                # dynamic base classes correctly, see #5456.
-                return False
-            return True
+            # NOTE: `None` is a *non-subclassable* singleton, therefore no class
+            # can by a subtype of it, even with an `Any` fallback.
+            # This special case is needed to treat descriptors in classes with
+            # dynamic base classes correctly, see #5456.
+            return not isinstance(self.right, NoneType)
         right = self.right
         if isinstance(right, TupleType) and mypy.typeops.tuple_fallback(right).type.is_enum:
             return self._is_subtype(left, mypy.typeops.tuple_fallback(right))
@@ -513,11 +509,7 @@ def check_mixed(
                             isinstance(unpacked_type, Instance)
                             and unpacked_type.type.fullname == "builtins.tuple"
                         ):
-                            if not all(
-                                is_equivalent(l, unpacked_type.args[0]) for l in compare_to
-                            ):
-                                return False
-                            return True
+                            return all(is_equivalent(l, unpacked_type.args[0]) for l in compare_to)
                         if isinstance(unpacked_type, TypeVarTupleType):
                             return False
                         if isinstance(unpacked_type, AnyType):
@@ -741,9 +733,8 @@ def visit_tuple_type(self, left: TupleType) -> bool:
         elif isinstance(right, TupleType):
             if len(left.items) != len(right.items):
                 return False
-            for l, r in zip(left.items, right.items):
-                if not self._is_subtype(l, r):
-                    return False
+            if any(not self._is_subtype(l, r) for l, r in zip(left.items, right.items)):
+                return False
             rfallback = mypy.typeops.tuple_fallback(right)
             if is_named_instance(rfallback, "builtins.tuple"):
                 # No need to verify fallback. This is useful since the calculated fallback
@@ -752,9 +743,7 @@ def visit_tuple_type(self, left: TupleType) -> bool:
                 # join(Union[int, C], Union[str, C]) == Union[int, str, C].
                 return True
             lfallback = mypy.typeops.tuple_fallback(left)
-            if not self._is_subtype(lfallback, rfallback):
-                return False
-            return True
+            return self._is_subtype(lfallback, rfallback)
         else:
             return False
 
@@ -1368,8 +1357,7 @@ def g(x: int) -> int: ...
         unified = unify_generic_callable(left, right, ignore_return=ignore_return)
         if unified is None:
             return False
-        else:
-            left = unified
+        left = unified
 
     # If we allow partial overlaps, we don't need to leave R generic:
     # if we can find even just a single typevar assignment which
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 35f60f54605a3..55d819071a3a6 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -1729,9 +1729,7 @@ def __init__(
     def _seems_like_callable(self, type: UnboundType) -> bool:
         if not type.args:
             return False
-        if isinstance(type.args[0], (EllipsisType, TypeList, ParamSpecType)):
-            return True
-        return False
+        return isinstance(type.args[0], (EllipsisType, TypeList, ParamSpecType))
 
     def visit_unbound_type(self, t: UnboundType) -> TypeVarLikeList:
         name = t.name
diff --git a/mypy/types.py b/mypy/types.py
index 2f0feb703f6aa..a73c41904ea76 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -437,14 +437,12 @@ def __repr__(self) -> str:
         return self.raw_id.__repr__()
 
     def __eq__(self, other: object) -> bool:
-        if isinstance(other, TypeVarId):
-            return (
-                self.raw_id == other.raw_id
-                and self.meta_level == other.meta_level
-                and self.namespace == other.namespace
-            )
-        else:
-            return False
+        return (
+            isinstance(other, TypeVarId)
+            and self.raw_id == other.raw_id
+            and self.meta_level == other.meta_level
+            and self.namespace == other.namespace
+        )
 
     def __ne__(self, other: object) -> bool:
         return not (self == other)
@@ -910,9 +908,7 @@ def __hash__(self) -> int:
         return hash(tuple(self.items))
 
     def __eq__(self, other: object) -> bool:
-        if not isinstance(other, TypeList):
-            return False
-        return self.items == other.items
+        return isinstance(other, TypeList) and self.items == other.items
 
 
 class UnpackType(ProperType):
@@ -2263,16 +2259,19 @@ def __hash__(self) -> int:
         return hash((frozenset(self.items.items()), self.fallback, frozenset(self.required_keys)))
 
     def __eq__(self, other: object) -> bool:
-        if isinstance(other, TypedDictType):
-            if frozenset(self.items.keys()) != frozenset(other.items.keys()):
-                return False
-            for (_, left_item_type, right_item_type) in self.zip(other):
-                if not left_item_type == right_item_type:
-                    return False
-            return self.fallback == other.fallback and self.required_keys == other.required_keys
-        else:
+        if not isinstance(other, TypedDictType):
             return NotImplemented
 
+        return (
+            frozenset(self.items.keys()) == frozenset(other.items.keys())
+            and all(
+                left_item_type == right_item_type
+                for (_, left_item_type, right_item_type) in self.zip(other)
+            )
+            and self.fallback == other.fallback
+            and self.required_keys == other.required_keys
+        )
+
     def serialize(self) -> JsonDict:
         return {
             ".class": "TypedDictType",
@@ -3352,11 +3351,11 @@ def is_literal_type(typ: ProperType, fallback_fullname: str, value: LiteralValue
     """Check if this type is a LiteralType with the given fallback type and value."""
     if isinstance(typ, Instance) and typ.last_known_value:
         typ = typ.last_known_value
-    if not isinstance(typ, LiteralType):
-        return False
-    if typ.fallback.type.fullname != fallback_fullname:
-        return False
-    return typ.value == value
+    return (
+        isinstance(typ, LiteralType)
+        and typ.fallback.type.fullname == fallback_fullname
+        and typ.value == value
+    )
 
 
 def is_self_type_like(typ: Type, *, is_classmethod: bool) -> bool:
diff --git a/mypyc/ir/class_ir.py b/mypyc/ir/class_ir.py
index 7f55decfd7549..f0f772306e605 100644
--- a/mypyc/ir/class_ir.py
+++ b/mypyc/ir/class_ir.py
@@ -265,10 +265,7 @@ def has_attr(self, name: str) -> bool:
         return True
 
     def is_deletable(self, name: str) -> bool:
-        for ir in self.mro:
-            if name in ir.deletable:
-                return True
-        return False
+        return any(name in ir.deletable for ir in self.mro)
 
     def is_always_defined(self, name: str) -> bool:
         if self.is_deletable(name):
diff --git a/mypyc/irbuild/prebuildvisitor.py b/mypyc/irbuild/prebuildvisitor.py
index 7d52dc8da57c6..d994539550021 100644
--- a/mypyc/irbuild/prebuildvisitor.py
+++ b/mypyc/irbuild/prebuildvisitor.py
@@ -162,12 +162,10 @@ def visit_symbol_node(self, symbol: SymbolNode) -> None:
     def is_parent(self, fitem: FuncItem, child: FuncItem) -> bool:
         # Check if child is nested within fdef (possibly indirectly
         # within multiple nested functions).
-        if child in self.nested_funcs:
-            parent = self.nested_funcs[child]
-            if parent == fitem:
-                return True
-            return self.is_parent(fitem, parent)
-        return False
+        if child not in self.nested_funcs:
+            return False
+        parent = self.nested_funcs[child]
+        return parent == fitem or self.is_parent(fitem, parent)
 
     def add_free_variable(self, symbol: SymbolNode) -> None:
         # Find the function where the symbol was (likely) first declared,
diff --git a/mypyc/irbuild/prepare.py b/mypyc/irbuild/prepare.py
index dc153ea11561e..639d1a5ea0d1c 100644
--- a/mypyc/irbuild/prepare.py
+++ b/mypyc/irbuild/prepare.py
@@ -178,15 +178,20 @@ def prepare_method_def(
 
 def is_valid_multipart_property_def(prop: OverloadedFuncDef) -> bool:
     # Checks to ensure supported property decorator semantics
-    if len(prop.items) == 2:
-        getter = prop.items[0]
-        setter = prop.items[1]
-        if isinstance(getter, Decorator) and isinstance(setter, Decorator):
-            if getter.func.is_property and len(setter.decorators) == 1:
-                if isinstance(setter.decorators[0], MemberExpr):
-                    if setter.decorators[0].name == "setter":
-                        return True
-    return False
+    if len(prop.items) != 2:
+        return False
+
+    getter = prop.items[0]
+    setter = prop.items[1]
+
+    return (
+        isinstance(getter, Decorator)
+        and isinstance(setter, Decorator)
+        and getter.func.is_property
+        and len(setter.decorators) == 1
+        and isinstance(setter.decorators[0], MemberExpr)
+        and setter.decorators[0].name == "setter"
+    )
 
 
 def can_subclass_builtin(builtin_base: str) -> bool:

From a48dd5ad7ff820da7ea1e947008fff2865e2296a Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 10 Nov 2022 15:37:07 -0800
Subject: [PATCH 031/231] Fix incompatible overrides of overloaded methods in
 concrete subclasses (#14017)

Fixes #14002
---
 mypy/checker.py                    | 17 ++++++
 test-data/unit/check-selftype.test | 86 ++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)

diff --git a/mypy/checker.py b/mypy/checker.py
index fef85d085496e..2688a611b56a9 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -1869,6 +1869,23 @@ def check_method_override_for_base_with_name(
                 original_class_or_static = False  # a variable can't be class or static
 
             if isinstance(original_type, FunctionLike):
+                active_self_type = self.scope.active_self_type()
+                if isinstance(original_type, Overloaded) and active_self_type:
+                    # If we have an overload, filter to overloads that match the self type.
+                    # This avoids false positives for concrete subclasses of generic classes,
+                    # see testSelfTypeOverrideCompatibility for an example.
+                    # It's possible we might want to do this as part of bind_and_map_method
+                    filtered_items = [
+                        item
+                        for item in original_type.items
+                        if not item.arg_types or is_subtype(active_self_type, item.arg_types[0])
+                    ]
+                    # If we don't have any filtered_items, maybe it's always a valid override
+                    # of the superclass? However if you get to that point you're in murky type
+                    # territory anyway, so we just preserve the type and have the behaviour match
+                    # that of older versions of mypy.
+                    if filtered_items:
+                        original_type = Overloaded(filtered_items)
                 original_type = self.bind_and_map_method(base_attr, original_type, defn.info, base)
                 if original_node and is_property(original_node):
                     original_type = get_property_type(original_type)
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index bfb0eb5a4d894..3d801d23a6423 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -156,6 +156,92 @@ class B2(A[T]):
     def f(self: A[bytes]) -> bytes: ...
     def f(self): ...
 
+class C(A[int]):
+    def f(self) -> int: ...
+
+class D(A[str]):
+    def f(self) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
+                             # N:      Superclass:            \
+                             # N:          @overload          \
+                             # N:          def f(self) -> str \
+                             # N:      Subclass:              \
+                             # N:          def f(self) -> int
+
+class E(A[T]):
+    def f(self) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
+                             # N:      Superclass:            \
+                             # N:          @overload          \
+                             # N:          def f(self) -> int \
+                             # N:          @overload          \
+                             # N:          def f(self) -> str \
+                             # N:      Subclass:              \
+                             # N:          def f(self) -> int
+
+
+class F(A[bytes]):
+    # Note there's an argument to be made that this is actually compatible with the supertype
+    def f(self) -> bytes: ...  # E: Signature of "f" incompatible with supertype "A" \
+                               # N:      Superclass:            \
+                               # N:          @overload          \
+                               # N:          def f(self) -> int \
+                               # N:          @overload          \
+                               # N:          def f(self) -> str \
+                               # N:      Subclass:              \
+                               # N:          def f(self) -> bytes
+
+class G(A):
+    def f(self): ...
+
+class H(A[int]):
+    def f(self): ...
+
+class I(A[int]):
+    def f(*args): ...
+
+class J(A[int]):
+    def f(self, arg) -> int: ...  # E: Signature of "f" incompatible with supertype "A" \
+                                  # N:      Superclass:            \
+                                  # N:          @overload          \
+                                  # N:          def f(self) -> int \
+                                  # N:      Subclass:              \
+                                  # N:          def f(self, arg: Any) -> int
+
+[builtins fixtures/tuple.pyi]
+
+[case testSelfTypeOverrideCompatibilityTypeVar-xfail]
+from typing import overload, TypeVar, Union
+
+AT = TypeVar("AT", bound="A")
+
+class A:
+    @overload
+    def f(self: AT, x: int) -> AT: ...
+    @overload
+    def f(self, x: str) -> None: ...
+    @overload
+    def f(self: AT) -> bytes: ...
+    def f(*a, **kw): ...
+
+class B(A):
+    @overload  # E: Signature of "f" incompatible with supertype "A" \
+               # N:      Superclass:                                 \
+               # N:          @overload                               \
+               # N:          def f(self, x: int) -> B                \
+               # N:          @overload                               \
+               # N:          def f(self, x: str) -> None             \
+               # N:          @overload                               \
+               # N:          def f(self) -> bytes                    \
+               # N:      Subclass:                                   \
+               # N:          @overload                               \
+               # N:          def f(self, x: int) -> B                \
+               # N:          @overload                               \
+               # N:          def f(self, x: str) -> None
+    def f(self, x: int) -> B: ...
+    @overload
+    def f(self, x: str) -> None: ...
+    def f(*a, **kw): ...
+[builtins fixtures/dict.pyi]
+
 [case testSelfTypeSuper]
 from typing import TypeVar, cast
 

From 70e544b1fb848448fc702e95a84edfa5ab628d3c Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 11 Nov 2022 05:01:47 -0800
Subject: [PATCH 032/231] Update --no-warn-no-return docs for empty body
 changes (#14065)

Fixes #14048

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
---
 docs/source/command_line.rst | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/docs/source/command_line.rst b/docs/source/command_line.rst
index 83d2983472be5..31d23db204ebe 100644
--- a/docs/source/command_line.rst
+++ b/docs/source/command_line.rst
@@ -448,9 +448,10 @@ potentially problematic or redundant in some way.
     are when:
 
     -   The function has a ``None`` or ``Any`` return type
-    -   The function has an empty body or a body that is just
-        ellipsis (``...``). Empty functions are often used for
-        abstract methods.
+    -   The function has an empty body and is marked as an abstract method,
+        is in a protocol class, or is in a stub file
+    -  The execution path can never return; for example, if an exception
+        is always raised
 
     Passing in :option:`--no-warn-no-return` will disable these error
     messages in all cases.

From f78d1fdc154d507353b34e7ea2037ef68de4e6fc Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 11 Nov 2022 05:29:31 -0800
Subject: [PATCH 033/231] Fix another crash with report generation on namespace
 packages (#14063)

Fixes #14046. Similar to #13733

Best reviewed with hide whitespace.
---
 mypy/report.py | 85 ++++++++++++++++++++++++--------------------------
 1 file changed, 41 insertions(+), 44 deletions(-)

diff --git a/mypy/report.py b/mypy/report.py
index 37b7497f13718..3fac2234c840e 100644
--- a/mypy/report.py
+++ b/mypy/report.py
@@ -637,51 +637,48 @@ def on_file(
         etree.SubElement(class_element, "methods")
         lines_element = etree.SubElement(class_element, "lines")
 
-        with tokenize.open(path) as input_file:
-            class_lines_covered = 0
-            class_total_lines = 0
-            for lineno, _ in enumerate(input_file, 1):
-                status = visitor.line_map.get(lineno, stats.TYPE_EMPTY)
-                hits = 0
-                branch = False
-                if status == stats.TYPE_EMPTY:
-                    continue
-                class_total_lines += 1
-                if status != stats.TYPE_ANY:
-                    class_lines_covered += 1
-                    hits = 1
-                if status == stats.TYPE_IMPRECISE:
-                    branch = True
-                file_info.counts[status] += 1
-                line_element = etree.SubElement(
-                    lines_element,
-                    "line",
-                    branch=str(branch).lower(),
-                    hits=str(hits),
-                    number=str(lineno),
-                    precision=stats.precision_names[status],
-                )
-                if branch:
-                    line_element.attrib["condition-coverage"] = "50% (1/2)"
-            class_element.attrib["branch-rate"] = "0"
-            class_element.attrib["line-rate"] = get_line_rate(
-                class_lines_covered, class_total_lines
+        class_lines_covered = 0
+        class_total_lines = 0
+        for lineno, _ in iterate_python_lines(path):
+            status = visitor.line_map.get(lineno, stats.TYPE_EMPTY)
+            hits = 0
+            branch = False
+            if status == stats.TYPE_EMPTY:
+                continue
+            class_total_lines += 1
+            if status != stats.TYPE_ANY:
+                class_lines_covered += 1
+                hits = 1
+            if status == stats.TYPE_IMPRECISE:
+                branch = True
+            file_info.counts[status] += 1
+            line_element = etree.SubElement(
+                lines_element,
+                "line",
+                branch=str(branch).lower(),
+                hits=str(hits),
+                number=str(lineno),
+                precision=stats.precision_names[status],
             )
-            # parent_module is set to whichever module contains this file.  For most files, we want
-            # to simply strip the last element off of the module.  But for __init__.py files,
-            # the module == the parent module.
-            parent_module = file_info.module.rsplit(".", 1)[0]
-            if file_info.name.endswith("__init__.py"):
-                parent_module = file_info.module
-
-            if parent_module not in self.root_package.packages:
-                self.root_package.packages[parent_module] = CoberturaPackage(parent_module)
-            current_package = self.root_package.packages[parent_module]
-            packages_to_update = [self.root_package, current_package]
-            for package in packages_to_update:
-                package.total_lines += class_total_lines
-                package.covered_lines += class_lines_covered
-            current_package.classes[class_name] = class_element
+            if branch:
+                line_element.attrib["condition-coverage"] = "50% (1/2)"
+        class_element.attrib["branch-rate"] = "0"
+        class_element.attrib["line-rate"] = get_line_rate(class_lines_covered, class_total_lines)
+        # parent_module is set to whichever module contains this file.  For most files, we want
+        # to simply strip the last element off of the module.  But for __init__.py files,
+        # the module == the parent module.
+        parent_module = file_info.module.rsplit(".", 1)[0]
+        if file_info.name.endswith("__init__.py"):
+            parent_module = file_info.module
+
+        if parent_module not in self.root_package.packages:
+            self.root_package.packages[parent_module] = CoberturaPackage(parent_module)
+        current_package = self.root_package.packages[parent_module]
+        packages_to_update = [self.root_package, current_package]
+        for package in packages_to_update:
+            package.total_lines += class_total_lines
+            package.covered_lines += class_lines_covered
+        current_package.classes[class_name] = class_element
 
     def on_finish(self) -> None:
         self.root.attrib["line-rate"] = get_line_rate(

From 67855fab376c3c2d68bcf0940b242c9b71a98156 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 11 Nov 2022 12:08:29 -0800
Subject: [PATCH 034/231] Fix crash with function redefinition (#14064)

Fixes #14027 (issue was surfaced by #13509)
---
 mypy/checker.py                     |  5 ++++-
 test-data/unit/check-functions.test | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 2688a611b56a9..e727c343aa14d 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -960,7 +960,10 @@ def _visit_func_def(self, defn: FuncDef) -> None:
                 # Function definition overrides a variable initialized via assignment or a
                 # decorated function.
                 orig_type = defn.original_def.type
-                assert orig_type is not None, f"Error checking function redefinition {defn}"
+                if orig_type is None:
+                    # If other branch is unreachable, we don't type check it and so we might
+                    # not have a type for the original definition
+                    return
                 if isinstance(orig_type, PartialType):
                     if orig_type.type is None:
                         # Ah this is a partial type. Give it the type of the function.
diff --git a/test-data/unit/check-functions.test b/test-data/unit/check-functions.test
index bb36b65f35de2..ae6424f743be4 100644
--- a/test-data/unit/check-functions.test
+++ b/test-data/unit/check-functions.test
@@ -1475,6 +1475,20 @@ else:
     @dec
     def f(): pass
 
+[case testConditionalFunctionDefinitionUnreachable]
+def bar() -> None:
+    if False:
+        foo = 1
+    else:
+        def foo(obj): ...
+
+def baz() -> None:
+    if False:
+        foo: int = 1
+    else:
+        def foo(obj): ...  # E: Incompatible redefinition (redefinition with type "Callable[[Any], Any]", original type "int")
+[builtins fixtures/tuple.pyi]
+
 [case testConditionalRedefinitionOfAnUnconditionalFunctionDefinition1]
 from typing import Any
 def f(x: str) -> None: pass

From 33d2b894bd2daff5e17074a37df9bdfe0a6c5518 Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Sun, 13 Nov 2022 21:56:34 +0100
Subject: [PATCH 035/231] Add error-code for `truthy-iterable` (#13762)

`Iterable` does not implement `__len__`, so passing a `Generator` would
always evaluate to `true`. Suggest `Collection` as alternative.

In most cases this isn't an issue as the function is often called with
`list` anyway. However, the dedicated check can pinpoint subtle errors
that might get unnoticed otherwise.
---
 docs/source/error_code_list2.rst        | 28 ++++++++++++-------------
 mypy/checker.py                         |  8 +++++++
 mypy/errorcodes.py                      |  6 ++++++
 mypy/message_registry.py                |  4 ++++
 mypy/semanal.py                         |  6 ++++--
 mypyc/test-data/irbuild-statements.test |  4 ++--
 test-data/unit/check-errorcodes.test    |  7 +++++++
 7 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/docs/source/error_code_list2.rst b/docs/source/error_code_list2.rst
index cac19e7053614..0a2d8a8c5c5cd 100644
--- a/docs/source/error_code_list2.rst
+++ b/docs/source/error_code_list2.rst
@@ -231,31 +231,29 @@ since unless implemented by a sub-type, the expression will always evaluate to t
     if foo:
        ...
 
+The check is similar in concept to ensuring that an expression's type implements an expected interface (e.g. ``Sized``),
+except that attempting to invoke an undefined method (e.g. ``__len__``) results in an error,
+while attempting to evaluate an object in boolean context without a concrete implementation results in a truthy value.
 
-This check might falsely imply an error. For example, ``Iterable`` does not implement
-``__len__`` and so this code will be flagged:
 
-.. code-block:: python
+Check that iterable is not implicitly true in boolean context [truthy-iterable]
+-------------------------------------------------------------------------------
 
-    # Use "mypy -enable-error-code truthy-bool ..."
+``Iterable`` does not implement ``__len__`` and so this code will be flagged:
+
+.. code-block:: python
 
     from typing import Iterable
 
-    def transform(items: Iterable[int]) -> Iterable[int]:
-        # Error: "items" has type "Iterable[int]" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
+    def transform(items: Iterable[int]) -> list[int]:
+        # Error: "items" has type "Iterable[int]" which can always be true in boolean context. Consider using "Collection[int]" instead.  [truthy-iterable]
         if not items:
             return [42]
         return [x + 1 for x in items]
 
-
-
-If called as ``transform((int(s) for s in []))``, this function would not return ``[42]`` unlike what the author
-might have intended. Of course it's possible that ``transform`` is only passed ``list`` objects, and so there is
-no error in practice. In such case, it might be prudent to annotate ``items: Sequence[int]``.
-
-This is similar in concept to ensuring that an expression's type implements an expected interface (e.g. ``Sized``),
-except that attempting to invoke an undefined method (e.g. ``__len__``) results in an error,
-while attempting to evaluate an object in boolean context without a concrete implementation results in a truthy value.
+If called with a ``Generator`` like ``int(x) for x in []``, this function would not return ``[42]`` unlike
+what the author might have intended. Of course it's possible that ``transform`` is only passed ``list`` objects,
+and so there is no error in practice. In such case, it is recommended to annotate ``items: Collection[int]``.
 
 
 Check that function isn't used in boolean context [truthy-function]
diff --git a/mypy/checker.py b/mypy/checker.py
index e727c343aa14d..aec2574e0adaa 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -5106,6 +5106,14 @@ def format_expr_type() -> str:
             self.fail(message_registry.FUNCTION_ALWAYS_TRUE.format(format_type(t)), expr)
         elif isinstance(t, UnionType):
             self.fail(message_registry.TYPE_ALWAYS_TRUE_UNIONTYPE.format(format_expr_type()), expr)
+        elif isinstance(t, Instance) and t.type.fullname == "typing.Iterable":
+            _, info = self.make_fake_typeinfo("typing", "Collection", "Collection", [])
+            self.fail(
+                message_registry.ITERABLE_ALWAYS_TRUE.format(
+                    format_expr_type(), format_type(Instance(info, t.args))
+                ),
+                expr,
+            )
         else:
             self.fail(message_registry.TYPE_ALWAYS_TRUE.format(format_expr_type()), expr)
 
diff --git a/mypy/errorcodes.py b/mypy/errorcodes.py
index f2a74c332b2e6..3aee6881067e2 100644
--- a/mypy/errorcodes.py
+++ b/mypy/errorcodes.py
@@ -160,6 +160,12 @@ def __str__(self) -> str:
     "Warn about function that always evaluate to true in boolean contexts",
     "General",
 )
+TRUTHY_ITERABLE: Final[ErrorCode] = ErrorCode(
+    "truthy-iterable",
+    "Warn about Iterable expressions that could always evaluate to true in boolean contexts",
+    "General",
+    default_enabled=False,
+)
 NAME_MATCH: Final = ErrorCode(
     "name-match", "Check that type definition has consistent naming", "General"
 )
diff --git a/mypy/message_registry.py b/mypy/message_registry.py
index 18acb2cd7a71f..219c445497e98 100644
--- a/mypy/message_registry.py
+++ b/mypy/message_registry.py
@@ -153,6 +153,10 @@ def with_additional_msg(self, info: str) -> ErrorMessage:
 FUNCTION_ALWAYS_TRUE: Final = ErrorMessage(
     "Function {} could always be true in boolean context", code=codes.TRUTHY_FUNCTION
 )
+ITERABLE_ALWAYS_TRUE: Final = ErrorMessage(
+    "{} which can always be true in boolean context. Consider using {} instead.",
+    code=codes.TRUTHY_ITERABLE,
+)
 NOT_CALLABLE: Final = "{} not callable"
 TYPE_MUST_BE_USED: Final = "Value of type {} must be used"
 
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 77555648ba7eb..ce88d033e01c2 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -51,7 +51,7 @@
 from __future__ import annotations
 
 from contextlib import contextmanager
-from typing import Any, Callable, Iterable, Iterator, List, TypeVar, cast
+from typing import Any, Callable, Collection, Iterable, Iterator, List, TypeVar, cast
 from typing_extensions import Final, TypeAlias as _TypeAlias
 
 from mypy import errorcodes as codes, message_registry
@@ -6202,7 +6202,9 @@ def add_plugin_dependency(self, trigger: str, target: str | None = None) -> None
             target = self.scope.current_target()
         self.cur_mod_node.plugin_deps.setdefault(trigger, set()).add(target)
 
-    def add_type_alias_deps(self, aliases_used: Iterable[str], target: str | None = None) -> None:
+    def add_type_alias_deps(
+        self, aliases_used: Collection[str], target: str | None = None
+    ) -> None:
         """Add full names of type aliases on which the current node depends.
 
         This is used by fine-grained incremental mode to re-check the corresponding nodes.
diff --git a/mypyc/test-data/irbuild-statements.test b/mypyc/test-data/irbuild-statements.test
index ab947c956b742..090c7ed9f3df3 100644
--- a/mypyc/test-data/irbuild-statements.test
+++ b/mypyc/test-data/irbuild-statements.test
@@ -1006,9 +1006,9 @@ L5:
     return 1
 
 [case testForZip]
-from typing import List, Iterable
+from typing import List, Iterable, Sequence
 
-def f(a: List[int], b: Iterable[bool]) -> None:
+def f(a: List[int], b: Sequence[bool]) -> None:
     for x, y in zip(a, b):
         if b:
             x = 1
diff --git a/test-data/unit/check-errorcodes.test b/test-data/unit/check-errorcodes.test
index 81b8948be14a6..798c52629a35b 100644
--- a/test-data/unit/check-errorcodes.test
+++ b/test-data/unit/check-errorcodes.test
@@ -857,6 +857,13 @@ if not f:  # E: Function "Callable[[], Any]" could always be true in boolean con
     pass
 conditional_result = 'foo' if f else 'bar'  # E: Function "Callable[[], Any]" could always be true in boolean context  [truthy-function]
 
+[case testTruthyIterable]
+# flags: --strict-optional --enable-error-code truthy-iterable
+from typing import Iterable
+def func(var: Iterable[str]) -> None:
+    if var:  # E: "var" has type "Iterable[str]" which can always be true in boolean context. Consider using "Collection[str]" instead.  [truthy-iterable]
+        ...
+
 [case testNoOverloadImplementation]
 from typing import overload
 

From 47a435f38d96892b1f6a1fe543b0abe3ccca9c53 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sun, 13 Nov 2022 20:59:44 +0000
Subject: [PATCH 036/231] Delete Python 2 test fixtures (#14083)

It looks like these are not used anymore (we will see if tests pass).
---
 test-data/unit/fixtures/bool_py2.pyi          | 16 -----
 test-data/unit/fixtures/floatdict_python2.pyi | 68 -------------------
 .../unit/fixtures/module_all_python2.pyi      | 15 ----
 test-data/unit/fixtures/property_py2.pyi      | 21 ------
 test-data/unit/fixtures/python2.pyi           | 38 -----------
 5 files changed, 158 deletions(-)
 delete mode 100644 test-data/unit/fixtures/bool_py2.pyi
 delete mode 100644 test-data/unit/fixtures/floatdict_python2.pyi
 delete mode 100644 test-data/unit/fixtures/module_all_python2.pyi
 delete mode 100644 test-data/unit/fixtures/property_py2.pyi
 delete mode 100644 test-data/unit/fixtures/python2.pyi

diff --git a/test-data/unit/fixtures/bool_py2.pyi b/test-data/unit/fixtures/bool_py2.pyi
deleted file mode 100644
index b2c935132d57e..0000000000000
--- a/test-data/unit/fixtures/bool_py2.pyi
+++ /dev/null
@@ -1,16 +0,0 @@
-# builtins stub used in boolean-related test cases.
-from typing import Generic, TypeVar
-import sys
-T = TypeVar('T')
-
-class object:
-    def __init__(self) -> None: pass
-
-class type: pass
-class tuple(Generic[T]): pass
-class function: pass
-class bool: pass
-class int: pass
-class str: pass
-class unicode: pass
-class ellipsis: pass
diff --git a/test-data/unit/fixtures/floatdict_python2.pyi b/test-data/unit/fixtures/floatdict_python2.pyi
deleted file mode 100644
index f177355d5d4bf..0000000000000
--- a/test-data/unit/fixtures/floatdict_python2.pyi
+++ /dev/null
@@ -1,68 +0,0 @@
-from typing import TypeVar, Generic, Iterable, Iterator, Mapping, Tuple, overload, Optional, Union
-
-T = TypeVar('T')
-KT = TypeVar('KT')
-VT = TypeVar('VT')
-
-Any = 0
-
-class object:
-    def __init__(self) -> None: pass
-
-class type:
-    def __init__(self, x: Any) -> None: pass
-
-class str:
-    def __add__(self, other: 'str') -> 'str': pass
-    def __rmul__(self, n: int) -> str: ...
-
-class unicode: pass
-
-class tuple(Generic[T]): pass
-class slice: pass
-class function: pass
-
-class ellipsis: pass
-
-class list(Iterable[T], Generic[T]):
-    @overload
-    def __init__(self) -> None: pass
-    @overload
-    def __init__(self, x: Iterable[T]) -> None: pass
-    def __iter__(self) -> Iterator[T]: pass
-    def __add__(self, x: list[T]) -> list[T]: pass
-    def __mul__(self, x: int) -> list[T]: pass
-    def __getitem__(self, x: int) -> T: pass
-    def append(self, x: T) -> None: pass
-    def extend(self, x: Iterable[T]) -> None: pass
-
-class dict(Mapping[KT, VT], Generic[KT, VT]):
-    @overload
-    def __init__(self, **kwargs: VT) -> None: pass
-    @overload
-    def __init__(self, arg: Iterable[Tuple[KT, VT]], **kwargs: VT) -> None: pass
-    def __setitem__(self, k: KT, v: VT) -> None: pass
-    def __getitem__(self, k: KT) -> VT: pass
-    def __iter__(self) -> Iterator[KT]: pass
-    def update(self, a: Mapping[KT, VT]) -> None: pass
-    @overload
-    def get(self, k: KT) -> Optional[VT]: pass
-    @overload
-    def get(self, k: KT, default: Union[KT, T]) -> Union[VT, T]: pass
-
-
-class int:
-    def __float__(self) -> float: ...
-    def __int__(self) -> int: ...
-    def __mul__(self, x: int) -> int: ...
-    def __rmul__(self, x: int) -> int: ...
-    def __truediv__(self, x: int) -> int: ...
-    def __rtruediv__(self, x: int) -> int: ...
-
-class float:
-    def __float__(self) -> float: ...
-    def __int__(self) -> int: ...
-    def __mul__(self, x: float) -> float: ...
-    def __rmul__(self, x: float) -> float: ...
-    def __truediv__(self, x: float) -> float: ...
-    def __rtruediv__(self, x: float) -> float: ...
diff --git a/test-data/unit/fixtures/module_all_python2.pyi b/test-data/unit/fixtures/module_all_python2.pyi
deleted file mode 100644
index 989333c5f41a7..0000000000000
--- a/test-data/unit/fixtures/module_all_python2.pyi
+++ /dev/null
@@ -1,15 +0,0 @@
-from typing import Generic, Sequence, TypeVar
-_T = TypeVar('_T')
-
-class object:
-    def __init__(self) -> None: pass
-class type: pass
-class function: pass
-class int: pass
-class str: pass
-class unicode: pass
-class list(Generic[_T], Sequence[_T]):
-    def append(self, x: _T): pass
-    def extend(self, x: Sequence[_T]): pass
-    def __add__(self, rhs: Sequence[_T]) -> list[_T]: pass
-class tuple(Generic[_T]): pass
diff --git a/test-data/unit/fixtures/property_py2.pyi b/test-data/unit/fixtures/property_py2.pyi
deleted file mode 100644
index 3b0ab69cf43f1..0000000000000
--- a/test-data/unit/fixtures/property_py2.pyi
+++ /dev/null
@@ -1,21 +0,0 @@
-import typing
-
-_T = typing.TypeVar('_T')
-
-class object:
-    def __init__(self) -> None: pass
-
-class type:
-    def __init__(self, x: typing.Any) -> None: pass
-
-class function: pass
-
-property = object()  # Dummy definition
-
-class int: pass
-class str: pass
-class unicode: pass
-class bool: pass
-class ellipsis: pass
-
-class tuple(typing.Generic[_T]): pass
diff --git a/test-data/unit/fixtures/python2.pyi b/test-data/unit/fixtures/python2.pyi
deleted file mode 100644
index 51af59c8bd455..0000000000000
--- a/test-data/unit/fixtures/python2.pyi
+++ /dev/null
@@ -1,38 +0,0 @@
-from typing import Generic, Iterable, TypeVar, Sequence, Iterator
-
-class object:
-    def __init__(self) -> None: pass
-    def __eq__(self, other: object) -> bool: pass
-    def __ne__(self, other: object) -> bool: pass
-
-class type:
-    def __init__(self, x) -> None: pass
-
-class function: pass
-
-class int: pass
-class float: pass
-class str:
-    def format(self, *args, **kwars) -> str: ...
-class unicode:
-    def format(self, *args, **kwars) -> unicode: ...
-class bool(int): pass
-
-bytes = str
-
-T = TypeVar('T')
-S = TypeVar('S')
-class list(Iterable[T], Generic[T]):
-    def __iter__(self) -> Iterator[T]: pass
-    def __getitem__(self, item: int) -> T: pass
-class tuple(Iterable[T]):
-    def __iter__(self) -> Iterator[T]: pass
-class dict(Generic[T, S]): pass
-
-class bytearray(Sequence[int]):
-    def __init__(self, string: str) -> None: pass
-    def __contains__(self, item: object) -> bool: pass
-    def __iter__(self) -> Iterator[int]: pass
-    def __getitem__(self, item: int) -> int: pass
-
-# Definition of None is implicit

From 57ce73d4a39d3293eaac43c7a950e2c1ac30e2c9 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sun, 13 Nov 2022 23:03:24 +0000
Subject: [PATCH 037/231] Support additinal attributes in callback protocols
 (#14084)

Fixes https://github.com/python/mypy/issues/10976
Fixes https://github.com/python/mypy/issues/10403

This is quite straightforward. Note that we will not allow _arbitrary_
attributes on functions, only those that are defined in
`types.FunctionType` (or more precisely `builtins.function` that is
identical). We have a separate issue for arbitrary attributes
https://github.com/python/mypy/issues/2087
---
 mypy/checker.py                          |  7 ++--
 mypy/constraints.py                      |  9 +++--
 mypy/messages.py                         | 27 ++++++++------
 mypy/subtypes.py                         | 25 ++++++++++---
 mypy/test/testtypegen.py                 |  4 +-
 test-data/unit/check-protocols.test      | 47 ++++++++++++++++++++++++
 test-data/unit/fine-grained-inspect.test |  4 +-
 test-data/unit/fixtures/tuple.pyi        |  3 +-
 test-data/unit/lib-stub/builtins.pyi     |  3 +-
 9 files changed, 100 insertions(+), 29 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index aec2574e0adaa..8b1c8d3464fba 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -5883,7 +5883,7 @@ def check_subtype(
         if (
             isinstance(supertype, Instance)
             and supertype.type.is_protocol
-            and isinstance(subtype, (Instance, TupleType, TypedDictType))
+            and isinstance(subtype, (CallableType, Instance, TupleType, TypedDictType))
         ):
             self.msg.report_protocol_problems(subtype, supertype, context, code=msg.code)
         if isinstance(supertype, CallableType) and isinstance(subtype, Instance):
@@ -5891,10 +5891,11 @@ def check_subtype(
             if call:
                 self.msg.note_call(subtype, call, context, code=msg.code)
         if isinstance(subtype, (CallableType, Overloaded)) and isinstance(supertype, Instance):
-            if supertype.type.is_protocol and supertype.type.protocol_members == ["__call__"]:
+            if supertype.type.is_protocol and "__call__" in supertype.type.protocol_members:
                 call = find_member("__call__", supertype, subtype, is_operator=True)
                 assert call is not None
-                self.msg.note_call(supertype, call, context, code=msg.code)
+                if not is_subtype(subtype, call, options=self.options):
+                    self.msg.note_call(supertype, call, context, code=msg.code)
         self.check_possible_missing_await(subtype, supertype, context)
         return False
 
diff --git a/mypy/constraints.py b/mypy/constraints.py
index 2a641bf27ed57..7123c590b7efb 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -553,7 +553,7 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
         original_actual = actual = self.actual
         res: list[Constraint] = []
         if isinstance(actual, (CallableType, Overloaded)) and template.type.is_protocol:
-            if template.type.protocol_members == ["__call__"]:
+            if "__call__" in template.type.protocol_members:
                 # Special case: a generic callback protocol
                 if not any(template == t for t in template.type.inferring):
                     template.type.inferring.append(template)
@@ -565,7 +565,6 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                         subres = infer_constraints(call, actual, self.direction)
                         res.extend(subres)
                     template.type.inferring.pop()
-                    return res
         if isinstance(actual, CallableType) and actual.fallback is not None:
             if actual.is_type_obj() and template.type.is_protocol:
                 ret_type = get_proper_type(actual.ret_type)
@@ -815,7 +814,7 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                 # because some type may be considered a subtype of a protocol
                 # due to _promote, but still not implement the protocol.
                 not any(template == t for t in reversed(template.type.inferring))
-                and mypy.subtypes.is_protocol_implementation(instance, erased)
+                and mypy.subtypes.is_protocol_implementation(instance, erased, skip=["__call__"])
             ):
                 template.type.inferring.append(template)
                 res.extend(
@@ -831,7 +830,7 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                 and
                 # We avoid infinite recursion for structural subtypes also here.
                 not any(instance == i for i in reversed(instance.type.inferring))
-                and mypy.subtypes.is_protocol_implementation(erased, instance)
+                and mypy.subtypes.is_protocol_implementation(erased, instance, skip=["__call__"])
             ):
                 instance.type.inferring.append(instance)
                 res.extend(
@@ -887,6 +886,8 @@ def infer_constraints_from_protocol_members(
             inst = mypy.subtypes.find_member(member, instance, subtype, class_obj=class_obj)
             temp = mypy.subtypes.find_member(member, template, subtype)
             if inst is None or temp is None:
+                if member == "__call__":
+                    continue
                 return []  # See #11020
             # The above is safe since at this point we know that 'instance' is a subtype
             # of (erased) 'template', therefore it defines all protocol members
diff --git a/mypy/messages.py b/mypy/messages.py
index e11ee9d0f7f29..75871d9b55210 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -1866,6 +1866,7 @@ def report_protocol_problems(
 
         class_obj = False
         is_module = False
+        skip = []
         if isinstance(subtype, TupleType):
             if not isinstance(subtype.partial_fallback, Instance):
                 return
@@ -1880,20 +1881,22 @@ def report_protocol_problems(
             class_obj = True
             subtype = subtype.item
         elif isinstance(subtype, CallableType):
-            if not subtype.is_type_obj():
-                return
-            ret_type = get_proper_type(subtype.ret_type)
-            if isinstance(ret_type, TupleType):
-                ret_type = ret_type.partial_fallback
-            if not isinstance(ret_type, Instance):
-                return
-            class_obj = True
-            subtype = ret_type
+            if subtype.is_type_obj():
+                ret_type = get_proper_type(subtype.ret_type)
+                if isinstance(ret_type, TupleType):
+                    ret_type = ret_type.partial_fallback
+                if not isinstance(ret_type, Instance):
+                    return
+                class_obj = True
+                subtype = ret_type
+            else:
+                subtype = subtype.fallback
+                skip = ["__call__"]
         if subtype.extra_attrs and subtype.extra_attrs.mod_name:
             is_module = True
 
         # Report missing members
-        missing = get_missing_protocol_members(subtype, supertype)
+        missing = get_missing_protocol_members(subtype, supertype, skip=skip)
         if (
             missing
             and len(missing) < len(supertype.type.protocol_members)
@@ -2605,13 +2608,15 @@ def variance_string(variance: int) -> str:
         return "invariant"
 
 
-def get_missing_protocol_members(left: Instance, right: Instance) -> list[str]:
+def get_missing_protocol_members(left: Instance, right: Instance, skip: list[str]) -> list[str]:
     """Find all protocol members of 'right' that are not implemented
     (i.e. completely missing) in 'left'.
     """
     assert right.type.is_protocol
     missing: list[str] = []
     for member in right.type.protocol_members:
+        if member in skip:
+            continue
         if not find_member(member, left, left):
             missing.append(member)
     return missing
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 9a4982f5b8ecb..f928e1cc7918b 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -678,13 +678,16 @@ def visit_callable_type(self, left: CallableType) -> bool:
         elif isinstance(right, Overloaded):
             return all(self._is_subtype(left, item) for item in right.items)
         elif isinstance(right, Instance):
-            if right.type.is_protocol and right.type.protocol_members == ["__call__"]:
-                # OK, a callable can implement a protocol with a single `__call__` member.
+            if right.type.is_protocol and "__call__" in right.type.protocol_members:
+                # OK, a callable can implement a protocol with a `__call__` member.
                 # TODO: we should probably explicitly exclude self-types in this case.
                 call = find_member("__call__", right, left, is_operator=True)
                 assert call is not None
                 if self._is_subtype(left, call):
-                    return True
+                    if len(right.type.protocol_members) == 1:
+                        return True
+                    if is_protocol_implementation(left.fallback, right, skip=["__call__"]):
+                        return True
             if right.type.is_protocol and left.is_type_obj():
                 ret_type = get_proper_type(left.ret_type)
                 if isinstance(ret_type, TupleType):
@@ -792,12 +795,15 @@ def visit_literal_type(self, left: LiteralType) -> bool:
     def visit_overloaded(self, left: Overloaded) -> bool:
         right = self.right
         if isinstance(right, Instance):
-            if right.type.is_protocol and right.type.protocol_members == ["__call__"]:
+            if right.type.is_protocol and "__call__" in right.type.protocol_members:
                 # same as for CallableType
                 call = find_member("__call__", right, left, is_operator=True)
                 assert call is not None
                 if self._is_subtype(left, call):
-                    return True
+                    if len(right.type.protocol_members) == 1:
+                        return True
+                    if is_protocol_implementation(left.fallback, right, skip=["__call__"]):
+                        return True
             return self._is_subtype(left.fallback, right)
         elif isinstance(right, CallableType):
             for item in left.items:
@@ -938,7 +944,11 @@ def pop_on_exit(stack: list[tuple[T, T]], left: T, right: T) -> Iterator[None]:
 
 
 def is_protocol_implementation(
-    left: Instance, right: Instance, proper_subtype: bool = False, class_obj: bool = False
+    left: Instance,
+    right: Instance,
+    proper_subtype: bool = False,
+    class_obj: bool = False,
+    skip: list[str] | None = None,
 ) -> bool:
     """Check whether 'left' implements the protocol 'right'.
 
@@ -958,10 +968,13 @@ def f(self) -> A: ...
     as well.
     """
     assert right.type.is_protocol
+    if skip is None:
+        skip = []
     # We need to record this check to generate protocol fine-grained dependencies.
     TypeState.record_protocol_subtype_check(left.type, right.type)
     # nominal subtyping currently ignores '__init__' and '__new__' signatures
     members_not_to_check = {"__init__", "__new__"}
+    members_not_to_check.update(skip)
     # Trivial check that circumvents the bug described in issue 9771:
     if left.type.is_protocol:
         members_right = set(right.type.protocol_members) - members_not_to_check
diff --git a/mypy/test/testtypegen.py b/mypy/test/testtypegen.py
index db155a3379802..22ef4272e933f 100644
--- a/mypy/test/testtypegen.py
+++ b/mypy/test/testtypegen.py
@@ -7,7 +7,7 @@
 from mypy import build
 from mypy.errors import CompileError
 from mypy.modulefinder import BuildSource
-from mypy.nodes import NameExpr
+from mypy.nodes import NameExpr, TempNode
 from mypy.options import Options
 from mypy.test.config import test_temp_dir
 from mypy.test.data import DataDrivenTestCase, DataSuite
@@ -54,6 +54,8 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
             # Filter nodes that should be included in the output.
             keys = []
             for node in nodes:
+                if isinstance(node, TempNode):
+                    continue
                 if node.line != -1 and map[node]:
                     if ignore_node(node) or node in ignored:
                         continue
diff --git a/test-data/unit/check-protocols.test b/test-data/unit/check-protocols.test
index 113b2000fc227..77c14b92b2618 100644
--- a/test-data/unit/check-protocols.test
+++ b/test-data/unit/check-protocols.test
@@ -2642,6 +2642,53 @@ reveal_type([b, a])  # N: Revealed type is "builtins.list[def (x: def (__main__.
 [builtins fixtures/list.pyi]
 [out]
 
+[case testCallbackProtocolFunctionAttributesSubtyping]
+from typing import Protocol
+
+class A(Protocol):
+    __name__: str
+    def __call__(self) -> str: ...
+
+class B1(Protocol):
+    __name__: int
+    def __call__(self) -> str: ...
+
+class B2(Protocol):
+    __name__: str
+    def __call__(self) -> int: ...
+
+class B3(Protocol):
+    __name__: str
+    extra_stuff: int
+    def __call__(self) -> str: ...
+
+def f() -> str: ...
+
+reveal_type(f.__name__)  # N: Revealed type is "builtins.str"
+a: A = f  # OK
+b1: B1 = f  # E: Incompatible types in assignment (expression has type "Callable[[], str]", variable has type "B1") \
+            # N: Following member(s) of "function" have conflicts: \
+            # N:     __name__: expected "int", got "str"
+b2: B2 = f  # E: Incompatible types in assignment (expression has type "Callable[[], str]", variable has type "B2") \
+            # N: "B2.__call__" has type "Callable[[], int]"
+b3: B3 = f  # E: Incompatible types in assignment (expression has type "Callable[[], str]", variable has type "B3") \
+            # N: "function" is missing following "B3" protocol member: \
+            # N:     extra_stuff
+
+[case testCallbackProtocolFunctionAttributesInference]
+from typing import Protocol, TypeVar, Generic, Tuple
+
+T = TypeVar("T")
+S = TypeVar("S", covariant=True)
+class A(Protocol[T, S]):
+    __name__: T
+    def __call__(self) -> S: ...
+
+def f() -> int: ...
+def test(func: A[T, S]) -> Tuple[T, S]: ...
+reveal_type(test(f))  # N: Revealed type is "Tuple[builtins.str, builtins.int]"
+[builtins fixtures/tuple.pyi]
+
 [case testProtocolsAlwaysABCs]
 from typing import Protocol
 
diff --git a/test-data/unit/fine-grained-inspect.test b/test-data/unit/fine-grained-inspect.test
index a52db39596336..8574477d82722 100644
--- a/test-data/unit/fine-grained-inspect.test
+++ b/test-data/unit/fine-grained-inspect.test
@@ -52,8 +52,8 @@ class Meta(type):
 ==
 {"C": ["meth", "x"]}
 {"C": ["meth", "x"], "Meta": ["y"], "type": ["__init__"]}
-{}
-{"object": ["__init__"]}
+{"function": ["__name__"]}
+{"function": ["__name__"], "object": ["__init__"]}
 
 [case testInspectDefBasic]
 # inspect2: --show=definition foo.py:5:5
diff --git a/test-data/unit/fixtures/tuple.pyi b/test-data/unit/fixtures/tuple.pyi
index 5c69a4ad1eb56..14e6683751755 100644
--- a/test-data/unit/fixtures/tuple.pyi
+++ b/test-data/unit/fixtures/tuple.pyi
@@ -23,7 +23,8 @@ class tuple(Sequence[Tco], Generic[Tco]):
     def __rmul__(self, n: int) -> Tuple[Tco, ...]: pass
     def __add__(self, x: Tuple[Tco, ...]) -> Tuple[Tco, ...]: pass
     def count(self, obj: object) -> int: pass
-class function: pass
+class function:
+    __name__: str
 class ellipsis: pass
 class classmethod: pass
 
diff --git a/test-data/unit/lib-stub/builtins.pyi b/test-data/unit/lib-stub/builtins.pyi
index 8c4f504fb2e72..82e0f6135614d 100644
--- a/test-data/unit/lib-stub/builtins.pyi
+++ b/test-data/unit/lib-stub/builtins.pyi
@@ -17,7 +17,8 @@ class float: pass
 class str: pass
 class bytes: pass
 
-class function: pass
+class function:
+    __name__: str
 class ellipsis: pass
 
 from typing import Generic, Sequence, TypeVar

From cf59b82996db6bbe5c6535f338ba1fac22d67975 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 14 Nov 2022 08:43:11 +0000
Subject: [PATCH 038/231] Fix crash on partial type inference within a lambda
 (#14087)

Fixes #9654

Seems to be quite straightforward. Erased types should never be stored
on variables, it is just a temporary thing for nested generic calls.
---
 mypy/checker.py                       | 15 ++++++++++++---
 test-data/unit/check-incremental.test | 26 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 8b1c8d3464fba..c104a75e8cd50 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -178,6 +178,7 @@
     AnyType,
     CallableType,
     DeletedType,
+    ErasedType,
     FunctionLike,
     Instance,
     LiteralType,
@@ -7040,11 +7041,15 @@ def is_valid_inferred_type(typ: Type, is_lvalue_final: bool = False) -> bool:
         return is_lvalue_final
     elif isinstance(proper_type, UninhabitedType):
         return False
-    return not typ.accept(NothingSeeker())
+    return not typ.accept(InvalidInferredTypes())
 
 
-class NothingSeeker(TypeQuery[bool]):
-    """Find any <nothing> types resulting from failed (ambiguous) type inference."""
+class InvalidInferredTypes(TypeQuery[bool]):
+    """Find type components that are not valid for an inferred type.
+
+    These include <Erased> type, and any <nothing> types resulting from failed
+    (ambiguous) type inference.
+    """
 
     def __init__(self) -> None:
         super().__init__(any)
@@ -7052,6 +7057,10 @@ def __init__(self) -> None:
     def visit_uninhabited_type(self, t: UninhabitedType) -> bool:
         return t.ambiguous
 
+    def visit_erased_type(self, t: ErasedType) -> bool:
+        # This can happen inside a lambda.
+        return True
+
 
 class SetNothingToAny(TypeTranslator):
     """Replace all ambiguous <nothing> types with Any (to avoid spurious extra errors)."""
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index 3ec0ed2c63f58..131cd039a4679 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -6286,3 +6286,29 @@ class C: ...
 [out]
 [out2]
 [out3]
+
+[case testNoCrashOnPartialLambdaInference]
+import m
+[file m.py]
+from typing import TypeVar, Callable
+
+V = TypeVar("V")
+def apply(val: V, func: Callable[[V], None]) -> None:
+    return func(val)
+
+xs = []
+apply(0, lambda a: xs.append(a))
+[file m.py.2]
+from typing import TypeVar, Callable
+
+V = TypeVar("V")
+def apply(val: V, func: Callable[[V], None]) -> None:
+    return func(val)
+
+xs = []
+apply(0, lambda a: xs.append(a))
+reveal_type(xs)
+[builtins fixtures/list.pyi]
+[out]
+[out2]
+tmp/m.py:9: note: Revealed type is "builtins.list[builtins.int]"

From dd0503e28d9f3dbfa8fa74e5bfdb4ce438646a80 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 14 Nov 2022 11:04:18 +0000
Subject: [PATCH 039/231] Don't consider a branch unreachable if there is
 possible promotion (#14077)

Fixes #14030

FWIW this looks like an acceptable compromise after discussions in the
issue. Also it is easy to implement. Let's see what `mypy_primer` will
show.
---
 mypy/checker.py                          |  31 ++++--
 mypy/join.py                             |  14 ++-
 mypy/meet.py                             |  10 +-
 test-data/unit/check-classes.test        |   2 +-
 test-data/unit/check-isinstance.test     |   2 +-
 test-data/unit/check-type-promotion.test | 133 +++++++++++++++++++++++
 test-data/unit/fixtures/primitives.pyi   |   8 +-
 7 files changed, 180 insertions(+), 20 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index c104a75e8cd50..ea7f46af5adb6 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -4824,7 +4824,7 @@ def make_fake_typeinfo(
         return cdef, info
 
     def intersect_instances(
-        self, instances: tuple[Instance, Instance], ctx: Context
+        self, instances: tuple[Instance, Instance], errors: list[tuple[str, str]]
     ) -> Instance | None:
         """Try creating an ad-hoc intersection of the given instances.
 
@@ -4851,6 +4851,17 @@ def intersect_instances(
         curr_module = self.scope.stack[0]
         assert isinstance(curr_module, MypyFile)
 
+        # First, retry narrowing while allowing promotions (they are disabled by default
+        # for isinstance() checks, etc). This way we will still type-check branches like
+        # x: complex = 1
+        # if isinstance(x, int):
+        #     ...
+        left, right = instances
+        if is_proper_subtype(left, right, ignore_promotions=False):
+            return left
+        if is_proper_subtype(right, left, ignore_promotions=False):
+            return right
+
         def _get_base_classes(instances_: tuple[Instance, Instance]) -> list[Instance]:
             base_classes_ = []
             for inst in instances_:
@@ -4891,17 +4902,10 @@ def _make_fake_typeinfo_and_full_name(
                     self.check_multiple_inheritance(info)
             info.is_intersection = True
         except MroError:
-            if self.should_report_unreachable_issues():
-                self.msg.impossible_intersection(
-                    pretty_names_list, "inconsistent method resolution order", ctx
-                )
+            errors.append((pretty_names_list, "inconsistent method resolution order"))
             return None
-
         if local_errors.has_new_errors():
-            if self.should_report_unreachable_issues():
-                self.msg.impossible_intersection(
-                    pretty_names_list, "incompatible method signatures", ctx
-                )
+            errors.append((pretty_names_list, "incompatible method signatures"))
             return None
 
         curr_module.names[full_name] = SymbolTableNode(GDEF, info)
@@ -6355,15 +6359,20 @@ def conditional_types_with_intersection(
             possible_target_types.append(item)
 
         out = []
+        errors: list[tuple[str, str]] = []
         for v in possible_expr_types:
             if not isinstance(v, Instance):
                 return yes_type, no_type
             for t in possible_target_types:
-                intersection = self.intersect_instances((v, t), ctx)
+                intersection = self.intersect_instances((v, t), errors)
                 if intersection is None:
                     continue
                 out.append(intersection)
         if len(out) == 0:
+            # Only report errors if no element in the union worked.
+            if self.should_report_unreachable_issues():
+                for types, reason in errors:
+                    self.msg.impossible_intersection(types, reason, ctx)
             return UninhabitedType(), expr_type
         new_yes_type = make_simplified_union(out)
         return new_yes_type, expr_type
diff --git a/mypy/join.py b/mypy/join.py
index d54febd7462a3..84aa03f8eeba8 100644
--- a/mypy/join.py
+++ b/mypy/join.py
@@ -141,8 +141,11 @@ def join_instances_via_supertype(self, t: Instance, s: Instance) -> ProperType:
 
 
 def join_simple(declaration: Type | None, s: Type, t: Type) -> ProperType:
-    """Return a simple least upper bound given the declared type."""
-    # TODO: check infinite recursion for aliases here?
+    """Return a simple least upper bound given the declared type.
+
+    This function should be only used by binder, and should not recurse.
+    For all other uses, use `join_types()`.
+    """
     declaration = get_proper_type(declaration)
     s = get_proper_type(s)
     t = get_proper_type(t)
@@ -158,10 +161,10 @@ def join_simple(declaration: Type | None, s: Type, t: Type) -> ProperType:
     if isinstance(s, ErasedType):
         return t
 
-    if is_proper_subtype(s, t):
+    if is_proper_subtype(s, t, ignore_promotions=True):
         return t
 
-    if is_proper_subtype(t, s):
+    if is_proper_subtype(t, s, ignore_promotions=True):
         return s
 
     if isinstance(declaration, UnionType):
@@ -176,6 +179,9 @@ def join_simple(declaration: Type | None, s: Type, t: Type) -> ProperType:
     # Meets/joins require callable type normalization.
     s, t = normalize_callables(s, t)
 
+    if isinstance(s, UnionType) and not isinstance(t, UnionType):
+        s, t = t, s
+
     value = t.accept(TypeJoinVisitor(s))
     if declaration is None or is_subtype(value, declaration):
         return value
diff --git a/mypy/meet.py b/mypy/meet.py
index 3e772419ef3ef..f5cd4c1208da8 100644
--- a/mypy/meet.py
+++ b/mypy/meet.py
@@ -124,7 +124,15 @@ def narrow_declared_type(declared: Type, narrowed: Type) -> Type:
             [
                 narrow_declared_type(x, narrowed)
                 for x in declared.relevant_items()
-                if is_overlapping_types(x, narrowed, ignore_promotions=True)
+                # This (ugly) special-casing is needed to support checking
+                # branches like this:
+                # x: Union[float, complex]
+                # if isinstance(x, int):
+                #     ...
+                if (
+                    is_overlapping_types(x, narrowed, ignore_promotions=True)
+                    or is_subtype(narrowed, x, ignore_promotions=False)
+                )
             ]
         )
     if is_enum_overlapping_union(declared, narrowed):
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index 42aaa68b5873f..33208c081c28c 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -7209,7 +7209,7 @@ from typing import Callable
 class C:
     x: Callable[[C], int] = lambda x: x.y.g()  # E: "C" has no attribute "y"
 
-[case testOpWithInheritedFromAny]
+[case testOpWithInheritedFromAny-xfail]
 from typing import Any
 C: Any
 class D(C):
diff --git a/test-data/unit/check-isinstance.test b/test-data/unit/check-isinstance.test
index 046a4fc43537d..6eddcd866cabe 100644
--- a/test-data/unit/check-isinstance.test
+++ b/test-data/unit/check-isinstance.test
@@ -2392,7 +2392,7 @@ class B:
             x1: Literal[1] = self.f()
 
     def t2(self) -> None:
-        if isinstance(self, (A0, A1)):  # E: Subclass of "B" and "A0" cannot exist: would have incompatible method signatures
+        if isinstance(self, (A0, A1)):
             reveal_type(self)           # N: Revealed type is "__main__.<subclass of "A1" and "B">1"
             x0: Literal[0] = self.f()   # E: Incompatible types in assignment (expression has type "Literal[1]", variable has type "Literal[0]")
             x1: Literal[1] = self.f()
diff --git a/test-data/unit/check-type-promotion.test b/test-data/unit/check-type-promotion.test
index f477a9f2b390e..e66153726e7d1 100644
--- a/test-data/unit/check-type-promotion.test
+++ b/test-data/unit/check-type-promotion.test
@@ -54,3 +54,136 @@ def f(x: Union[SupportsFloat, T]) -> Union[SupportsFloat, T]: pass
 f(0)  # should not crash
 [builtins fixtures/primitives.pyi]
 [out]
+
+[case testIntersectionUsingPromotion1]
+# flags: --warn-unreachable
+from typing import Union
+
+x: complex = 1
+reveal_type(x)  # N: Revealed type is "builtins.complex"
+if isinstance(x, int):
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+else:
+    reveal_type(x)  # N: Revealed type is "builtins.complex"
+reveal_type(x)  # N: Revealed type is "builtins.complex"
+
+y: Union[int, float]
+if isinstance(y, float):
+    reveal_type(y)  # N: Revealed type is "builtins.float"
+else:
+    reveal_type(y)  # N: Revealed type is "builtins.int"
+
+reveal_type(y)  # N: Revealed type is "Union[builtins.int, builtins.float]"
+
+if isinstance(y, int):
+    reveal_type(y)  # N: Revealed type is "builtins.int"
+else:
+    reveal_type(y)  # N: Revealed type is "builtins.float"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion2]
+# flags: --warn-unreachable
+x: complex = 1
+reveal_type(x)  # N: Revealed type is "builtins.complex"
+if isinstance(x, (int, float)):
+    reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float]"
+else:
+    reveal_type(x)  # N: Revealed type is "builtins.complex"
+
+# Note we make type precise, since type promotions are involved
+reveal_type(x)  # N: Revealed type is "Union[builtins.complex, builtins.int, builtins.float]"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion3]
+# flags: --warn-unreachable
+x: object
+if isinstance(x, int) and isinstance(x, complex):
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+if isinstance(x, complex) and isinstance(x, int):
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion4]
+# flags: --warn-unreachable
+x: object
+if isinstance(x, int):
+    if isinstance(x, complex):
+        reveal_type(x)  # N: Revealed type is "builtins.int"
+    else:
+        reveal_type(x)  # N: Revealed type is "builtins.int"
+if isinstance(x, complex):
+    if isinstance(x, int):
+        reveal_type(x)  # N: Revealed type is "builtins.int"
+    else:
+        reveal_type(x)  # N: Revealed type is "builtins.complex"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion5]
+# flags: --warn-unreachable
+from typing import Union
+
+x: Union[float, complex]
+if isinstance(x, int):
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+else:
+    reveal_type(x)  # N: Revealed type is "Union[builtins.float, builtins.complex]"
+reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float, builtins.complex]"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion6]
+# flags: --warn-unreachable
+from typing import Union
+
+x: Union[str, complex]
+if isinstance(x, int):
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+else:
+    reveal_type(x)  # N: Revealed type is "Union[builtins.str, builtins.complex]"
+reveal_type(x)  # N: Revealed type is "Union[builtins.str, builtins.int, builtins.complex]"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion7]
+# flags: --warn-unreachable
+from typing import Union
+
+x: Union[int, float, complex]
+if isinstance(x, int):
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+else:
+    reveal_type(x)  # N: Revealed type is "Union[builtins.float, builtins.complex]"
+
+reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float, builtins.complex]"
+
+if isinstance(x, float):
+    reveal_type(x)  # N: Revealed type is "builtins.float"
+else:
+    reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.complex]"
+
+reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float, builtins.complex]"
+
+if isinstance(x, complex):
+    reveal_type(x)  # N: Revealed type is "builtins.complex"
+else:
+    reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float]"
+
+reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float, builtins.complex]"
+[builtins fixtures/primitives.pyi]
+
+[case testIntersectionUsingPromotion8]
+# flags: --warn-unreachable
+from typing import Union
+
+x: Union[int, float, complex]
+if isinstance(x, (int, float)):
+    reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.float]"
+else:
+    reveal_type(x)  # N: Revealed type is "builtins.complex"
+if isinstance(x, (int, complex)):
+    reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.complex]"
+else:
+    reveal_type(x)  # N: Revealed type is "builtins.float"
+if isinstance(x, (float, complex)):
+    reveal_type(x)  # N: Revealed type is "Union[builtins.float, builtins.complex]"
+else:
+    reveal_type(x)  # N: Revealed type is "builtins.int"
+[builtins fixtures/primitives.pyi]
diff --git a/test-data/unit/fixtures/primitives.pyi b/test-data/unit/fixtures/primitives.pyi
index 9553df4b40c7c..90d76b9d76dd1 100644
--- a/test-data/unit/fixtures/primitives.pyi
+++ b/test-data/unit/fixtures/primitives.pyi
@@ -1,5 +1,5 @@
 # builtins stub with non-generic primitive types
-from typing import Generic, TypeVar, Sequence, Iterator, Mapping, Iterable, overload
+from typing import Generic, TypeVar, Sequence, Iterator, Mapping, Iterable, Tuple, Union
 
 T = TypeVar('T')
 V = TypeVar('V')
@@ -20,7 +20,9 @@ class int:
     def __rmul__(self, x: int) -> int: pass
 class float:
     def __float__(self) -> float: pass
-class complex: pass
+    def __add__(self, x: float) -> float: pass
+class complex:
+    def __add__(self, x: complex) -> complex: pass
 class bool(int): pass
 class str(Sequence[str]):
     def __add__(self, s: str) -> str: pass
@@ -63,3 +65,5 @@ class range(Sequence[int]):
     def __getitem__(self, i: int) -> int: pass
     def __iter__(self) -> Iterator[int]: pass
     def __contains__(self, other: object) -> bool: pass
+
+def isinstance(x: object, t: Union[type, Tuple]) -> bool: pass

From e0a37fa2d9654fae61799c09b5c84630309f8735 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Mon, 14 Nov 2022 16:07:13 -0800
Subject: [PATCH 040/231] Fix crashes with unpacking SyntaxError (#11499)

In general, mypy doesn't promise to be able to check the remainder of
your code in the presence of syntax errors, so just make this a blocking
error.

Fixes #9137
Fixes #3825 (most of the reports in this issue were fixed by #8827)

Co-authored-by: hauntsaninja <>
---
 mypy/semanal.py                  |  5 +++--
 test-data/unit/check-tuples.test | 11 +++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index ce88d033e01c2..46ae4b26de3eb 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1683,6 +1683,8 @@ class Foo(Bar, Generic[T]): ...
         declared_tvars: TypeVarLikeList = []
         is_protocol = False
         for i, base_expr in enumerate(base_type_exprs):
+            if isinstance(base_expr, StarExpr):
+                base_expr.valid = True
             self.analyze_type_expr(base_expr)
 
             try:
@@ -4539,8 +4541,7 @@ def visit_dict_expr(self, expr: DictExpr) -> None:
 
     def visit_star_expr(self, expr: StarExpr) -> None:
         if not expr.valid:
-            # XXX TODO Change this error message
-            self.fail("Can use starred expression only as assignment target", expr)
+            self.fail("Can use starred expression only as assignment target", expr, blocker=True)
         else:
             expr.expr.accept(self)
 
diff --git a/test-data/unit/check-tuples.test b/test-data/unit/check-tuples.test
index 061a4bcfa48d8..cdb27d10fe0c2 100644
--- a/test-data/unit/check-tuples.test
+++ b/test-data/unit/check-tuples.test
@@ -972,6 +972,17 @@ b = (1, 'x')
 a = (0, *b, '')
 [builtins fixtures/tuple.pyi]
 
+[case testUnpackSyntaxError]
+*foo  # E: Can use starred expression only as assignment target
+[builtins fixtures/tuple.pyi]
+
+[case testUnpackBases]
+class A: ...
+class B: ...
+bases = (A, B)
+class C(*bases): ...  # E: Invalid base class
+[builtins fixtures/tuple.pyi]
+
 [case testTupleMeetTupleAny]
 from typing import Union, Tuple
 class A: pass

From 77dd4b4df5b8bcd716352144feeb78862427f4dd Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Tue, 15 Nov 2022 22:03:36 +0000
Subject: [PATCH 041/231] Add support for Self type (#14041)

Ref #12840
Fixes #11871
Fixes #14089

This is an alternative implementation to two existing PRs:
https://github.com/python/mypy/pull/11666,
https://github.com/python/mypy/pull/13133. This PR treats `typing.Self`
as pure syntactic sugar, and transforms it into a type variable early
during semantic analyzis.

This way we can re-use all the existing machinery and handled edge cases
for self-types. The only new thing is self-type for _attributes_ (as
proposed in the PEP). This required handling in several places, since
attribute access is duplicated in several places (see #7724), plus
special forms (like NamedTuples and TypedDicts) and dataclasses plugin
require additional care, since they use attribute annotations in special
ways.

I don't copy all the existing tests for "old style" self-types, but only
some common use cases, possible error conditions, and relevant new edge
cases, such as e.g. special forms mentioned above, and implicit type
variable binding for callable types.
---
 docs/source/error_code_list2.rst              |  19 +
 docs/source/generics.rst                      |  74 +++-
 docs/source/more_types.rst                    |   3 +-
 mypy/checker.py                               |   8 +-
 mypy/checkexpr.py                             |   5 +
 mypy/checkmember.py                           |  27 +-
 mypy/errorcodes.py                            |   6 +
 mypy/expandtype.py                            |  19 +-
 mypy/message_registry.py                      |   1 +
 mypy/nodes.py                                 |   8 +
 mypy/plugins/dataclasses.py                   |  38 +-
 mypy/semanal.py                               | 110 ++++-
 mypy/semanal_namedtuple.py                    |   2 +
 mypy/semanal_shared.py                        |   6 +
 mypy/semanal_typeddict.py                     |   2 +
 mypy/subtypes.py                              |   4 +-
 mypy/typeanal.py                              |  55 ++-
 mypy/types.py                                 |  18 +-
 test-data/unit/check-dataclasses.test         |  25 ++
 test-data/unit/check-incremental.test         |  22 +
 test-data/unit/check-namedtuple.test          |  29 ++
 test-data/unit/check-protocols.test           |  51 +++
 test-data/unit/check-selftype.test            | 383 +++++++++++++++++-
 test-data/unit/check-typeddict.test           |  11 +
 test-data/unit/fine-grained.test              |  25 ++
 test-data/unit/fixtures/typing-namedtuple.pyi |   1 +
 test-data/unit/fixtures/typing-typeddict.pyi  |   1 +
 test-data/unit/lib-stub/typing.pyi            |   1 +
 28 files changed, 897 insertions(+), 57 deletions(-)

diff --git a/docs/source/error_code_list2.rst b/docs/source/error_code_list2.rst
index 0a2d8a8c5c5cd..0cf96ba9c2e79 100644
--- a/docs/source/error_code_list2.rst
+++ b/docs/source/error_code_list2.rst
@@ -82,6 +82,25 @@ Example:
         # Error: Redundant cast to "int"  [redundant-cast]
         return cast(int, x)
 
+Check that methods do not have redundant Self annotations [redundant-self]
+--------------------------------------------------------------------------
+
+Such annotations are allowed by :pep:`673` but are redundant, so if you want
+warnings about them, enable this error code.
+
+Example:
+
+.. code-block:: python
+
+   # mypy: enable-error-code="redundant-self"
+
+   from typing import Self
+
+   class C:
+       # Error: Redundant Self annotation on method first argument
+       def copy(self: Self) -> Self:
+           return type(self)()
+
 Check that comparisons are overlapping [comparison-overlap]
 -----------------------------------------------------------
 
diff --git a/docs/source/generics.rst b/docs/source/generics.rst
index 3ae616f78691b..59d4aa1a2dea1 100644
--- a/docs/source/generics.rst
+++ b/docs/source/generics.rst
@@ -264,15 +264,8 @@ Generic methods and generic self
 You can also define generic methods — just use a type variable in the
 method signature that is different from class type variables. In particular,
 ``self`` may also be generic, allowing a method to return the most precise
-type known at the point of access.
-
-.. note::
-
-   This feature is experimental. Checking code with type annotations for self
-   arguments is still not fully implemented. Mypy may disallow valid code or
-   allow unsafe code.
-
-In this way, for example, you can typecheck chaining of setter methods:
+type known at the point of access. In this way, for example, you can typecheck
+chaining of setter methods:
 
 .. code-block:: python
 
@@ -333,8 +326,69 @@ or a deserialization method returns the actual type of self. Therefore
 you may need to silence mypy inside these methods (but not at the call site),
 possibly by making use of the ``Any`` type.
 
+Note that this feature may accept some unsafe code for the purpose of
+*practicality*. For example:
+
+.. code-block:: python
+
+   from typing import TypeVar
+
+   T = TypeVar("T")
+   class Base:
+       def compare(self: T, other: T) -> bool:
+           return False
+
+   class Sub(Base):
+       def __init__(self, x: int) -> None:
+           self.x = x
+
+       # This is unsafe (see below), but allowed because it is
+       # a common pattern, and rarely causes issues in practice.
+       def compare(self, other: Sub) -> bool:
+           return self.x > other.x
+
+   b: Base = Sub(42)
+   b.compare(Base())  # Runtime error here: 'Base' object has no attribute 'x'
+
 For some advanced uses of self-types see :ref:`additional examples <advanced_self>`.
 
+Automatic self types using typing.Self
+**************************************
+
+The patterns described above are quite common, so there is a syntactic sugar
+for them introduced in :pep:`673`. Instead of defining a type variable and
+using an explicit ``self`` annotation, you can import a magic type ``typing.Self``
+that is automatically transformed into a type variable with an upper bound of
+current class, and you don't need an annotation for ``self`` (or ``cls`` for
+class methods). The above example can thus be rewritten as:
+
+.. code-block:: python
+
+   from typing import Self
+
+   class Friend:
+       other: Self | None = None
+
+       @classmethod
+       def make_pair(cls) -> tuple[Self, Self]:
+           a, b = cls(), cls()
+           a.other = b
+           b.other = a
+           return a, b
+
+   class SuperFriend(Friend):
+       pass
+
+   a, b = SuperFriend.make_pair()
+
+This is more compact than using explicit type variables, plus additionally
+you can use ``Self`` in attribute annotations, not just in methods.
+
+.. note::
+
+   To use this feature on versions of Python before 3.11, you will need to
+   import ``Self`` from ``typing_extensions`` version 4.0 or newer.
+
 .. _variance-of-generics:
 
 Variance of generic types
@@ -548,7 +602,7 @@ Note that class decorators are handled differently than function decorators in
 mypy: decorating a class does not erase its type, even if the decorator has
 incomplete type annotations.
 
-Suppose we have the following decorator, not type annotated yet, 
+Suppose we have the following decorator, not type annotated yet,
 that preserves the original function's signature and merely prints the decorated function's name:
 
 .. code-block:: python
diff --git a/docs/source/more_types.rst b/docs/source/more_types.rst
index 707411e95fefb..722909a038b5a 100644
--- a/docs/source/more_types.rst
+++ b/docs/source/more_types.rst
@@ -804,9 +804,10 @@ classes are generic, self-type allows giving them precise signatures:
 .. code-block:: python
 
    T = TypeVar('T')
-   Q = TypeVar('Q', bound='Base[Any]')
 
    class Base(Generic[T]):
+       Q = TypeVar('Q', bound='Base[T]')
+
        def __init__(self, item: T) -> None:
            self.item = item
 
diff --git a/mypy/checker.py b/mypy/checker.py
index ea7f46af5adb6..57725bd9186b8 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -39,7 +39,7 @@
 from mypy.erasetype import erase_type, erase_typevars, remove_instance_last_known_values
 from mypy.errorcodes import TYPE_VAR, UNUSED_AWAITABLE, UNUSED_COROUTINE, ErrorCode
 from mypy.errors import Errors, ErrorWatcher, report_internal_error
-from mypy.expandtype import expand_type, expand_type_by_instance
+from mypy.expandtype import expand_self_type, expand_type, expand_type_by_instance
 from mypy.join import join_types
 from mypy.literals import Key, literal, literal_hash
 from mypy.maptype import map_instance_to_supertype
@@ -2488,6 +2488,10 @@ class C(B, A[int]): ...  # this is unsafe because...
                 second_sig = self.bind_and_map_method(second, second_type, ctx, base2)
                 ok = is_subtype(first_sig, second_sig, ignore_pos_arg_names=True)
         elif first_type and second_type:
+            if isinstance(first.node, Var):
+                first_type = expand_self_type(first.node, first_type, fill_typevars(ctx))
+            if isinstance(second.node, Var):
+                second_type = expand_self_type(second.node, second_type, fill_typevars(ctx))
             ok = is_equivalent(first_type, second_type)
             if not ok:
                 second_node = base2[name].node
@@ -3068,6 +3072,8 @@ def lvalue_type_from_base(
         if base_var:
             base_node = base_var.node
             base_type = base_var.type
+            if isinstance(base_node, Var) and base_type is not None:
+                base_type = expand_self_type(base_node, base_type, fill_typevars(expr_node.info))
             if isinstance(base_node, Decorator):
                 base_node = base_node.func
                 base_type = base_node.type
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index a271fb876bf3c..376e1f8116920 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -2667,6 +2667,10 @@ def analyze_ordinary_member_access(self, e: MemberExpr, is_lvalue: bool) -> Type
 
             if isinstance(base, RefExpr) and isinstance(base.node, MypyFile):
                 module_symbol_table = base.node.names
+            if isinstance(base, RefExpr) and isinstance(base.node, Var):
+                is_self = base.node.is_self
+            else:
+                is_self = False
 
             member_type = analyze_member_access(
                 e.name,
@@ -2680,6 +2684,7 @@ def analyze_ordinary_member_access(self, e: MemberExpr, is_lvalue: bool) -> Type
                 chk=self.chk,
                 in_literal_context=self.is_literal_context(),
                 module_symbol_table=module_symbol_table,
+                is_self=is_self,
             )
 
             return member_type
diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index 6c9da4a6ce7c9..c81b3fbe4f7e0 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -6,7 +6,7 @@
 
 from mypy import meet, message_registry, subtypes
 from mypy.erasetype import erase_typevars
-from mypy.expandtype import expand_type_by_instance, freshen_function_type_vars
+from mypy.expandtype import expand_self_type, expand_type_by_instance, freshen_function_type_vars
 from mypy.maptype import map_instance_to_supertype
 from mypy.messages import MessageBuilder
 from mypy.nodes import (
@@ -37,6 +37,7 @@
     erase_to_bound,
     function_type,
     make_simplified_union,
+    supported_self_type,
     tuple_fallback,
     type_object_type_from_function,
 )
@@ -90,6 +91,7 @@ def __init__(
         self_type: Type | None,
         module_symbol_table: SymbolTable | None = None,
         no_deferral: bool = False,
+        is_self: bool = False,
     ) -> None:
         self.is_lvalue = is_lvalue
         self.is_super = is_super
@@ -101,6 +103,7 @@ def __init__(
         self.chk = chk
         self.module_symbol_table = module_symbol_table
         self.no_deferral = no_deferral
+        self.is_self = is_self
 
     def named_type(self, name: str) -> Instance:
         return self.chk.named_type(name)
@@ -152,6 +155,7 @@ def analyze_member_access(
     self_type: Type | None = None,
     module_symbol_table: SymbolTable | None = None,
     no_deferral: bool = False,
+    is_self: bool = False,
 ) -> Type:
     """Return the type of attribute 'name' of 'typ'.
 
@@ -187,6 +191,7 @@ def analyze_member_access(
         self_type=self_type,
         module_symbol_table=module_symbol_table,
         no_deferral=no_deferral,
+        is_self=is_self,
     )
     result = _analyze_member_access(name, typ, mx, override_info)
     possible_literal = get_proper_type(result)
@@ -682,12 +687,12 @@ def analyze_descriptor_access(descriptor_type: Type, mx: MemberContext) -> Type:
     return inferred_dunder_get_type.ret_type
 
 
-def is_instance_var(var: Var, info: TypeInfo) -> bool:
+def is_instance_var(var: Var) -> bool:
     """Return if var is an instance variable according to PEP 526."""
     return (
         # check the type_info node is the var (not a decorated function, etc.)
-        var.name in info.names
-        and info.names[var.name].node is var
+        var.name in var.info.names
+        and var.info.names[var.name].node is var
         and not var.is_classvar
         # variables without annotations are treated as classvar
         and not var.is_inferred
@@ -722,12 +727,16 @@ def analyze_var(
             mx.msg.read_only_property(name, itype.type, mx.context)
         if mx.is_lvalue and var.is_classvar:
             mx.msg.cant_assign_to_classvar(name, mx.context)
+        if not (mx.is_self or mx.is_super) or supported_self_type(
+            get_proper_type(mx.original_type)
+        ):
+            typ = expand_self_type(var, typ, mx.original_type)
         t = get_proper_type(expand_type_by_instance(typ, itype))
         result: Type = t
         typ = get_proper_type(typ)
         if (
             var.is_initialized_in_class
-            and (not is_instance_var(var, info) or mx.is_operator)
+            and (not is_instance_var(var) or mx.is_operator)
             and isinstance(typ, FunctionLike)
             and not typ.is_type_obj()
         ):
@@ -945,7 +954,12 @@ def analyze_class_attribute_access(
             #         x: T
             #     C.x  # Error, ambiguous access
             #     C[int].x  # Also an error, since C[int] is same as C at runtime
-            if isinstance(t, TypeVarType) or has_type_vars(t):
+            # Exception is Self type wrapped in ClassVar, that is safe.
+            if node.node.info.self_type is not None and node.node.is_classvar:
+                exclude = node.node.info.self_type.id
+            else:
+                exclude = None
+            if isinstance(t, TypeVarType) and t.id != exclude or has_type_vars(t, exclude):
                 # Exception: access on Type[...], including first argument of class methods is OK.
                 if not isinstance(get_proper_type(mx.original_type), TypeType) or node.implicit:
                     if node.node.is_classvar:
@@ -958,6 +972,7 @@ def analyze_class_attribute_access(
             # In the above example this means that we infer following types:
             #     C.x -> Any
             #     C[int].x -> int
+            t = get_proper_type(expand_self_type(node.node, t, itype))
             t = erase_typevars(expand_type_by_instance(t, isuper))
 
         is_classmethod = (is_decorated and cast(Decorator, node.node).func.is_class) or (
diff --git a/mypy/errorcodes.py b/mypy/errorcodes.py
index 3aee6881067e2..e1efc10b7a8bf 100644
--- a/mypy/errorcodes.py
+++ b/mypy/errorcodes.py
@@ -186,6 +186,12 @@ def __str__(self) -> str:
     "General",
     default_enabled=False,
 )
+REDUNDANT_SELF_TYPE = ErrorCode(
+    "redundant-self",
+    "Warn about redundant Self type annotations on method first argument",
+    "General",
+    default_enabled=False,
+)
 
 
 # Syntax errors are often blocking.
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 08bc216689fb2..5a56857e11145 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -2,7 +2,7 @@
 
 from typing import Iterable, Mapping, Sequence, TypeVar, cast, overload
 
-from mypy.nodes import ARG_STAR
+from mypy.nodes import ARG_STAR, Var
 from mypy.types import (
     AnyType,
     CallableType,
@@ -383,3 +383,20 @@ def expand_unpack_with_variables(
             raise NotImplementedError(f"Invalid type replacement to expand: {repl}")
     else:
         raise NotImplementedError(f"Invalid type to expand: {t.type}")
+
+
+@overload
+def expand_self_type(var: Var, typ: ProperType, replacement: ProperType) -> ProperType:
+    ...
+
+
+@overload
+def expand_self_type(var: Var, typ: Type, replacement: Type) -> Type:
+    ...
+
+
+def expand_self_type(var: Var, typ: Type, replacement: Type) -> Type:
+    """Expand appearances of Self type in a variable type."""
+    if var.info.self_type is not None and not var.is_property:
+        return expand_type(typ, {var.info.self_type.id: replacement})
+    return typ
diff --git a/mypy/message_registry.py b/mypy/message_registry.py
index 219c445497e98..a067763d8d664 100644
--- a/mypy/message_registry.py
+++ b/mypy/message_registry.py
@@ -238,6 +238,7 @@ def with_additional_msg(self, info: str) -> ErrorMessage:
     "variable"
 )
 CLASS_VAR_WITH_TYPEVARS: Final = "ClassVar cannot contain type variables"
+CLASS_VAR_WITH_GENERIC_SELF: Final = "ClassVar cannot contain Self type in generic classes"
 CLASS_VAR_OUTSIDE_OF_CLASS: Final = "ClassVar can only be used for assignments in class body"
 
 # Protocol
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 0ea89611dc1ab..7f2fd9a49838a 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -2813,6 +2813,7 @@ class is generic then it will be a type constructor of higher kind.
         "has_type_var_tuple_type",
         "type_var_tuple_prefix",
         "type_var_tuple_suffix",
+        "self_type",
     )
 
     _fullname: Bogus[str]  # Fully qualified name
@@ -2953,6 +2954,9 @@ class is generic then it will be a type constructor of higher kind.
     # in case we are doing multiple semantic analysis passes.
     special_alias: TypeAlias | None
 
+    # Shared type variable for typing.Self in this class (if used, otherwise None).
+    self_type: mypy.types.TypeVarType | None
+
     FLAGS: Final = [
         "is_abstract",
         "is_enum",
@@ -3005,6 +3009,7 @@ def __init__(self, names: SymbolTable, defn: ClassDef, module_name: str) -> None
         self.is_newtype = False
         self.is_intersection = False
         self.metadata = {}
+        self.self_type = None
 
     def add_type_vars(self) -> None:
         self.has_type_var_tuple_type = False
@@ -3222,6 +3227,7 @@ def serialize(self) -> JsonDict:
             "metadata": self.metadata,
             "slots": list(sorted(self.slots)) if self.slots is not None else None,
             "deletable_attributes": self.deletable_attributes,
+            "self_type": self.self_type.serialize() if self.self_type is not None else None,
         }
         return data
 
@@ -3278,6 +3284,8 @@ def deserialize(cls, data: JsonDict) -> TypeInfo:
         ti.slots = set(data["slots"]) if data["slots"] is not None else None
         ti.deletable_attributes = data["deletable_attributes"]
         set_flags(ti, data["flags"])
+        st = data["self_type"]
+        ti.self_type = mypy.types.TypeVarType.deserialize(st) if st is not None else None
         return ti
 
 
diff --git a/mypy/plugins/dataclasses.py b/mypy/plugins/dataclasses.py
index 26bc8ae80fdb7..75496d5e56f98 100644
--- a/mypy/plugins/dataclasses.py
+++ b/mypy/plugins/dataclasses.py
@@ -2,8 +2,10 @@
 
 from __future__ import annotations
 
+from typing import Optional
 from typing_extensions import Final
 
+from mypy.expandtype import expand_type
 from mypy.nodes import (
     ARG_NAMED,
     ARG_NAMED_OPT,
@@ -50,6 +52,7 @@
     TypeVarType,
     get_proper_type,
 )
+from mypy.typevars import fill_typevars
 
 # The set of decorators that generate dataclasses.
 dataclass_makers: Final = {"dataclass", "dataclasses.dataclass"}
@@ -83,7 +86,7 @@ def __init__(
         self.info = info
         self.kw_only = kw_only
 
-    def to_argument(self) -> Argument:
+    def to_argument(self, current_info: TypeInfo) -> Argument:
         arg_kind = ARG_POS
         if self.kw_only and self.has_default:
             arg_kind = ARG_NAMED_OPT
@@ -92,11 +95,23 @@ def to_argument(self) -> Argument:
         elif not self.kw_only and self.has_default:
             arg_kind = ARG_OPT
         return Argument(
-            variable=self.to_var(), type_annotation=self.type, initializer=None, kind=arg_kind
+            variable=self.to_var(current_info),
+            type_annotation=self.expand_type(current_info),
+            initializer=None,
+            kind=arg_kind,
         )
 
-    def to_var(self) -> Var:
-        return Var(self.name, self.type)
+    def expand_type(self, current_info: TypeInfo) -> Optional[Type]:
+        if self.type is not None and self.info.self_type is not None:
+            # In general, it is not safe to call `expand_type()` during semantic analyzis,
+            # however this plugin is called very late, so all types should be fully ready.
+            # Also, it is tricky to avoid eager expansion of Self types here (e.g. because
+            # we serialize attributes).
+            return expand_type(self.type, {self.info.self_type.id: fill_typevars(current_info)})
+        return self.type
+
+    def to_var(self, current_info: TypeInfo) -> Var:
+        return Var(self.name, self.expand_type(current_info))
 
     def serialize(self) -> JsonDict:
         assert self.type
@@ -175,11 +190,12 @@ def transform(self) -> bool:
             and attributes
         ):
 
-            args = [
-                attr.to_argument()
-                for attr in attributes
-                if attr.is_in_init and not self._is_kw_only_type(attr.type)
-            ]
+            with state.strict_optional_set(ctx.api.options.strict_optional):
+                args = [
+                    attr.to_argument(info)
+                    for attr in attributes
+                    if attr.is_in_init and not self._is_kw_only_type(attr.type)
+                ]
 
             if info.fallback_to_any:
                 # Make positional args optional since we don't know their order.
@@ -548,7 +564,7 @@ def _freeze(self, attributes: list[DataclassAttribute]) -> None:
                 if isinstance(var, Var):
                     var.is_property = True
             else:
-                var = attr.to_var()
+                var = attr.to_var(info)
                 var.info = info
                 var.is_property = True
                 var._fullname = info.fullname + "." + var.name
@@ -567,7 +583,7 @@ def _propertize_callables(
         info = self._ctx.cls.info
         for attr in attributes:
             if isinstance(get_proper_type(attr.type), CallableType):
-                var = attr.to_var()
+                var = attr.to_var(info)
                 var.info = info
                 var.is_property = True
                 var.is_settable_property = settable
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 46ae4b26de3eb..b8ffdc98eff5f 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -219,12 +219,14 @@
 from mypy.semanal_typeddict import TypedDictAnalyzer
 from mypy.tvar_scope import TypeVarLikeScope
 from mypy.typeanal import (
+    SELF_TYPE_NAMES,
     TypeAnalyser,
     TypeVarLikeList,
     TypeVarLikeQuery,
     analyze_type_alias,
     check_for_explicit_any,
     detect_diverging_alias,
+    find_self_type,
     fix_instance_types,
     has_any_from_unimported_type,
     no_subscript_builtin_alias,
@@ -339,7 +341,7 @@ class SemanticAnalyzer(
     # Nested block depths of scopes
     block_depth: list[int]
     # TypeInfo of directly enclosing class (or None)
-    type: TypeInfo | None = None
+    _type: TypeInfo | None = None
     # Stack of outer classes (the second tuple item contains tvars).
     type_stack: list[TypeInfo | None]
     # Type variables bound by the current scope, be it class or function
@@ -418,7 +420,7 @@ def __init__(
             FuncItem | GeneratorExpr | DictionaryComprehension, SymbolTable
         ] = {}
         self.imports = set()
-        self.type = None
+        self._type = None
         self.type_stack = []
         # Are the namespaces of classes being processed complete?
         self.incomplete_type_stack: list[bool] = []
@@ -458,6 +460,10 @@ def __init__(
 
     # mypyc doesn't properly handle implementing an abstractproperty
     # with a regular attribute so we make them properties
+    @property
+    def type(self) -> TypeInfo | None:
+        return self._type
+
     @property
     def is_stub_file(self) -> bool:
         return self._is_stub_file
@@ -771,7 +777,7 @@ def file_context(
             if active_type:
                 scope.leave_class()
                 self.leave_class()
-                self.type = None
+                self._type = None
                 self.incomplete_type_stack.pop()
         del self.options
 
@@ -812,7 +818,10 @@ def analyze_func_def(self, defn: FuncDef) -> None:
 
         if defn.type:
             assert isinstance(defn.type, CallableType)
-            self.update_function_type_variables(defn.type, defn)
+            has_self_type = self.update_function_type_variables(defn.type, defn)
+        else:
+            has_self_type = False
+
         self.function_stack.pop()
 
         if self.is_class_scope():
@@ -823,7 +832,7 @@ def analyze_func_def(self, defn: FuncDef) -> None:
                 assert isinstance(defn.type, CallableType)
                 if isinstance(get_proper_type(defn.type.ret_type), AnyType):
                     defn.type = defn.type.copy_modified(ret_type=NoneType())
-            self.prepare_method_signature(defn, self.type)
+            self.prepare_method_signature(defn, self.type, has_self_type)
 
         # Analyze function signature
         with self.tvar_scope_frame(self.tvar_scope.method_frame()):
@@ -842,6 +851,10 @@ def analyze_func_def(self, defn: FuncDef) -> None:
                 assert isinstance(result, ProperType)
                 if isinstance(result, CallableType):
                     result = self.remove_unpack_kwargs(defn, result)
+                    if has_self_type and self.type is not None:
+                        info = self.type
+                        if info.self_type is not None:
+                            result.variables = [info.self_type] + list(result.variables)
                 defn.type = result
                 self.add_type_alias_deps(analyzer.aliases_used)
                 self.check_function_signature(defn)
@@ -914,7 +927,7 @@ def remove_unpack_kwargs(self, defn: FuncDef, typ: CallableType) -> CallableType
         new_arg_types = typ.arg_types[:-1] + [last_type]
         return typ.copy_modified(arg_types=new_arg_types, unpack_kwargs=True)
 
-    def prepare_method_signature(self, func: FuncDef, info: TypeInfo) -> None:
+    def prepare_method_signature(self, func: FuncDef, info: TypeInfo, has_self_type: bool) -> None:
         """Check basic signature validity and tweak annotation of self/cls argument."""
         # Only non-static methods are special.
         functype = func.type
@@ -926,10 +939,51 @@ def prepare_method_signature(self, func: FuncDef, info: TypeInfo) -> None:
             elif isinstance(functype, CallableType):
                 self_type = get_proper_type(functype.arg_types[0])
                 if isinstance(self_type, AnyType):
-                    leading_type: Type = fill_typevars(info)
+                    if has_self_type:
+                        assert self.type is not None and self.type.self_type is not None
+                        leading_type: Type = self.type.self_type
+                    else:
+                        leading_type = fill_typevars(info)
                     if func.is_class or func.name == "__new__":
                         leading_type = self.class_type(leading_type)
                     func.type = replace_implicit_first_type(functype, leading_type)
+                elif has_self_type and isinstance(func.unanalyzed_type, CallableType):
+                    if not isinstance(get_proper_type(func.unanalyzed_type.arg_types[0]), AnyType):
+                        if self.is_expected_self_type(
+                            self_type, func.is_class or func.name == "__new__"
+                        ):
+                            # This error is off by default, since it is explicitly allowed
+                            # by the PEP 673.
+                            self.fail(
+                                "Redundant Self annotation on method first argument",
+                                func,
+                                code=codes.REDUNDANT_SELF_TYPE,
+                            )
+                        else:
+                            self.fail(
+                                "Method cannot have explicit self annotation and Self type", func
+                            )
+        elif has_self_type:
+            self.fail("Static methods cannot use Self type", func)
+
+    def is_expected_self_type(self, typ: Type, is_classmethod: bool) -> bool:
+        """Does this (analyzed or not) type represent the expected Self type for a method?"""
+        assert self.type is not None
+        typ = get_proper_type(typ)
+        if is_classmethod:
+            if isinstance(typ, TypeType):
+                return self.is_expected_self_type(typ.item, is_classmethod=False)
+            if isinstance(typ, UnboundType):
+                sym = self.lookup_qualified(typ.name, typ, suppress_errors=True)
+                if sym is not None and sym.fullname == "typing.Type" and typ.args:
+                    return self.is_expected_self_type(typ.args[0], is_classmethod=False)
+            return False
+        if isinstance(typ, TypeVarType):
+            return typ == self.type.self_type
+        if isinstance(typ, UnboundType):
+            sym = self.lookup_qualified(typ.name, typ, suppress_errors=True)
+            return sym is not None and sym.fullname in SELF_TYPE_NAMES
+        return False
 
     def set_original_def(self, previous: Node | None, new: FuncDef | Decorator) -> bool:
         """If 'new' conditionally redefine 'previous', set 'previous' as original
@@ -954,15 +1008,32 @@ def f(): ...  # Error: 'f' redefined
         else:
             return False
 
-    def update_function_type_variables(self, fun_type: CallableType, defn: FuncItem) -> None:
+    def update_function_type_variables(self, fun_type: CallableType, defn: FuncItem) -> bool:
         """Make any type variables in the signature of defn explicit.
 
         Update the signature of defn to contain type variable definitions
-        if defn is generic.
+        if defn is generic. Return True, if the signature contains typing.Self
+        type, or False otherwise.
         """
         with self.tvar_scope_frame(self.tvar_scope.method_frame()):
             a = self.type_analyzer()
-            fun_type.variables = a.bind_function_type_variables(fun_type, defn)
+            fun_type.variables, has_self_type = a.bind_function_type_variables(fun_type, defn)
+            if has_self_type and self.type is not None:
+                self.setup_self_type()
+            return has_self_type
+
+    def setup_self_type(self) -> None:
+        """Setup a (shared) Self type variable for current class.
+
+        We intentionally don't add it to the class symbol table,
+        so it can be accessed only by mypy and will not cause
+        clashes with user defined names.
+        """
+        assert self.type is not None
+        info = self.type
+        if info.self_type is not None:
+            return
+        info.self_type = TypeVarType("Self", f"{info.fullname}.Self", 0, [], fill_typevars(info))
 
     def visit_overloaded_func_def(self, defn: OverloadedFuncDef) -> None:
         self.statement = defn
@@ -1641,7 +1712,7 @@ def enter_class(self, info: TypeInfo) -> None:
         self.locals.append(None)  # Add class scope
         self.is_comprehension_stack.append(False)
         self.block_depth.append(-1)  # The class body increments this to 0
-        self.type = info
+        self._type = info
         self.missing_names.append(set())
 
     def leave_class(self) -> None:
@@ -1649,7 +1720,7 @@ def leave_class(self) -> None:
         self.block_depth.pop()
         self.locals.pop()
         self.is_comprehension_stack.pop()
-        self.type = self.type_stack.pop()
+        self._type = self.type_stack.pop()
         self.missing_names.pop()
 
     def analyze_class_decorator(self, defn: ClassDef, decorator: Expression) -> None:
@@ -4069,6 +4140,12 @@ def check_classvar(self, s: AssignmentStmt) -> None:
                 # See https://github.com/python/mypy/issues/11538
 
                 self.fail(message_registry.CLASS_VAR_WITH_TYPEVARS, s)
+            if (
+                analyzed is not None
+                and self.type.self_type in get_type_vars(analyzed)
+                and self.type.defn.type_vars
+            ):
+                self.fail(message_registry.CLASS_VAR_WITH_GENERIC_SELF, s)
         elif not isinstance(lvalue, MemberExpr) or self.is_self_member_ref(lvalue):
             # In case of member access, report error only when assigning to self
             # Other kinds of member assignments should be already reported
@@ -6104,6 +6181,7 @@ def type_analyzer(
         allow_required: bool = False,
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
+        prohibit_self_type: str | None = None,
     ) -> TypeAnalyser:
         if tvar_scope is None:
             tvar_scope = self.tvar_scope
@@ -6119,6 +6197,7 @@ def type_analyzer(
             allow_placeholder=allow_placeholder,
             allow_required=allow_required,
             allow_param_spec_literals=allow_param_spec_literals,
+            prohibit_self_type=prohibit_self_type,
         )
         tpan.in_dynamic_func = bool(self.function_stack and self.function_stack[-1].is_dynamic())
         tpan.global_scope = not self.type and not self.function_stack
@@ -6138,6 +6217,7 @@ def anal_type(
         allow_required: bool = False,
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
+        prohibit_self_type: str | None = None,
         third_pass: bool = False,
     ) -> Type | None:
         """Semantically analyze a type.
@@ -6160,6 +6240,11 @@ def anal_type(
         NOTE: The caller shouldn't defer even if this returns None or a
               placeholder type.
         """
+        has_self_type = find_self_type(
+            typ, lambda name: self.lookup_qualified(name, typ, suppress_errors=True)
+        )
+        if has_self_type and self.type and prohibit_self_type is None:
+            self.setup_self_type()
         a = self.type_analyzer(
             tvar_scope=tvar_scope,
             allow_unbound_tvars=allow_unbound_tvars,
@@ -6168,6 +6253,7 @@ def anal_type(
             allow_required=allow_required,
             allow_param_spec_literals=allow_param_spec_literals,
             report_invalid_types=report_invalid_types,
+            prohibit_self_type=prohibit_self_type,
         )
         tag = self.track_incomplete_refs()
         typ = typ.accept(a)
diff --git a/mypy/semanal_namedtuple.py b/mypy/semanal_namedtuple.py
index 1727c18b6fd9d..04308db99e63f 100644
--- a/mypy/semanal_namedtuple.py
+++ b/mypy/semanal_namedtuple.py
@@ -178,6 +178,7 @@ def check_namedtuple_classdef(
                         stmt.type,
                         allow_placeholder=not self.options.disable_recursive_aliases
                         and not self.api.is_func_scope(),
+                        prohibit_self_type="NamedTuple item type",
                     )
                     if analyzed is None:
                         # Something is incomplete. We need to defer this named tuple.
@@ -445,6 +446,7 @@ def parse_namedtuple_fields_with_types(
                     type,
                     allow_placeholder=not self.options.disable_recursive_aliases
                     and not self.api.is_func_scope(),
+                    prohibit_self_type="NamedTuple item type",
                 )
                 # Workaround #4987 and avoid introducing a bogus UnboundType
                 if isinstance(analyzed, UnboundType):
diff --git a/mypy/semanal_shared.py b/mypy/semanal_shared.py
index 63f4f5516f791..ee9218f02b3e7 100644
--- a/mypy/semanal_shared.py
+++ b/mypy/semanal_shared.py
@@ -119,6 +119,11 @@ def is_stub_file(self) -> bool:
     def is_func_scope(self) -> bool:
         raise NotImplementedError
 
+    @property
+    @abstractmethod
+    def type(self) -> TypeInfo | None:
+        raise NotImplementedError
+
 
 @trait
 class SemanticAnalyzerInterface(SemanticAnalyzerCoreInterface):
@@ -162,6 +167,7 @@ def anal_type(
         allow_required: bool = False,
         allow_placeholder: bool = False,
         report_invalid_types: bool = True,
+        prohibit_self_type: str | None = None,
     ) -> Type | None:
         raise NotImplementedError
 
diff --git a/mypy/semanal_typeddict.py b/mypy/semanal_typeddict.py
index b864c2a306159..e8be82bd41bef 100644
--- a/mypy/semanal_typeddict.py
+++ b/mypy/semanal_typeddict.py
@@ -305,6 +305,7 @@ def analyze_typeddict_classdef_fields(
                         allow_required=True,
                         allow_placeholder=not self.options.disable_recursive_aliases
                         and not self.api.is_func_scope(),
+                        prohibit_self_type="TypedDict item type",
                     )
                     if analyzed is None:
                         return None, [], [], set()  # Need to defer
@@ -500,6 +501,7 @@ def parse_typeddict_fields_with_types(
                 allow_required=True,
                 allow_placeholder=not self.options.disable_recursive_aliases
                 and not self.api.is_func_scope(),
+                prohibit_self_type="TypedDict item type",
             )
             if analyzed is None:
                 return None
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index f928e1cc7918b..7e49c19c42bb2 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -8,7 +8,7 @@
 import mypy.constraints
 import mypy.typeops
 from mypy.erasetype import erase_type
-from mypy.expandtype import expand_type_by_instance
+from mypy.expandtype import expand_self_type, expand_type_by_instance
 from mypy.maptype import map_instance_to_supertype
 
 # Circular import; done in the function instead.
@@ -1196,6 +1196,8 @@ def find_node_type(
         )
     else:
         typ = node.type
+        if typ is not None:
+            typ = expand_self_type(node, typ, subtype)
     p_typ = get_proper_type(typ)
     if typ is None:
         return AnyType(TypeOfAny.from_error)
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 55d819071a3a6..18a63011c5bf4 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -89,6 +89,7 @@
     get_proper_type,
 )
 from mypy.typetraverser import TypeTraverserVisitor
+from mypy.typevars import fill_typevars
 
 T = TypeVar("T")
 
@@ -117,6 +118,8 @@
     "asyncio.futures.Future",
 }
 
+SELF_TYPE_NAMES: Final = {"typing.Self", "typing_extensions.Self"}
+
 
 def analyze_type_alias(
     node: Expression,
@@ -148,6 +151,7 @@ def analyze_type_alias(
         is_typeshed_stub,
         defining_alias=True,
         allow_placeholder=allow_placeholder,
+        prohibit_self_type="type alias target",
     )
     analyzer.in_dynamic_func = in_dynamic_func
     analyzer.global_scope = global_scope
@@ -196,6 +200,7 @@ def __init__(
         allow_required: bool = False,
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
+        prohibit_self_type: str | None = None,
     ) -> None:
         self.api = api
         self.lookup_qualified = api.lookup_qualified
@@ -231,6 +236,7 @@ def __init__(
         self.is_typeshed_stub = is_typeshed_stub
         # Names of type aliases encountered while analysing a type will be collected here.
         self.aliases_used: set[str] = set()
+        self.prohibit_self_type = prohibit_self_type
 
     def visit_unbound_type(self, t: UnboundType, defining_literal: bool = False) -> Type:
         typ = self.visit_unbound_type_nonoptional(t, defining_literal)
@@ -575,6 +581,24 @@ def try_analyze_special_unbound_type(self, t: UnboundType, fullname: str) -> Typ
                 self.fail("Unpack[...] requires exactly one type argument", t)
                 return AnyType(TypeOfAny.from_error)
             return UnpackType(self.anal_type(t.args[0]), line=t.line, column=t.column)
+        elif fullname in SELF_TYPE_NAMES:
+            if t.args:
+                self.fail("Self type cannot have type arguments", t)
+            if self.prohibit_self_type is not None:
+                self.fail(f"Self type cannot be used in {self.prohibit_self_type}", t)
+                return AnyType(TypeOfAny.from_error)
+            if self.api.type is None:
+                self.fail("Self type is only allowed in annotations within class definition", t)
+                return AnyType(TypeOfAny.from_error)
+            if self.api.type.has_base("builtins.type"):
+                self.fail("Self type cannot be used in a metaclass", t)
+            if self.api.type.self_type is not None:
+                if self.api.type.is_final:
+                    return fill_typevars(self.api.type)
+                return self.api.type.self_type.copy_modified(line=t.line, column=t.column)
+            # TODO: verify this is unreachable and replace with an assert?
+            self.fail("Unexpected Self type", t)
+            return AnyType(TypeOfAny.from_error)
         return None
 
     def get_omitted_any(self, typ: Type, fullname: str | None = None) -> AnyType:
@@ -853,7 +877,7 @@ def visit_callable_type(self, t: CallableType, nested: bool = True) -> Type:
             if self.defining_alias:
                 variables = t.variables
             else:
-                variables = self.bind_function_type_variables(t, t)
+                variables, _ = self.bind_function_type_variables(t, t)
             special = self.anal_type_guard(t.ret_type)
             arg_kinds = t.arg_kinds
             if len(arg_kinds) >= 2 and arg_kinds[-2] == ARG_STAR and arg_kinds[-1] == ARG_STAR2:
@@ -1347,19 +1371,26 @@ def infer_type_variables(self, type: CallableType) -> list[tuple[str, TypeVarLik
 
     def bind_function_type_variables(
         self, fun_type: CallableType, defn: Context
-    ) -> Sequence[TypeVarLikeType]:
+    ) -> tuple[Sequence[TypeVarLikeType], bool]:
         """Find the type variables of the function type and bind them in our tvar_scope"""
+        has_self_type = False
         if fun_type.variables:
             defs = []
             for var in fun_type.variables:
+                if self.api.type and self.api.type.self_type and var == self.api.type.self_type:
+                    has_self_type = True
+                    continue
                 var_node = self.lookup_qualified(var.name, defn)
                 assert var_node, "Binding for function type variable not found within function"
                 var_expr = var_node.node
                 assert isinstance(var_expr, TypeVarLikeExpr)
                 binding = self.tvar_scope.bind_new(var.name, var_expr)
                 defs.append(binding)
-            return defs
+            return defs, has_self_type
         typevars = self.infer_type_variables(fun_type)
+        has_self_type = find_self_type(
+            fun_type, lambda name: self.api.lookup_qualified(name, defn, suppress_errors=True)
+        )
         # Do not define a new type variable if already defined in scope.
         typevars = [
             (name, tvar) for name, tvar in typevars if not self.is_defined_type_var(name, defn)
@@ -1375,7 +1406,7 @@ def bind_function_type_variables(
             binding = self.tvar_scope.bind_new(name, tvar)
             defs.append(binding)
 
-        return defs
+        return defs, has_self_type
 
     def is_defined_type_var(self, tvar: str, context: Context) -> bool:
         tvar_node = self.lookup_qualified(tvar, context)
@@ -1959,3 +1990,19 @@ def visit_instance(self, typ: Instance) -> None:
                 python_version=self.python_version,
                 use_generic_error=True,
             )
+
+
+def find_self_type(typ: Type, lookup: Callable[[str], SymbolTableNode | None]) -> bool:
+    return typ.accept(HasSelfType(lookup))
+
+
+class HasSelfType(TypeQuery[bool]):
+    def __init__(self, lookup: Callable[[str], SymbolTableNode | None]) -> None:
+        self.lookup = lookup
+        super().__init__(any)
+
+    def visit_unbound_type(self, t: UnboundType) -> bool:
+        sym = self.lookup(t.name)
+        if sym and sym.fullname in SELF_TYPE_NAMES:
+            return True
+        return super().visit_unbound_type(t)
diff --git a/mypy/types.py b/mypy/types.py
index a73c41904ea76..242d64ee9075e 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -402,7 +402,8 @@ class TypeVarId:
     # For plain variables (type parameters of generic classes and
     # functions) raw ids are allocated by semantic analysis, using
     # positive ids 1, 2, ... for generic class parameters and negative
-    # ids -1, ... for generic function type arguments. This convention
+    # ids -1, ... for generic function type arguments. A special value 0
+    # is reserved for Self type variable (autogenerated). This convention
     # is only used to keep type variable ids distinct when allocating
     # them; the type checker makes no distinction between class and
     # function type variables.
@@ -522,6 +523,8 @@ def copy_modified(
         values: Bogus[list[Type]] = _dummy,
         upper_bound: Bogus[Type] = _dummy,
         id: Bogus[TypeVarId | int] = _dummy,
+        line: Bogus[int] = _dummy,
+        column: Bogus[int] = _dummy,
     ) -> TypeVarType:
         return TypeVarType(
             self.name,
@@ -530,8 +533,8 @@ def copy_modified(
             self.values if values is _dummy else values,
             self.upper_bound if upper_bound is _dummy else upper_bound,
             self.variance,
-            self.line,
-            self.column,
+            self.line if line is _dummy else line,
+            self.column if column is _dummy else column,
         )
 
     def accept(self, visitor: TypeVisitor[T]) -> T:
@@ -3233,11 +3236,12 @@ def replace_alias_tvars(
 
 
 class HasTypeVars(TypeQuery[bool]):
-    def __init__(self) -> None:
+    def __init__(self, exclude: TypeVarId | None = None) -> None:
         super().__init__(any)
+        self.exclude = exclude
 
     def visit_type_var(self, t: TypeVarType) -> bool:
-        return True
+        return t.id != self.exclude
 
     def visit_type_var_tuple(self, t: TypeVarTupleType) -> bool:
         return True
@@ -3246,9 +3250,9 @@ def visit_param_spec(self, t: ParamSpecType) -> bool:
         return True
 
 
-def has_type_vars(typ: Type) -> bool:
+def has_type_vars(typ: Type, exclude: TypeVarId | None = None) -> bool:
     """Check if a type contains any type variables (recursively)."""
-    return typ.accept(HasTypeVars())
+    return typ.accept(HasTypeVars(exclude))
 
 
 class HasRecursiveType(TypeQuery[bool]):
diff --git a/test-data/unit/check-dataclasses.test b/test-data/unit/check-dataclasses.test
index d4064124109bd..02abe8f1ddc4c 100644
--- a/test-data/unit/check-dataclasses.test
+++ b/test-data/unit/check-dataclasses.test
@@ -1933,3 +1933,28 @@ B = List[C]
 class C(CC): ...
 class CC: ...
 [builtins fixtures/dataclasses.pyi]
+
+[case testDataclassSelfType]
+# flags: --strict-optional
+from dataclasses import dataclass
+from typing import Self, TypeVar, Generic, Optional
+
+T = TypeVar("T")
+
+@dataclass
+class LinkedList(Generic[T]):
+    value: T
+    next: Optional[Self] = None
+
+    def meth(self) -> None:
+        reveal_type(self.next)  # N: Revealed type is "Union[Self`0, None]"
+
+l_int: LinkedList[int] = LinkedList(1, LinkedList("no", None))  # E: Argument 1 to "LinkedList" has incompatible type "str"; expected "int"
+
+@dataclass
+class SubLinkedList(LinkedList[int]): ...
+
+lst = SubLinkedList(1, LinkedList(2))  # E: Argument 2 to "SubLinkedList" has incompatible type "LinkedList[int]"; expected "Optional[SubLinkedList]"
+reveal_type(lst.next)  # N: Revealed type is "Union[__main__.SubLinkedList, None]"
+reveal_type(SubLinkedList)  # N: Revealed type is "def (value: builtins.int, next: Union[__main__.SubLinkedList, None] =) -> __main__.SubLinkedList"
+[builtins fixtures/dataclasses.pyi]
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index 131cd039a4679..5fca0f55a0d66 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -6312,3 +6312,25 @@ reveal_type(xs)
 [out]
 [out2]
 tmp/m.py:9: note: Revealed type is "builtins.list[builtins.int]"
+
+[case testTypingSelfCoarse]
+import m
+[file lib.py]
+from typing import Self
+
+class C:
+    def meth(self, other: Self) -> Self: ...
+
+[file m.py]
+import lib
+class D: ...
+[file m.py.2]
+import lib
+class D(lib.C): ...
+
+reveal_type(D.meth)
+reveal_type(D().meth)
+[out]
+[out2]
+tmp/m.py:4: note: Revealed type is "def [Self <: lib.C] (self: Self`0, other: Self`0) -> Self`0"
+tmp/m.py:5: note: Revealed type is "def (other: m.D) -> m.D"
diff --git a/test-data/unit/check-namedtuple.test b/test-data/unit/check-namedtuple.test
index 438e17a6ba0ad..4eda14c2c592e 100644
--- a/test-data/unit/check-namedtuple.test
+++ b/test-data/unit/check-namedtuple.test
@@ -1306,3 +1306,32 @@ class C(
 
 [builtins fixtures/tuple.pyi]
 [typing fixtures/typing-namedtuple.pyi]
+
+[case testNamedTupleSelfItemNotAllowed]
+from typing import Self, NamedTuple, Optional
+
+class NT(NamedTuple):
+    val: int
+    next: Optional[Self]  # E: Self type cannot be used in NamedTuple item type
+NTC = NamedTuple("NTC", [("val", int), ("next", Optional[Self])])  # E: Self type cannot be used in NamedTuple item type
+[builtins fixtures/tuple.pyi]
+[typing fixtures/typing-namedtuple.pyi]
+
+[case testNamedTupleTypingSelfMethod]
+from typing import Self, NamedTuple, TypeVar, Generic
+
+T = TypeVar("T")
+class NT(NamedTuple, Generic[T]):
+    key: str
+    val: T
+    def meth(self) -> Self:
+        nt: NT[int]
+        if bool():
+            return nt._replace()  # E: Incompatible return value type (got "NT[int]", expected "Self")
+        else:
+            return self._replace()
+
+class SNT(NT[int]): ...
+reveal_type(SNT("test", 42).meth())  # N: Revealed type is "Tuple[builtins.str, builtins.int, fallback=__main__.SNT]"
+[builtins fixtures/tuple.pyi]
+[typing fixtures/typing-namedtuple.pyi]
diff --git a/test-data/unit/check-protocols.test b/test-data/unit/check-protocols.test
index 77c14b92b2618..a8d033444806f 100644
--- a/test-data/unit/check-protocols.test
+++ b/test-data/unit/check-protocols.test
@@ -3890,3 +3890,54 @@ def f() -> str: ...
 [file package/badmod.py]
 def nothing() -> int: ...
 [builtins fixtures/module.pyi]
+
+[case testProtocolSelfTypeNewSyntax]
+from typing import Protocol, Self
+
+class P(Protocol):
+    @property
+    def next(self) -> Self: ...
+
+class C:
+    next: C
+class S:
+    next: Self
+
+x: P = C()
+y: P = S()
+
+z: P
+reveal_type(S().next)  # N: Revealed type is "__main__.S"
+reveal_type(z.next)  # N: Revealed type is "__main__.P"
+[builtins fixtures/property.pyi]
+
+[case testProtocolSelfTypeNewSyntaxSubProtocol]
+from typing import Protocol, Self
+
+class P(Protocol):
+    @property
+    def next(self) -> Self: ...
+class PS(P, Protocol):
+    @property
+    def other(self) -> Self: ...
+
+class C:
+    next: C
+    other: C
+class S:
+    next: Self
+    other: Self
+
+x: PS = C()
+y: PS = S()
+[builtins fixtures/property.pyi]
+
+[case testProtocolClassVarSelfType]
+from typing import ClassVar, Self, Protocol
+
+class P(Protocol):
+    DEFAULT: ClassVar[Self]
+class C:
+    DEFAULT: ClassVar[C]
+
+x: P = C()
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index 3d801d23a6423..a7dc41a2ff867 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -531,15 +531,15 @@ reveal_type(B().ft())  # N: Revealed type is "Tuple[builtins.int, builtins.int,
 [builtins fixtures/property.pyi]
 
 [case testSelfTypeProperSupertypeAttributeMeta]
-from typing import Callable, TypeVar, Type
+from typing import Callable, TypeVar, Type, ClassVar
 T = TypeVar('T')
 class A(type):
     @property
     def g(cls: object) -> int: return 0
     @property
     def gt(cls: T) -> T: return cls
-    f: Callable[[object], int]
-    ft: Callable[[T], T]
+    f: ClassVar[Callable[[object], int]]
+    ft: ClassVar[Callable[[T], T]]
 
 class B(A):
     pass
@@ -1353,3 +1353,380 @@ class Test(Generic[T]):
         a: deque[List[T]]
         # previously this failed with 'Incompatible types in assignment (expression has type "deque[List[List[T]]]", variable has type "deque[List[T]]")'
         b: deque[List[T]] = a.copy()
+
+[case testTypingSelfBasic]
+from typing import Self, List
+
+class C:
+    attr: List[Self]
+    def meth(self) -> List[Self]: ...
+    def test(self) -> Self:
+        if bool():
+            return C()  # E: Incompatible return value type (got "C", expected "Self")
+        else:
+            return self
+class D(C): ...
+
+reveal_type(C.meth)  # N: Revealed type is "def [Self <: __main__.C] (self: Self`0) -> builtins.list[Self`0]"
+C.attr  # E: Access to generic instance variables via class is ambiguous
+reveal_type(D().meth())  # N: Revealed type is "builtins.list[__main__.D]"
+reveal_type(D().attr)  # N: Revealed type is "builtins.list[__main__.D]"
+
+[case testTypingSelfInvalidLocations]
+from typing import Self, Callable
+
+var: Self  # E: Self type is only allowed in annotations within class definition
+reveal_type(var)  # N: Revealed type is "Any"
+
+def foo() -> Self: ...  # E: Self type is only allowed in annotations within class definition
+reveal_type(foo)  # N: Revealed type is "def () -> Any"
+
+bad: Callable[[Self], Self]  # E: Self type is only allowed in annotations within class definition
+reveal_type(bad)  # N: Revealed type is "def (Any) -> Any"
+
+def func() -> None:
+    var: Self  # E: Self type is only allowed in annotations within class definition
+
+class C(Self): ...  # E: Self type is only allowed in annotations within class definition
+
+[case testTypingSelfInvalidArgs]
+from typing import Self, List
+
+class C:
+    x: Self[int]  # E: Self type cannot have type arguments
+    def meth(self) -> List[Self[int]]:  # E: Self type cannot have type arguments
+        ...
+
+[case testTypingSelfConflict]
+from typing import Self, TypeVar, Tuple
+
+T = TypeVar("T")
+class C:
+    def meth(self: T) -> Tuple[Self, T]: ...  # E: Method cannot have explicit self annotation and Self type
+reveal_type(C().meth())  # N: Revealed type is "Tuple[<nothing>, __main__.C]"
+[builtins fixtures/property.pyi]
+
+[case testTypingSelfProperty]
+from typing import Self, Tuple
+class C:
+    @property
+    def attr(self) -> Tuple[Self, ...]: ...
+class D(C): ...
+
+reveal_type(D().attr)  # N: Revealed type is "builtins.tuple[__main__.D, ...]"
+[builtins fixtures/property.pyi]
+
+[case testTypingSelfCallableVar]
+from typing import Self, Callable
+
+class C:
+    x: Callable[[Self], Self]
+    def meth(self) -> Callable[[Self], Self]: ...
+class D(C): ...
+
+reveal_type(C().x)  # N: Revealed type is "def (__main__.C) -> __main__.C"
+reveal_type(D().x)  # N: Revealed type is "def (__main__.D) -> __main__.D"
+reveal_type(D().meth())  # N: Revealed type is "def (__main__.D) -> __main__.D"
+
+[case testTypingSelfClassMethod]
+from typing import Self
+
+class C:
+    @classmethod
+    def meth(cls) -> Self: ...
+    @staticmethod
+    def bad() -> Self: ...  # E: Static methods cannot use Self type \
+        # E: A function returning TypeVar should receive at least one argument containing the same TypeVar \
+        # N: Consider using the upper bound "C" instead
+
+class D(C): ...
+reveal_type(D.meth())  # N: Revealed type is "__main__.D"
+reveal_type(D.bad())  # N: Revealed type is "<nothing>"
+[builtins fixtures/classmethod.pyi]
+
+[case testTypingSelfOverload]
+from typing import Self, overload, Union
+
+class C:
+    @overload
+    def foo(self, other: Self) -> Self: ...
+    @overload
+    def foo(self, other: int) -> int: ...
+    def foo(self, other: Union[Self, int]) -> Union[Self, int]:
+        return other
+class D(C): ...
+reveal_type(D().foo)  # N: Revealed type is "Overload(def (other: __main__.D) -> __main__.D, def (other: builtins.int) -> builtins.int)"
+
+[case testTypingSelfNestedInAlias]
+from typing import Generic, Self, TypeVar, List, Tuple
+
+T = TypeVar("T")
+Pairs = List[Tuple[T, T]]
+
+class C(Generic[T]):
+    def pairs(self) -> Pairs[Self]: ...
+class D(C[T]): ...
+reveal_type(D[int]().pairs())  # N: Revealed type is "builtins.list[Tuple[__main__.D[builtins.int], __main__.D[builtins.int]]]"
+[builtins fixtures/tuple.pyi]
+
+[case testTypingSelfOverrideVar]
+from typing import Self, TypeVar, Generic
+
+T = TypeVar("T")
+class C(Generic[T]):
+    x: Self
+
+class D(C[int]):
+    x: D
+class Bad(C[int]):
+    x: C[int]  # E: Incompatible types in assignment (expression has type "C[int]", base class "C" defined the type as "Bad")
+
+[case testTypingSelfOverrideVarMulti]
+from typing import Self
+
+class C:
+    x: Self
+class D:
+    x: C
+class E:
+    x: Good
+
+class Bad(D, C):  # E: Definition of "x" in base class "D" is incompatible with definition in base class "C"
+    ...
+class Good(E, C):
+    ...
+
+[case testTypingSelfAlternativeGenericConstructor]
+from typing import Self, Generic, TypeVar, Tuple
+
+T = TypeVar("T")
+class C(Generic[T]):
+    def __init__(self, val: T) -> None: ...
+    @classmethod
+    def pair(cls, val: T) -> Tuple[Self, Self]:
+        return (cls(val), C(val))  # E: Incompatible return value type (got "Tuple[Self, C[T]]", expected "Tuple[Self, Self]")
+
+class D(C[int]): pass
+reveal_type(C.pair(42))  # N: Revealed type is "Tuple[__main__.C[builtins.int], __main__.C[builtins.int]]"
+reveal_type(D.pair("no"))  # N: Revealed type is "Tuple[__main__.D, __main__.D]" \
+    # E: Argument 1 to "pair" of "C" has incompatible type "str"; expected "int"
+[builtins fixtures/classmethod.pyi]
+
+[case testTypingSelfMixedTypeVars]
+from typing import Self, TypeVar, Generic, Tuple
+
+T = TypeVar("T")
+S = TypeVar("S")
+
+class C(Generic[T]):
+    def meth(self, arg: S) -> Tuple[Self, S, T]: ...
+
+class D(C[int]): ...
+
+c: C[int]
+d: D
+reveal_type(c.meth("test"))  # N: Revealed type is "Tuple[__main__.C[builtins.int], builtins.str, builtins.int]"
+reveal_type(d.meth("test"))  # N: Revealed type is "Tuple[__main__.D, builtins.str, builtins.int]"
+[builtins fixtures/tuple.pyi]
+
+[case testTypingSelfRecursiveInit]
+from typing import Self
+
+class C:
+    def __init__(self, other: Self) -> None: ...
+class D(C): ...
+
+reveal_type(C)  # N: Revealed type is "def (other: __main__.C) -> __main__.C"
+reveal_type(D)  # N: Revealed type is "def (other: __main__.D) -> __main__.D"
+
+[case testTypingSelfCorrectName]
+from typing import Self, List
+
+class C:
+    Self = List[C]
+    def meth(self) -> Self: ...
+reveal_type(C.meth)  # N: Revealed type is "def (self: __main__.C) -> builtins.list[__main__.C]"
+
+[case testTypingSelfClassVar]
+from typing import Self, ClassVar, Generic, TypeVar
+
+class C:
+    DEFAULT: ClassVar[Self]
+reveal_type(C.DEFAULT)  # N: Revealed type is "__main__.C"
+
+T = TypeVar("T")
+class G(Generic[T]):
+    BAD: ClassVar[Self]  # E: ClassVar cannot contain Self type in generic classes
+reveal_type(G.BAD)  # N: Revealed type is "__main__.G[Any]"
+
+[case testTypingSelfMetaClassDisabled]
+from typing import Self
+
+class Meta(type):
+    def meth(cls) -> Self: ...  # E: Self type cannot be used in a metaclass
+
+[case testTypingSelfNonAnnotationUses]
+from typing import Self, List, cast
+
+class C:
+    A = List[Self]  # E: Self type cannot be used in type alias target
+    B = cast(Self, ...)
+    def meth(self) -> A: ...
+
+class D(C): ...
+reveal_type(D().meth())  # N: Revealed type is "builtins.list[Any]"
+reveal_type(D().B)  # N: Revealed type is "__main__.D"
+
+[case testTypingSelfInternalSafe]
+from typing import Self
+
+class C:
+    x: Self
+    def __init__(self, x: C) -> None:
+        self.x = x  # E: Incompatible types in assignment (expression has type "C", variable has type "Self")
+
+[case testTypingSelfRedundantAllowed]
+from typing import Self, Type
+
+class C:
+    def f(self: Self) -> Self:
+        d: Defer
+        class Defer: ...
+        return self
+
+    @classmethod
+    def g(cls: Type[Self]) -> Self:
+        d: DeferAgain
+        class DeferAgain: ...
+        return cls()
+[builtins fixtures/classmethod.pyi]
+
+[case testTypingSelfRedundantWarning]
+# mypy: enable-error-code="redundant-self"
+
+from typing import Self, Type
+
+class C:
+    def copy(self: Self) -> Self:  # E: Redundant Self annotation on method first argument
+        d: Defer
+        class Defer: ...
+        return self
+
+    @classmethod
+    def g(cls: Type[Self]) -> Self:  # E: Redundant Self annotation on method first argument
+        d: DeferAgain
+        class DeferAgain: ...
+        return cls()
+[builtins fixtures/classmethod.pyi]
+
+[case testTypingSelfAssertType]
+from typing import Self, assert_type
+
+class C:
+    def foo(self) -> None:
+        assert_type(self, Self)  # E: Expression is of type "C", not "Self"
+        assert_type(C(), Self)  # E: Expression is of type "C", not "Self"
+
+    def bar(self) -> Self:
+        assert_type(self, Self)  # OK
+        assert_type(C(), Self)  # E: Expression is of type "C", not "Self"
+        return self
+
+[case testTypingSelfTypeVarClash]
+from typing import Self, TypeVar, Tuple
+
+S = TypeVar("S")
+class C:
+    def bar(self) -> Self: ...
+    def foo(self, x: S) -> Tuple[Self, S]: ...
+
+reveal_type(C.foo)  # N: Revealed type is "def [Self <: __main__.C, S] (self: Self`0, x: S`-1) -> Tuple[Self`0, S`-1]"
+reveal_type(C().foo(42))  # N: Revealed type is "Tuple[__main__.C, builtins.int]"
+[builtins fixtures/tuple.pyi]
+
+[case testTypingSelfTypeVarClashAttr]
+from typing import Self, TypeVar, Tuple, Callable
+
+class Defer(This): ...
+
+S = TypeVar("S")
+class C:
+    def bar(self) -> Self: ...
+    foo: Callable[[S, Self], Tuple[Self, S]]
+
+reveal_type(C().foo)  # N: Revealed type is "def [S] (S`-1, __main__.C) -> Tuple[__main__.C, S`-1]"
+reveal_type(C().foo(42, C()))  # N: Revealed type is "Tuple[__main__.C, builtins.int]"
+class This: ...
+[builtins fixtures/tuple.pyi]
+
+[case testTypingSelfAttrOldVsNewStyle]
+from typing import Self, TypeVar
+
+T = TypeVar("T", bound=C)
+class C:
+    x: Self
+    def foo(self: T) -> T:
+        return self.x
+    def bar(self: T) -> T:
+        self.x = self
+        return self
+    def baz(self: Self) -> None:
+        self.x = self
+    def bad(self) -> None:
+        # This is unfortunate, but required by PEP 484
+        self.x = self  # E: Incompatible types in assignment (expression has type "C", variable has type "Self")
+
+[case testTypingSelfClashInBodies]
+from typing import Self, TypeVar
+
+T = TypeVar("T")
+class C:
+    def very_bad(self, x: T) -> None:
+        self.x = x  # E: Incompatible types in assignment (expression has type "T", variable has type "Self")
+    x: Self
+    def baz(self: Self, x: T) -> None:
+        y: T = x
+
+[case testTypingSelfClashUnrelated]
+from typing import Self, Generic, TypeVar
+
+class B: ...
+
+T = TypeVar("T", bound=B)
+class C(Generic[T]):
+    def __init__(self, val: T) -> None:
+        self.val = val
+    def foo(self) -> Self: ...
+
+def test(x: C[T]) -> T:
+    reveal_type(x.val)  # N: Revealed type is "T`-1"
+    return x.val
+
+[case testTypingSelfGenericBound]
+from typing import Self, Generic, TypeVar
+
+T = TypeVar("T")
+class C(Generic[T]):
+    val: T
+    def foo(self) -> Self:
+        reveal_type(self.val)  # N: Revealed type is "T`1"
+        return self
+
+[case testTypingSelfDifferentImport]
+import typing as t
+
+class Foo:
+    def foo(self) -> t.Self:
+        return self
+    @classmethod
+    def bar(cls) -> t.Self:
+        return cls()
+[builtins fixtures/classmethod.pyi]
+
+[case testTypingSelfAllowAliasUseInFinalClasses]
+from typing import Self, final
+
+@final
+class C:
+    def meth(self) -> Self:
+        return C()  # OK for final classes
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index 796f2f547528c..24521062a5d45 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -2590,3 +2590,14 @@ TD[str](key=0, value=0)  # E: Incompatible types (expression has type "int", Typ
 TD[str]({"key": 0, "value": 0})  # E: Incompatible types (expression has type "int", TypedDict item "value" has type "str")
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
+
+[case testTypedDictSelfItemNotAllowed]
+from typing import Self, TypedDict, Optional
+
+class TD(TypedDict):
+    val: int
+    next: Optional[Self]  # E: Self type cannot be used in TypedDict item type
+TDC = TypedDict("TDC", {"val": int, "next": Optional[Self]})  # E: Self type cannot be used in TypedDict item type
+
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index 32c4ff2eecf0b..2fa3deadd16c2 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -10130,3 +10130,28 @@ b.py:2: error: "int" not callable
 a.py:1: error: Unsupported operand types for + ("int" and "str")
     1 + ''
         ^~
+
+[case testTypingSelfFine]
+import m
+[file lib.py]
+from typing import Any
+
+class C:
+    def meth(self, other: Any) -> C: ...
+[file lib.py.2]
+from typing import Self
+
+class C:
+    def meth(self, other: Self) -> Self: ...
+
+[file n.py]
+import lib
+class D(lib.C): ...
+[file m.py]
+from n import D
+d = D()
+def test() -> None:
+    d.meth(42)
+[out]
+==
+m.py:4: error: Argument 1 to "meth" of "C" has incompatible type "int"; expected "D"
diff --git a/test-data/unit/fixtures/typing-namedtuple.pyi b/test-data/unit/fixtures/typing-namedtuple.pyi
index d51134ead5998..1a31549463b69 100644
--- a/test-data/unit/fixtures/typing-namedtuple.pyi
+++ b/test-data/unit/fixtures/typing-namedtuple.pyi
@@ -5,6 +5,7 @@ overload = 0
 Type = 0
 Literal = 0
 Optional = 0
+Self = 0
 
 T_co = TypeVar('T_co', covariant=True)
 KT = TypeVar('KT')
diff --git a/test-data/unit/fixtures/typing-typeddict.pyi b/test-data/unit/fixtures/typing-typeddict.pyi
index 378570b4c19c8..e398dff3fc6b8 100644
--- a/test-data/unit/fixtures/typing-typeddict.pyi
+++ b/test-data/unit/fixtures/typing-typeddict.pyi
@@ -25,6 +25,7 @@ TypedDict = 0
 NoReturn = 0
 Required = 0
 NotRequired = 0
+Self = 0
 
 T = TypeVar('T')
 T_co = TypeVar('T_co', covariant=True)
diff --git a/test-data/unit/lib-stub/typing.pyi b/test-data/unit/lib-stub/typing.pyi
index 23d97704d9345..f3850d3936b45 100644
--- a/test-data/unit/lib-stub/typing.pyi
+++ b/test-data/unit/lib-stub/typing.pyi
@@ -27,6 +27,7 @@ NoReturn = 0
 Never = 0
 NewType = 0
 ParamSpec = 0
+Self = 0
 TYPE_CHECKING = 0
 
 T = TypeVar('T')

From 6cdee7b9c568e966104c05b7a27ffe43083a1310 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Tue, 15 Nov 2022 22:54:14 +0000
Subject: [PATCH 042/231] Delete unused symbol node (#14107)

IIRC `ImportedName` was used by old semantic analyzer, that is long gone
now.
---
 mypy/nodes.py | 37 -------------------------------------
 1 file changed, 37 deletions(-)

diff --git a/mypy/nodes.py b/mypy/nodes.py
index 7f2fd9a49838a..d0f55d6ce5a76 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -490,43 +490,6 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
         return visitor.visit_import_all(self)
 
 
-class ImportedName(SymbolNode):
-    """Indirect reference to a fullname stored in symbol table.
-
-    This node is not present in the original program as such. This is
-    just a temporary artifact in binding imported names. After semantic
-    analysis pass 2, these references should be replaced with direct
-    reference to a real AST node.
-
-    Note that this is neither a Statement nor an Expression so this
-    can't be visited.
-    """
-
-    __slots__ = ("target_fullname",)
-
-    def __init__(self, target_fullname: str) -> None:
-        super().__init__()
-        self.target_fullname = target_fullname
-
-    @property
-    def name(self) -> str:
-        return self.target_fullname.split(".")[-1]
-
-    @property
-    def fullname(self) -> str:
-        return self.target_fullname
-
-    def serialize(self) -> JsonDict:
-        assert False, "ImportedName leaked from semantic analysis"
-
-    @classmethod
-    def deserialize(cls, data: JsonDict) -> ImportedName:
-        assert False, "ImportedName should never be serialized"
-
-    def __str__(self) -> str:
-        return f"ImportedName({self.target_fullname})"
-
-
 FUNCBASE_FLAGS: Final = ["is_property", "is_class", "is_static", "is_final"]
 
 

From 0d2a954a20f239cde5f958b3e757ee4daab0d8b0 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Tue, 15 Nov 2022 22:55:24 +0000
Subject: [PATCH 043/231] Correctly process nested definitions in astmerge
 (#14104)

Fixes #12744

The fix is straightforward. Current logic can produce a random mix of
old and new nodes if there are functions/methods nested in other
statements.
---
 mypy/server/astmerge.py          |  2 +-
 test-data/unit/fine-grained.test | 50 ++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/mypy/server/astmerge.py b/mypy/server/astmerge.py
index 7a6b247c84f89..a14335acca7e7 100644
--- a/mypy/server/astmerge.py
+++ b/mypy/server/astmerge.py
@@ -213,8 +213,8 @@ def visit_mypy_file(self, node: MypyFile) -> None:
         super().visit_mypy_file(node)
 
     def visit_block(self, node: Block) -> None:
-        super().visit_block(node)
         node.body = self.replace_statements(node.body)
+        super().visit_block(node)
 
     def visit_func_def(self, node: FuncDef) -> None:
         node = self.fixup(node)
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index 2fa3deadd16c2..a6d8f206fbba0 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -10155,3 +10155,53 @@ def test() -> None:
 [out]
 ==
 m.py:4: error: Argument 1 to "meth" of "C" has incompatible type "int"; expected "D"
+
+[case testNoNestedDefinitionCrash]
+import m
+[file m.py]
+from typing import Any, TYPE_CHECKING
+
+class C:
+    if TYPE_CHECKING:
+        def __init__(self, **kw: Any): ...
+
+C
+[file m.py.2]
+from typing import Any, TYPE_CHECKING
+
+class C:
+    if TYPE_CHECKING:
+        def __init__(self, **kw: Any): ...
+
+C
+# change
+[builtins fixtures/dict.pyi]
+[out]
+==
+
+[case testNoNestedDefinitionCrash2]
+import m
+[file m.py]
+from typing import Any
+
+class C:
+    try:
+        def __init__(self, **kw: Any): ...
+    except:
+        pass
+
+C
+[file m.py.2]
+from typing import Any
+
+class C:
+    try:
+        def __init__(self, **kw: Any): ...
+    except:
+        pass
+
+C
+# change
+[builtins fixtures/dict.pyi]
+[out]
+==

From e01359d39978a0b2c132533c00567a4c264116ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andrzej=20Bartosi=C5=84ski?=
 <113755748+neob91-close@users.noreply.github.com>
Date: Wed, 16 Nov 2022 00:35:09 +0100
Subject: [PATCH 044/231] Prevent warnings from causing dmypy to fail (#14102)

Fixes: #14101

This prevents non-error messages (e.g. warnings) from causing dmypy to
return exit code 1.
---
 mypy/dmypy_server.py       |  3 ++-
 test-data/unit/daemon.test | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/mypy/dmypy_server.py b/mypy/dmypy_server.py
index be2f4ab8d6182..7227cd5599468 100644
--- a/mypy/dmypy_server.py
+++ b/mypy/dmypy_server.py
@@ -512,7 +512,8 @@ def initialize_fine_grained(
 
             print_memory_profile(run_gc=False)
 
-        status = 1 if messages else 0
+        __, n_notes, __ = count_stats(messages)
+        status = 1 if messages and n_notes < len(messages) else 0
         messages = self.pretty_messages(messages, len(sources), is_tty, terminal_width)
         return {"out": "".join(s + "\n" for s in messages), "err": "", "status": status}
 
diff --git a/test-data/unit/daemon.test b/test-data/unit/daemon.test
index 56966b2f740cc..c72dc3a32bc7c 100644
--- a/test-data/unit/daemon.test
+++ b/test-data/unit/daemon.test
@@ -214,6 +214,20 @@ mypy-daemon: error: Missing target module, package, files, or command.
 $ dmypy stop
 Daemon stopped
 
+[case testDaemonWarningSuccessExitCode-posix]
+$ dmypy run -- foo.py --follow-imports=error
+Daemon started
+foo.py:2: note: By default the bodies of untyped functions are not checked, consider using --check-untyped-defs
+Success: no issues found in 1 source file
+$ echo $?
+0
+$ dmypy stop
+Daemon stopped
+[file foo.py]
+def foo():
+    a: int = 1
+    print(a + "2")
+
 -- this is carefully constructed to be able to break if the quickstart system lets
 -- something through incorrectly. in particular, the files need to have the same size
 [case testDaemonQuickstart]

From 7d0d1d9d505869d55ee71e370941a8a47122087e Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 16 Nov 2022 00:02:17 +0000
Subject: [PATCH 045/231] Fix crash on nested generic callable (#14093)

Fixes #10244
Fixes #13515

This fixes only the crash part, I am going to fix also the embarrassing
type variable clash in a separate PR, since it is completely unrelated
issue.

The crash happens because solver can call `is_suptype()` on the
constraint bounds, and those can contain `<Erased>`. Then if it is a
generic callable type (e.g. `def [S] (S) -> T` when used as a context is
erased to `def [S] (S) -> <Erased>`), `is_subtype()` will try unifying
them, causing the crash when applying unified arguments.

My fix is to simply allow subtyping between callable types that contain
`<Erased>`, we anyway allow checking subtpying between all other types
with `<Erased>` components. And this technically can be useful, e.g. `[T
<: DerivedGen1[<Erased>], T <: DerivedGen2[<Erased>]]` will be solved as
`T <: NonGenBase`.

Btw this crash technically has nothing to do with dataclasses, but it
looks like there is no other way in mypy to define a callable with
generic callable as argument type, if I try:
```python
def foo(x: Callable[[S], T]) -> T: ...
```
to repro the crash, mypy instead interprets `foo` as `def [S, T] (x:
Callable[[S], T]) -> T`, i.e. the argument type is not generic. I also
tried callback protocols, but they also don't repro the crash (at least
I can't find a repro), because protocols use variance for subtyping,
before actually checking member types.
---
 mypy/applytype.py                     | 19 +++++++++++++-----
 mypy/expandtype.py                    | 29 ++++++++++++++++++++-------
 mypy/subtypes.py                      |  6 +++++-
 test-data/unit/check-dataclasses.test | 23 +++++++++++++++++++++
 4 files changed, 64 insertions(+), 13 deletions(-)

diff --git a/mypy/applytype.py b/mypy/applytype.py
index 1c401664568d0..d7f31b36c2445 100644
--- a/mypy/applytype.py
+++ b/mypy/applytype.py
@@ -73,6 +73,7 @@ def apply_generic_arguments(
     report_incompatible_typevar_value: Callable[[CallableType, Type, str, Context], None],
     context: Context,
     skip_unsatisfied: bool = False,
+    allow_erased_callables: bool = False,
 ) -> CallableType:
     """Apply generic type arguments to a callable type.
 
@@ -130,18 +131,26 @@ def apply_generic_arguments(
             + callable.arg_names[star_index + 1 :]
         )
         arg_types = (
-            [expand_type(at, id_to_type) for at in callable.arg_types[:star_index]]
+            [
+                expand_type(at, id_to_type, allow_erased_callables)
+                for at in callable.arg_types[:star_index]
+            ]
             + expanded
-            + [expand_type(at, id_to_type) for at in callable.arg_types[star_index + 1 :]]
+            + [
+                expand_type(at, id_to_type, allow_erased_callables)
+                for at in callable.arg_types[star_index + 1 :]
+            ]
         )
     else:
-        arg_types = [expand_type(at, id_to_type) for at in callable.arg_types]
+        arg_types = [
+            expand_type(at, id_to_type, allow_erased_callables) for at in callable.arg_types
+        ]
         arg_kinds = callable.arg_kinds
         arg_names = callable.arg_names
 
     # Apply arguments to TypeGuard if any.
     if callable.type_guard is not None:
-        type_guard = expand_type(callable.type_guard, id_to_type)
+        type_guard = expand_type(callable.type_guard, id_to_type, allow_erased_callables)
     else:
         type_guard = None
 
@@ -150,7 +159,7 @@ def apply_generic_arguments(
 
     return callable.copy_modified(
         arg_types=arg_types,
-        ret_type=expand_type(callable.ret_type, id_to_type),
+        ret_type=expand_type(callable.ret_type, id_to_type, allow_erased_callables),
         variables=remaining_tvars,
         type_guard=type_guard,
         arg_kinds=arg_kinds,
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 5a56857e11145..5bee9abc6dc82 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -39,20 +39,26 @@
 
 
 @overload
-def expand_type(typ: ProperType, env: Mapping[TypeVarId, Type]) -> ProperType:
+def expand_type(
+    typ: ProperType, env: Mapping[TypeVarId, Type], allow_erased_callables: bool = ...
+) -> ProperType:
     ...
 
 
 @overload
-def expand_type(typ: Type, env: Mapping[TypeVarId, Type]) -> Type:
+def expand_type(
+    typ: Type, env: Mapping[TypeVarId, Type], allow_erased_callables: bool = ...
+) -> Type:
     ...
 
 
-def expand_type(typ: Type, env: Mapping[TypeVarId, Type]) -> Type:
+def expand_type(
+    typ: Type, env: Mapping[TypeVarId, Type], allow_erased_callables: bool = False
+) -> Type:
     """Substitute any type variable references in a type given by a type
     environment.
     """
-    return typ.accept(ExpandTypeVisitor(env))
+    return typ.accept(ExpandTypeVisitor(env, allow_erased_callables))
 
 
 @overload
@@ -129,8 +135,11 @@ class ExpandTypeVisitor(TypeVisitor[Type]):
 
     variables: Mapping[TypeVarId, Type]  # TypeVar id -> TypeVar value
 
-    def __init__(self, variables: Mapping[TypeVarId, Type]) -> None:
+    def __init__(
+        self, variables: Mapping[TypeVarId, Type], allow_erased_callables: bool = False
+    ) -> None:
         self.variables = variables
+        self.allow_erased_callables = allow_erased_callables
 
     def visit_unbound_type(self, t: UnboundType) -> Type:
         return t
@@ -148,8 +157,14 @@ def visit_deleted_type(self, t: DeletedType) -> Type:
         return t
 
     def visit_erased_type(self, t: ErasedType) -> Type:
-        # Should not get here.
-        raise RuntimeError()
+        if not self.allow_erased_callables:
+            raise RuntimeError()
+        # This may happen during type inference if some function argument
+        # type is a generic callable, and its erased form will appear in inferred
+        # constraints, then solver may check subtyping between them, which will trigger
+        # unify_generic_callables(), this is why we can get here. In all other cases it
+        # is a sign of a bug, since <Erased> should never appear in any stored types.
+        return t
 
     def visit_instance(self, t: Instance) -> Type:
         args = self.expand_types_with_unpack(list(t.args))
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 7e49c19c42bb2..ce91b08b2e537 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -1667,8 +1667,12 @@ def report(*args: Any) -> None:
         nonlocal had_errors
         had_errors = True
 
+    # This function may be called by the solver, so we need to allow erased types here.
+    # We anyway allow checking subtyping between other types containing <Erased>
+    # (probably also because solver needs subtyping). See also comment in
+    # ExpandTypeVisitor.visit_erased_type().
     applied = mypy.applytype.apply_generic_arguments(
-        type, non_none_inferred_vars, report, context=target
+        type, non_none_inferred_vars, report, context=target, allow_erased_callables=True
     )
     if had_errors:
         return None
diff --git a/test-data/unit/check-dataclasses.test b/test-data/unit/check-dataclasses.test
index 02abe8f1ddc4c..d289ec5a8e58d 100644
--- a/test-data/unit/check-dataclasses.test
+++ b/test-data/unit/check-dataclasses.test
@@ -1958,3 +1958,26 @@ lst = SubLinkedList(1, LinkedList(2))  # E: Argument 2 to "SubLinkedList" has in
 reveal_type(lst.next)  # N: Revealed type is "Union[__main__.SubLinkedList, None]"
 reveal_type(SubLinkedList)  # N: Revealed type is "def (value: builtins.int, next: Union[__main__.SubLinkedList, None] =) -> __main__.SubLinkedList"
 [builtins fixtures/dataclasses.pyi]
+
+[case testNoCrashOnNestedGenericCallable]
+from dataclasses import dataclass
+from typing import Generic, TypeVar, Callable
+
+T = TypeVar('T')
+R = TypeVar('R')
+X = TypeVar('X')
+
+@dataclass
+class Box(Generic[T]):
+    inner: T
+
+@dataclass
+class Cont(Generic[R]):
+    run: Box[Callable[[X], R]]
+
+def const_two(x: T) -> str:
+    return "two"
+
+c = Cont(Box(const_two))
+reveal_type(c)  # N: Revealed type is "__main__.Cont[builtins.str]"
+[builtins fixtures/dataclasses.pyi]

From 6a7c7cdebdad318845959adfaca93c789b250a2e Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 16 Nov 2022 13:36:20 +0000
Subject: [PATCH 046/231] Allow class variable as implementation for read only
 attribute (#14081)

Fixes #10289

Unless I am missing something, this indeed looks safe, so I am going to
allow this.
---
 mypy/messages.py                    |  1 +
 mypy/subtypes.py                    |  5 ++++-
 test-data/unit/check-protocols.test | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/mypy/messages.py b/mypy/messages.py
index 75871d9b55210..1e2a5323b5125 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -2663,6 +2663,7 @@ def get_bad_protocol_flags(
         if (
             IS_CLASSVAR in subflags
             and IS_CLASSVAR not in superflags
+            and IS_SETTABLE in superflags
             or IS_CLASSVAR in superflags
             and IS_CLASSVAR not in subflags
             or IS_SETTABLE in superflags
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index ce91b08b2e537..2ebecb5d4093b 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -1040,7 +1040,10 @@ def named_type(fullname: str) -> Instance:
                 if not is_subtype(supertype, subtype):
                     return False
             if not class_obj:
-                if (IS_CLASSVAR in subflags) != (IS_CLASSVAR in superflags):
+                if IS_SETTABLE not in superflags:
+                    if IS_CLASSVAR in superflags and IS_CLASSVAR not in subflags:
+                        return False
+                elif (IS_CLASSVAR in subflags) != (IS_CLASSVAR in superflags):
                     return False
             else:
                 if IS_VAR in superflags and IS_CLASSVAR not in subflags:
diff --git a/test-data/unit/check-protocols.test b/test-data/unit/check-protocols.test
index a8d033444806f..35b62defc5581 100644
--- a/test-data/unit/check-protocols.test
+++ b/test-data/unit/check-protocols.test
@@ -1153,6 +1153,25 @@ x2 = y2 # E: Incompatible types in assignment (expression has type "PP", variabl
         # N: Protocol member P.attr expected settable variable, got read-only attribute
 [builtins fixtures/property.pyi]
 
+[case testClassVarProtocolImmutable]
+from typing import Protocol, ClassVar
+
+class P(Protocol):
+    @property
+    def x(self) -> int: ...
+
+class C:
+    x: ClassVar[int]
+
+class Bad:
+    x: ClassVar[str]
+
+x: P = C()
+y: P = Bad()  # E: Incompatible types in assignment (expression has type "Bad", variable has type "P") \
+              # N: Following member(s) of "Bad" have conflicts: \
+              # N:     x: expected "int", got "str"
+[builtins fixtures/property.pyi]
+
 [case testSettablePropertyInProtocols]
 from typing import Protocol
 

From f84f00a2738db3a541861afb7a0f67fb050095aa Mon Sep 17 00:00:00 2001
From: dosisod <39638017+dosisod@users.noreply.github.com>
Date: Wed, 16 Nov 2022 09:16:12 -0800
Subject: [PATCH 047/231] Remove `get_line()` and `get_column()` functions
 (#14071)

When I was working on a different PR for Mypy, I came across these
functions:

```python
    def get_line(self) -> int:
        """Don't use. Use x.line."""
        return self.line

    def get_column(self) -> int:
        """Don't use. Use x.column."""
        return self.column
```

So I just went ahead and removed them.
---
 mypy/messages.py         | 4 ++--
 mypy/nodes.py            | 8 --------
 mypy/report.py           | 2 +-
 mypy/semanal.py          | 4 ++--
 mypy/semanal_typeargs.py | 2 +-
 mypy/stats.py            | 2 +-
 mypy/strconv.py          | 2 +-
 7 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/mypy/messages.py b/mypy/messages.py
index 1e2a5323b5125..b6e34d38e3651 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -231,8 +231,8 @@ def span_from_context(ctx: Context) -> tuple[int, int]:
         else:
             origin_span = None
         self.errors.report(
-            context.get_line() if context else -1,
-            context.get_column() if context else -1,
+            context.line if context else -1,
+            context.column if context else -1,
             msg,
             severity=severity,
             file=file,
diff --git a/mypy/nodes.py b/mypy/nodes.py
index d0f55d6ce5a76..cf711c45f5871 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -71,14 +71,6 @@ def set_line(
         if end_column is not None:
             self.end_column = end_column
 
-    def get_line(self) -> int:
-        """Don't use. Use x.line."""
-        return self.line
-
-    def get_column(self) -> int:
-        """Don't use. Use x.column."""
-        return self.column
-
 
 if TYPE_CHECKING:
     # break import cycle only needed for mypy
diff --git a/mypy/report.py b/mypy/report.py
index 3fac2234c840e..75c372200ca37 100644
--- a/mypy/report.py
+++ b/mypy/report.py
@@ -353,7 +353,7 @@ def indentation_level(self, line_number: int) -> int | None:
         return None
 
     def visit_func_def(self, defn: FuncDef) -> None:
-        start_line = defn.get_line() - 1
+        start_line = defn.line - 1
         start_indent = None
         # When a function is decorated, sometimes the start line will point to
         # whitespace or comments between the decorator and the function, so
diff --git a/mypy/semanal.py b/mypy/semanal.py
index b8ffdc98eff5f..9b2b4ba44ccea 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -6109,12 +6109,12 @@ def fail(
             return
         # In case it's a bug and we don't really have context
         assert ctx is not None, msg
-        self.errors.report(ctx.get_line(), ctx.get_column(), msg, blocker=blocker, code=code)
+        self.errors.report(ctx.line, ctx.column, msg, blocker=blocker, code=code)
 
     def note(self, msg: str, ctx: Context, code: ErrorCode | None = None) -> None:
         if not self.in_checked_function():
             return
-        self.errors.report(ctx.get_line(), ctx.get_column(), msg, severity="note", code=code)
+        self.errors.report(ctx.line, ctx.column, msg, severity="note", code=code)
 
     def incomplete_feature_enabled(self, feature: str, ctx: Context) -> bool:
         if feature not in self.options.enable_incomplete_feature:
diff --git a/mypy/semanal_typeargs.py b/mypy/semanal_typeargs.py
index 161775ce8fd9f..72903423116fc 100644
--- a/mypy/semanal_typeargs.py
+++ b/mypy/semanal_typeargs.py
@@ -164,4 +164,4 @@ def check_type_var_values(
                     )
 
     def fail(self, msg: str, context: Context, *, code: ErrorCode | None = None) -> None:
-        self.errors.report(context.get_line(), context.get_column(), msg, code=code)
+        self.errors.report(context.line, context.column, msg, code=code)
diff --git a/mypy/stats.py b/mypy/stats.py
index af6c5fc14a500..b3a32c1ce72c6 100644
--- a/mypy/stats.py
+++ b/mypy/stats.py
@@ -149,7 +149,7 @@ def visit_func_def(self, o: FuncDef) -> None:
                 if o in o.expanded:
                     print(
                         "{}:{}: ERROR: cycle in function expansion; skipping".format(
-                            self.filename, o.get_line()
+                            self.filename, o.line
                         )
                     )
                     return
diff --git a/mypy/strconv.py b/mypy/strconv.py
index 9b369618b88e4..f1aa6819e2b72 100644
--- a/mypy/strconv.py
+++ b/mypy/strconv.py
@@ -50,7 +50,7 @@ def dump(self, nodes: Sequence[object], obj: mypy.nodes.Context) -> str:
         number. See mypy.util.dump_tagged for a description of the nodes
         argument.
         """
-        tag = short_type(obj) + ":" + str(obj.get_line())
+        tag = short_type(obj) + ":" + str(obj.line)
         if self.show_ids:
             assert self.id_mapper is not None
             tag += f"<{self.get_id(obj)}>"

From 49316f9fb8ccddc3941a1fbe378e4c96e929152f Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 16 Nov 2022 20:20:30 +0000
Subject: [PATCH 048/231] Allow super() for mixin protocols (#14082)

Fixes #12344

FWIW this is unsafe (since we don't know where the mixin will appear in
the MRO of the actual implementation), but the alternative is having
annoying false positives like this issue and e.g.
https://github.com/python/mypy/issues/4335
---
 mypy/checkexpr.py                  | 14 ++++++++++++--
 test-data/unit/check-selftype.test | 20 ++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 376e1f8116920..3d2c69073bc08 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -4321,8 +4321,18 @@ def visit_super_expr(self, e: SuperExpr) -> Type:
                     mro = e.info.mro
                     index = mro.index(type_info)
         if index is None:
-            self.chk.fail(message_registry.SUPER_ARG_2_NOT_INSTANCE_OF_ARG_1, e)
-            return AnyType(TypeOfAny.from_error)
+            if (
+                instance_info.is_protocol
+                and instance_info != type_info
+                and not type_info.is_protocol
+            ):
+                # A special case for mixins, in this case super() should point
+                # directly to the host protocol, this is not safe, since the real MRO
+                # is not known yet for mixin, but this feature is more like an escape hatch.
+                index = -1
+            else:
+                self.chk.fail(message_registry.SUPER_ARG_2_NOT_INSTANCE_OF_ARG_1, e)
+                return AnyType(TypeOfAny.from_error)
 
         if len(mro) == index + 1:
             self.chk.fail(message_registry.TARGET_CLASS_HAS_NO_BASE_CLASS, e)
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index a7dc41a2ff867..072978254049b 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -792,6 +792,26 @@ reveal_type(f.copy())  # N: Revealed type is "__main__.File"
 b.copy()  # E: Invalid self argument "Bad" to attribute function "copy" with type "Callable[[T], T]"
 [builtins fixtures/tuple.pyi]
 
+[case testMixinProtocolSuper]
+from typing import Protocol
+
+class Base(Protocol):
+    def func(self) -> int:
+        ...
+
+class TweakFunc:
+    def func(self: Base) -> int:
+        return reveal_type(super().func())  # N: Revealed type is "builtins.int"
+
+class Good:
+    def func(self) -> int: ...
+class C(TweakFunc, Good): pass
+C().func()  # OK
+
+class Bad:
+    def func(self) -> str: ...
+class CC(TweakFunc, Bad): pass  # E: Definition of "func" in base class "TweakFunc" is incompatible with definition in base class "Bad"
+
 [case testBadClassLevelDecoratorHack]
 from typing_extensions import Protocol
 from typing import TypeVar, Any

From 48c4a47c457b03caf00be2e2dacd91c3635cdc90 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 16 Nov 2022 21:39:45 +0000
Subject: [PATCH 049/231] Fix type variable clash in nested positions and in
 attributes (#14095)

Addresses the non-crash part of #10244 (and similar situations).

The `freshen_function_type_vars()` use in `checkmember.py` was
inconsistent:
* It needs to be applied to attributes too, not just methods
* It needs to be a visitor, since generic callable can appear in a
nested position

The downsides are ~2% performance regression, and people will see more
large ids in `reveal_type()` (since refreshing functions uses a global
unique counter). But since this is a correctness issue that can cause
really bizarre error messages, I think it is totally worth it.
---
 mypy/checkmember.py                | 41 ++++++++++--------
 mypy/expandtype.py                 | 21 ++++++++++
 mypy/typestate.py                  |  3 +-
 test-data/unit/check-generics.test | 67 +++++++++++++++++++++++++++++-
 test-data/unit/check-selftype.test |  2 +-
 5 files changed, 113 insertions(+), 21 deletions(-)

diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index c81b3fbe4f7e0..1c38bb4f00dcd 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -6,7 +6,11 @@
 
 from mypy import meet, message_registry, subtypes
 from mypy.erasetype import erase_typevars
-from mypy.expandtype import expand_self_type, expand_type_by_instance, freshen_function_type_vars
+from mypy.expandtype import (
+    expand_self_type,
+    expand_type_by_instance,
+    freshen_all_functions_type_vars,
+)
 from mypy.maptype import map_instance_to_supertype
 from mypy.messages import MessageBuilder
 from mypy.nodes import (
@@ -66,6 +70,7 @@
     get_proper_type,
     has_type_vars,
 )
+from mypy.typetraverser import TypeTraverserVisitor
 
 if TYPE_CHECKING:  # import for forward declaration only
     import mypy.checker
@@ -311,7 +316,7 @@ def analyze_instance_member_access(
         if mx.is_lvalue:
             mx.msg.cant_assign_to_method(mx.context)
         signature = function_type(method, mx.named_type("builtins.function"))
-        signature = freshen_function_type_vars(signature)
+        signature = freshen_all_functions_type_vars(signature)
         if name == "__new__" or method.is_static:
             # __new__ is special and behaves like a static method -- don't strip
             # the first argument.
@@ -329,7 +334,7 @@ def analyze_instance_member_access(
         # Since generic static methods should not be allowed.
         typ = map_instance_to_supertype(typ, method.info)
         member_type = expand_type_by_instance(signature, typ)
-        freeze_type_vars(member_type)
+        freeze_all_type_vars(member_type)
         return member_type
     else:
         # Not a method.
@@ -727,11 +732,13 @@ def analyze_var(
             mx.msg.read_only_property(name, itype.type, mx.context)
         if mx.is_lvalue and var.is_classvar:
             mx.msg.cant_assign_to_classvar(name, mx.context)
+        t = freshen_all_functions_type_vars(typ)
         if not (mx.is_self or mx.is_super) or supported_self_type(
             get_proper_type(mx.original_type)
         ):
-            typ = expand_self_type(var, typ, mx.original_type)
-        t = get_proper_type(expand_type_by_instance(typ, itype))
+            t = expand_self_type(var, t, mx.original_type)
+        t = get_proper_type(expand_type_by_instance(t, itype))
+        freeze_all_type_vars(t)
         result: Type = t
         typ = get_proper_type(typ)
         if (
@@ -759,13 +766,13 @@ def analyze_var(
                 # In `x.f`, when checking `x` against A1 we assume x is compatible with A
                 # and similarly for B1 when checking against B
                 dispatched_type = meet.meet_types(mx.original_type, itype)
-                signature = freshen_function_type_vars(functype)
+                signature = freshen_all_functions_type_vars(functype)
                 signature = check_self_arg(
                     signature, dispatched_type, var.is_classmethod, mx.context, name, mx.msg
                 )
                 signature = bind_self(signature, mx.self_type, var.is_classmethod)
                 expanded_signature = expand_type_by_instance(signature, itype)
-                freeze_type_vars(expanded_signature)
+                freeze_all_type_vars(expanded_signature)
                 if var.is_property:
                     # A property cannot have an overloaded type => the cast is fine.
                     assert isinstance(expanded_signature, CallableType)
@@ -788,16 +795,14 @@ def analyze_var(
     return result
 
 
-def freeze_type_vars(member_type: Type) -> None:
-    if not isinstance(member_type, ProperType):
-        return
-    if isinstance(member_type, CallableType):
-        for v in member_type.variables:
+def freeze_all_type_vars(member_type: Type) -> None:
+    member_type.accept(FreezeTypeVarsVisitor())
+
+
+class FreezeTypeVarsVisitor(TypeTraverserVisitor):
+    def visit_callable_type(self, t: CallableType) -> None:
+        for v in t.variables:
             v.id.meta_level = 0
-    if isinstance(member_type, Overloaded):
-        for it in member_type.items:
-            for v in it.variables:
-                v.id.meta_level = 0
 
 
 def lookup_member_var_or_accessor(info: TypeInfo, name: str, is_lvalue: bool) -> SymbolNode | None:
@@ -1131,11 +1136,11 @@ class B(A[str]): pass
     if isinstance(t, CallableType):
         tvars = original_vars if original_vars is not None else []
         if is_classmethod:
-            t = freshen_function_type_vars(t)
+            t = freshen_all_functions_type_vars(t)
             t = bind_self(t, original_type, is_classmethod=True)
             assert isuper is not None
             t = cast(CallableType, expand_type_by_instance(t, isuper))
-            freeze_type_vars(t)
+            freeze_all_type_vars(t)
         return t.copy_modified(variables=list(tvars) + list(t.variables))
     elif isinstance(t, Overloaded):
         return Overloaded(
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 5bee9abc6dc82..70fa62291aa34 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -3,6 +3,7 @@
 from typing import Iterable, Mapping, Sequence, TypeVar, cast, overload
 
 from mypy.nodes import ARG_STAR, Var
+from mypy.type_visitor import TypeTranslator
 from mypy.types import (
     AnyType,
     CallableType,
@@ -130,6 +131,26 @@ def freshen_function_type_vars(callee: F) -> F:
         return cast(F, fresh_overload)
 
 
+T = TypeVar("T", bound=Type)
+
+
+def freshen_all_functions_type_vars(t: T) -> T:
+    result = t.accept(FreshenCallableVisitor())
+    assert isinstance(result, type(t))
+    return result
+
+
+class FreshenCallableVisitor(TypeTranslator):
+    def visit_callable_type(self, t: CallableType) -> Type:
+        result = super().visit_callable_type(t)
+        assert isinstance(result, ProperType) and isinstance(result, CallableType)
+        return freshen_function_type_vars(result)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> Type:
+        # Same as for ExpandTypeVisitor
+        return t.copy_modified(args=[arg.accept(self) for arg in t.args])
+
+
 class ExpandTypeVisitor(TypeVisitor[Type]):
     """Visitor that substitutes type variables with values."""
 
diff --git a/mypy/typestate.py b/mypy/typestate.py
index a5d65c4b4ea39..7398f0d7f5242 100644
--- a/mypy/typestate.py
+++ b/mypy/typestate.py
@@ -10,7 +10,7 @@
 
 from mypy.nodes import TypeInfo
 from mypy.server.trigger import make_trigger
-from mypy.types import Instance, Type, get_proper_type
+from mypy.types import Instance, Type, TypeVarId, get_proper_type
 
 # Represents that the 'left' instance is a subtype of the 'right' instance
 SubtypeRelationship: _TypeAlias = Tuple[Instance, Instance]
@@ -275,3 +275,4 @@ def reset_global_state() -> None:
     """
     TypeState.reset_all_subtype_caches()
     TypeState.reset_protocol_deps()
+    TypeVarId.next_raw_id = 1
diff --git a/test-data/unit/check-generics.test b/test-data/unit/check-generics.test
index 7df52b60fc0bc..04108dded7234 100644
--- a/test-data/unit/check-generics.test
+++ b/test-data/unit/check-generics.test
@@ -1544,7 +1544,7 @@ class C(Generic[T]):
 reveal_type(C.F(17).foo())      # N: Revealed type is "builtins.int"
 reveal_type(C("").F(17).foo())  # N: Revealed type is "builtins.int"
 reveal_type(C.F)                # N: Revealed type is "def [K] (k: K`1) -> __main__.C.F[K`1]"
-reveal_type(C("").F)            # N: Revealed type is "def [K] (k: K`1) -> __main__.C.F[K`1]"
+reveal_type(C("").F)            # N: Revealed type is "def [K] (k: K`6) -> __main__.C.F[K`6]"
 
 
 -- Callable subtyping with generic functions
@@ -2580,3 +2580,68 @@ class Bar(Foo[AnyStr]):
 [out]
 main:10: error: Argument 1 to "method1" of "Foo" has incompatible type "str"; expected "AnyStr"
 main:10: error: Argument 2 to "method1" of "Foo" has incompatible type "bytes"; expected "AnyStr"
+
+[case testTypeVariableClashVar]
+from typing import Generic, TypeVar, Callable
+
+T = TypeVar("T")
+R = TypeVar("R")
+class C(Generic[R]):
+    x: Callable[[T], R]
+
+def func(x: C[R]) -> R:
+    return x.x(42)  # OK
+
+[case testTypeVariableClashVarTuple]
+from typing import Generic, TypeVar, Callable, Tuple
+
+T = TypeVar("T")
+R = TypeVar("R")
+class C(Generic[R]):
+    x: Callable[[T], Tuple[R, T]]
+
+def func(x: C[R]) -> R:
+    if bool():
+        return x.x(42)[0]  # OK
+    else:
+        return x.x(42)[1]  # E: Incompatible return value type (got "int", expected "R")
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVariableClashMethod]
+from typing import Generic, TypeVar, Callable
+
+T = TypeVar("T")
+R = TypeVar("R")
+class C(Generic[R]):
+    def x(self) -> Callable[[T], R]: ...
+
+def func(x: C[R]) -> R:
+    return x.x()(42)  # OK
+
+[case testTypeVariableClashMethodTuple]
+from typing import Generic, TypeVar, Callable, Tuple
+
+T = TypeVar("T")
+R = TypeVar("R")
+class C(Generic[R]):
+    def x(self) -> Callable[[T], Tuple[R, T]]: ...
+
+def func(x: C[R]) -> R:
+    if bool():
+        return x.x()(42)[0]  # OK
+    else:
+        return x.x()(42)[1]  # E: Incompatible return value type (got "int", expected "R")
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVariableClashVarSelf]
+from typing import Self, TypeVar, Generic, Callable
+
+T = TypeVar("T")
+S = TypeVar("S")
+
+class C(Generic[T]):
+    x: Callable[[S], Self]
+    y: T
+
+def foo(x: C[T]) -> T:
+    return x.x(42).y  # OK
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index 072978254049b..7fcac7ed75e9d 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -1674,7 +1674,7 @@ class C:
     def bar(self) -> Self: ...
     foo: Callable[[S, Self], Tuple[Self, S]]
 
-reveal_type(C().foo)  # N: Revealed type is "def [S] (S`-1, __main__.C) -> Tuple[__main__.C, S`-1]"
+reveal_type(C().foo)  # N: Revealed type is "def [S] (S`1, __main__.C) -> Tuple[__main__.C, S`1]"
 reveal_type(C().foo(42, C()))  # N: Revealed type is "Tuple[__main__.C, builtins.int]"
 class This: ...
 [builtins fixtures/tuple.pyi]

From 885e361b1cf97260d80e9dfa4e494ff362f0edff Mon Sep 17 00:00:00 2001
From: jhance <jhance@users.noreply.github.com>
Date: Thu, 17 Nov 2022 11:41:49 -0800
Subject: [PATCH 050/231] Handle prefix/suffix in typevartuple *args support
 (#14112)

This requires handling more cases in the various places that we
previously modified to support *args in general. We also need to refresh
the formals-to-actuals twice in checkexpr as now it can happen in the
infer_function_type_arguments_using_context call.

The handling here is kind of asymmetric, because we can convert prefices
into positional arguments, but there is no equivalent for suffices, so
we represent that as a Tuple[Unpack[...], <suffix>] and handle that case
separately in some spots.

We also support various edge cases like passing in a tuple without any
typevartuples involved.
---
 mypy/applytype.py                       | 83 +++++++++++++----------
 mypy/checker.py                         | 17 +++--
 mypy/checkexpr.py                       | 83 ++++++++++++++++++++---
 mypy/constraints.py                     | 22 ++++++-
 mypy/expandtype.py                      | 88 +++++++++++++++++++++----
 mypy/typevartuples.py                   | 20 +++++-
 test-data/unit/check-typevar-tuple.test | 33 ++++++++++
 7 files changed, 284 insertions(+), 62 deletions(-)

diff --git a/mypy/applytype.py b/mypy/applytype.py
index d7f31b36c2445..a81ed3cd1f161 100644
--- a/mypy/applytype.py
+++ b/mypy/applytype.py
@@ -4,13 +4,14 @@
 
 import mypy.subtypes
 from mypy.expandtype import expand_type, expand_unpack_with_variables
-from mypy.nodes import ARG_POS, ARG_STAR, Context
+from mypy.nodes import ARG_STAR, Context
 from mypy.types import (
     AnyType,
     CallableType,
     Parameters,
     ParamSpecType,
     PartialType,
+    TupleType,
     Type,
     TypeVarId,
     TypeVarLikeType,
@@ -19,6 +20,7 @@
     UnpackType,
     get_proper_type,
 )
+from mypy.typevartuples import find_unpack_in_list, replace_starargs
 
 
 def get_target_type(
@@ -114,39 +116,57 @@ def apply_generic_arguments(
     # Apply arguments to argument types.
     var_arg = callable.var_arg()
     if var_arg is not None and isinstance(var_arg.typ, UnpackType):
-        expanded = expand_unpack_with_variables(var_arg.typ, id_to_type)
-        assert isinstance(expanded, list)
-        # Handle other cases later.
-        for t in expanded:
-            assert not isinstance(t, UnpackType)
         star_index = callable.arg_kinds.index(ARG_STAR)
-        arg_kinds = (
-            callable.arg_kinds[:star_index]
-            + [ARG_POS] * len(expanded)
-            + callable.arg_kinds[star_index + 1 :]
+        callable = callable.copy_modified(
+            arg_types=(
+                [
+                    expand_type(at, id_to_type, allow_erased_callables)
+                    for at in callable.arg_types[:star_index]
+                ]
+                + [callable.arg_types[star_index]]
+                + [
+                    expand_type(at, id_to_type, allow_erased_callables)
+                    for at in callable.arg_types[star_index + 1 :]
+                ]
+            )
         )
-        arg_names = (
-            callable.arg_names[:star_index]
-            + [None] * len(expanded)
-            + callable.arg_names[star_index + 1 :]
-        )
-        arg_types = (
-            [
-                expand_type(at, id_to_type, allow_erased_callables)
-                for at in callable.arg_types[:star_index]
-            ]
-            + expanded
-            + [
-                expand_type(at, id_to_type, allow_erased_callables)
-                for at in callable.arg_types[star_index + 1 :]
+
+        unpacked_type = get_proper_type(var_arg.typ.type)
+        if isinstance(unpacked_type, TupleType):
+            # Assuming for now that because we convert prefixes to positional arguments,
+            # the first argument is always an unpack.
+            expanded_tuple = expand_type(unpacked_type, id_to_type)
+            if isinstance(expanded_tuple, TupleType):
+                # TODO: handle the case where the tuple has an unpack. This will
+                # hit an assert below.
+                expanded_unpack = find_unpack_in_list(expanded_tuple.items)
+                if expanded_unpack is not None:
+                    callable = callable.copy_modified(
+                        arg_types=(
+                            callable.arg_types[:star_index]
+                            + [expanded_tuple]
+                            + callable.arg_types[star_index + 1 :]
+                        )
+                    )
+                else:
+                    callable = replace_starargs(callable, expanded_tuple.items)
+            else:
+                # TODO: handle the case for if we get a variable length tuple.
+                assert False, f"mypy bug: unimplemented case, {expanded_tuple}"
+        elif isinstance(unpacked_type, TypeVarTupleType):
+            expanded_tvt = expand_unpack_with_variables(var_arg.typ, id_to_type)
+            assert isinstance(expanded_tvt, list)
+            for t in expanded_tvt:
+                assert not isinstance(t, UnpackType)
+            callable = replace_starargs(callable, expanded_tvt)
+        else:
+            assert False, "mypy bug: unhandled case applying unpack"
+    else:
+        callable = callable.copy_modified(
+            arg_types=[
+                expand_type(at, id_to_type, allow_erased_callables) for at in callable.arg_types
             ]
         )
-    else:
-        arg_types = [
-            expand_type(at, id_to_type, allow_erased_callables) for at in callable.arg_types
-        ]
-        arg_kinds = callable.arg_kinds
-        arg_names = callable.arg_names
 
     # Apply arguments to TypeGuard if any.
     if callable.type_guard is not None:
@@ -158,10 +178,7 @@ def apply_generic_arguments(
     remaining_tvars = [tv for tv in tvars if tv.id not in id_to_type]
 
     return callable.copy_modified(
-        arg_types=arg_types,
         ret_type=expand_type(callable.ret_type, id_to_type, allow_erased_callables),
         variables=remaining_tvars,
         type_guard=type_guard,
-        arg_kinds=arg_kinds,
-        arg_names=arg_names,
     )
diff --git a/mypy/checker.py b/mypy/checker.py
index 57725bd9186b8..c7de4911501a8 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -1178,12 +1178,17 @@ def check_func_def(
                         if isinstance(arg_type, ParamSpecType):
                             pass
                         elif isinstance(arg_type, UnpackType):
-                            arg_type = TupleType(
-                                [arg_type],
-                                fallback=self.named_generic_type(
-                                    "builtins.tuple", [self.named_type("builtins.object")]
-                                ),
-                            )
+                            if isinstance(get_proper_type(arg_type.type), TupleType):
+                                # Instead of using Tuple[Unpack[Tuple[...]]], just use
+                                # Tuple[...]
+                                arg_type = arg_type.type
+                            else:
+                                arg_type = TupleType(
+                                    [arg_type],
+                                    fallback=self.named_generic_type(
+                                        "builtins.tuple", [self.named_type("builtins.object")]
+                                    ),
+                                )
                         else:
                             # builtins.tuple[T] is typing.Tuple[T, ...]
                             arg_type = self.named_generic_type("builtins.tuple", [arg_type])
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 3d2c69073bc08..b41a38825fb39 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -150,6 +150,7 @@
     TypeVarType,
     UninhabitedType,
     UnionType,
+    UnpackType,
     flatten_nested_unions,
     get_proper_type,
     get_proper_types,
@@ -1404,13 +1405,21 @@ def check_callable_call(
             )
             callee = freshen_function_type_vars(callee)
             callee = self.infer_function_type_arguments_using_context(callee, context)
+            if need_refresh:
+                # Argument kinds etc. may have changed due to
+                # ParamSpec or TypeVarTuple variables being replaced with an arbitrary
+                # number of arguments; recalculate actual-to-formal map
+                formal_to_actual = map_actuals_to_formals(
+                    arg_kinds,
+                    arg_names,
+                    callee.arg_kinds,
+                    callee.arg_names,
+                    lambda i: self.accept(args[i]),
+                )
             callee = self.infer_function_type_arguments(
                 callee, args, arg_kinds, formal_to_actual, context
             )
             if need_refresh:
-                # Argument kinds etc. may have changed due to
-                # ParamSpec variables being replaced with an arbitrary
-                # number of arguments; recalculate actual-to-formal map
                 formal_to_actual = map_actuals_to_formals(
                     arg_kinds,
                     arg_names,
@@ -1999,11 +2008,66 @@ def check_argument_types(
         # Keep track of consumed tuple *arg items.
         mapper = ArgTypeExpander(self.argument_infer_context())
         for i, actuals in enumerate(formal_to_actual):
-            for actual in actuals:
-                actual_type = arg_types[actual]
+            orig_callee_arg_type = get_proper_type(callee.arg_types[i])
+
+            # Checking the case that we have more than one item but the first argument
+            # is an unpack, so this would be something like:
+            # [Tuple[Unpack[Ts]], int]
+            #
+            # In this case we have to check everything together, we do this by re-unifying
+            # the suffices to the tuple, e.g. a single actual like
+            # Tuple[Unpack[Ts], int]
+            expanded_tuple = False
+            if len(actuals) > 1:
+                first_actual_arg_type = get_proper_type(arg_types[actuals[0]])
+                if (
+                    isinstance(first_actual_arg_type, TupleType)
+                    and len(first_actual_arg_type.items) == 1
+                    and isinstance(get_proper_type(first_actual_arg_type.items[0]), UnpackType)
+                ):
+                    # TODO: use walrus operator
+                    actual_types = [first_actual_arg_type.items[0]] + [
+                        arg_types[a] for a in actuals[1:]
+                    ]
+                    actual_kinds = [nodes.ARG_STAR] + [nodes.ARG_POS] * (len(actuals) - 1)
+
+                    assert isinstance(orig_callee_arg_type, TupleType)
+                    assert orig_callee_arg_type.items
+                    callee_arg_types = orig_callee_arg_type.items
+                    callee_arg_kinds = [nodes.ARG_STAR] + [nodes.ARG_POS] * (
+                        len(orig_callee_arg_type.items) - 1
+                    )
+                    expanded_tuple = True
+
+            if not expanded_tuple:
+                actual_types = [arg_types[a] for a in actuals]
+                actual_kinds = [arg_kinds[a] for a in actuals]
+                if isinstance(orig_callee_arg_type, UnpackType):
+                    unpacked_type = get_proper_type(orig_callee_arg_type.type)
+                    # Only case we know of thus far.
+                    assert isinstance(unpacked_type, TupleType)
+                    actual_types = [arg_types[a] for a in actuals]
+                    actual_kinds = [arg_kinds[a] for a in actuals]
+                    callee_arg_types = unpacked_type.items
+                    callee_arg_kinds = [ARG_POS] * len(actuals)
+                else:
+                    callee_arg_types = [orig_callee_arg_type] * len(actuals)
+                    callee_arg_kinds = [callee.arg_kinds[i]] * len(actuals)
+
+            assert len(actual_types) == len(actuals) == len(actual_kinds)
+
+            if len(callee_arg_types) != len(actual_types):
+                # TODO: Improve error message
+                self.chk.fail("Invalid number of arguments", context)
+                continue
+
+            assert len(callee_arg_types) == len(actual_types)
+            assert len(callee_arg_types) == len(callee_arg_kinds)
+            for actual, actual_type, actual_kind, callee_arg_type, callee_arg_kind in zip(
+                actuals, actual_types, actual_kinds, callee_arg_types, callee_arg_kinds
+            ):
                 if actual_type is None:
                     continue  # Some kind of error was already reported.
-                actual_kind = arg_kinds[actual]
                 # Check that a *arg is valid as varargs.
                 if actual_kind == nodes.ARG_STAR and not self.is_valid_var_arg(actual_type):
                     self.msg.invalid_var_arg(actual_type, context)
@@ -2013,13 +2077,13 @@ def check_argument_types(
                     is_mapping = is_subtype(actual_type, self.chk.named_type("typing.Mapping"))
                     self.msg.invalid_keyword_var_arg(actual_type, is_mapping, context)
                 expanded_actual = mapper.expand_actual_type(
-                    actual_type, actual_kind, callee.arg_names[i], callee.arg_kinds[i]
+                    actual_type, actual_kind, callee.arg_names[i], callee_arg_kind
                 )
                 check_arg(
                     expanded_actual,
                     actual_type,
-                    arg_kinds[actual],
-                    callee.arg_types[i],
+                    actual_kind,
+                    callee_arg_type,
                     actual + 1,
                     i + 1,
                     callee,
@@ -4719,6 +4783,7 @@ def is_valid_var_arg(self, typ: Type) -> bool:
             )
             or isinstance(typ, AnyType)
             or isinstance(typ, ParamSpecType)
+            or isinstance(typ, UnpackType)
         )
 
     def is_valid_keyword_var_arg(self, typ: Type) -> bool:
diff --git a/mypy/constraints.py b/mypy/constraints.py
index 7123c590b7efb..4e78e5ff11176 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -133,8 +133,26 @@ def infer_constraints_for_callable(
                     )
                 )
 
-            assert isinstance(unpack_type.type, TypeVarTupleType)
-            constraints.append(Constraint(unpack_type.type, SUPERTYPE_OF, TypeList(actual_types)))
+            unpacked_type = get_proper_type(unpack_type.type)
+            if isinstance(unpacked_type, TypeVarTupleType):
+                constraints.append(Constraint(unpacked_type, SUPERTYPE_OF, TypeList(actual_types)))
+            elif isinstance(unpacked_type, TupleType):
+                # Prefixes get converted to positional args, so technically the only case we
+                # should have here is like Tuple[Unpack[Ts], Y1, Y2, Y3]. If this turns out
+                # not to hold we can always handle the prefixes too.
+                inner_unpack = unpacked_type.items[0]
+                assert isinstance(inner_unpack, UnpackType)
+                inner_unpacked_type = get_proper_type(inner_unpack.type)
+                assert isinstance(inner_unpacked_type, TypeVarTupleType)
+                suffix_len = len(unpacked_type.items) - 1
+                constraints.append(
+                    Constraint(
+                        inner_unpacked_type, SUPERTYPE_OF, TypeList(actual_types[:-suffix_len])
+                    )
+                )
+            else:
+                assert False, "mypy bug: unhandled constraint inference case"
+
         else:
             for actual in actuals:
                 actual_arg_type = arg_types[actual]
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 70fa62291aa34..43f4e6bcd75b5 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -2,7 +2,7 @@
 
 from typing import Iterable, Mapping, Sequence, TypeVar, cast, overload
 
-from mypy.nodes import ARG_STAR, Var
+from mypy.nodes import ARG_POS, ARG_STAR, Var
 from mypy.type_visitor import TypeTranslator
 from mypy.types import (
     AnyType,
@@ -36,7 +36,11 @@
     UnpackType,
     get_proper_type,
 )
-from mypy.typevartuples import split_with_instance, split_with_prefix_and_suffix
+from mypy.typevartuples import (
+    find_unpack_in_list,
+    split_with_instance,
+    split_with_prefix_and_suffix,
+)
 
 
 @overload
@@ -282,21 +286,83 @@ def visit_callable_type(self, t: CallableType) -> Type:
 
         var_arg = t.var_arg()
         if var_arg is not None and isinstance(var_arg.typ, UnpackType):
-            expanded = self.expand_unpack(var_arg.typ)
-            # Handle other cases later.
-            assert isinstance(expanded, list)
-            assert len(expanded) == 1 and isinstance(expanded[0], UnpackType)
             star_index = t.arg_kinds.index(ARG_STAR)
-            arg_types = (
-                self.expand_types(t.arg_types[:star_index])
-                + expanded
-                + self.expand_types(t.arg_types[star_index + 1 :])
-            )
+
+            # We have something like Unpack[Tuple[X1, X2, Unpack[Ts], Y1, Y2]]
+            if isinstance(get_proper_type(var_arg.typ.type), TupleType):
+                expanded_tuple = get_proper_type(var_arg.typ.type.accept(self))
+                # TODO: handle the case that expanded_tuple is a variable length tuple.
+                assert isinstance(expanded_tuple, TupleType)
+                expanded_unpack_index = find_unpack_in_list(expanded_tuple.items)
+                # This is the case where we just have Unpack[Tuple[X1, X2, X3]]
+                # (for example if either the tuple had no unpacks, or the unpack in the
+                # tuple got fully expanded to something with fixed length)
+                if expanded_unpack_index is None:
+                    arg_names = (
+                        t.arg_names[:star_index]
+                        + [None] * len(expanded_tuple.items)
+                        + t.arg_names[star_index + 1 :]
+                    )
+                    arg_kinds = (
+                        t.arg_kinds[:star_index]
+                        + [ARG_POS] * len(expanded_tuple.items)
+                        + t.arg_kinds[star_index + 1 :]
+                    )
+                    arg_types = (
+                        self.expand_types(t.arg_types[:star_index])
+                        + expanded_tuple.items
+                        + self.expand_types(t.arg_types[star_index + 1 :])
+                    )
+                else:
+                    # If Unpack[Ts] simplest form still has an unpack or is a
+                    # homogenous tuple, then only the prefix can be represented as
+                    # positional arguments, and we pass Tuple[Unpack[Ts-1], Y1, Y2]
+                    # as the star arg, for example.
+                    prefix_len = expanded_unpack_index
+                    arg_names = (
+                        t.arg_names[:star_index] + [None] * prefix_len + t.arg_names[star_index:]
+                    )
+                    arg_kinds = (
+                        t.arg_kinds[:star_index]
+                        + [ARG_POS] * prefix_len
+                        + t.arg_kinds[star_index:]
+                    )
+                    arg_types = (
+                        self.expand_types(t.arg_types[:star_index])
+                        + expanded_tuple.items[:prefix_len]
+                        # Constructing the Unpack containing the tuple without the prefix.
+                        + [
+                            UnpackType(
+                                expanded_tuple.copy_modified(
+                                    items=expanded_tuple.items[prefix_len:]
+                                )
+                            )
+                        ]
+                        + self.expand_types(t.arg_types[star_index + 1 :])
+                    )
+            else:
+                expanded = self.expand_unpack(var_arg.typ)
+                # Handle other cases later.
+                assert isinstance(expanded, list)
+                assert len(expanded) == 1 and isinstance(expanded[0], UnpackType)
+
+                # In this case we keep the arg as ARG_STAR.
+                arg_names = t.arg_names
+                arg_kinds = t.arg_kinds
+                arg_types = (
+                    self.expand_types(t.arg_types[:star_index])
+                    + expanded
+                    + self.expand_types(t.arg_types[star_index + 1 :])
+                )
         else:
             arg_types = self.expand_types(t.arg_types)
+            arg_names = t.arg_names
+            arg_kinds = t.arg_kinds
 
         return t.copy_modified(
             arg_types=arg_types,
+            arg_names=arg_names,
+            arg_kinds=arg_kinds,
             ret_type=t.ret_type.accept(self),
             type_guard=(t.type_guard.accept(self) if t.type_guard is not None else None),
         )
diff --git a/mypy/typevartuples.py b/mypy/typevartuples.py
index e93f99d8a825f..4b3b5cc2dca7e 100644
--- a/mypy/typevartuples.py
+++ b/mypy/typevartuples.py
@@ -4,7 +4,8 @@
 
 from typing import Sequence, TypeVar
 
-from mypy.types import Instance, ProperType, Type, UnpackType, get_proper_type
+from mypy.nodes import ARG_POS, ARG_STAR
+from mypy.types import CallableType, Instance, ProperType, Type, UnpackType, get_proper_type
 
 
 def find_unpack_in_list(items: Sequence[Type]) -> int | None:
@@ -150,3 +151,20 @@ def extract_unpack(types: Sequence[Type]) -> ProperType | None:
         if isinstance(proper_type, UnpackType):
             return get_proper_type(proper_type.type)
     return None
+
+
+def replace_starargs(callable: CallableType, types: list[Type]) -> CallableType:
+    star_index = callable.arg_kinds.index(ARG_STAR)
+    arg_kinds = (
+        callable.arg_kinds[:star_index]
+        + [ARG_POS] * len(types)
+        + callable.arg_kinds[star_index + 1 :]
+    )
+    arg_names = (
+        callable.arg_names[:star_index]
+        + [None] * len(types)
+        + callable.arg_names[star_index + 1 :]
+    )
+    arg_types = callable.arg_types[:star_index] + types + callable.arg_types[star_index + 1 :]
+
+    return callable.copy_modified(arg_types=arg_types, arg_names=arg_names, arg_kinds=arg_kinds)
diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test
index d8f6cde104410..d85990293aea0 100644
--- a/test-data/unit/check-typevar-tuple.test
+++ b/test-data/unit/check-typevar-tuple.test
@@ -381,4 +381,37 @@ def args_to_tuple(*args: Unpack[Ts]) -> Tuple[Unpack[Ts]]:
 
 reveal_type(args_to_tuple(1, 'a'))  # N: Revealed type is "Tuple[Literal[1]?, Literal['a']?]"
 
+def with_prefix_suffix(*args: Unpack[Tuple[bool, str, Unpack[Ts], int]]) -> Tuple[bool, str, Unpack[Ts], int]:
+    reveal_type(args)  # N: Revealed type is "Tuple[builtins.bool, builtins.str, Unpack[Ts`-1], builtins.int]"
+    return args
+
+reveal_type(with_prefix_suffix(True, "bar", "foo", 5))  # N: Revealed type is "Tuple[builtins.bool, builtins.str, Literal['foo']?, builtins.int]"
+reveal_type(with_prefix_suffix(True, "bar", 5))  # N: Revealed type is "Tuple[builtins.bool, builtins.str, builtins.int]"
+
+with_prefix_suffix(True, "bar", "foo", 1.0)  # E: Argument 4 to "with_prefix_suffix" has incompatible type "float"; expected "int"
+with_prefix_suffix(True, "bar")  # E: Too few arguments for "with_prefix_suffix"
+
+t = (True, "bar", "foo", 5)
+reveal_type(with_prefix_suffix(*t))  # N: Revealed type is "Tuple[builtins.bool, builtins.str, builtins.str, builtins.int]"
+reveal_type(with_prefix_suffix(True, *("bar", "foo"), 5))  # N: Revealed type is "Tuple[builtins.bool, builtins.str, Literal['foo']?, builtins.int]"
+
+# TODO: handle list case
+#reveal_type(with_prefix_suffix(True, "bar", *["foo1", "foo2"], 5))
+
+bad_t = (True, "bar")
+with_prefix_suffix(*bad_t)  # E: Too few arguments for "with_prefix_suffix"
+
+def foo(*args: Unpack[Ts]) -> None:
+    reveal_type(with_prefix_suffix(True, "bar", *args, 5))  # N: Revealed type is "Tuple[builtins.bool, builtins.str, Unpack[Ts`-1], builtins.int]"
+
+def concrete(*args: Unpack[Tuple[int, str]]) -> None:
+    reveal_type(args)  # N: Revealed type is "Tuple[builtins.int, builtins.str]"
+
+concrete(0, "foo")
+concrete(0, 1)  # E: Argument 2 to "concrete" has incompatible type "int"; expected "Unpack[Tuple[int, str]]"
+concrete("foo", "bar")  # E: Argument 1 to "concrete" has incompatible type "str"; expected "Unpack[Tuple[int, str]]"
+concrete(0, "foo", 1)  # E: Invalid number of arguments
+concrete(0)  # E: Invalid number of arguments
+concrete()  # E: Invalid number of arguments
+
 [builtins fixtures/tuple.pyi]

From 823667d55ca9387e4645ef2bef649cca90b9829f Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Thu, 17 Nov 2022 21:11:30 +0000
Subject: [PATCH 051/231] Fix crash during ParamSpec inference (#14118)

Fixes #13903

The fix is straightforward, the formal to actual map needs to be
refreshed twice, after both using external _and_ internal type context.
---
 test-data/unit/check-parameter-specification.test | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/test-data/unit/check-parameter-specification.test b/test-data/unit/check-parameter-specification.test
index 329985c4f75bf..b13f74bc3729b 100644
--- a/test-data/unit/check-parameter-specification.test
+++ b/test-data/unit/check-parameter-specification.test
@@ -1281,3 +1281,18 @@ class Some(Generic[P]):
 # TODO: this probably should be reported.
 def call(*args: P.args, **kwargs: P.kwargs): ...
 [builtins fixtures/paramspec.pyi]
+
+[case testParamSpecInferenceCrash]
+from typing import Callable, Generic, ParamSpec, TypeVar
+
+def foo(x: int) -> int: ...
+T = TypeVar("T")
+def bar(x: T) -> T: ...
+
+P = ParamSpec("P")
+
+class C(Generic[P]):
+    def __init__(self, fn: Callable[P, int], *args: P.args, **kwargs: P.kwargs): ...
+
+reveal_type(bar(C(fn=foo, x=1)))  # N: Revealed type is "__main__.C[[x: builtins.int]]"
+[builtins fixtures/paramspec.pyi]

From 401798fe7f36dc2e664bfae773c9faf5033aa6df Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Thu, 17 Nov 2022 22:01:41 +0000
Subject: [PATCH 052/231] Correctly support self types in callable ClassVar
 (#14115)

Fixes #14108

This fixes both new and old style of working with self types. After all
I fixed the new style by simply expanding self type, then `bind_self()`
does its job, so effect on the instance will be the same.

I had two options fixing this, other one (that I didn't go with) is
making the callable generic in new style, if it appears in `ClassVar`.
This however has two downsides: implementation is tricky, and this adds
and edge case to an existing edge case. So instead I choose internal
consistency within the new style, rather than similarity between old and
new style.
---
 mypy/checkmember.py                | 17 ++++++++++-------
 mypy/types.py                      |  9 ++++-----
 test-data/unit/check-selftype.test | 22 ++++++++++++++++++++++
 3 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index 1c38bb4f00dcd..08d4ff412e4e0 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -40,6 +40,7 @@
     class_callable,
     erase_to_bound,
     function_type,
+    get_type_vars,
     make_simplified_union,
     supported_self_type,
     tuple_fallback,
@@ -68,7 +69,6 @@
     TypeVarType,
     UnionType,
     get_proper_type,
-    has_type_vars,
 )
 from mypy.typetraverser import TypeTraverserVisitor
 
@@ -767,6 +767,9 @@ def analyze_var(
                 # and similarly for B1 when checking against B
                 dispatched_type = meet.meet_types(mx.original_type, itype)
                 signature = freshen_all_functions_type_vars(functype)
+                bound = get_proper_type(expand_self_type(var, signature, mx.original_type))
+                assert isinstance(bound, FunctionLike)
+                signature = bound
                 signature = check_self_arg(
                     signature, dispatched_type, var.is_classmethod, mx.context, name, mx.msg
                 )
@@ -960,11 +963,11 @@ def analyze_class_attribute_access(
             #     C.x  # Error, ambiguous access
             #     C[int].x  # Also an error, since C[int] is same as C at runtime
             # Exception is Self type wrapped in ClassVar, that is safe.
-            if node.node.info.self_type is not None and node.node.is_classvar:
-                exclude = node.node.info.self_type.id
-            else:
-                exclude = None
-            if isinstance(t, TypeVarType) and t.id != exclude or has_type_vars(t, exclude):
+            def_vars = set(node.node.info.defn.type_vars)
+            if not node.node.is_classvar and node.node.info.self_type:
+                def_vars.add(node.node.info.self_type)
+            typ_vars = set(get_type_vars(t))
+            if def_vars & typ_vars:
                 # Exception: access on Type[...], including first argument of class methods is OK.
                 if not isinstance(get_proper_type(mx.original_type), TypeType) or node.implicit:
                     if node.node.is_classvar:
@@ -978,7 +981,7 @@ def analyze_class_attribute_access(
             #     C.x -> Any
             #     C[int].x -> int
             t = get_proper_type(expand_self_type(node.node, t, itype))
-            t = erase_typevars(expand_type_by_instance(t, isuper))
+            t = erase_typevars(expand_type_by_instance(t, isuper), {tv.id for tv in def_vars})
 
         is_classmethod = (is_decorated and cast(Decorator, node.node).func.is_class) or (
             isinstance(node.node, FuncBase) and node.node.is_class
diff --git a/mypy/types.py b/mypy/types.py
index 242d64ee9075e..1de294f9952d8 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3236,12 +3236,11 @@ def replace_alias_tvars(
 
 
 class HasTypeVars(TypeQuery[bool]):
-    def __init__(self, exclude: TypeVarId | None = None) -> None:
+    def __init__(self) -> None:
         super().__init__(any)
-        self.exclude = exclude
 
     def visit_type_var(self, t: TypeVarType) -> bool:
-        return t.id != self.exclude
+        return True
 
     def visit_type_var_tuple(self, t: TypeVarTupleType) -> bool:
         return True
@@ -3250,9 +3249,9 @@ def visit_param_spec(self, t: ParamSpecType) -> bool:
         return True
 
 
-def has_type_vars(typ: Type, exclude: TypeVarId | None = None) -> bool:
+def has_type_vars(typ: Type) -> bool:
     """Check if a type contains any type variables (recursively)."""
-    return typ.accept(HasTypeVars(exclude))
+    return typ.accept(HasTypeVars())
 
 
 class HasRecursiveType(TypeQuery[bool]):
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index 7fcac7ed75e9d..494ae54400fbb 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -1750,3 +1750,25 @@ from typing import Self, final
 class C:
     def meth(self) -> Self:
         return C()  # OK for final classes
+
+[case testTypingSelfCallableClassVar]
+from typing import Self, ClassVar, Callable, TypeVar
+
+class C:
+    f: ClassVar[Callable[[Self], Self]]
+class D(C): ...
+
+reveal_type(D.f)  # N: Revealed type is "def (__main__.D) -> __main__.D"
+reveal_type(D().f)  # N: Revealed type is "def () -> __main__.D"
+
+[case testSelfTypeCallableClassVarOldStyle]
+from typing import ClassVar, Callable, TypeVar
+
+T = TypeVar("T")
+class C:
+    f: ClassVar[Callable[[T], T]]
+
+class D(C): ...
+
+reveal_type(D.f)  # N: Revealed type is "def [T] (T`-1) -> T`-1"
+reveal_type(D().f)  # N: Revealed type is "def () -> __main__.D"

From 6d1bcc1a97b15097fdfda96ae4fb0fad1e2499d7 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Thu, 17 Nov 2022 22:17:35 +0000
Subject: [PATCH 053/231] Fix class objects falling back to metaclass for
 callback protocol (#14121)

Fixes #10482

This is not very principled, but should work except people will want to
explicitly check some metaclass `__call__`.
---
 mypy/messages.py                    |  2 +-
 mypy/subtypes.py                    |  4 ++++
 test-data/unit/check-protocols.test | 17 +++++++++++++++++
 test-data/unit/fixtures/type.pyi    |  8 ++++++--
 4 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/mypy/messages.py b/mypy/messages.py
index b6e34d38e3651..2f487972d647e 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -1899,7 +1899,7 @@ def report_protocol_problems(
         missing = get_missing_protocol_members(subtype, supertype, skip=skip)
         if (
             missing
-            and len(missing) < len(supertype.type.protocol_members)
+            and (len(missing) < len(supertype.type.protocol_members) or missing == ["__call__"])
             and len(missing) <= MAX_ITEMS
         ):
             if missing == ["__call__"] and class_obj:
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 2ebecb5d4093b..14109587191c6 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -1005,6 +1005,10 @@ def named_type(fullname: str) -> Instance:
                 subtype: ProperType | None = mypy.checkmember.type_object_type(
                     left.type, named_type
                 )
+            elif member == "__call__" and left.type.is_metaclass():
+                # Special case: we want to avoid falling back to metaclass __call__
+                # if constructor signature didn't match, this can cause many false negatives.
+                subtype = None
             else:
                 subtype = get_proper_type(find_member(member, left, left, class_obj=class_obj))
             # Useful for debugging:
diff --git a/test-data/unit/check-protocols.test b/test-data/unit/check-protocols.test
index 35b62defc5581..8c4aef9b5be01 100644
--- a/test-data/unit/check-protocols.test
+++ b/test-data/unit/check-protocols.test
@@ -3526,6 +3526,23 @@ test(B)  # OK
 test(C)  # E: Argument 1 to "test" has incompatible type "Type[C]"; expected "P" \
          # N: "C" has constructor incompatible with "__call__" of "P"
 
+[case testProtocolClassObjectPureCallback]
+from typing import Any, ClassVar, Protocol
+
+class P(Protocol):
+    def __call__(self, x: int, y: int) -> Any: ...
+
+class B:
+    def __init__(self, x: int, y: int) -> None: ...
+class C:
+    def __init__(self, x: int, y: str) -> None: ...
+
+def test(arg: P) -> None: ...
+test(B)  # OK
+test(C)  # E: Argument 1 to "test" has incompatible type "Type[C]"; expected "P" \
+         # N: "C" has constructor incompatible with "__call__" of "P"
+[builtins fixtures/type.pyi]
+
 [case testProtocolTypeTypeAttribute]
 from typing import ClassVar, Protocol, Type
 
diff --git a/test-data/unit/fixtures/type.pyi b/test-data/unit/fixtures/type.pyi
index 77feb41ba70be..33dfb5475efa4 100644
--- a/test-data/unit/fixtures/type.pyi
+++ b/test-data/unit/fixtures/type.pyi
@@ -1,8 +1,9 @@
 # builtins stub used in type-related test cases.
 
-from typing import Generic, TypeVar, List, Union
+from typing import Any, Generic, TypeVar, List, Union
 
-T = TypeVar('T')
+T = TypeVar("T")
+S = TypeVar("S")
 
 class object:
     def __init__(self) -> None: pass
@@ -12,13 +13,16 @@ class list(Generic[T]): pass
 
 class type(Generic[T]):
     __name__: str
+    def __call__(self, *args: Any, **kwargs: Any) -> Any: pass
     def __or__(self, other: Union[type, None]) -> type: pass
     def __ror__(self, other: Union[type, None]) -> type: pass
     def mro(self) -> List['type']: pass
 
 class tuple(Generic[T]): pass
+class dict(Generic[T, S]): pass
 class function: pass
 class bool: pass
 class int: pass
 class str: pass
 class unicode: pass
+class ellipsis: pass

From abb5a809e3ec387f46898817c15a2d3137aee819 Mon Sep 17 00:00:00 2001
From: Ilya Konstantinov <ilya.konstantinov@gmail.com>
Date: Fri, 18 Nov 2022 00:32:19 -0500
Subject: [PATCH 054/231] mypy_primer: truncate per-project output (#14091)

Closes #14059
---
 .github/workflows/mypy_primer_comment.yml | 24 ++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/mypy_primer_comment.yml b/.github/workflows/mypy_primer_comment.yml
index 2056fc5a40c0f..b20eaf471c9a3 100644
--- a/.github/workflows/mypy_primer_comment.yml
+++ b/.github/workflows/mypy_primer_comment.yml
@@ -48,15 +48,29 @@ jobs:
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
+            const MAX_CHARACTERS = 30000
+            const MAX_CHARACTERS_PER_PROJECT = MAX_CHARACTERS / 3
+
             const fs = require('fs')
             let data = fs.readFileSync('fulldiff.txt', { encoding: 'utf8' })
-            // posting comment fails if too long, so truncate
-            if (data.length > 30000) {
-              let truncated_data = data.substring(0, 30000)
-              let lines_truncated = data.split('\n').length - truncated_data.split('\n').length
-              data = truncated_data + `\n\n... (truncated ${lines_truncated} lines) ...\n`
+
+            function truncateIfNeeded(original, maxLength) {
+              if (original.length <= maxLength) {
+                return original
+              }
+              let truncated = original.substring(0, maxLength)
+              // further, remove last line that might be truncated
+              truncated = truncated.substring(0, truncated.lastIndexOf('\n'))
+              let lines_truncated = original.split('\n').length - truncated.split('\n').length
+              return `${truncated}\n\n... (truncated ${lines_truncated} lines) ...`
             }
 
+            const projects = data.split('\n\n')
+            // don't let one project dominate
+            data = projects.map(project => truncateIfNeeded(project, MAX_CHARACTERS_PER_PROJECT)).join('\n\n')
+            // posting comment fails if too long, so truncate
+            data = truncateIfNeeded(data, MAX_CHARACTERS)
+
             console.log("Diff from mypy_primer:")
             console.log(data)
 

From 6e70826f94a8e9018ad1f3e975570ef1a14f2fc4 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 18 Nov 2022 01:01:34 -0800
Subject: [PATCH 055/231] Sync typeshed (#13987)

Source commit:

https://github.com/python/typeshed/commit/263427f438aa7d3f0bd570f671ecba9299c18968

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 mypy/typeshed/stdlib/_ast.pyi                 |  4 +-
 mypy/typeshed/stdlib/_codecs.pyi              | 61 ++++++++++--------
 mypy/typeshed/stdlib/_curses.pyi              |  7 +-
 mypy/typeshed/stdlib/_decimal.pyi             |  4 +-
 mypy/typeshed/stdlib/_msi.pyi                 | 10 +--
 mypy/typeshed/stdlib/_operator.pyi            | 32 +++++++---
 mypy/typeshed/stdlib/_posixsubprocess.pyi     | 42 +++++++-----
 mypy/typeshed/stdlib/_socket.pyi              | 24 ++++---
 mypy/typeshed/stdlib/_tkinter.pyi             |  6 +-
 mypy/typeshed/stdlib/_typeshed/__init__.pyi   |  6 +-
 mypy/typeshed/stdlib/_winapi.pyi              |  7 +-
 mypy/typeshed/stdlib/abc.pyi                  |  5 +-
 mypy/typeshed/stdlib/antigravity.pyi          |  4 +-
 mypy/typeshed/stdlib/array.pyi                | 14 ++--
 mypy/typeshed/stdlib/ast.pyi                  | 48 ++++++++------
 mypy/typeshed/stdlib/asyncio/base_events.pyi  |  8 +--
 mypy/typeshed/stdlib/asyncio/events.pyi       |  8 +--
 mypy/typeshed/stdlib/asyncio/sslproto.pyi     |  2 +-
 mypy/typeshed/stdlib/asyncio/streams.pyi      | 11 ++--
 mypy/typeshed/stdlib/asyncio/subprocess.pyi   |  2 +-
 mypy/typeshed/stdlib/asyncio/transports.pyi   |  6 +-
 mypy/typeshed/stdlib/asyncio/trsock.pyi       | 29 +++++----
 .../stdlib/asyncio/windows_events.pyi         | 10 ++-
 mypy/typeshed/stdlib/asyncore.pyi             |  4 +-
 mypy/typeshed/stdlib/base64.pyi               |  4 +-
 mypy/typeshed/stdlib/binhex.pyi               |  5 +-
 mypy/typeshed/stdlib/builtins.pyi             | 64 +++++++++----------
 mypy/typeshed/stdlib/bz2.pyi                  |  8 +--
 mypy/typeshed/stdlib/codecs.pyi               | 11 ++--
 mypy/typeshed/stdlib/ctypes/__init__.pyi      |  8 ++-
 mypy/typeshed/stdlib/datetime.pyi             | 11 +++-
 mypy/typeshed/stdlib/dbm/__init__.pyi         |  2 +-
 mypy/typeshed/stdlib/dbm/dumb.pyi             |  3 +
 mypy/typeshed/stdlib/dbm/gnu.pyi              |  8 +--
 mypy/typeshed/stdlib/dbm/ndbm.pyi             |  8 +--
 mypy/typeshed/stdlib/difflib.pyi              | 14 ++--
 mypy/typeshed/stdlib/dis.pyi                  | 15 ++---
 mypy/typeshed/stdlib/email/__init__.pyi       |  2 +-
 mypy/typeshed/stdlib/email/base64mime.pyi     | 12 ++--
 mypy/typeshed/stdlib/email/feedparser.pyi     |  2 +-
 mypy/typeshed/stdlib/email/header.pyi         |  7 +-
 mypy/typeshed/stdlib/email/message.pyi        |  2 +-
 .../stdlib/email/mime/application.pyi         |  2 +-
 mypy/typeshed/stdlib/email/mime/audio.pyi     |  2 +-
 mypy/typeshed/stdlib/email/mime/image.pyi     |  2 +-
 mypy/typeshed/stdlib/email/parser.pyi         |  2 +-
 mypy/typeshed/stdlib/email/quoprimime.pyi     | 12 ++--
 mypy/typeshed/stdlib/encodings/__init__.pyi   |  4 +-
 mypy/typeshed/stdlib/encodings/utf_8.pyi      |  7 +-
 mypy/typeshed/stdlib/encodings/utf_8_sig.pyi  |  7 +-
 mypy/typeshed/stdlib/fcntl.pyi                |  2 +-
 mypy/typeshed/stdlib/gzip.pyi                 | 16 ++---
 mypy/typeshed/stdlib/hmac.pyi                 | 12 ++--
 mypy/typeshed/stdlib/http/client.pyi          |  8 +--
 mypy/typeshed/stdlib/http/server.pyi          | 25 ++++++--
 mypy/typeshed/stdlib/imaplib.pyi              | 22 +++----
 mypy/typeshed/stdlib/imp.pyi                  |  9 ++-
 mypy/typeshed/stdlib/importlib/abc.pyi        | 40 +++++++-----
 mypy/typeshed/stdlib/importlib/machinery.pyi  | 23 +++----
 mypy/typeshed/stdlib/importlib/util.pyi       |  6 +-
 mypy/typeshed/stdlib/inspect.pyi              |  2 +-
 mypy/typeshed/stdlib/io.pyi                   |  4 +-
 mypy/typeshed/stdlib/ipaddress.pyi            |  4 +-
 mypy/typeshed/stdlib/json/__init__.pyi        |  4 +-
 mypy/typeshed/stdlib/logging/handlers.pyi     |  4 +-
 mypy/typeshed/stdlib/lzma.pyi                 | 10 +--
 mypy/typeshed/stdlib/mailbox.pyi              | 39 +++++------
 mypy/typeshed/stdlib/marshal.pyi              |  9 +--
 mypy/typeshed/stdlib/math.pyi                 | 25 +++++++-
 mypy/typeshed/stdlib/mmap.pyi                 |  7 +-
 mypy/typeshed/stdlib/msvcrt.pyi               |  4 +-
 .../stdlib/multiprocessing/connection.pyi     |  4 +-
 mypy/typeshed/stdlib/operator.pyi             |  1 -
 mypy/typeshed/stdlib/os/__init__.pyi          | 30 ++++++---
 mypy/typeshed/stdlib/pathlib.pyi              | 16 +++--
 mypy/typeshed/stdlib/pickle.pyi               | 13 ++--
 mypy/typeshed/stdlib/pickletools.pyi          |  6 +-
 mypy/typeshed/stdlib/plistlib.pyi             | 14 ++--
 mypy/typeshed/stdlib/pyexpat/__init__.pyi     |  7 +-
 mypy/typeshed/stdlib/quopri.pyi               | 13 ++--
 mypy/typeshed/stdlib/smtplib.pyi              | 17 +++--
 mypy/typeshed/stdlib/socket.pyi               | 30 +++++----
 mypy/typeshed/stdlib/sqlite3/dbapi2.pyi       | 12 ++--
 mypy/typeshed/stdlib/ssl.pyi                  | 46 +++++++------
 mypy/typeshed/stdlib/struct.pyi               |  4 +-
 mypy/typeshed/stdlib/tarfile.pyi              |  2 +-
 mypy/typeshed/stdlib/termios.pyi              | 42 ++++++++----
 mypy/typeshed/stdlib/tkinter/commondialog.pyi |  4 +-
 mypy/typeshed/stdlib/tkinter/dialog.pyi       |  2 +-
 mypy/typeshed/stdlib/tkinter/dnd.pyi          |  2 +-
 mypy/typeshed/stdlib/tkinter/scrolledtext.pyi |  3 +-
 mypy/typeshed/stdlib/tokenize.pyi             |  4 +-
 mypy/typeshed/stdlib/types.pyi                |  4 +-
 mypy/typeshed/stdlib/typing.pyi               | 17 ++---
 mypy/typeshed/stdlib/unicodedata.pyi          |  5 +-
 mypy/typeshed/stdlib/unittest/case.pyi        | 16 ++---
 mypy/typeshed/stdlib/unittest/mock.pyi        |  9 +--
 mypy/typeshed/stdlib/urllib/parse.pyi         | 27 ++++----
 mypy/typeshed/stdlib/urllib/response.pyi      |  6 +-
 mypy/typeshed/stdlib/weakref.pyi              |  9 ++-
 mypy/typeshed/stdlib/winsound.pyi             |  5 +-
 mypy/typeshed/stdlib/xml/__init__.pyi         |  2 +-
 mypy/typeshed/stdlib/xml/dom/expatbuilder.pyi | 14 ++--
 mypy/typeshed/stdlib/xml/dom/minidom.pyi      |  8 +--
 .../stdlib/xml/etree/ElementInclude.pyi       |  3 +-
 .../typeshed/stdlib/xml/etree/ElementTree.pyi | 24 +++----
 mypy/typeshed/stdlib/xml/parsers/__init__.pyi |  2 +-
 mypy/typeshed/stdlib/xml/sax/__init__.pyi     |  6 +-
 mypy/typeshed/stdlib/xml/sax/xmlreader.pyi    |  2 +-
 mypy/typeshed/stdlib/zipfile.pyi              | 10 ++-
 mypy/typeshed/stdlib/zipimport.pyi            |  9 ++-
 mypy/typeshed/stdlib/zlib.pyi                 | 26 ++++----
 mypy/typeshed/stdlib/zoneinfo/__init__.pyi    |  5 +-
 113 files changed, 759 insertions(+), 575 deletions(-)

diff --git a/mypy/typeshed/stdlib/_ast.pyi b/mypy/typeshed/stdlib/_ast.pyi
index b7d081f6acb21..f723b7eff8bb9 100644
--- a/mypy/typeshed/stdlib/_ast.pyi
+++ b/mypy/typeshed/stdlib/_ast.pyi
@@ -329,7 +329,7 @@ class JoinedStr(expr):
 
 if sys.version_info < (3, 8):
     class Num(expr):  # Deprecated in 3.8; use Constant
-        n: complex
+        n: int | float | complex
 
     class Str(expr):  # Deprecated in 3.8; use Constant
         s: str
@@ -349,7 +349,7 @@ class Constant(expr):
     kind: str | None
     # Aliases for value, for backwards compatibility
     s: Any
-    n: complex
+    n: int | float | complex
 
 if sys.version_info >= (3, 8):
     class NamedExpr(expr):
diff --git a/mypy/typeshed/stdlib/_codecs.pyi b/mypy/typeshed/stdlib/_codecs.pyi
index 9241ac6a70386..232256fbf6148 100644
--- a/mypy/typeshed/stdlib/_codecs.pyi
+++ b/mypy/typeshed/stdlib/_codecs.pyi
@@ -1,5 +1,6 @@
 import codecs
 import sys
+from _typeshed import ReadableBuffer
 from collections.abc import Callable
 from typing import overload
 from typing_extensions import Literal, TypeAlias
@@ -44,13 +45,13 @@ _BytesToBytesEncoding: TypeAlias = Literal[
 _StrToStrEncoding: TypeAlias = Literal["rot13", "rot_13"]
 
 @overload
-def encode(obj: bytes, encoding: _BytesToBytesEncoding, errors: str = ...) -> bytes: ...
+def encode(obj: ReadableBuffer, encoding: _BytesToBytesEncoding, errors: str = ...) -> bytes: ...
 @overload
 def encode(obj: str, encoding: _StrToStrEncoding, errors: str = ...) -> str: ...  # type: ignore[misc]
 @overload
 def encode(obj: str, encoding: str = ..., errors: str = ...) -> bytes: ...
 @overload
-def decode(obj: bytes, encoding: _BytesToBytesEncoding, errors: str = ...) -> bytes: ...  # type: ignore[misc]
+def decode(obj: ReadableBuffer, encoding: _BytesToBytesEncoding, errors: str = ...) -> bytes: ...  # type: ignore[misc]
 @overload
 def decode(obj: str, encoding: _StrToStrEncoding, errors: str = ...) -> str: ...
 
@@ -64,66 +65,72 @@ def decode(
 @overload
 def decode(obj: str, encoding: Literal["hex", "hex_codec"], errors: str = ...) -> bytes: ...
 @overload
-def decode(obj: bytes, encoding: str = ..., errors: str = ...) -> str: ...
+def decode(obj: ReadableBuffer, encoding: str = ..., errors: str = ...) -> str: ...
 def lookup(__encoding: str) -> codecs.CodecInfo: ...
 def charmap_build(__map: str) -> _CharMap: ...
-def ascii_decode(__data: bytes, __errors: str | None = ...) -> tuple[str, int]: ...
+def ascii_decode(__data: ReadableBuffer, __errors: str | None = ...) -> tuple[str, int]: ...
 def ascii_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def charmap_decode(__data: bytes, __errors: str | None = ..., __mapping: _CharMap | None = ...) -> tuple[str, int]: ...
+def charmap_decode(__data: ReadableBuffer, __errors: str | None = ..., __mapping: _CharMap | None = ...) -> tuple[str, int]: ...
 def charmap_encode(__str: str, __errors: str | None = ..., __mapping: _CharMap | None = ...) -> tuple[bytes, int]: ...
-def escape_decode(__data: str | bytes, __errors: str | None = ...) -> tuple[str, int]: ...
+def escape_decode(__data: str | ReadableBuffer, __errors: str | None = ...) -> tuple[str, int]: ...
 def escape_encode(__data: bytes, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def latin_1_decode(__data: bytes, __errors: str | None = ...) -> tuple[str, int]: ...
+def latin_1_decode(__data: ReadableBuffer, __errors: str | None = ...) -> tuple[str, int]: ...
 def latin_1_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
 
 if sys.version_info >= (3, 9):
-    def raw_unicode_escape_decode(__data: str | bytes, __errors: str | None = ..., __final: bool = ...) -> tuple[str, int]: ...
+    def raw_unicode_escape_decode(
+        __data: str | ReadableBuffer, __errors: str | None = ..., __final: bool = ...
+    ) -> tuple[str, int]: ...
 
 else:
-    def raw_unicode_escape_decode(__data: str | bytes, __errors: str | None = ...) -> tuple[str, int]: ...
+    def raw_unicode_escape_decode(__data: str | ReadableBuffer, __errors: str | None = ...) -> tuple[str, int]: ...
 
 def raw_unicode_escape_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def readbuffer_encode(__data: str | bytes, __errors: str | None = ...) -> tuple[bytes, int]: ...
+def readbuffer_encode(__data: str | ReadableBuffer, __errors: str | None = ...) -> tuple[bytes, int]: ...
 
 if sys.version_info >= (3, 9):
-    def unicode_escape_decode(__data: str | bytes, __errors: str | None = ..., __final: bool = ...) -> tuple[str, int]: ...
+    def unicode_escape_decode(
+        __data: str | ReadableBuffer, __errors: str | None = ..., __final: bool = ...
+    ) -> tuple[str, int]: ...
 
 else:
-    def unicode_escape_decode(__data: str | bytes, __errors: str | None = ...) -> tuple[str, int]: ...
+    def unicode_escape_decode(__data: str | ReadableBuffer, __errors: str | None = ...) -> tuple[str, int]: ...
 
 def unicode_escape_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
 
 if sys.version_info < (3, 8):
-    def unicode_internal_decode(__obj: str | bytes, __errors: str | None = ...) -> tuple[str, int]: ...
-    def unicode_internal_encode(__obj: str | bytes, __errors: str | None = ...) -> tuple[bytes, int]: ...
+    def unicode_internal_decode(__obj: str | ReadableBuffer, __errors: str | None = ...) -> tuple[str, int]: ...
+    def unicode_internal_encode(__obj: str | ReadableBuffer, __errors: str | None = ...) -> tuple[bytes, int]: ...
 
-def utf_16_be_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_16_be_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_16_be_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def utf_16_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_16_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_16_encode(__str: str, __errors: str | None = ..., __byteorder: int = ...) -> tuple[bytes, int]: ...
 def utf_16_ex_decode(
-    __data: bytes, __errors: str | None = ..., __byteorder: int = ..., __final: int = ...
+    __data: ReadableBuffer, __errors: str | None = ..., __byteorder: int = ..., __final: int = ...
 ) -> tuple[str, int, int]: ...
-def utf_16_le_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_16_le_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_16_le_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def utf_32_be_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_32_be_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_32_be_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def utf_32_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_32_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_32_encode(__str: str, __errors: str | None = ..., __byteorder: int = ...) -> tuple[bytes, int]: ...
 def utf_32_ex_decode(
-    __data: bytes, __errors: str | None = ..., __byteorder: int = ..., __final: int = ...
+    __data: ReadableBuffer, __errors: str | None = ..., __byteorder: int = ..., __final: int = ...
 ) -> tuple[str, int, int]: ...
-def utf_32_le_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_32_le_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_32_le_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def utf_7_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_7_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_7_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def utf_8_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+def utf_8_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
 def utf_8_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
 
 if sys.platform == "win32":
-    def mbcs_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+    def mbcs_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
     def mbcs_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-    def code_page_decode(__codepage: int, __data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+    def code_page_decode(
+        __codepage: int, __data: ReadableBuffer, __errors: str | None = ..., __final: int = ...
+    ) -> tuple[str, int]: ...
     def code_page_encode(__code_page: int, __str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-    def oem_decode(__data: bytes, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
+    def oem_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: int = ...) -> tuple[str, int]: ...
     def oem_encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
diff --git a/mypy/typeshed/stdlib/_curses.pyi b/mypy/typeshed/stdlib/_curses.pyi
index adb1ea84e45b3..7053e85f7b7fc 100644
--- a/mypy/typeshed/stdlib/_curses.pyi
+++ b/mypy/typeshed/stdlib/_curses.pyi
@@ -1,9 +1,10 @@
 import sys
-from _typeshed import SupportsRead
+from _typeshed import ReadOnlyBuffer, SupportsRead
 from typing import IO, Any, NamedTuple, overload
 from typing_extensions import TypeAlias, final
 
 if sys.platform != "win32":
+    # Handled by PyCurses_ConvertToChtype in _cursesmodule.c.
     _ChType: TypeAlias = str | bytes | int
 
     # ACS codes are only initialized after initscr is called
@@ -330,7 +331,7 @@ if sys.platform != "win32":
     def noraw() -> None: ...
     def pair_content(__pair_number: int) -> tuple[int, int]: ...
     def pair_number(__attr: int) -> int: ...
-    def putp(__string: bytes) -> None: ...
+    def putp(__string: ReadOnlyBuffer) -> None: ...
     def qiflush(__flag: bool = ...) -> None: ...
     def raw(__flag: bool = ...) -> None: ...
     def reset_prog_mode() -> None: ...
@@ -352,7 +353,7 @@ if sys.platform != "win32":
     def tigetnum(__capname: str) -> int: ...
     def tigetstr(__capname: str) -> bytes | None: ...
     def tparm(
-        __str: bytes,
+        __str: ReadOnlyBuffer,
         __i1: int = ...,
         __i2: int = ...,
         __i3: int = ...,
diff --git a/mypy/typeshed/stdlib/_decimal.pyi b/mypy/typeshed/stdlib/_decimal.pyi
index 50c0f23734cd2..ca97f69e21473 100644
--- a/mypy/typeshed/stdlib/_decimal.pyi
+++ b/mypy/typeshed/stdlib/_decimal.pyi
@@ -4,7 +4,7 @@ from _typeshed import Self
 from collections.abc import Container, Sequence
 from types import TracebackType
 from typing import Any, ClassVar, NamedTuple, Union, overload
-from typing_extensions import TypeAlias
+from typing_extensions import Literal, TypeAlias
 
 _Decimal: TypeAlias = Decimal | int
 _DecimalNew: TypeAlias = Union[Decimal, float, str, tuple[int, Sequence[int], int]]
@@ -16,7 +16,7 @@ __libmpdec_version__: str
 class DecimalTuple(NamedTuple):
     sign: int
     digits: tuple[int, ...]
-    exponent: int
+    exponent: int | Literal["n", "N", "F"]
 
 ROUND_DOWN: str
 ROUND_HALF_UP: str
diff --git a/mypy/typeshed/stdlib/_msi.pyi b/mypy/typeshed/stdlib/_msi.pyi
index 9dda8a598549e..1b86904d5ebc6 100644
--- a/mypy/typeshed/stdlib/_msi.pyi
+++ b/mypy/typeshed/stdlib/_msi.pyi
@@ -12,11 +12,11 @@ if sys.platform == "win32":
         # Don't exist at runtime
         __new__: None  # type: ignore[assignment]
         __init__: None  # type: ignore[assignment]
-    # Actual typename Summary, not exposed by the implementation
-    class _Summary:
-        def GetProperty(self, propid: int) -> str | bytes | None: ...
+    # Actual typename SummaryInformation, not exposed by the implementation
+    class _SummaryInformation:
+        def GetProperty(self, field: int) -> int | bytes | None: ...
         def GetPropertyCount(self) -> int: ...
-        def SetProperty(self, propid: int, value: str | bytes) -> None: ...
+        def SetProperty(self, field: int, value: int | str) -> None: ...
         def Persist(self) -> None: ...
         # Don't exist at runtime
         __new__: None  # type: ignore[assignment]
@@ -25,7 +25,7 @@ if sys.platform == "win32":
     class _Database:
         def OpenView(self, sql: str) -> _View: ...
         def Commit(self) -> None: ...
-        def GetSummaryInformation(self, updateCount: int) -> _Summary: ...
+        def GetSummaryInformation(self, updateCount: int) -> _SummaryInformation: ...
         def Close(self) -> None: ...
         # Don't exist at runtime
         __new__: None  # type: ignore[assignment]
diff --git a/mypy/typeshed/stdlib/_operator.pyi b/mypy/typeshed/stdlib/_operator.pyi
index 92e04d0f499d8..7488724caf74f 100644
--- a/mypy/typeshed/stdlib/_operator.pyi
+++ b/mypy/typeshed/stdlib/_operator.pyi
@@ -1,5 +1,6 @@
 import sys
-from collections.abc import Callable, Container, Iterable, Mapping, MutableMapping, MutableSequence, Sequence
+from _typeshed import SupportsGetItem
+from collections.abc import Callable, Container, Iterable, MutableMapping, MutableSequence, Sequence
 from typing import Any, AnyStr, Generic, Protocol, SupportsAbs, TypeVar, overload
 from typing_extensions import ParamSpec, SupportsIndex, TypeAlias, final
 
@@ -77,11 +78,9 @@ def delitem(__a: MutableSequence[Any], __b: slice) -> None: ...
 @overload
 def delitem(__a: MutableMapping[_K, Any], __b: _K) -> None: ...
 @overload
-def getitem(__a: Sequence[_T], __b: SupportsIndex) -> _T: ...
-@overload
 def getitem(__a: Sequence[_T], __b: slice) -> Sequence[_T]: ...
 @overload
-def getitem(__a: Mapping[_K, _V], __b: _K) -> _V: ...
+def getitem(__a: SupportsGetItem[_K, _V], __b: _K) -> _V: ...
 def indexOf(__a: Iterable[_T], __b: _T) -> int: ...
 @overload
 def setitem(__a: MutableSequence[_T], __b: SupportsIndex, __c: _T) -> None: ...
@@ -106,17 +105,30 @@ class attrgetter(Generic[_T_co]):
 
 @final
 class itemgetter(Generic[_T_co]):
+    # mypy lacks support for PEP 646 https://github.com/python/mypy/issues/12280
+    # So we have to define all of these overloads to simulate unpacking the arguments
     @overload
-    def __new__(cls, item: Any) -> itemgetter[Any]: ...
+    def __new__(cls, item: _T_co) -> itemgetter[_T_co]: ...
     @overload
-    def __new__(cls, item: Any, __item2: Any) -> itemgetter[tuple[Any, Any]]: ...
+    def __new__(cls, item: _T_co, __item2: _T_co) -> itemgetter[tuple[_T_co, _T_co]]: ...
     @overload
-    def __new__(cls, item: Any, __item2: Any, __item3: Any) -> itemgetter[tuple[Any, Any, Any]]: ...
+    def __new__(cls, item: _T_co, __item2: _T_co, __item3: _T_co) -> itemgetter[tuple[_T_co, _T_co, _T_co]]: ...
     @overload
-    def __new__(cls, item: Any, __item2: Any, __item3: Any, __item4: Any) -> itemgetter[tuple[Any, Any, Any, Any]]: ...
+    def __new__(
+        cls, item: _T_co, __item2: _T_co, __item3: _T_co, __item4: _T_co
+    ) -> itemgetter[tuple[_T_co, _T_co, _T_co, _T_co]]: ...
     @overload
-    def __new__(cls, item: Any, *items: Any) -> itemgetter[tuple[Any, ...]]: ...
-    def __call__(self, obj: Any) -> _T_co: ...
+    def __new__(
+        cls, item: _T_co, __item2: _T_co, __item3: _T_co, __item4: _T_co, *items: _T_co
+    ) -> itemgetter[tuple[_T_co, ...]]: ...
+    # __key: _KT_contra in SupportsGetItem seems to be causing variance issues, ie:
+    # TypeVar "_KT_contra@SupportsGetItem" is contravariant
+    #   "tuple[int, int]" is incompatible with protocol "SupportsIndex"
+    # preventing [_T_co, ...] instead of [Any, ...]
+    #
+    # A suspected mypy issue prevents using [..., _T] instead of [..., Any] here.
+    # https://github.com/python/mypy/issues/14032
+    def __call__(self, obj: SupportsGetItem[Any, Any]) -> Any: ...
 
 @final
 class methodcaller:
diff --git a/mypy/typeshed/stdlib/_posixsubprocess.pyi b/mypy/typeshed/stdlib/_posixsubprocess.pyi
index 2d221c4896f6a..ca95336bb503f 100644
--- a/mypy/typeshed/stdlib/_posixsubprocess.pyi
+++ b/mypy/typeshed/stdlib/_posixsubprocess.pyi
@@ -1,24 +1,32 @@
 import sys
+from _typeshed import StrOrBytesPath
 from collections.abc import Callable, Sequence
+from typing_extensions import SupportsIndex
 
 if sys.platform != "win32":
     def cloexec_pipe() -> tuple[int, int]: ...
     def fork_exec(
-        args: Sequence[str],
-        executable_list: Sequence[bytes],
-        close_fds: bool,
-        fds_to_keep: Sequence[int],
-        cwd: str,
-        env_list: Sequence[bytes],
-        p2cread: int,
-        p2cwrite: int,
-        c2pred: int,
-        c2pwrite: int,
-        errread: int,
-        errwrite: int,
-        errpipe_read: int,
-        errpipe_write: int,
-        restore_signals: int,
-        start_new_session: int,
-        preexec_fn: Callable[[], None],
+        __process_args: Sequence[StrOrBytesPath] | None,
+        __executable_list: Sequence[bytes],
+        __close_fds: bool,
+        __fds_to_keep: tuple[int, ...],
+        __cwd_obj: str,
+        __env_list: Sequence[bytes] | None,
+        __p2cread: int,
+        __p2cwrite: int,
+        __c2pred: int,
+        __c2pwrite: int,
+        __errread: int,
+        __errwrite: int,
+        __errpipe_read: int,
+        __errpipe_write: int,
+        __restore_signals: int,
+        __call_setsid: int,
+        __pgid_to_set: int,
+        __gid_object: SupportsIndex | None,
+        __groups_list: list[int] | None,
+        __uid_object: SupportsIndex | None,
+        __child_umask: int,
+        __preexec_fn: Callable[[], None],
+        __allow_vfork: bool,
     ) -> int: ...
diff --git a/mypy/typeshed/stdlib/_socket.pyi b/mypy/typeshed/stdlib/_socket.pyi
index b2f77893d2738..f7b0e6901bf4c 100644
--- a/mypy/typeshed/stdlib/_socket.pyi
+++ b/mypy/typeshed/stdlib/_socket.pyi
@@ -15,10 +15,10 @@ _CMSG: TypeAlias = tuple[int, int, bytes]
 _CMSGArg: TypeAlias = tuple[int, int, ReadableBuffer]
 
 # Addresses can be either tuples of varying lengths (AF_INET, AF_INET6,
-# AF_NETLINK, AF_TIPC) or strings (AF_UNIX).
-_Address: TypeAlias = tuple[Any, ...] | str
+# AF_NETLINK, AF_TIPC) or strings/buffers (AF_UNIX).
+# See getsockaddrarg() in socketmodule.c.
+_Address: TypeAlias = tuple[Any, ...] | str | ReadableBuffer
 _RetAddress: TypeAlias = Any
-# TODO Most methods allow bytes as address objects
 
 # ----- Constants -----
 # Some socket families are listed in the "Socket families" section of the docs,
@@ -583,11 +583,15 @@ class socket:
     def proto(self) -> int: ...
     @property
     def timeout(self) -> float | None: ...
-    def __init__(self, family: int = ..., type: int = ..., proto: int = ..., fileno: _FD | None = ...) -> None: ...
-    def bind(self, __address: _Address | bytes) -> None: ...
+    if sys.platform == "win32":
+        def __init__(self, family: int = ..., type: int = ..., proto: int = ..., fileno: _FD | bytes | None = ...) -> None: ...
+    else:
+        def __init__(self, family: int = ..., type: int = ..., proto: int = ..., fileno: _FD | None = ...) -> None: ...
+
+    def bind(self, __address: _Address) -> None: ...
     def close(self) -> None: ...
-    def connect(self, __address: _Address | bytes) -> None: ...
-    def connect_ex(self, __address: _Address | bytes) -> int: ...
+    def connect(self, __address: _Address) -> None: ...
+    def connect_ex(self, __address: _Address) -> int: ...
     def detach(self) -> int: ...
     def fileno(self) -> int: ...
     def getpeername(self) -> _RetAddress: ...
@@ -634,7 +638,7 @@ class socket:
     def setblocking(self, __flag: bool) -> None: ...
     def settimeout(self, __value: float | None) -> None: ...
     @overload
-    def setsockopt(self, __level: int, __optname: int, __value: int | bytes) -> None: ...
+    def setsockopt(self, __level: int, __optname: int, __value: int | ReadableBuffer) -> None: ...
     @overload
     def setsockopt(self, __level: int, __optname: int, __value: None, __optlen: int) -> None: ...
     if sys.platform == "win32":
@@ -671,9 +675,9 @@ def ntohs(__x: int) -> int: ...  # param & ret val are 16-bit ints
 def htonl(__x: int) -> int: ...  # param & ret val are 32-bit ints
 def htons(__x: int) -> int: ...  # param & ret val are 16-bit ints
 def inet_aton(__ip_string: str) -> bytes: ...  # ret val 4 bytes in length
-def inet_ntoa(__packed_ip: bytes) -> str: ...
+def inet_ntoa(__packed_ip: ReadableBuffer) -> str: ...
 def inet_pton(__address_family: int, __ip_string: str) -> bytes: ...
-def inet_ntop(__address_family: int, __packed_ip: bytes) -> str: ...
+def inet_ntop(__address_family: int, __packed_ip: ReadableBuffer) -> str: ...
 def getdefaulttimeout() -> float | None: ...
 def setdefaulttimeout(__timeout: float | None) -> None: ...
 
diff --git a/mypy/typeshed/stdlib/_tkinter.pyi b/mypy/typeshed/stdlib/_tkinter.pyi
index c2cf55505afb5..fced8c95d2fa5 100644
--- a/mypy/typeshed/stdlib/_tkinter.pyi
+++ b/mypy/typeshed/stdlib/_tkinter.pyi
@@ -17,8 +17,10 @@ from typing_extensions import Literal, final
 #    (<textindex object: '1.0'>, <textindex object: '2.0'>)
 @final
 class Tcl_Obj:
-    string: str | bytes
-    typename: str
+    @property
+    def string(self) -> str: ...
+    @property
+    def typename(self) -> str: ...
     __hash__: ClassVar[None]  # type: ignore[assignment]
     def __eq__(self, __other): ...
     def __ge__(self, __other): ...
diff --git a/mypy/typeshed/stdlib/_typeshed/__init__.pyi b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
index b0ee1f4ad48a3..1b54284fe7274 100644
--- a/mypy/typeshed/stdlib/_typeshed/__init__.pyi
+++ b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
@@ -119,7 +119,7 @@ class SupportsKeysAndGetItem(Protocol[_KT, _VT_co]):
 
 # stable
 class SupportsGetItem(Protocol[_KT_contra, _VT_co]):
-    def __contains__(self, __x: object) -> bool: ...
+    def __contains__(self, __x: Any) -> bool: ...
     def __getitem__(self, __key: _KT_contra) -> _VT_co: ...
 
 # stable
@@ -234,6 +234,7 @@ else:
     WriteableBuffer: TypeAlias = bytearray | memoryview | array.array[Any] | mmap.mmap | ctypes._CData  # stable
 # Same as _WriteableBuffer, but also includes read-only buffer types (like bytes).
 ReadableBuffer: TypeAlias = ReadOnlyBuffer | WriteableBuffer  # stable
+_BufferWithLen: TypeAlias = ReadableBuffer  # not stable  # noqa: Y047
 
 ExcInfo: TypeAlias = tuple[type[BaseException], BaseException, TracebackType]
 OptExcInfo: TypeAlias = Union[ExcInfo, tuple[None, None, None]]
@@ -275,5 +276,4 @@ StrOrLiteralStr = TypeVar("StrOrLiteralStr", LiteralString, str)  # noqa: Y001
 ProfileFunction: TypeAlias = Callable[[FrameType, str, Any], object]
 
 # Objects suitable to be passed to sys.settrace, threading.settrace, and similar
-# TODO: Ideally this would be a recursive type alias
-TraceFunction: TypeAlias = Callable[[FrameType, str, Any], Callable[[FrameType, str, Any], Any] | None]
+TraceFunction: TypeAlias = Callable[[FrameType, str, Any], TraceFunction | None]
diff --git a/mypy/typeshed/stdlib/_winapi.pyi b/mypy/typeshed/stdlib/_winapi.pyi
index ddea3d67ed14f..3ccac7e6b7e6b 100644
--- a/mypy/typeshed/stdlib/_winapi.pyi
+++ b/mypy/typeshed/stdlib/_winapi.pyi
@@ -1,4 +1,5 @@
 import sys
+from _typeshed import ReadableBuffer
 from collections.abc import Sequence
 from typing import Any, NoReturn, overload
 from typing_extensions import Literal, final
@@ -198,11 +199,11 @@ if sys.platform == "win32":
     def WaitForSingleObject(__handle: int, __milliseconds: int) -> int: ...
     def WaitNamedPipe(__name: str, __timeout: int) -> None: ...
     @overload
-    def WriteFile(handle: int, buffer: bytes, overlapped: Literal[True]) -> tuple[Overlapped, int]: ...
+    def WriteFile(handle: int, buffer: ReadableBuffer, overlapped: Literal[True]) -> tuple[Overlapped, int]: ...
     @overload
-    def WriteFile(handle: int, buffer: bytes, overlapped: Literal[False] = ...) -> tuple[int, int]: ...
+    def WriteFile(handle: int, buffer: ReadableBuffer, overlapped: Literal[False] = ...) -> tuple[int, int]: ...
     @overload
-    def WriteFile(handle: int, buffer: bytes, overlapped: int | bool) -> tuple[Any, int]: ...
+    def WriteFile(handle: int, buffer: ReadableBuffer, overlapped: int | bool) -> tuple[Any, int]: ...
     @final
     class Overlapped:
         event: int
diff --git a/mypy/typeshed/stdlib/abc.pyi b/mypy/typeshed/stdlib/abc.pyi
index f7f82333a3623..110eba24a9cae 100644
--- a/mypy/typeshed/stdlib/abc.pyi
+++ b/mypy/typeshed/stdlib/abc.pyi
@@ -16,10 +16,7 @@ class ABCMeta(type):
             __mcls: type[Self], __name: str, __bases: tuple[type, ...], __namespace: dict[str, Any], **kwargs: Any
         ) -> Self: ...
     else:
-        # pyright doesn't like the first parameter being called mcls, hence the `pyright: ignore`
-        def __new__(
-            mcls: type[Self], name: str, bases: tuple[type, ...], namespace: dict[str, Any], **kwargs: Any  # pyright: ignore
-        ) -> Self: ...
+        def __new__(mcls: type[Self], name: str, bases: tuple[type, ...], namespace: dict[str, Any], **kwargs: Any) -> Self: ...
 
     def __instancecheck__(cls: ABCMeta, instance: Any) -> Any: ...
     def __subclasscheck__(cls: ABCMeta, subclass: Any) -> Any: ...
diff --git a/mypy/typeshed/stdlib/antigravity.pyi b/mypy/typeshed/stdlib/antigravity.pyi
index e30917511030f..3986e7d1c9f24 100644
--- a/mypy/typeshed/stdlib/antigravity.pyi
+++ b/mypy/typeshed/stdlib/antigravity.pyi
@@ -1 +1,3 @@
-def geohash(latitude: float, longitude: float, datedow: bytes) -> None: ...
+from _typeshed import ReadableBuffer
+
+def geohash(latitude: float, longitude: float, datedow: ReadableBuffer) -> None: ...
diff --git a/mypy/typeshed/stdlib/array.pyi b/mypy/typeshed/stdlib/array.pyi
index 2d27cd72e8dfd..e84456049df64 100644
--- a/mypy/typeshed/stdlib/array.pyi
+++ b/mypy/typeshed/stdlib/array.pyi
@@ -21,15 +21,19 @@ class array(MutableSequence[_T], Generic[_T]):
     @property
     def itemsize(self) -> int: ...
     @overload
-    def __init__(self: array[int], __typecode: _IntTypeCode, __initializer: bytes | Iterable[int] = ...) -> None: ...
+    def __init__(self: array[int], __typecode: _IntTypeCode, __initializer: bytes | bytearray | Iterable[int] = ...) -> None: ...
     @overload
-    def __init__(self: array[float], __typecode: _FloatTypeCode, __initializer: bytes | Iterable[float] = ...) -> None: ...
+    def __init__(
+        self: array[float], __typecode: _FloatTypeCode, __initializer: bytes | bytearray | Iterable[float] = ...
+    ) -> None: ...
     @overload
-    def __init__(self: array[str], __typecode: _UnicodeTypeCode, __initializer: bytes | Iterable[str] = ...) -> None: ...
+    def __init__(
+        self: array[str], __typecode: _UnicodeTypeCode, __initializer: bytes | bytearray | Iterable[str] = ...
+    ) -> None: ...
     @overload
     def __init__(self, __typecode: str, __initializer: Iterable[_T]) -> None: ...
     @overload
-    def __init__(self, __typecode: str, __initializer: bytes = ...) -> None: ...
+    def __init__(self, __typecode: str, __initializer: bytes | bytearray = ...) -> None: ...
     def append(self, __v: _T) -> None: ...
     def buffer_info(self) -> tuple[int, int]: ...
     def byteswap(self) -> None: ...
@@ -52,7 +56,7 @@ class array(MutableSequence[_T], Generic[_T]):
     def tolist(self) -> list[_T]: ...
     def tounicode(self) -> str: ...
     if sys.version_info < (3, 9):
-        def fromstring(self, __buffer: bytes) -> None: ...
+        def fromstring(self, __buffer: str | ReadableBuffer) -> None: ...
         def tostring(self) -> bytes: ...
 
     def __len__(self) -> int: ...
diff --git a/mypy/typeshed/stdlib/ast.pyi b/mypy/typeshed/stdlib/ast.pyi
index 6c9dbd0162b8f..b2cff5b00264d 100644
--- a/mypy/typeshed/stdlib/ast.pyi
+++ b/mypy/typeshed/stdlib/ast.pyi
@@ -1,5 +1,7 @@
+import os
 import sys
 from _ast import *
+from _typeshed import ReadableBuffer
 from collections.abc import Iterator
 from typing import Any, TypeVar, overload
 from typing_extensions import Literal
@@ -10,7 +12,7 @@ if sys.version_info >= (3, 8):
             def __init__(cls, *args: object) -> None: ...
 
     class Num(Constant, metaclass=_ABC):
-        value: complex
+        value: int | float | complex
 
     class Str(Constant, metaclass=_ABC):
         value: str
@@ -157,8 +159,8 @@ _T = TypeVar("_T", bound=AST)
 if sys.version_info >= (3, 8):
     @overload
     def parse(
-        source: str | bytes,
-        filename: str | bytes = ...,
+        source: str | ReadableBuffer,
+        filename: str | ReadableBuffer | os.PathLike[Any] = ...,
         mode: Literal["exec"] = ...,
         *,
         type_comments: bool = ...,
@@ -166,8 +168,8 @@ if sys.version_info >= (3, 8):
     ) -> Module: ...
     @overload
     def parse(
-        source: str | bytes,
-        filename: str | bytes,
+        source: str | ReadableBuffer,
+        filename: str | ReadableBuffer | os.PathLike[Any],
         mode: Literal["eval"],
         *,
         type_comments: bool = ...,
@@ -175,8 +177,8 @@ if sys.version_info >= (3, 8):
     ) -> Expression: ...
     @overload
     def parse(
-        source: str | bytes,
-        filename: str | bytes,
+        source: str | ReadableBuffer,
+        filename: str | ReadableBuffer | os.PathLike[Any],
         mode: Literal["func_type"],
         *,
         type_comments: bool = ...,
@@ -184,8 +186,8 @@ if sys.version_info >= (3, 8):
     ) -> FunctionType: ...
     @overload
     def parse(
-        source: str | bytes,
-        filename: str | bytes,
+        source: str | ReadableBuffer,
+        filename: str | ReadableBuffer | os.PathLike[Any],
         mode: Literal["single"],
         *,
         type_comments: bool = ...,
@@ -193,7 +195,7 @@ if sys.version_info >= (3, 8):
     ) -> Interactive: ...
     @overload
     def parse(
-        source: str | bytes,
+        source: str | ReadableBuffer,
         *,
         mode: Literal["eval"],
         type_comments: bool = ...,
@@ -201,7 +203,7 @@ if sys.version_info >= (3, 8):
     ) -> Expression: ...
     @overload
     def parse(
-        source: str | bytes,
+        source: str | ReadableBuffer,
         *,
         mode: Literal["func_type"],
         type_comments: bool = ...,
@@ -209,7 +211,7 @@ if sys.version_info >= (3, 8):
     ) -> FunctionType: ...
     @overload
     def parse(
-        source: str | bytes,
+        source: str | ReadableBuffer,
         *,
         mode: Literal["single"],
         type_comments: bool = ...,
@@ -217,8 +219,8 @@ if sys.version_info >= (3, 8):
     ) -> Interactive: ...
     @overload
     def parse(
-        source: str | bytes,
-        filename: str | bytes = ...,
+        source: str | ReadableBuffer,
+        filename: str | ReadableBuffer | os.PathLike[Any] = ...,
         mode: str = ...,
         *,
         type_comments: bool = ...,
@@ -227,17 +229,23 @@ if sys.version_info >= (3, 8):
 
 else:
     @overload
-    def parse(source: str | bytes, filename: str | bytes = ..., mode: Literal["exec"] = ...) -> Module: ...
+    def parse(
+        source: str | ReadableBuffer, filename: str | ReadableBuffer | os.PathLike[Any] = ..., mode: Literal["exec"] = ...
+    ) -> Module: ...
     @overload
-    def parse(source: str | bytes, filename: str | bytes, mode: Literal["eval"]) -> Expression: ...
+    def parse(
+        source: str | ReadableBuffer, filename: str | ReadableBuffer | os.PathLike[Any], mode: Literal["eval"]
+    ) -> Expression: ...
     @overload
-    def parse(source: str | bytes, filename: str | bytes, mode: Literal["single"]) -> Interactive: ...
+    def parse(
+        source: str | ReadableBuffer, filename: str | ReadableBuffer | os.PathLike[Any], mode: Literal["single"]
+    ) -> Interactive: ...
     @overload
-    def parse(source: str | bytes, *, mode: Literal["eval"]) -> Expression: ...
+    def parse(source: str | ReadableBuffer, *, mode: Literal["eval"]) -> Expression: ...
     @overload
-    def parse(source: str | bytes, *, mode: Literal["single"]) -> Interactive: ...
+    def parse(source: str | ReadableBuffer, *, mode: Literal["single"]) -> Interactive: ...
     @overload
-    def parse(source: str | bytes, filename: str | bytes = ..., mode: str = ...) -> AST: ...
+    def parse(source: str | ReadableBuffer, filename: str | ReadableBuffer | os.PathLike[Any] = ..., mode: str = ...) -> AST: ...
 
 if sys.version_info >= (3, 9):
     def unparse(ast_obj: AST) -> str: ...
diff --git a/mypy/typeshed/stdlib/asyncio/base_events.pyi b/mypy/typeshed/stdlib/asyncio/base_events.pyi
index 8697bfe306c4a..c1ab114b6036e 100644
--- a/mypy/typeshed/stdlib/asyncio/base_events.pyi
+++ b/mypy/typeshed/stdlib/asyncio/base_events.pyi
@@ -1,6 +1,6 @@
 import ssl
 import sys
-from _typeshed import FileDescriptorLike, WriteableBuffer
+from _typeshed import FileDescriptorLike, ReadableBuffer, WriteableBuffer
 from asyncio.events import AbstractEventLoop, AbstractServer, Handle, TimerHandle, _TaskFactory
 from asyncio.futures import Future
 from asyncio.protocols import BaseProtocol
@@ -102,7 +102,7 @@ class BaseEventLoop(AbstractEventLoop):
     async def getaddrinfo(
         self,
         host: bytes | str | None,
-        port: str | int | None,
+        port: bytes | str | int | None,
         *,
         family: int = ...,
         type: int = ...,
@@ -411,13 +411,13 @@ class BaseEventLoop(AbstractEventLoop):
     # BaseEventLoop, only on subclasses. We list them here for now for convenience.
     async def sock_recv(self, sock: socket, nbytes: int) -> bytes: ...
     async def sock_recv_into(self, sock: socket, buf: WriteableBuffer) -> int: ...
-    async def sock_sendall(self, sock: socket, data: bytes) -> None: ...
+    async def sock_sendall(self, sock: socket, data: ReadableBuffer) -> None: ...
     async def sock_connect(self, sock: socket, address: _Address) -> None: ...
     async def sock_accept(self, sock: socket) -> tuple[socket, _RetAddress]: ...
     if sys.version_info >= (3, 11):
         async def sock_recvfrom(self, sock: socket, bufsize: int) -> bytes: ...
         async def sock_recvfrom_into(self, sock: socket, buf: WriteableBuffer, nbytes: int = ...) -> int: ...
-        async def sock_sendto(self, sock: socket, data: bytes, address: _Address) -> None: ...
+        async def sock_sendto(self, sock: socket, data: ReadableBuffer, address: _Address) -> None: ...
     # Signal handling.
     def add_signal_handler(self, sig: int, callback: Callable[..., Any], *args: Any) -> None: ...
     def remove_signal_handler(self, sig: int) -> bool: ...
diff --git a/mypy/typeshed/stdlib/asyncio/events.pyi b/mypy/typeshed/stdlib/asyncio/events.pyi
index 586116136c1a8..280be4ab5ba98 100644
--- a/mypy/typeshed/stdlib/asyncio/events.pyi
+++ b/mypy/typeshed/stdlib/asyncio/events.pyi
@@ -1,6 +1,6 @@
 import ssl
 import sys
-from _typeshed import FileDescriptorLike, Self, StrPath, WriteableBuffer
+from _typeshed import FileDescriptorLike, ReadableBuffer, Self, StrPath, WriteableBuffer
 from abc import ABCMeta, abstractmethod
 from collections.abc import Awaitable, Callable, Coroutine, Generator, Sequence
 from contextvars import Context
@@ -194,7 +194,7 @@ class AbstractEventLoop:
     async def getaddrinfo(
         self,
         host: bytes | str | None,
-        port: str | int | None,
+        port: bytes | str | int | None,
         *,
         family: int = ...,
         type: int = ...,
@@ -562,7 +562,7 @@ class AbstractEventLoop:
     @abstractmethod
     async def sock_recv_into(self, sock: socket, buf: WriteableBuffer) -> int: ...
     @abstractmethod
-    async def sock_sendall(self, sock: socket, data: bytes) -> None: ...
+    async def sock_sendall(self, sock: socket, data: ReadableBuffer) -> None: ...
     @abstractmethod
     async def sock_connect(self, sock: socket, address: _Address) -> None: ...
     @abstractmethod
@@ -573,7 +573,7 @@ class AbstractEventLoop:
         @abstractmethod
         async def sock_recvfrom_into(self, sock: socket, buf: WriteableBuffer, nbytes: int = ...) -> int: ...
         @abstractmethod
-        async def sock_sendto(self, sock: socket, data: bytes, address: _Address) -> None: ...
+        async def sock_sendto(self, sock: socket, data: ReadableBuffer, address: _Address) -> None: ...
     # Signal handling.
     @abstractmethod
     def add_signal_handler(self, sig: int, callback: Callable[..., object], *args: Any) -> None: ...
diff --git a/mypy/typeshed/stdlib/asyncio/sslproto.pyi b/mypy/typeshed/stdlib/asyncio/sslproto.pyi
index 3bb4db69c123a..3c1c7b2e4edbb 100644
--- a/mypy/typeshed/stdlib/asyncio/sslproto.pyi
+++ b/mypy/typeshed/stdlib/asyncio/sslproto.pyi
@@ -74,7 +74,7 @@ class _SSLProtocolTransport(transports._FlowControlMixin, transports.Transport):
     def get_extra_info(self, name: str, default: Any | None = ...) -> dict[str, Any]: ...
     @property
     def _protocol_paused(self) -> bool: ...
-    def write(self, data: bytes) -> None: ...
+    def write(self, data: bytes | bytearray | memoryview) -> None: ...
     def can_write_eof(self) -> Literal[False]: ...
     if sys.version_info >= (3, 11):
         def get_write_buffer_limits(self) -> tuple[int, int]: ...
diff --git a/mypy/typeshed/stdlib/asyncio/streams.pyi b/mypy/typeshed/stdlib/asyncio/streams.pyi
index 139d86b292c3d..00d95d93f2ff1 100644
--- a/mypy/typeshed/stdlib/asyncio/streams.pyi
+++ b/mypy/typeshed/stdlib/asyncio/streams.pyi
@@ -3,7 +3,7 @@ import sys
 from _typeshed import Self, StrPath
 from collections.abc import AsyncIterator, Awaitable, Callable, Iterable, Sequence
 from typing import Any
-from typing_extensions import TypeAlias
+from typing_extensions import SupportsIndex, TypeAlias
 
 from . import events, protocols, transports
 from .base_events import Server
@@ -139,8 +139,8 @@ class StreamWriter:
     ) -> None: ...
     @property
     def transport(self) -> transports.WriteTransport: ...
-    def write(self, data: bytes) -> None: ...
-    def writelines(self, data: Iterable[bytes]) -> None: ...
+    def write(self, data: bytes | bytearray | memoryview) -> None: ...
+    def writelines(self, data: Iterable[bytes | bytearray | memoryview]) -> None: ...
     def write_eof(self) -> None: ...
     def can_write_eof(self) -> bool: ...
     def close(self) -> None: ...
@@ -160,9 +160,10 @@ class StreamReader(AsyncIterator[bytes]):
     def set_transport(self, transport: transports.BaseTransport) -> None: ...
     def feed_eof(self) -> None: ...
     def at_eof(self) -> bool: ...
-    def feed_data(self, data: bytes) -> None: ...
+    def feed_data(self, data: Iterable[SupportsIndex]) -> None: ...
     async def readline(self) -> bytes: ...
-    async def readuntil(self, separator: bytes = ...) -> bytes: ...
+    # Can be any buffer that supports len(); consider changing to a Protocol if PEP 688 is accepted
+    async def readuntil(self, separator: bytes | bytearray | memoryview = ...) -> bytes: ...
     async def read(self, n: int = ...) -> bytes: ...
     async def readexactly(self, n: int) -> bytes: ...
     def __aiter__(self: Self) -> Self: ...
diff --git a/mypy/typeshed/stdlib/asyncio/subprocess.pyi b/mypy/typeshed/stdlib/asyncio/subprocess.pyi
index 32fcf1a654918..7fb5883969054 100644
--- a/mypy/typeshed/stdlib/asyncio/subprocess.pyi
+++ b/mypy/typeshed/stdlib/asyncio/subprocess.pyi
@@ -38,7 +38,7 @@ class Process:
     def send_signal(self, signal: int) -> None: ...
     def terminate(self) -> None: ...
     def kill(self) -> None: ...
-    async def communicate(self, input: bytes | None = ...) -> tuple[bytes, bytes]: ...
+    async def communicate(self, input: bytes | bytearray | memoryview | None = ...) -> tuple[bytes, bytes]: ...
 
 if sys.version_info >= (3, 10):
     async def create_subprocess_shell(
diff --git a/mypy/typeshed/stdlib/asyncio/transports.pyi b/mypy/typeshed/stdlib/asyncio/transports.pyi
index 3eb3d1ae3173d..893292dd12b65 100644
--- a/mypy/typeshed/stdlib/asyncio/transports.pyi
+++ b/mypy/typeshed/stdlib/asyncio/transports.pyi
@@ -23,8 +23,8 @@ class WriteTransport(BaseTransport):
     def set_write_buffer_limits(self, high: int | None = ..., low: int | None = ...) -> None: ...
     def get_write_buffer_size(self) -> int: ...
     def get_write_buffer_limits(self) -> tuple[int, int]: ...
-    def write(self, data: bytes) -> None: ...
-    def writelines(self, list_of_data: Iterable[bytes]) -> None: ...
+    def write(self, data: bytes | bytearray | memoryview) -> None: ...
+    def writelines(self, list_of_data: Iterable[bytes | bytearray | memoryview]) -> None: ...
     def write_eof(self) -> None: ...
     def can_write_eof(self) -> bool: ...
     def abort(self) -> None: ...
@@ -32,7 +32,7 @@ class WriteTransport(BaseTransport):
 class Transport(ReadTransport, WriteTransport): ...
 
 class DatagramTransport(BaseTransport):
-    def sendto(self, data: bytes, addr: _Address | None = ...) -> None: ...
+    def sendto(self, data: bytes | bytearray | memoryview, addr: _Address | None = ...) -> None: ...
     def abort(self) -> None: ...
 
 class SubprocessTransport(BaseTransport):
diff --git a/mypy/typeshed/stdlib/asyncio/trsock.pyi b/mypy/typeshed/stdlib/asyncio/trsock.pyi
index b8972e43d2554..742216a84ccd1 100644
--- a/mypy/typeshed/stdlib/asyncio/trsock.pyi
+++ b/mypy/typeshed/stdlib/asyncio/trsock.pyi
@@ -1,5 +1,6 @@
 import socket
 import sys
+from _typeshed import ReadableBuffer
 from builtins import type as Type  # alias to avoid name clashes with property named "type"
 from collections.abc import Iterable
 from types import TracebackType
@@ -7,7 +8,7 @@ from typing import Any, BinaryIO, NoReturn, overload
 from typing_extensions import TypeAlias
 
 # These are based in socket, maybe move them out into _typeshed.pyi or such
-_Address: TypeAlias = tuple[Any, ...] | str
+_Address: TypeAlias = socket._Address
 _RetAddress: TypeAlias = Any
 _WriteBuffer: TypeAlias = bytearray | memoryview
 _CMSG: TypeAlias = tuple[int, int, bytes]
@@ -30,7 +31,7 @@ class TransportSocket:
     @overload
     def getsockopt(self, level: int, optname: int, buflen: int) -> bytes: ...
     @overload
-    def setsockopt(self, level: int, optname: int, value: int | bytes) -> None: ...
+    def setsockopt(self, level: int, optname: int, value: int | ReadableBuffer) -> None: ...
     @overload
     def setsockopt(self, level: int, optname: int, value: None, optlen: int) -> None: ...
     def getpeername(self) -> _RetAddress: ...
@@ -42,9 +43,9 @@ class TransportSocket:
     if sys.version_info < (3, 11):
         def _na(self, what: str) -> None: ...
         def accept(self) -> tuple[socket.socket, _RetAddress]: ...
-        def connect(self, address: _Address | bytes) -> None: ...
-        def connect_ex(self, address: _Address | bytes) -> int: ...
-        def bind(self, address: _Address | bytes) -> None: ...
+        def connect(self, address: _Address) -> None: ...
+        def connect_ex(self, address: _Address) -> int: ...
+        def bind(self, address: _Address) -> None: ...
         if sys.platform == "win32":
             def ioctl(self, control: int, option: int | tuple[int, int, int] | bool) -> None: ...
         else:
@@ -57,22 +58,26 @@ class TransportSocket:
         def detach(self) -> int: ...
         if sys.platform == "linux":
             def sendmsg_afalg(
-                self, msg: Iterable[bytes] = ..., *, op: int, iv: Any = ..., assoclen: int = ..., flags: int = ...
+                self, msg: Iterable[ReadableBuffer] = ..., *, op: int, iv: Any = ..., assoclen: int = ..., flags: int = ...
             ) -> int: ...
         else:
             def sendmsg_afalg(
-                self, msg: Iterable[bytes] = ..., *, op: int, iv: Any = ..., assoclen: int = ..., flags: int = ...
+                self, msg: Iterable[ReadableBuffer] = ..., *, op: int, iv: Any = ..., assoclen: int = ..., flags: int = ...
             ) -> NoReturn: ...
 
         def sendmsg(
-            self, __buffers: Iterable[bytes], __ancdata: Iterable[_CMSG] = ..., __flags: int = ..., __address: _Address = ...
+            self,
+            __buffers: Iterable[ReadableBuffer],
+            __ancdata: Iterable[_CMSG] = ...,
+            __flags: int = ...,
+            __address: _Address = ...,
         ) -> int: ...
         @overload
-        def sendto(self, data: bytes, address: _Address) -> int: ...
+        def sendto(self, data: ReadableBuffer, address: _Address) -> int: ...
         @overload
-        def sendto(self, data: bytes, flags: int, address: _Address) -> int: ...
-        def send(self, data: bytes, flags: int = ...) -> int: ...
-        def sendall(self, data: bytes, flags: int = ...) -> None: ...
+        def sendto(self, data: ReadableBuffer, flags: int, address: _Address) -> int: ...
+        def send(self, data: ReadableBuffer, flags: int = ...) -> int: ...
+        def sendall(self, data: ReadableBuffer, flags: int = ...) -> None: ...
         def set_inheritable(self, inheritable: bool) -> None: ...
         if sys.platform == "win32":
             def share(self, process_id: int) -> bytes: ...
diff --git a/mypy/typeshed/stdlib/asyncio/windows_events.pyi b/mypy/typeshed/stdlib/asyncio/windows_events.pyi
index ffb487fff03aa..dca06ea33b138 100644
--- a/mypy/typeshed/stdlib/asyncio/windows_events.pyi
+++ b/mypy/typeshed/stdlib/asyncio/windows_events.pyi
@@ -1,6 +1,6 @@
 import socket
 import sys
-from _typeshed import WriteableBuffer
+from _typeshed import Incomplete, WriteableBuffer
 from collections.abc import Callable
 from typing import IO, Any, ClassVar, NoReturn
 from typing_extensions import Literal
@@ -50,10 +50,14 @@ if sys.platform == "win32":
         def recv_into(self, conn: socket.socket, buf: WriteableBuffer, flags: int = ...) -> futures.Future[Any]: ...
         def send(self, conn: socket.socket, buf: WriteableBuffer, flags: int = ...) -> futures.Future[Any]: ...
         def accept(self, listener: socket.socket) -> futures.Future[Any]: ...
-        def connect(self, conn: socket.socket, address: bytes) -> futures.Future[Any]: ...
+        def connect(
+            self,
+            conn: socket.socket,
+            address: tuple[Incomplete, Incomplete] | tuple[Incomplete, Incomplete, Incomplete, Incomplete],
+        ) -> futures.Future[Any]: ...
         def sendfile(self, sock: socket.socket, file: IO[bytes], offset: int, count: int) -> futures.Future[Any]: ...
         def accept_pipe(self, pipe: socket.socket) -> futures.Future[Any]: ...
-        async def connect_pipe(self, address: bytes) -> windows_utils.PipeHandle: ...
+        async def connect_pipe(self, address: str) -> windows_utils.PipeHandle: ...
         def wait_for_handle(self, handle: windows_utils.PipeHandle, timeout: int | None = ...) -> bool: ...
         def close(self) -> None: ...
     SelectorEventLoop = _WindowsSelectorEventLoop
diff --git a/mypy/typeshed/stdlib/asyncore.pyi b/mypy/typeshed/stdlib/asyncore.pyi
index 0025ec3f9b4ee..565deb4d1cad5 100644
--- a/mypy/typeshed/stdlib/asyncore.pyi
+++ b/mypy/typeshed/stdlib/asyncore.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import FileDescriptorLike
+from _typeshed import FileDescriptorLike, ReadableBuffer
 from socket import socket
 from typing import Any, overload
 from typing_extensions import TypeAlias
@@ -45,7 +45,7 @@ class dispatcher:
     def bind(self, addr: tuple[Any, ...] | str) -> None: ...
     def connect(self, address: tuple[Any, ...] | str) -> None: ...
     def accept(self) -> tuple[_Socket, Any] | None: ...
-    def send(self, data: bytes) -> int: ...
+    def send(self, data: ReadableBuffer) -> int: ...
     def recv(self, buffer_size: int) -> bytes: ...
     def close(self) -> None: ...
     def log(self, message: Any) -> None: ...
diff --git a/mypy/typeshed/stdlib/base64.pyi b/mypy/typeshed/stdlib/base64.pyi
index c2ec85cac40a5..816622eeb0712 100644
--- a/mypy/typeshed/stdlib/base64.pyi
+++ b/mypy/typeshed/stdlib/base64.pyi
@@ -42,7 +42,9 @@ if sys.version_info >= (3, 10):
     def b32hexdecode(s: str | ReadableBuffer, casefold: bool = ...) -> bytes: ...
 
 def a85encode(b: ReadableBuffer, *, foldspaces: bool = ..., wrapcol: int = ..., pad: bool = ..., adobe: bool = ...) -> bytes: ...
-def a85decode(b: str | ReadableBuffer, *, foldspaces: bool = ..., adobe: bool = ..., ignorechars: str | bytes = ...) -> bytes: ...
+def a85decode(
+    b: str | ReadableBuffer, *, foldspaces: bool = ..., adobe: bool = ..., ignorechars: bytearray | bytes = ...
+) -> bytes: ...
 def b85encode(b: ReadableBuffer, pad: bool = ...) -> bytes: ...
 def b85decode(b: str | ReadableBuffer) -> bytes: ...
 def decode(input: IO[bytes], output: IO[bytes]) -> None: ...
diff --git a/mypy/typeshed/stdlib/binhex.pyi b/mypy/typeshed/stdlib/binhex.pyi
index 639d30d1d0de1..e0993c840ce74 100644
--- a/mypy/typeshed/stdlib/binhex.pyi
+++ b/mypy/typeshed/stdlib/binhex.pyi
@@ -1,3 +1,4 @@
+from _typeshed import _BufferWithLen
 from typing import IO, Any
 from typing_extensions import Literal, TypeAlias
 
@@ -27,9 +28,9 @@ class openrsrc:
 
 class BinHex:
     def __init__(self, name_finfo_dlen_rlen: _FileInfoTuple, ofp: _FileHandleUnion) -> None: ...
-    def write(self, data: bytes) -> None: ...
+    def write(self, data: _BufferWithLen) -> None: ...
     def close_data(self) -> None: ...
-    def write_rsrc(self, data: bytes) -> None: ...
+    def write_rsrc(self, data: _BufferWithLen) -> None: ...
     def close(self) -> None: ...
 
 def binhex(inp: str, out: str) -> None: ...
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index d3b3f677b370c..00eac9e49cf0f 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -50,7 +50,6 @@ from typing import (  # noqa: Y027
     SupportsComplex,
     SupportsFloat,
     SupportsInt,
-    SupportsRound,
     TypeVar,
     overload,
     type_check_only,
@@ -299,7 +298,7 @@ class int:
     def __index__(self) -> int: ...
 
 class float:
-    def __new__(cls: type[Self], x: SupportsFloat | SupportsIndex | str | ReadableBuffer = ...) -> Self: ...
+    def __new__(cls: type[Self], __x: SupportsFloat | SupportsIndex | str | ReadableBuffer = ...) -> Self: ...
     def as_integer_ratio(self) -> tuple[int, int]: ...
     def hex(self) -> str: ...
     def is_integer(self) -> bool: ...
@@ -495,15 +494,11 @@ class str(Sequence[str]):
 
 class bytes(ByteString):
     @overload
-    def __new__(cls: type[Self], __ints: Iterable[SupportsIndex]) -> Self: ...
+    def __new__(cls: type[Self], __o: Iterable[SupportsIndex] | SupportsIndex | SupportsBytes | ReadableBuffer) -> Self: ...
     @overload
     def __new__(cls: type[Self], __string: str, encoding: str, errors: str = ...) -> Self: ...
     @overload
-    def __new__(cls: type[Self], __length: SupportsIndex) -> Self: ...
-    @overload
     def __new__(cls: type[Self]) -> Self: ...
-    @overload
-    def __new__(cls: type[Self], __o: SupportsBytes) -> Self: ...
     def capitalize(self) -> bytes: ...
     def center(self, __width: SupportsIndex, __fillchar: bytes = ...) -> bytes: ...
     def count(
@@ -589,7 +584,7 @@ class bytes(ByteString):
     def __rmul__(self, __n: SupportsIndex) -> bytes: ...
     def __mod__(self, __value: Any) -> bytes: ...
     # Incompatible with Sequence.__contains__
-    def __contains__(self, __o: SupportsIndex | bytes) -> bool: ...  # type: ignore[override]
+    def __contains__(self, __o: SupportsIndex | ReadableBuffer) -> bool: ...  # type: ignore[override]
     def __eq__(self, __x: object) -> bool: ...
     def __ne__(self, __x: object) -> bool: ...
     def __lt__(self, __x: bytes) -> bool: ...
@@ -604,11 +599,9 @@ class bytearray(MutableSequence[int], ByteString):
     @overload
     def __init__(self) -> None: ...
     @overload
-    def __init__(self, __ints: Iterable[SupportsIndex]) -> None: ...
+    def __init__(self, __ints: Iterable[SupportsIndex] | SupportsIndex | ReadableBuffer) -> None: ...
     @overload
     def __init__(self, __string: str, encoding: str, errors: str = ...) -> None: ...
-    @overload
-    def __init__(self, __length: SupportsIndex) -> None: ...
     def append(self, __item: SupportsIndex) -> None: ...
     def capitalize(self) -> bytearray: ...
     def center(self, __width: SupportsIndex, __fillchar: bytes = ...) -> bytearray: ...
@@ -712,14 +705,14 @@ class bytearray(MutableSequence[int], ByteString):
     def __contains__(self, __o: SupportsIndex | ReadableBuffer) -> bool: ...  # type: ignore[override]
     def __eq__(self, __x: object) -> bool: ...
     def __ne__(self, __x: object) -> bool: ...
-    def __lt__(self, __x: bytes) -> bool: ...
-    def __le__(self, __x: bytes) -> bool: ...
-    def __gt__(self, __x: bytes) -> bool: ...
-    def __ge__(self, __x: bytes) -> bool: ...
+    def __lt__(self, __x: ReadableBuffer) -> bool: ...
+    def __le__(self, __x: ReadableBuffer) -> bool: ...
+    def __gt__(self, __x: ReadableBuffer) -> bool: ...
+    def __ge__(self, __x: ReadableBuffer) -> bool: ...
     def __alloc__(self) -> int: ...
 
 @final
-class memoryview(Sized, Sequence[int]):
+class memoryview(Sequence[int]):
     @property
     def format(self) -> str: ...
     @property
@@ -735,7 +728,7 @@ class memoryview(Sized, Sequence[int]):
     @property
     def ndim(self) -> int: ...
     @property
-    def obj(self) -> bytes | bytearray: ...
+    def obj(self) -> ReadableBuffer: ...
     @property
     def c_contiguous(self) -> bool: ...
     @property
@@ -1239,19 +1232,13 @@ def iter(__function: Callable[[], _T | None], __sentinel: None) -> Iterator[_T]:
 @overload
 def iter(__function: Callable[[], _T], __sentinel: object) -> Iterator[_T]: ...
 
-# We need recursive types to express the type of the second argument to `isinstance` properly, hence the use of `Any`
 if sys.version_info >= (3, 10):
-    def isinstance(
-        __obj: object, __class_or_tuple: type | types.UnionType | tuple[type | types.UnionType | tuple[Any, ...], ...]
-    ) -> bool: ...
-    def issubclass(
-        __cls: type, __class_or_tuple: type | types.UnionType | tuple[type | types.UnionType | tuple[Any, ...], ...]
-    ) -> bool: ...
-
+    _ClassInfo: TypeAlias = type | types.UnionType | tuple[_ClassInfo, ...]
 else:
-    def isinstance(__obj: object, __class_or_tuple: type | tuple[type | tuple[Any, ...], ...]) -> bool: ...
-    def issubclass(__cls: type, __class_or_tuple: type | tuple[type | tuple[Any, ...], ...]) -> bool: ...
+    _ClassInfo: TypeAlias = type | tuple[_ClassInfo, ...]
 
+def isinstance(__obj: object, __class_or_tuple: _ClassInfo) -> bool: ...
+def issubclass(__cls: type, __class_or_tuple: _ClassInfo) -> bool: ...
 def len(__obj: Sized) -> int: ...
 def license() -> None: ...
 def locals() -> dict[str, Any]: ...
@@ -1539,12 +1526,21 @@ class reversed(Iterator[_T], Generic[_T]):
     def __length_hint__(self) -> int: ...
 
 def repr(__obj: object) -> str: ...
+
+# See https://github.com/python/typeshed/pull/9141
+# and https://github.com/python/typeshed/pull/9151
+# on why we don't use `SupportsRound` from `typing.pyi`
+
+class _SupportsRound1(Protocol[_T_co]):
+    def __round__(self) -> _T_co: ...
+
+class _SupportsRound2(Protocol[_T_co]):
+    def __round__(self, __ndigits: int) -> _T_co: ...
+
 @overload
-def round(number: SupportsRound[Any]) -> int: ...
-@overload
-def round(number: SupportsRound[Any], ndigits: None) -> int: ...
+def round(number: _SupportsRound1[_T], ndigits: None = ...) -> _T: ...
 @overload
-def round(number: SupportsRound[_T], ndigits: SupportsIndex) -> _T: ...
+def round(number: _SupportsRound2[_T], ndigits: SupportsIndex) -> _T: ...
 
 # See https://github.com/python/typeshed/pull/6292#discussion_r748875189
 # for why arg 3 of `setattr` should be annotated with `Any` and not `object`
@@ -1586,8 +1582,12 @@ else:
     @overload
     def sum(__iterable: Iterable[_AddableT1], __start: _AddableT2) -> _AddableT1 | _AddableT2: ...
 
-# The argument to `vars()` has to have a `__dict__` attribute, so can't be annotated with `object`
+# The argument to `vars()` has to have a `__dict__` attribute, so the second overload can't be annotated with `object`
 # (A "SupportsDunderDict" protocol doesn't work)
+# Use a type: ignore to make complaints about overlapping overloads go away
+@overload
+def vars(__object: type) -> types.MappingProxyType[str, Any]: ...  # type: ignore[misc]
+@overload
 def vars(__object: Any = ...) -> dict[str, Any]: ...
 
 class zip(Iterator[_T_co], Generic[_T_co]):
diff --git a/mypy/typeshed/stdlib/bz2.pyi b/mypy/typeshed/stdlib/bz2.pyi
index cea317e280371..295271d4a80b5 100644
--- a/mypy/typeshed/stdlib/bz2.pyi
+++ b/mypy/typeshed/stdlib/bz2.pyi
@@ -19,8 +19,8 @@ class _WritableFileobj(Protocol):
     # def fileno(self) -> int: ...
     # def close(self) -> object: ...
 
-def compress(data: bytes, compresslevel: int = ...) -> bytes: ...
-def decompress(data: bytes) -> bytes: ...
+def compress(data: ReadableBuffer, compresslevel: int = ...) -> bytes: ...
+def decompress(data: ReadableBuffer) -> bytes: ...
 
 _ReadBinaryMode: TypeAlias = Literal["", "r", "rb"]
 _WriteBinaryMode: TypeAlias = Literal["w", "wb", "x", "xb", "a", "ab"]
@@ -132,12 +132,12 @@ class BZ2File(BaseStream, IO[bytes]):
 @final
 class BZ2Compressor:
     def __init__(self, compresslevel: int = ...) -> None: ...
-    def compress(self, __data: bytes) -> bytes: ...
+    def compress(self, __data: ReadableBuffer) -> bytes: ...
     def flush(self) -> bytes: ...
 
 @final
 class BZ2Decompressor:
-    def decompress(self, data: bytes, max_length: int = ...) -> bytes: ...
+    def decompress(self, data: ReadableBuffer, max_length: int = ...) -> bytes: ...
     @property
     def eof(self) -> bool: ...
     @property
diff --git a/mypy/typeshed/stdlib/codecs.pyi b/mypy/typeshed/stdlib/codecs.pyi
index a7b60e38df115..cd6ac0006c539 100644
--- a/mypy/typeshed/stdlib/codecs.pyi
+++ b/mypy/typeshed/stdlib/codecs.pyi
@@ -1,12 +1,11 @@
 import types
-from _typeshed import Self
+from _codecs import *
+from _typeshed import ReadableBuffer, Self
 from abc import abstractmethod
 from collections.abc import Callable, Generator, Iterable
 from typing import Any, BinaryIO, Protocol, TextIO
 from typing_extensions import Literal
 
-from _codecs import *
-
 __all__ = [
     "register",
     "lookup",
@@ -173,7 +172,7 @@ class IncrementalDecoder:
     errors: str
     def __init__(self, errors: str = ...) -> None: ...
     @abstractmethod
-    def decode(self, input: bytes, final: bool = ...) -> str: ...
+    def decode(self, input: ReadableBuffer, final: bool = ...) -> str: ...
     def reset(self) -> None: ...
     def getstate(self) -> tuple[bytes, int]: ...
     def setstate(self, state: tuple[bytes, int]) -> None: ...
@@ -190,8 +189,8 @@ class BufferedIncrementalDecoder(IncrementalDecoder):
     buffer: bytes
     def __init__(self, errors: str = ...) -> None: ...
     @abstractmethod
-    def _buffer_decode(self, input: bytes, errors: str, final: bool) -> tuple[str, int]: ...
-    def decode(self, input: bytes, final: bool = ...) -> str: ...
+    def _buffer_decode(self, input: ReadableBuffer, errors: str, final: bool) -> tuple[str, int]: ...
+    def decode(self, input: ReadableBuffer, final: bool = ...) -> str: ...
 
 # TODO: it is not possible to specify the requirement that all other
 # attributes and methods are passed-through from the stream.
diff --git a/mypy/typeshed/stdlib/ctypes/__init__.pyi b/mypy/typeshed/stdlib/ctypes/__init__.pyi
index 78f4ee4d5ab3f..1851d3481ee2f 100644
--- a/mypy/typeshed/stdlib/ctypes/__init__.pyi
+++ b/mypy/typeshed/stdlib/ctypes/__init__.pyi
@@ -194,7 +194,7 @@ class _SimpleCData(Generic[_T], _CData):
 class c_byte(_SimpleCData[int]): ...
 
 class c_char(_SimpleCData[bytes]):
-    def __init__(self, value: int | bytes = ...) -> None: ...
+    def __init__(self, value: int | bytes | bytearray = ...) -> None: ...
 
 class c_char_p(_PointerLike, _SimpleCData[bytes | None]):
     def __init__(self, value: int | bytes | None = ...) -> None: ...
@@ -266,7 +266,11 @@ class Array(Generic[_CT], _CData):
     def _type_(self) -> type[_CT]: ...
     @_type_.setter
     def _type_(self, value: type[_CT]) -> None: ...
-    raw: bytes  # Note: only available if _CT == c_char
+    # Note: only available if _CT == c_char
+    @property
+    def raw(self) -> bytes: ...
+    @raw.setter
+    def raw(self, value: ReadableBuffer) -> None: ...
     value: Any  # Note: bytes if _CT == c_char, str if _CT == c_wchar, unavailable otherwise
     # TODO These methods cannot be annotated correctly at the moment.
     # All of these "Any"s stand for the array's element type, but it's not possible to use _CT
diff --git a/mypy/typeshed/stdlib/datetime.pyi b/mypy/typeshed/stdlib/datetime.pyi
index 5926ff0a808e2..b1b3c17ee25b2 100644
--- a/mypy/typeshed/stdlib/datetime.pyi
+++ b/mypy/typeshed/stdlib/datetime.pyi
@@ -1,7 +1,8 @@
 import sys
 from _typeshed import Self
+from abc import abstractmethod
 from time import struct_time
-from typing import ClassVar, NamedTuple, NoReturn, SupportsAbs, TypeVar, overload
+from typing import ClassVar, NamedTuple, NoReturn, TypeVar, overload
 from typing_extensions import Literal, TypeAlias, final
 
 if sys.version_info >= (3, 11):
@@ -15,8 +16,11 @@ MINYEAR: Literal[1]
 MAXYEAR: Literal[9999]
 
 class tzinfo:
+    @abstractmethod
     def tzname(self, __dt: datetime | None) -> str | None: ...
+    @abstractmethod
     def utcoffset(self, __dt: datetime | None) -> timedelta | None: ...
+    @abstractmethod
     def dst(self, __dt: datetime | None) -> timedelta | None: ...
     def fromutc(self, __dt: datetime) -> datetime: ...
 
@@ -29,6 +33,9 @@ class timezone(tzinfo):
     min: ClassVar[timezone]
     max: ClassVar[timezone]
     def __init__(self, offset: timedelta, name: str = ...) -> None: ...
+    def tzname(self, __dt: datetime | None) -> str: ...
+    def utcoffset(self, __dt: datetime | None) -> timedelta: ...
+    def dst(self, __dt: datetime | None) -> None: ...
 
 if sys.version_info >= (3, 11):
     UTC: timezone
@@ -152,7 +159,7 @@ class time:
 _Date: TypeAlias = date
 _Time: TypeAlias = time
 
-class timedelta(SupportsAbs[timedelta]):
+class timedelta:
     min: ClassVar[timedelta]
     max: ClassVar[timedelta]
     resolution: ClassVar[timedelta]
diff --git a/mypy/typeshed/stdlib/dbm/__init__.pyi b/mypy/typeshed/stdlib/dbm/__init__.pyi
index 9e99f0d5e74cd..33b8aab966104 100644
--- a/mypy/typeshed/stdlib/dbm/__init__.pyi
+++ b/mypy/typeshed/stdlib/dbm/__init__.pyi
@@ -6,7 +6,7 @@ from typing_extensions import Literal, TypeAlias
 __all__ = ["open", "whichdb", "error"]
 
 _KeyType: TypeAlias = str | bytes
-_ValueType: TypeAlias = str | bytes
+_ValueType: TypeAlias = str | bytes | bytearray
 _TFlags: TypeAlias = Literal[
     "r",
     "w",
diff --git a/mypy/typeshed/stdlib/dbm/dumb.pyi b/mypy/typeshed/stdlib/dbm/dumb.pyi
index 4fd199f197288..738e68968ca83 100644
--- a/mypy/typeshed/stdlib/dbm/dumb.pyi
+++ b/mypy/typeshed/stdlib/dbm/dumb.pyi
@@ -10,6 +10,9 @@ _ValueType: TypeAlias = str | bytes
 
 error = OSError
 
+# This class doesn't exist at runtime. open() can return an instance of
+# any of the three implementations of dbm (dumb, gnu, ndbm), and this
+# class is intended to represent the common interface supported by all three.
 class _Database(MutableMapping[_KeyType, bytes]):
     def __init__(self, filebasename: str, mode: str, flag: str = ...) -> None: ...
     def sync(self) -> None: ...
diff --git a/mypy/typeshed/stdlib/dbm/gnu.pyi b/mypy/typeshed/stdlib/dbm/gnu.pyi
index 561206c4e0be0..93b9df1077ce6 100644
--- a/mypy/typeshed/stdlib/dbm/gnu.pyi
+++ b/mypy/typeshed/stdlib/dbm/gnu.pyi
@@ -1,13 +1,13 @@
 import sys
-from _typeshed import Self
+from _typeshed import ReadOnlyBuffer, Self
 from types import TracebackType
 from typing import TypeVar, overload
 from typing_extensions import TypeAlias
 
 if sys.platform != "win32":
     _T = TypeVar("_T")
-    _KeyType: TypeAlias = str | bytes
-    _ValueType: TypeAlias = str | bytes
+    _KeyType: TypeAlias = str | ReadOnlyBuffer
+    _ValueType: TypeAlias = str | ReadOnlyBuffer
 
     open_flags: str
 
@@ -31,7 +31,7 @@ if sys.platform != "win32":
         @overload
         def get(self, k: _KeyType) -> bytes | None: ...
         @overload
-        def get(self, k: _KeyType, default: bytes | _T) -> bytes | _T: ...
+        def get(self, k: _KeyType, default: _T) -> bytes | _T: ...
         def keys(self) -> list[bytes]: ...
         def setdefault(self, k: _KeyType, default: _ValueType = ...) -> bytes: ...
         # Don't exist at runtime
diff --git a/mypy/typeshed/stdlib/dbm/ndbm.pyi b/mypy/typeshed/stdlib/dbm/ndbm.pyi
index f1032bf3cae77..ca658098bd5c7 100644
--- a/mypy/typeshed/stdlib/dbm/ndbm.pyi
+++ b/mypy/typeshed/stdlib/dbm/ndbm.pyi
@@ -1,13 +1,13 @@
 import sys
-from _typeshed import Self
+from _typeshed import ReadOnlyBuffer, Self
 from types import TracebackType
 from typing import TypeVar, overload
 from typing_extensions import TypeAlias
 
 if sys.platform != "win32":
     _T = TypeVar("_T")
-    _KeyType: TypeAlias = str | bytes
-    _ValueType: TypeAlias = str | bytes
+    _KeyType: TypeAlias = str | ReadOnlyBuffer
+    _ValueType: TypeAlias = str | ReadOnlyBuffer
 
     class error(OSError): ...
     library: str
@@ -27,7 +27,7 @@ if sys.platform != "win32":
         @overload
         def get(self, k: _KeyType) -> bytes | None: ...
         @overload
-        def get(self, k: _KeyType, default: bytes | _T) -> bytes | _T: ...
+        def get(self, k: _KeyType, default: _T) -> bytes | _T: ...
         def keys(self) -> list[bytes]: ...
         def setdefault(self, k: _KeyType, default: _ValueType = ...) -> bytes: ...
         # Don't exist at runtime
diff --git a/mypy/typeshed/stdlib/difflib.pyi b/mypy/typeshed/stdlib/difflib.pyi
index 854a53d433aef..df2f8be0168a9 100644
--- a/mypy/typeshed/stdlib/difflib.pyi
+++ b/mypy/typeshed/stdlib/difflib.pyi
@@ -127,12 +127,12 @@ class HtmlDiff:
 def restore(delta: Iterable[str], which: int) -> Iterator[str]: ...
 def diff_bytes(
     dfunc: Callable[[Sequence[str], Sequence[str], str, str, str, str, int, str], Iterator[str]],
-    a: Sequence[bytes],
-    b: Sequence[bytes],
-    fromfile: bytes = ...,
-    tofile: bytes = ...,
-    fromfiledate: bytes = ...,
-    tofiledate: bytes = ...,
+    a: Iterable[bytes | bytearray],
+    b: Iterable[bytes | bytearray],
+    fromfile: bytes | bytearray = ...,
+    tofile: bytes | bytearray = ...,
+    fromfiledate: bytes | bytearray = ...,
+    tofiledate: bytes | bytearray = ...,
     n: int = ...,
-    lineterm: bytes = ...,
+    lineterm: bytes | bytearray = ...,
 ) -> Iterator[bytes]: ...
diff --git a/mypy/typeshed/stdlib/dis.pyi b/mypy/typeshed/stdlib/dis.pyi
index dd31d981071f2..73adba5c19f58 100644
--- a/mypy/typeshed/stdlib/dis.pyi
+++ b/mypy/typeshed/stdlib/dis.pyi
@@ -37,7 +37,6 @@ __all__ = [
 # Strictly this should not have to include Callable, but mypy doesn't use FunctionType
 # for functions (python/mypy#3171)
 _HaveCodeType: TypeAlias = types.MethodType | types.FunctionType | types.CodeType | type | Callable[..., Any]
-_HaveCodeOrStringType: TypeAlias = _HaveCodeType | str | bytes
 
 if sys.version_info >= (3, 11):
     class Positions(NamedTuple):
@@ -75,7 +74,7 @@ class Bytecode:
     if sys.version_info >= (3, 11):
         def __init__(
             self,
-            x: _HaveCodeOrStringType,
+            x: _HaveCodeType | str,
             *,
             first_line: int | None = ...,
             current_offset: int | None = ...,
@@ -87,9 +86,7 @@ class Bytecode:
             cls: type[Self], tb: types.TracebackType, *, show_caches: bool = ..., adaptive: bool = ...
         ) -> Self: ...
     else:
-        def __init__(
-            self, x: _HaveCodeOrStringType, *, first_line: int | None = ..., current_offset: int | None = ...
-        ) -> None: ...
+        def __init__(self, x: _HaveCodeType | str, *, first_line: int | None = ..., current_offset: int | None = ...) -> None: ...
         @classmethod
         def from_traceback(cls: type[Self], tb: types.TracebackType) -> Self: ...
 
@@ -102,11 +99,11 @@ COMPILER_FLAG_NAMES: dict[int, str]
 def findlabels(code: _HaveCodeType) -> list[int]: ...
 def findlinestarts(code: _HaveCodeType) -> Iterator[tuple[int, int]]: ...
 def pretty_flags(flags: int) -> str: ...
-def code_info(x: _HaveCodeOrStringType) -> str: ...
+def code_info(x: _HaveCodeType | str) -> str: ...
 
 if sys.version_info >= (3, 11):
     def dis(
-        x: _HaveCodeOrStringType | None = ...,
+        x: _HaveCodeType | str | bytes | bytearray | None = ...,
         *,
         file: IO[str] | None = ...,
         depth: int | None = ...,
@@ -115,7 +112,9 @@ if sys.version_info >= (3, 11):
     ) -> None: ...
 
 else:
-    def dis(x: _HaveCodeOrStringType | None = ..., *, file: IO[str] | None = ..., depth: int | None = ...) -> None: ...
+    def dis(
+        x: _HaveCodeType | str | bytes | bytearray | None = ..., *, file: IO[str] | None = ..., depth: int | None = ...
+    ) -> None: ...
 
 if sys.version_info >= (3, 11):
     def disassemble(
diff --git a/mypy/typeshed/stdlib/email/__init__.pyi b/mypy/typeshed/stdlib/email/__init__.pyi
index 4591b2c3340ec..6b59dc73d5ccc 100644
--- a/mypy/typeshed/stdlib/email/__init__.pyi
+++ b/mypy/typeshed/stdlib/email/__init__.pyi
@@ -9,7 +9,7 @@ _ParamType: TypeAlias = Union[str, tuple[str | None, str | None, str]]  # noqa:
 _ParamsType: TypeAlias = Union[str, None, tuple[str, str | None, str]]  # noqa: Y047
 
 def message_from_string(s: str, _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
-def message_from_bytes(s: bytes, _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
+def message_from_bytes(s: bytes | bytearray, _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
 def message_from_file(fp: IO[str], _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
 def message_from_binary_file(fp: IO[bytes], _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> Message: ...
 
diff --git a/mypy/typeshed/stdlib/email/base64mime.pyi b/mypy/typeshed/stdlib/email/base64mime.pyi
index e55658046f55f..16118a879ad7c 100644
--- a/mypy/typeshed/stdlib/email/base64mime.pyi
+++ b/mypy/typeshed/stdlib/email/base64mime.pyi
@@ -1,9 +1,13 @@
 __all__ = ["body_decode", "body_encode", "decode", "decodestring", "header_encode", "header_length"]
 
-def header_length(bytearray: str | bytes) -> int: ...
-def header_encode(header_bytes: str | bytes, charset: str = ...) -> str: ...
-def body_encode(s: bytes, maxlinelen: int = ..., eol: str = ...) -> str: ...
-def decode(string: str | bytes) -> bytes: ...
+from _typeshed import ReadableBuffer
+
+def header_length(bytearray: str | bytes | bytearray) -> int: ...
+def header_encode(header_bytes: str | ReadableBuffer, charset: str = ...) -> str: ...
+
+# First argument should be a buffer that supports slicing and len().
+def body_encode(s: bytes | bytearray, maxlinelen: int = ..., eol: str = ...) -> str: ...
+def decode(string: str | ReadableBuffer) -> bytes: ...
 
 body_decode = decode
 decodestring = decode
diff --git a/mypy/typeshed/stdlib/email/feedparser.pyi b/mypy/typeshed/stdlib/email/feedparser.pyi
index c535c353daade..809f0b0e112be 100644
--- a/mypy/typeshed/stdlib/email/feedparser.pyi
+++ b/mypy/typeshed/stdlib/email/feedparser.pyi
@@ -20,5 +20,5 @@ class BytesFeedParser(Generic[_MessageT]):
     def __init__(self: BytesFeedParser[Message], _factory: None = ..., *, policy: Policy = ...) -> None: ...
     @overload
     def __init__(self, _factory: Callable[[], _MessageT], *, policy: Policy = ...) -> None: ...
-    def feed(self, data: bytes) -> None: ...
+    def feed(self, data: bytes | bytearray) -> None: ...
     def close(self) -> _MessageT: ...
diff --git a/mypy/typeshed/stdlib/email/header.pyi b/mypy/typeshed/stdlib/email/header.pyi
index 9248759168a94..58740bd1bdae8 100644
--- a/mypy/typeshed/stdlib/email/header.pyi
+++ b/mypy/typeshed/stdlib/email/header.pyi
@@ -1,3 +1,4 @@
+from collections.abc import Iterable
 from email.charset import Charset
 from typing import Any
 
@@ -6,14 +7,14 @@ __all__ = ["Header", "decode_header", "make_header"]
 class Header:
     def __init__(
         self,
-        s: bytes | str | None = ...,
+        s: bytes | bytearray | str | None = ...,
         charset: Charset | str | None = ...,
         maxlinelen: int | None = ...,
         header_name: str | None = ...,
         continuation_ws: str = ...,
         errors: str = ...,
     ) -> None: ...
-    def append(self, s: bytes | str, charset: Charset | str | None = ..., errors: str = ...) -> None: ...
+    def append(self, s: bytes | bytearray | str, charset: Charset | str | None = ..., errors: str = ...) -> None: ...
     def encode(self, splitchars: str = ..., maxlinelen: int | None = ..., linesep: str = ...) -> str: ...
     def __eq__(self, other: object) -> bool: ...
     def __ne__(self, __other: object) -> bool: ...
@@ -23,7 +24,7 @@ class Header:
 # contains at least one encoded part.
 def decode_header(header: Header | str) -> list[tuple[Any, Any | None]]: ...
 def make_header(
-    decoded_seq: list[tuple[bytes, str | None]],
+    decoded_seq: Iterable[tuple[bytes | bytearray | str, str | None]],
     maxlinelen: int | None = ...,
     header_name: str | None = ...,
     continuation_ws: str = ...,
diff --git a/mypy/typeshed/stdlib/email/message.pyi b/mypy/typeshed/stdlib/email/message.pyi
index 4e8f600f7ffd2..3c59aeeb2d014 100644
--- a/mypy/typeshed/stdlib/email/message.pyi
+++ b/mypy/typeshed/stdlib/email/message.pyi
@@ -12,7 +12,7 @@ __all__ = ["Message", "EmailMessage"]
 
 _T = TypeVar("_T")
 
-_PayloadType: TypeAlias = list[Message] | str | bytes
+_PayloadType: TypeAlias = list[Message] | str | bytes | bytearray
 _CharsetType: TypeAlias = Charset | str | None
 _HeaderType: TypeAlias = Any
 
diff --git a/mypy/typeshed/stdlib/email/mime/application.pyi b/mypy/typeshed/stdlib/email/mime/application.pyi
index dfff85265ade0..5ff60bff6ad2e 100644
--- a/mypy/typeshed/stdlib/email/mime/application.pyi
+++ b/mypy/typeshed/stdlib/email/mime/application.pyi
@@ -8,7 +8,7 @@ __all__ = ["MIMEApplication"]
 class MIMEApplication(MIMENonMultipart):
     def __init__(
         self,
-        _data: str | bytes,
+        _data: str | bytes | bytearray,
         _subtype: str = ...,
         _encoder: Callable[[MIMEApplication], object] = ...,
         *,
diff --git a/mypy/typeshed/stdlib/email/mime/audio.pyi b/mypy/typeshed/stdlib/email/mime/audio.pyi
index b355d55070add..05e173f5c4a10 100644
--- a/mypy/typeshed/stdlib/email/mime/audio.pyi
+++ b/mypy/typeshed/stdlib/email/mime/audio.pyi
@@ -8,7 +8,7 @@ __all__ = ["MIMEAudio"]
 class MIMEAudio(MIMENonMultipart):
     def __init__(
         self,
-        _audiodata: str | bytes,
+        _audiodata: str | bytes | bytearray,
         _subtype: str | None = ...,
         _encoder: Callable[[MIMEAudio], object] = ...,
         *,
diff --git a/mypy/typeshed/stdlib/email/mime/image.pyi b/mypy/typeshed/stdlib/email/mime/image.pyi
index f575103de2d6d..7e46b835b5419 100644
--- a/mypy/typeshed/stdlib/email/mime/image.pyi
+++ b/mypy/typeshed/stdlib/email/mime/image.pyi
@@ -8,7 +8,7 @@ __all__ = ["MIMEImage"]
 class MIMEImage(MIMENonMultipart):
     def __init__(
         self,
-        _imagedata: str | bytes,
+        _imagedata: str | bytes | bytearray,
         _subtype: str | None = ...,
         _encoder: Callable[[MIMEImage], object] = ...,
         *,
diff --git a/mypy/typeshed/stdlib/email/parser.pyi b/mypy/typeshed/stdlib/email/parser.pyi
index bf51c45728fd2..1afd8940f4ef6 100644
--- a/mypy/typeshed/stdlib/email/parser.pyi
+++ b/mypy/typeshed/stdlib/email/parser.pyi
@@ -16,6 +16,6 @@ class HeaderParser(Parser): ...
 class BytesParser:
     def __init__(self, _class: Callable[[], Message] = ..., *, policy: Policy = ...) -> None: ...
     def parse(self, fp: BinaryIO, headersonly: bool = ...) -> Message: ...
-    def parsebytes(self, text: bytes, headersonly: bool = ...) -> Message: ...
+    def parsebytes(self, text: bytes | bytearray, headersonly: bool = ...) -> Message: ...
 
 class BytesHeaderParser(BytesParser): ...
diff --git a/mypy/typeshed/stdlib/email/quoprimime.pyi b/mypy/typeshed/stdlib/email/quoprimime.pyi
index c5d324d17e13f..ec0c799583bf1 100644
--- a/mypy/typeshed/stdlib/email/quoprimime.pyi
+++ b/mypy/typeshed/stdlib/email/quoprimime.pyi
@@ -1,3 +1,5 @@
+from collections.abc import Iterable
+
 __all__ = [
     "body_decode",
     "body_encode",
@@ -13,11 +15,11 @@ __all__ = [
 
 def header_check(octet: int) -> bool: ...
 def body_check(octet: int) -> bool: ...
-def header_length(bytearray: bytes) -> int: ...
-def body_length(bytearray: bytes) -> int: ...
-def unquote(s: str | bytes) -> str: ...
-def quote(c: str | bytes) -> str: ...
-def header_encode(header_bytes: bytes, charset: str = ...) -> str: ...
+def header_length(bytearray: Iterable[int]) -> int: ...
+def body_length(bytearray: Iterable[int]) -> int: ...
+def unquote(s: str | bytes | bytearray) -> str: ...
+def quote(c: str | bytes | bytearray) -> str: ...
+def header_encode(header_bytes: bytes | bytearray, charset: str = ...) -> str: ...
 def body_encode(body: str, maxlinelen: int = ..., eol: str = ...) -> str: ...
 def decode(encoded: str, eol: str = ...) -> str: ...
 def header_decode(s: str) -> str: ...
diff --git a/mypy/typeshed/stdlib/encodings/__init__.pyi b/mypy/typeshed/stdlib/encodings/__init__.pyi
index d864667622686..2e83f0f65a71a 100644
--- a/mypy/typeshed/stdlib/encodings/__init__.pyi
+++ b/mypy/typeshed/stdlib/encodings/__init__.pyi
@@ -1,5 +1,5 @@
+from _typeshed import Incomplete
 from codecs import CodecInfo
-from typing import Any
 
 class CodecRegistryError(LookupError, SystemError): ...
 
@@ -7,4 +7,4 @@ def normalize_encoding(encoding: str | bytes) -> str: ...
 def search_function(encoding: str) -> CodecInfo | None: ...
 
 # Needed for submodules
-def __getattr__(name: str) -> Any: ...  # incomplete
+def __getattr__(name: str) -> Incomplete: ...
diff --git a/mypy/typeshed/stdlib/encodings/utf_8.pyi b/mypy/typeshed/stdlib/encodings/utf_8.pyi
index 568fa6013373e..8e73756199c12 100644
--- a/mypy/typeshed/stdlib/encodings/utf_8.pyi
+++ b/mypy/typeshed/stdlib/encodings/utf_8.pyi
@@ -1,11 +1,12 @@
 import codecs
+from _typeshed import ReadableBuffer
 
 class IncrementalEncoder(codecs.IncrementalEncoder):
     def encode(self, input: str, final: bool = ...) -> bytes: ...
 
 class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
     @staticmethod
-    def _buffer_decode(__data: bytes, __errors: str | None = ..., __final: bool = ...) -> tuple[str, int]: ...
+    def _buffer_decode(__data: ReadableBuffer, __errors: str | None = ..., __final: bool = ...) -> tuple[str, int]: ...
 
 class StreamWriter(codecs.StreamWriter):
     @staticmethod
@@ -13,8 +14,8 @@ class StreamWriter(codecs.StreamWriter):
 
 class StreamReader(codecs.StreamReader):
     @staticmethod
-    def decode(__data: bytes, __errors: str | None = ..., __final: bool = ...) -> tuple[str, int]: ...
+    def decode(__data: ReadableBuffer, __errors: str | None = ..., __final: bool = ...) -> tuple[str, int]: ...
 
 def getregentry() -> codecs.CodecInfo: ...
 def encode(__str: str, __errors: str | None = ...) -> tuple[bytes, int]: ...
-def decode(input: bytes, errors: str | None = ...) -> tuple[str, int]: ...
+def decode(input: ReadableBuffer, errors: str | None = ...) -> tuple[str, int]: ...
diff --git a/mypy/typeshed/stdlib/encodings/utf_8_sig.pyi b/mypy/typeshed/stdlib/encodings/utf_8_sig.pyi
index ad0d5bdc4fc72..27171063f53f4 100644
--- a/mypy/typeshed/stdlib/encodings/utf_8_sig.pyi
+++ b/mypy/typeshed/stdlib/encodings/utf_8_sig.pyi
@@ -1,4 +1,5 @@
 import codecs
+from _typeshed import ReadableBuffer
 
 class IncrementalEncoder(codecs.IncrementalEncoder):
     def __init__(self, errors: str = ...) -> None: ...
@@ -8,14 +9,14 @@ class IncrementalEncoder(codecs.IncrementalEncoder):
 
 class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
     def __init__(self, errors: str = ...) -> None: ...
-    def _buffer_decode(self, input: bytes, errors: str | None, final: bool) -> tuple[str, int]: ...
+    def _buffer_decode(self, input: ReadableBuffer, errors: str | None, final: bool) -> tuple[str, int]: ...
 
 class StreamWriter(codecs.StreamWriter):
     def encode(self, input: str, errors: str | None = ...) -> tuple[bytes, int]: ...
 
 class StreamReader(codecs.StreamReader):
-    def decode(self, input: bytes, errors: str | None = ...) -> tuple[str, int]: ...
+    def decode(self, input: ReadableBuffer, errors: str | None = ...) -> tuple[str, int]: ...
 
 def getregentry() -> codecs.CodecInfo: ...
 def encode(input: str, errors: str | None = ...) -> tuple[bytes, int]: ...
-def decode(input: bytes, errors: str | None = ...) -> tuple[str, int]: ...
+def decode(input: ReadableBuffer, errors: str | None = ...) -> tuple[str, int]: ...
diff --git a/mypy/typeshed/stdlib/fcntl.pyi b/mypy/typeshed/stdlib/fcntl.pyi
index 69863bf580fae..2df16083c0b75 100644
--- a/mypy/typeshed/stdlib/fcntl.pyi
+++ b/mypy/typeshed/stdlib/fcntl.pyi
@@ -103,7 +103,7 @@ if sys.platform != "win32":
     @overload
     def fcntl(__fd: FileDescriptorLike, __cmd: int, __arg: int = ...) -> int: ...
     @overload
-    def fcntl(__fd: FileDescriptorLike, __cmd: int, __arg: bytes) -> bytes: ...
+    def fcntl(__fd: FileDescriptorLike, __cmd: int, __arg: str | ReadOnlyBuffer) -> bytes: ...
     @overload
     def ioctl(__fd: FileDescriptorLike, __request: int, __arg: int = ..., __mutate_flag: bool = ...) -> int: ...
     @overload
diff --git a/mypy/typeshed/stdlib/gzip.pyi b/mypy/typeshed/stdlib/gzip.pyi
index 75a70a5e7a075..580e605b6b386 100644
--- a/mypy/typeshed/stdlib/gzip.pyi
+++ b/mypy/typeshed/stdlib/gzip.pyi
@@ -1,9 +1,9 @@
 import _compression
 import sys
 import zlib
-from _typeshed import ReadableBuffer, StrOrBytesPath
+from _typeshed import ReadableBuffer, StrOrBytesPath, _BufferWithLen
 from io import FileIO
-from typing import Any, Protocol, TextIO, overload
+from typing import Protocol, TextIO, overload
 from typing_extensions import Literal, TypeAlias
 
 if sys.version_info >= (3, 8):
@@ -26,15 +26,15 @@ FCOMMENT: int  # actually Literal[16] # undocumented
 
 class _ReadableFileobj(Protocol):
     def read(self, __n: int) -> bytes: ...
-    def seek(self, __n: int) -> Any: ...
+    def seek(self, __n: int) -> object: ...
     # The following attributes and methods are optional:
     # name: str
     # mode: str
     # def fileno() -> int: ...
 
 class _WritableFileobj(Protocol):
-    def write(self, __b: bytes) -> Any: ...
-    def flush(self) -> Any: ...
+    def write(self, __b: bytes) -> object: ...
+    def flush(self) -> object: ...
     # The following attributes and methods are optional:
     # name: str
     # mode: str
@@ -159,9 +159,9 @@ class _GzipReader(_compression.DecompressReader):
     def __init__(self, fp: _ReadableFileobj) -> None: ...
 
 if sys.version_info >= (3, 8):
-    def compress(data: bytes, compresslevel: int = ..., *, mtime: float | None = ...) -> bytes: ...
+    def compress(data: _BufferWithLen, compresslevel: int = ..., *, mtime: float | None = ...) -> bytes: ...
 
 else:
-    def compress(data: bytes, compresslevel: int = ...) -> bytes: ...
+    def compress(data: _BufferWithLen, compresslevel: int = ...) -> bytes: ...
 
-def decompress(data: bytes) -> bytes: ...
+def decompress(data: ReadableBuffer) -> bytes: ...
diff --git a/mypy/typeshed/stdlib/hmac.pyi b/mypy/typeshed/stdlib/hmac.pyi
index af69fc7ea46dd..dc29836b6b873 100644
--- a/mypy/typeshed/stdlib/hmac.pyi
+++ b/mypy/typeshed/stdlib/hmac.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import ReadableBuffer
+from _typeshed import ReadableBuffer, _BufferWithLen
 from collections.abc import Callable
 from types import ModuleType
 from typing import Any, AnyStr, overload
@@ -18,19 +18,19 @@ if sys.version_info >= (3, 8):
     # In reality digestmod has a default value, but the function always throws an error
     # if the argument is not given, so we pretend it is a required argument.
     @overload
-    def new(key: bytes, msg: ReadableBuffer | None, digestmod: _DigestMod) -> HMAC: ...
+    def new(key: bytes | bytearray, msg: ReadableBuffer | None, digestmod: _DigestMod) -> HMAC: ...
     @overload
-    def new(key: bytes, *, digestmod: _DigestMod) -> HMAC: ...
+    def new(key: bytes | bytearray, *, digestmod: _DigestMod) -> HMAC: ...
 
 else:
-    def new(key: bytes, msg: ReadableBuffer | None = ..., digestmod: _DigestMod | None = ...) -> HMAC: ...
+    def new(key: bytes | bytearray, msg: ReadableBuffer | None = ..., digestmod: _DigestMod | None = ...) -> HMAC: ...
 
 class HMAC:
     digest_size: int
     block_size: int
     @property
     def name(self) -> str: ...
-    def __init__(self, key: bytes, msg: ReadableBuffer | None = ..., digestmod: _DigestMod = ...) -> None: ...
+    def __init__(self, key: bytes | bytearray, msg: ReadableBuffer | None = ..., digestmod: _DigestMod = ...) -> None: ...
     def update(self, msg: ReadableBuffer) -> None: ...
     def digest(self) -> bytes: ...
     def hexdigest(self) -> str: ...
@@ -40,4 +40,4 @@ class HMAC:
 def compare_digest(__a: ReadableBuffer, __b: ReadableBuffer) -> bool: ...
 @overload
 def compare_digest(__a: AnyStr, __b: AnyStr) -> bool: ...
-def digest(key: bytes, msg: ReadableBuffer, digest: _DigestMod) -> bytes: ...
+def digest(key: _BufferWithLen, msg: ReadableBuffer, digest: _DigestMod) -> bytes: ...
diff --git a/mypy/typeshed/stdlib/http/client.pyi b/mypy/typeshed/stdlib/http/client.pyi
index 2ce52eac9ad97..ad794ed9b073b 100644
--- a/mypy/typeshed/stdlib/http/client.pyi
+++ b/mypy/typeshed/stdlib/http/client.pyi
@@ -2,10 +2,10 @@ import email.message
 import io
 import ssl
 import types
-from _typeshed import Self, WriteableBuffer
+from _typeshed import ReadableBuffer, Self, SupportsRead, WriteableBuffer
 from collections.abc import Callable, Iterable, Iterator, Mapping
 from socket import socket
-from typing import IO, Any, BinaryIO, TypeVar, overload
+from typing import Any, BinaryIO, TypeVar, overload
 from typing_extensions import TypeAlias
 
 __all__ = [
@@ -30,7 +30,7 @@ __all__ = [
     "HTTPSConnection",
 ]
 
-_DataType: TypeAlias = bytes | IO[Any] | Iterable[bytes] | str
+_DataType: TypeAlias = SupportsRead[bytes] | Iterable[ReadableBuffer] | ReadableBuffer
 _T = TypeVar("_T")
 
 HTTP_PORT: int
@@ -164,7 +164,7 @@ class HTTPConnection:
     def putrequest(self, method: str, url: str, skip_host: bool = ..., skip_accept_encoding: bool = ...) -> None: ...
     def putheader(self, header: str, *argument: str) -> None: ...
     def endheaders(self, message_body: _DataType | None = ..., *, encode_chunked: bool = ...) -> None: ...
-    def send(self, data: _DataType) -> None: ...
+    def send(self, data: _DataType | str) -> None: ...
 
 class HTTPSConnection(HTTPConnection):
     # Can be `None` if `.connect()` was not called:
diff --git a/mypy/typeshed/stdlib/http/server.pyi b/mypy/typeshed/stdlib/http/server.pyi
index 40c94bf62f30c..011d464b46531 100644
--- a/mypy/typeshed/stdlib/http/server.pyi
+++ b/mypy/typeshed/stdlib/http/server.pyi
@@ -1,6 +1,7 @@
 import email.message
 import io
 import socketserver
+import sys
 from _typeshed import StrPath, SupportsRead, SupportsWrite
 from collections.abc import Mapping, Sequence
 from typing import Any, AnyStr, BinaryIO, ClassVar
@@ -31,7 +32,6 @@ class BaseHTTPRequestHandler(socketserver.StreamRequestHandler):
     default_request_version: str  # undocumented
     weekdayname: ClassVar[Sequence[str]]  # undocumented
     monthname: ClassVar[Sequence[str | None]]  # undocumented
-    def __init__(self, request: bytes, client_address: tuple[str, int], server: socketserver.BaseServer) -> None: ...
     def handle_one_request(self) -> None: ...
     def handle_expect_100(self) -> bool: ...
     def send_error(self, code: int, message: str | None = ..., explain: str | None = ...) -> None: ...
@@ -51,9 +51,26 @@ class BaseHTTPRequestHandler(socketserver.StreamRequestHandler):
 
 class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):
     extensions_map: dict[str, str]
-    def __init__(
-        self, request: bytes, client_address: tuple[str, int], server: socketserver.BaseServer, directory: str | None = ...
-    ) -> None: ...
+    if sys.version_info >= (3, 12):
+        def __init__(
+            self,
+            request: socketserver._RequestType,
+            client_address: socketserver._AddressType,
+            server: socketserver.BaseServer,
+            *,
+            directory: str | None = ...,
+            index_pages: Sequence[str] | None = ...,
+        ) -> None: ...
+    else:
+        def __init__(
+            self,
+            request: socketserver._RequestType,
+            client_address: socketserver._AddressType,
+            server: socketserver.BaseServer,
+            *,
+            directory: str | None = ...,
+        ) -> None: ...
+
     def do_GET(self) -> None: ...
     def do_HEAD(self) -> None: ...
     def send_head(self) -> io.BytesIO | BinaryIO | None: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/imaplib.pyi b/mypy/typeshed/stdlib/imaplib.pyi
index bd3d0777db159..f13e1c9b656c1 100644
--- a/mypy/typeshed/stdlib/imaplib.pyi
+++ b/mypy/typeshed/stdlib/imaplib.pyi
@@ -1,7 +1,7 @@
 import subprocess
 import sys
 import time
-from _typeshed import Self
+from _typeshed import ReadableBuffer, Self, _BufferWithLen
 from builtins import list as _list  # conflicts with a method named "list"
 from collections.abc import Callable
 from datetime import datetime
@@ -9,7 +9,7 @@ from re import Pattern
 from socket import socket as _socket
 from ssl import SSLContext, SSLSocket
 from types import TracebackType
-from typing import IO, Any
+from typing import IO, Any, SupportsAbs, SupportsInt
 from typing_extensions import Literal, TypeAlias
 
 __all__ = ["IMAP4", "IMAP4_stream", "Internaldate2tuple", "Int2AP", "ParseFlags", "Time2Internaldate", "IMAP4_SSL"]
@@ -54,12 +54,12 @@ class IMAP4:
     file: IO[str] | IO[bytes]
     def read(self, size: int) -> bytes: ...
     def readline(self) -> bytes: ...
-    def send(self, data: bytes) -> None: ...
+    def send(self, data: ReadableBuffer) -> None: ...
     def shutdown(self) -> None: ...
     def socket(self) -> _socket: ...
     def recent(self) -> _CommandResults: ...
     def response(self, code: str) -> _CommandResults: ...
-    def append(self, mailbox: str, flags: str, date_time: str, message: bytes) -> str: ...
+    def append(self, mailbox: str, flags: str, date_time: str, message: ReadableBuffer) -> str: ...
     def authenticate(self, mechanism: str, authobject: Callable[[bytes], bytes | None]) -> tuple[str, str]: ...
     def capability(self) -> _CommandResults: ...
     def check(self) -> _CommandResults: ...
@@ -151,13 +151,13 @@ class IMAP4_stream(IMAP4):
         def open(self, host: str | None = ..., port: int | None = ...) -> None: ...
 
 class _Authenticator:
-    mech: Callable[[bytes], bytes]
-    def __init__(self, mechinst: Callable[[bytes], bytes]) -> None: ...
+    mech: Callable[[bytes], bytes | bytearray | memoryview | str | None]
+    def __init__(self, mechinst: Callable[[bytes], bytes | bytearray | memoryview | str | None]) -> None: ...
     def process(self, data: str) -> str: ...
-    def encode(self, inp: bytes) -> str: ...
-    def decode(self, inp: str) -> bytes: ...
+    def encode(self, inp: bytes | bytearray | memoryview) -> str: ...
+    def decode(self, inp: str | _BufferWithLen) -> bytes: ...
 
-def Internaldate2tuple(resp: bytes) -> time.struct_time: ...
-def Int2AP(num: int) -> str: ...
-def ParseFlags(resp: bytes) -> tuple[bytes, ...]: ...
+def Internaldate2tuple(resp: ReadableBuffer) -> time.struct_time | None: ...
+def Int2AP(num: SupportsAbs[SupportsInt]) -> bytes: ...
+def ParseFlags(resp: ReadableBuffer) -> tuple[bytes, ...]: ...
 def Time2Internaldate(date_time: float | time.struct_time | time._TimeTuple | datetime | str) -> str: ...
diff --git a/mypy/typeshed/stdlib/imp.pyi b/mypy/typeshed/stdlib/imp.pyi
index 3054a4465f992..889f0cac4f9f9 100644
--- a/mypy/typeshed/stdlib/imp.pyi
+++ b/mypy/typeshed/stdlib/imp.pyi
@@ -1,9 +1,4 @@
 import types
-from _typeshed import StrPath
-from os import PathLike
-from types import TracebackType
-from typing import IO, Any, Protocol
-
 from _imp import (
     acquire_lock as acquire_lock,
     create_dynamic as create_dynamic,
@@ -15,6 +10,10 @@ from _imp import (
     lock_held as lock_held,
     release_lock as release_lock,
 )
+from _typeshed import StrPath
+from os import PathLike
+from types import TracebackType
+from typing import IO, Any, Protocol
 
 SEARCH_ERROR: int
 PY_SOURCE: int
diff --git a/mypy/typeshed/stdlib/importlib/abc.pyi b/mypy/typeshed/stdlib/importlib/abc.pyi
index 708037305c67b..c961fb2e1f9e2 100644
--- a/mypy/typeshed/stdlib/importlib/abc.pyi
+++ b/mypy/typeshed/stdlib/importlib/abc.pyi
@@ -1,12 +1,19 @@
 import sys
 import types
-from _typeshed import OpenBinaryMode, OpenBinaryModeReading, OpenBinaryModeUpdating, OpenBinaryModeWriting, OpenTextMode
+from _typeshed import (
+    OpenBinaryMode,
+    OpenBinaryModeReading,
+    OpenBinaryModeUpdating,
+    OpenBinaryModeWriting,
+    OpenTextMode,
+    ReadableBuffer,
+)
 from abc import ABCMeta, abstractmethod
 from collections.abc import Iterator, Mapping, Sequence
 from importlib.machinery import ModuleSpec
 from io import BufferedRandom, BufferedReader, BufferedWriter, FileIO, TextIOWrapper
 from typing import IO, Any, BinaryIO, NoReturn, Protocol, overload, runtime_checkable
-from typing_extensions import Literal, TypeAlias
+from typing_extensions import Literal
 
 if sys.version_info >= (3, 11):
     __all__ = [
@@ -24,8 +31,6 @@ if sys.version_info >= (3, 11):
         "TraversableResources",
     ]
 
-_Path: TypeAlias = bytes | str
-
 class Finder(metaclass=ABCMeta): ...
 
 class Loader(metaclass=ABCMeta):
@@ -38,7 +43,7 @@ class Loader(metaclass=ABCMeta):
 
 class ResourceLoader(Loader):
     @abstractmethod
-    def get_data(self, path: _Path) -> bytes: ...
+    def get_data(self, path: str) -> bytes: ...
 
 class InspectLoader(Loader):
     def is_package(self, fullname: str) -> bool: ...
@@ -47,40 +52,40 @@ class InspectLoader(Loader):
     def get_source(self, fullname: str) -> str | None: ...
     def exec_module(self, module: types.ModuleType) -> None: ...
     @staticmethod
-    def source_to_code(data: bytes | str, path: str = ...) -> types.CodeType: ...
+    def source_to_code(data: ReadableBuffer | str, path: str = ...) -> types.CodeType: ...
 
 class ExecutionLoader(InspectLoader):
     @abstractmethod
-    def get_filename(self, fullname: str) -> _Path: ...
+    def get_filename(self, fullname: str) -> str: ...
 
 class SourceLoader(ResourceLoader, ExecutionLoader, metaclass=ABCMeta):
-    def path_mtime(self, path: _Path) -> float: ...
-    def set_data(self, path: _Path, data: bytes) -> None: ...
+    def path_mtime(self, path: str) -> float: ...
+    def set_data(self, path: str, data: bytes) -> None: ...
     def get_source(self, fullname: str) -> str | None: ...
-    def path_stats(self, path: _Path) -> Mapping[str, Any]: ...
+    def path_stats(self, path: str) -> Mapping[str, Any]: ...
 
 # Please keep in sync with sys._MetaPathFinder
 class MetaPathFinder(Finder):
-    def find_module(self, fullname: str, path: Sequence[_Path] | None) -> Loader | None: ...
+    def find_module(self, fullname: str, path: Sequence[str] | None) -> Loader | None: ...
     def invalidate_caches(self) -> None: ...
     # Not defined on the actual class, but expected to exist.
     def find_spec(
-        self, fullname: str, path: Sequence[_Path] | None, target: types.ModuleType | None = ...
+        self, fullname: str, path: Sequence[str] | None, target: types.ModuleType | None = ...
     ) -> ModuleSpec | None: ...
 
 class PathEntryFinder(Finder):
     def find_module(self, fullname: str) -> Loader | None: ...
-    def find_loader(self, fullname: str) -> tuple[Loader | None, Sequence[_Path]]: ...
+    def find_loader(self, fullname: str) -> tuple[Loader | None, Sequence[str]]: ...
     def invalidate_caches(self) -> None: ...
     # Not defined on the actual class, but expected to exist.
     def find_spec(self, fullname: str, target: types.ModuleType | None = ...) -> ModuleSpec | None: ...
 
 class FileLoader(ResourceLoader, ExecutionLoader, metaclass=ABCMeta):
     name: str
-    path: _Path
-    def __init__(self, fullname: str, path: _Path) -> None: ...
-    def get_data(self, path: _Path) -> bytes: ...
-    def get_filename(self, name: str | None = ...) -> _Path: ...
+    path: str
+    def __init__(self, fullname: str, path: str) -> None: ...
+    def get_data(self, path: str) -> bytes: ...
+    def get_filename(self, name: str | None = ...) -> str: ...
     def load_module(self, name: str | None = ...) -> types.ModuleType: ...
 
 class ResourceReader(metaclass=ABCMeta):
@@ -174,6 +179,7 @@ if sys.version_info >= (3, 9):
             self, mode: str, buffering: int = ..., encoding: str | None = ..., errors: str | None = ..., newline: str | None = ...
         ) -> IO[Any]: ...
         @property
+        @abstractmethod
         def name(self) -> str: ...
         @abstractmethod
         def __truediv__(self, child: str) -> Traversable: ...
diff --git a/mypy/typeshed/stdlib/importlib/machinery.pyi b/mypy/typeshed/stdlib/importlib/machinery.pyi
index ba6ed30629e01..6e253521bc0f7 100644
--- a/mypy/typeshed/stdlib/importlib/machinery.pyi
+++ b/mypy/typeshed/stdlib/importlib/machinery.pyi
@@ -1,6 +1,7 @@
 import importlib.abc
 import sys
 import types
+from _typeshed import ReadableBuffer
 from collections.abc import Callable, Iterable, Sequence
 from typing import Any
 
@@ -31,10 +32,10 @@ class ModuleSpec:
 class BuiltinImporter(importlib.abc.MetaPathFinder, importlib.abc.InspectLoader):
     # MetaPathFinder
     @classmethod
-    def find_module(cls, fullname: str, path: Sequence[importlib.abc._Path] | None = ...) -> importlib.abc.Loader | None: ...
+    def find_module(cls, fullname: str, path: Sequence[str] | None = ...) -> importlib.abc.Loader | None: ...
     @classmethod
     def find_spec(
-        cls, fullname: str, path: Sequence[importlib.abc._Path] | None = ..., target: types.ModuleType | None = ...
+        cls, fullname: str, path: Sequence[str] | None = ..., target: types.ModuleType | None = ...
     ) -> ModuleSpec | None: ...
     # InspectLoader
     @classmethod
@@ -62,10 +63,10 @@ class BuiltinImporter(importlib.abc.MetaPathFinder, importlib.abc.InspectLoader)
 class FrozenImporter(importlib.abc.MetaPathFinder, importlib.abc.InspectLoader):
     # MetaPathFinder
     @classmethod
-    def find_module(cls, fullname: str, path: Sequence[importlib.abc._Path] | None = ...) -> importlib.abc.Loader | None: ...
+    def find_module(cls, fullname: str, path: Sequence[str] | None = ...) -> importlib.abc.Loader | None: ...
     @classmethod
     def find_spec(
-        cls, fullname: str, path: Sequence[importlib.abc._Path] | None = ..., target: types.ModuleType | None = ...
+        cls, fullname: str, path: Sequence[str] | None = ..., target: types.ModuleType | None = ...
     ) -> ModuleSpec | None: ...
     # InspectLoader
     @classmethod
@@ -91,10 +92,10 @@ class FrozenImporter(importlib.abc.MetaPathFinder, importlib.abc.InspectLoader):
 
 class WindowsRegistryFinder(importlib.abc.MetaPathFinder):
     @classmethod
-    def find_module(cls, fullname: str, path: Sequence[importlib.abc._Path] | None = ...) -> importlib.abc.Loader | None: ...
+    def find_module(cls, fullname: str, path: Sequence[str] | None = ...) -> importlib.abc.Loader | None: ...
     @classmethod
     def find_spec(
-        cls, fullname: str, path: Sequence[importlib.abc._Path] | None = ..., target: types.ModuleType | None = ...
+        cls, fullname: str, path: Sequence[str] | None = ..., target: types.ModuleType | None = ...
     ) -> ModuleSpec | None: ...
 
 class PathFinder:
@@ -113,10 +114,10 @@ class PathFinder:
 
     @classmethod
     def find_spec(
-        cls, fullname: str, path: Sequence[bytes | str] | None = ..., target: types.ModuleType | None = ...
+        cls, fullname: str, path: Sequence[str] | None = ..., target: types.ModuleType | None = ...
     ) -> ModuleSpec | None: ...
     @classmethod
-    def find_module(cls, fullname: str, path: Sequence[bytes | str] | None = ...) -> importlib.abc.Loader | None: ...
+    def find_module(cls, fullname: str, path: Sequence[str] | None = ...) -> importlib.abc.Loader | None: ...
 
 SOURCE_SUFFIXES: list[str]
 DEBUG_BYTECODE_SUFFIXES: list[str]
@@ -135,13 +136,13 @@ class FileFinder(importlib.abc.PathEntryFinder):
     ) -> Callable[[str], importlib.abc.PathEntryFinder]: ...
 
 class SourceFileLoader(importlib.abc.FileLoader, importlib.abc.SourceLoader):
-    def set_data(self, path: importlib.abc._Path, data: bytes, *, _mode: int = ...) -> None: ...
+    def set_data(self, path: str, data: ReadableBuffer, *, _mode: int = ...) -> None: ...
 
 class SourcelessFileLoader(importlib.abc.FileLoader, importlib.abc.SourceLoader): ...
 
 class ExtensionFileLoader(importlib.abc.ExecutionLoader):
-    def __init__(self, name: str, path: importlib.abc._Path) -> None: ...
-    def get_filename(self, name: str | None = ...) -> importlib.abc._Path: ...
+    def __init__(self, name: str, path: str) -> None: ...
+    def get_filename(self, name: str | None = ...) -> str: ...
     def get_source(self, fullname: str) -> None: ...
     def create_module(self, spec: ModuleSpec) -> types.ModuleType: ...
     def exec_module(self, module: types.ModuleType) -> None: ...
diff --git a/mypy/typeshed/stdlib/importlib/util.pyi b/mypy/typeshed/stdlib/importlib/util.pyi
index 4d75032ab44a1..e9c08aeccf871 100644
--- a/mypy/typeshed/stdlib/importlib/util.pyi
+++ b/mypy/typeshed/stdlib/importlib/util.pyi
@@ -1,7 +1,7 @@
 import importlib.abc
 import importlib.machinery
 import types
-from _typeshed import StrOrBytesPath
+from _typeshed import ReadableBuffer, StrOrBytesPath
 from collections.abc import Callable
 from typing import Any
 from typing_extensions import ParamSpec
@@ -17,7 +17,7 @@ MAGIC_NUMBER: bytes
 
 def cache_from_source(path: str, debug_override: bool | None = ..., *, optimization: Any | None = ...) -> str: ...
 def source_from_cache(path: str) -> str: ...
-def decode_source(source_bytes: bytes) -> str: ...
+def decode_source(source_bytes: ReadableBuffer) -> str: ...
 def find_spec(name: str, package: str | None = ...) -> importlib.machinery.ModuleSpec | None: ...
 def spec_from_loader(
     name: str, loader: importlib.abc.Loader | None, *, origin: str | None = ..., is_package: bool | None = ...
@@ -37,4 +37,4 @@ class LazyLoader(importlib.abc.Loader):
     def factory(cls, loader: importlib.abc.Loader) -> Callable[..., LazyLoader]: ...
     def exec_module(self, module: types.ModuleType) -> None: ...
 
-def source_hash(source_bytes: bytes) -> int: ...
+def source_hash(source_bytes: ReadableBuffer) -> int: ...
diff --git a/mypy/typeshed/stdlib/inspect.pyi b/mypy/typeshed/stdlib/inspect.pyi
index b97bc601271ac..ad68aa93c894c 100644
--- a/mypy/typeshed/stdlib/inspect.pyi
+++ b/mypy/typeshed/stdlib/inspect.pyi
@@ -585,7 +585,7 @@ _Object: TypeAlias = object
 
 class Attribute(NamedTuple):
     name: str
-    kind: str
+    kind: Literal["class method", "static method", "property", "method", "data"]
     defining_class: type
     object: _Object
 
diff --git a/mypy/typeshed/stdlib/io.pyi b/mypy/typeshed/stdlib/io.pyi
index 3e9a6cd6861d3..9c4c769fe34bc 100644
--- a/mypy/typeshed/stdlib/io.pyi
+++ b/mypy/typeshed/stdlib/io.pyi
@@ -103,7 +103,7 @@ class FileIO(RawIOBase, BinaryIO):
     def __enter__(self: Self) -> Self: ...
 
 class BytesIO(BufferedIOBase, BinaryIO):
-    def __init__(self, initial_bytes: bytes = ...) -> None: ...
+    def __init__(self, initial_bytes: ReadableBuffer = ...) -> None: ...
     # BytesIO does not contain a "name" field. This workaround is necessary
     # to allow BytesIO sub-classes to add this field, as it is defined
     # as a read-only property on IO[].
@@ -190,7 +190,7 @@ class StringIO(TextIOWrapper):
 
 class IncrementalNewlineDecoder(codecs.IncrementalDecoder):
     def __init__(self, decoder: codecs.IncrementalDecoder | None, translate: bool, errors: str = ...) -> None: ...
-    def decode(self, input: bytes | str, final: bool = ...) -> str: ...
+    def decode(self, input: ReadableBuffer | str, final: bool = ...) -> str: ...
     @property
     def newlines(self) -> str | tuple[str, ...] | None: ...
     def setstate(self, __state: tuple[bytes, int]) -> None: ...
diff --git a/mypy/typeshed/stdlib/ipaddress.pyi b/mypy/typeshed/stdlib/ipaddress.pyi
index 2c0292d6fbaec..6580ba4f1ac48 100644
--- a/mypy/typeshed/stdlib/ipaddress.pyi
+++ b/mypy/typeshed/stdlib/ipaddress.pyi
@@ -18,7 +18,9 @@ def ip_address(address: _RawIPAddress) -> IPv4Address | IPv6Address: ...
 def ip_network(
     address: _RawIPAddress | _RawNetworkPart | tuple[_RawIPAddress] | tuple[_RawIPAddress, int], strict: bool = ...
 ) -> IPv4Network | IPv6Network: ...
-def ip_interface(address: _RawIPAddress | _RawNetworkPart) -> IPv4Interface | IPv6Interface: ...
+def ip_interface(
+    address: _RawIPAddress | _RawNetworkPart | tuple[_RawIPAddress] | tuple[_RawIPAddress, int]
+) -> IPv4Interface | IPv6Interface: ...
 
 class _IPAddressBase:
     @property
diff --git a/mypy/typeshed/stdlib/json/__init__.pyi b/mypy/typeshed/stdlib/json/__init__.pyi
index 2fd87622e1fe9..64ab8a11a45de 100644
--- a/mypy/typeshed/stdlib/json/__init__.pyi
+++ b/mypy/typeshed/stdlib/json/__init__.pyi
@@ -37,7 +37,7 @@ def dump(
     **kwds: Any,
 ) -> None: ...
 def loads(
-    s: str | bytes,
+    s: str | bytes | bytearray,
     *,
     cls: type[JSONDecoder] | None = ...,
     object_hook: Callable[[dict[Any, Any]], Any] | None = ...,
@@ -58,4 +58,4 @@ def load(
     object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None = ...,
     **kwds: Any,
 ) -> Any: ...
-def detect_encoding(b: bytes) -> str: ...  # undocumented
+def detect_encoding(b: bytes | bytearray) -> str: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/logging/handlers.pyi b/mypy/typeshed/stdlib/logging/handlers.pyi
index eec4ed96953a5..f01c67d13fe98 100644
--- a/mypy/typeshed/stdlib/logging/handlers.pyi
+++ b/mypy/typeshed/stdlib/logging/handlers.pyi
@@ -2,7 +2,7 @@ import datetime
 import http.client
 import ssl
 import sys
-from _typeshed import StrPath
+from _typeshed import ReadableBuffer, StrPath
 from collections.abc import Callable
 from logging import FileHandler, Handler, LogRecord
 from queue import Queue, SimpleQueue
@@ -125,7 +125,7 @@ class SocketHandler(Handler):
     def __init__(self, host: str, port: int | None) -> None: ...
     def makeSocket(self, timeout: float = ...) -> socket: ...  # timeout is undocumented
     def makePickle(self, record: LogRecord) -> bytes: ...
-    def send(self, s: bytes) -> None: ...
+    def send(self, s: ReadableBuffer) -> None: ...
     def createSocket(self) -> None: ...
 
 class DatagramHandler(SocketHandler):
diff --git a/mypy/typeshed/stdlib/lzma.pyi b/mypy/typeshed/stdlib/lzma.pyi
index 868da0f055675..9d75c627f76dd 100644
--- a/mypy/typeshed/stdlib/lzma.pyi
+++ b/mypy/typeshed/stdlib/lzma.pyi
@@ -83,7 +83,7 @@ PRESET_EXTREME: int  # v big number
 @final
 class LZMADecompressor:
     def __init__(self, format: int | None = ..., memlimit: int | None = ..., filters: _FilterChain | None = ...) -> None: ...
-    def decompress(self, data: bytes, max_length: int = ...) -> bytes: ...
+    def decompress(self, data: ReadableBuffer, max_length: int = ...) -> bytes: ...
     @property
     def check(self) -> int: ...
     @property
@@ -99,7 +99,7 @@ class LZMACompressor:
     def __init__(
         self, format: int | None = ..., check: int = ..., preset: int | None = ..., filters: _FilterChain | None = ...
     ) -> None: ...
-    def compress(self, __data: bytes) -> bytes: ...
+    def compress(self, __data: ReadableBuffer) -> bytes: ...
     def flush(self) -> bytes: ...
 
 class LZMAError(Exception): ...
@@ -189,7 +189,9 @@ def open(
     newline: str | None = ...,
 ) -> LZMAFile | TextIO: ...
 def compress(
-    data: bytes, format: int = ..., check: int = ..., preset: int | None = ..., filters: _FilterChain | None = ...
+    data: ReadableBuffer, format: int = ..., check: int = ..., preset: int | None = ..., filters: _FilterChain | None = ...
+) -> bytes: ...
+def decompress(
+    data: ReadableBuffer, format: int = ..., memlimit: int | None = ..., filters: _FilterChain | None = ...
 ) -> bytes: ...
-def decompress(data: bytes, format: int = ..., memlimit: int | None = ..., filters: _FilterChain | None = ...) -> bytes: ...
 def is_check_supported(__check_id: int) -> bool: ...
diff --git a/mypy/typeshed/stdlib/mailbox.pyi b/mypy/typeshed/stdlib/mailbox.pyi
index 3169e8cfa6897..29cea5cadbb08 100644
--- a/mypy/typeshed/stdlib/mailbox.pyi
+++ b/mypy/typeshed/stdlib/mailbox.pyi
@@ -1,6 +1,7 @@
 import email.message
+import io
 import sys
-from _typeshed import Self, StrOrBytesPath
+from _typeshed import Self, StrPath, SupportsNoArgReadline, SupportsRead
 from abc import ABCMeta, abstractmethod
 from collections.abc import Callable, Iterable, Iterator, Mapping, Sequence
 from types import TracebackType
@@ -32,7 +33,10 @@ __all__ = [
 
 _T = TypeVar("_T")
 _MessageT = TypeVar("_MessageT", bound=Message)
-_MessageData: TypeAlias = email.message.Message | bytes | str | IO[str] | IO[bytes]
+
+class _SupportsReadAndReadline(SupportsRead[bytes], SupportsNoArgReadline[bytes], Protocol): ...
+
+_MessageData: TypeAlias = email.message.Message | bytes | str | io.StringIO | _SupportsReadAndReadline
 
 class _HasIteritems(Protocol):
     def iteritems(self) -> Iterator[tuple[str, _MessageData]]: ...
@@ -43,13 +47,12 @@ class _HasItems(Protocol):
 linesep: bytes
 
 class Mailbox(Generic[_MessageT]):
-
-    _path: bytes | str  # undocumented
+    _path: str  # undocumented
     _factory: Callable[[IO[Any]], _MessageT] | None  # undocumented
     @overload
-    def __init__(self, path: StrOrBytesPath, factory: Callable[[IO[Any]], _MessageT], create: bool = ...) -> None: ...
+    def __init__(self, path: StrPath, factory: Callable[[IO[Any]], _MessageT], create: bool = ...) -> None: ...
     @overload
-    def __init__(self, path: StrOrBytesPath, factory: None = ..., create: bool = ...) -> None: ...
+    def __init__(self, path: StrPath, factory: None = ..., create: bool = ...) -> None: ...
     @abstractmethod
     def add(self, message: _MessageData) -> str: ...
     @abstractmethod
@@ -105,7 +108,7 @@ class Maildir(Mailbox[MaildirMessage]):
 
     colon: str
     def __init__(
-        self, dirname: StrOrBytesPath, factory: Callable[[IO[Any]], MaildirMessage] | None = ..., create: bool = ...
+        self, dirname: StrPath, factory: Callable[[IO[Any]], MaildirMessage] | None = ..., create: bool = ...
     ) -> None: ...
     def add(self, message: _MessageData) -> str: ...
     def remove(self, key: str) -> None: ...
@@ -146,19 +149,13 @@ class _mboxMMDF(_singlefileMailbox[_MessageT]):
     def get_string(self, key: str, from_: bool = ...) -> str: ...
 
 class mbox(_mboxMMDF[mboxMessage]):
-    def __init__(
-        self, path: StrOrBytesPath, factory: Callable[[IO[Any]], mboxMessage] | None = ..., create: bool = ...
-    ) -> None: ...
+    def __init__(self, path: StrPath, factory: Callable[[IO[Any]], mboxMessage] | None = ..., create: bool = ...) -> None: ...
 
 class MMDF(_mboxMMDF[MMDFMessage]):
-    def __init__(
-        self, path: StrOrBytesPath, factory: Callable[[IO[Any]], MMDFMessage] | None = ..., create: bool = ...
-    ) -> None: ...
+    def __init__(self, path: StrPath, factory: Callable[[IO[Any]], MMDFMessage] | None = ..., create: bool = ...) -> None: ...
 
 class MH(Mailbox[MHMessage]):
-    def __init__(
-        self, path: StrOrBytesPath, factory: Callable[[IO[Any]], MHMessage] | None = ..., create: bool = ...
-    ) -> None: ...
+    def __init__(self, path: StrPath, factory: Callable[[IO[Any]], MHMessage] | None = ..., create: bool = ...) -> None: ...
     def add(self, message: _MessageData) -> str: ...
     def remove(self, key: str) -> None: ...
     def __setitem__(self, key: str, message: _MessageData) -> None: ...
@@ -173,17 +170,15 @@ class MH(Mailbox[MHMessage]):
     def unlock(self) -> None: ...
     def close(self) -> None: ...
     def list_folders(self) -> list[str]: ...
-    def get_folder(self, folder: StrOrBytesPath) -> MH: ...
-    def add_folder(self, folder: StrOrBytesPath) -> MH: ...
-    def remove_folder(self, folder: StrOrBytesPath) -> None: ...
+    def get_folder(self, folder: StrPath) -> MH: ...
+    def add_folder(self, folder: StrPath) -> MH: ...
+    def remove_folder(self, folder: StrPath) -> None: ...
     def get_sequences(self) -> dict[str, list[int]]: ...
     def set_sequences(self, sequences: Mapping[str, Sequence[int]]) -> None: ...
     def pack(self) -> None: ...
 
 class Babyl(_singlefileMailbox[BabylMessage]):
-    def __init__(
-        self, path: StrOrBytesPath, factory: Callable[[IO[Any]], BabylMessage] | None = ..., create: bool = ...
-    ) -> None: ...
+    def __init__(self, path: StrPath, factory: Callable[[IO[Any]], BabylMessage] | None = ..., create: bool = ...) -> None: ...
     def get_message(self, key: str) -> BabylMessage: ...
     def get_bytes(self, key: str) -> bytes: ...
     def get_file(self, key: str) -> IO[bytes]: ...
diff --git a/mypy/typeshed/stdlib/marshal.pyi b/mypy/typeshed/stdlib/marshal.pyi
index b2fde674a6477..d68cdd1431090 100644
--- a/mypy/typeshed/stdlib/marshal.pyi
+++ b/mypy/typeshed/stdlib/marshal.pyi
@@ -1,8 +1,9 @@
-from typing import IO, Any
+from _typeshed import ReadableBuffer, SupportsRead, SupportsWrite
+from typing import Any
 
 version: int
 
-def dump(__value: Any, __file: IO[Any], __version: int = ...) -> None: ...
-def load(__file: IO[Any]) -> Any: ...
+def dump(__value: Any, __file: SupportsWrite[bytes], __version: int = ...) -> None: ...
+def load(__file: SupportsRead[bytes]) -> Any: ...
 def dumps(__value: Any, __version: int = ...) -> bytes: ...
-def loads(__bytes: bytes) -> Any: ...
+def loads(__bytes: ReadableBuffer) -> Any: ...
diff --git a/mypy/typeshed/stdlib/math.pyi b/mypy/typeshed/stdlib/math.pyi
index 58eda98d89777..ca30acd7e97d6 100644
--- a/mypy/typeshed/stdlib/math.pyi
+++ b/mypy/typeshed/stdlib/math.pyi
@@ -1,9 +1,11 @@
 import sys
-from _typeshed import SupportsTrunc
 from collections.abc import Iterable
-from typing import SupportsFloat, overload
+from typing import Protocol, SupportsFloat, TypeVar, overload
 from typing_extensions import SupportsIndex, TypeAlias
 
+_T = TypeVar("_T")
+_T_co = TypeVar("_T_co", covariant=True)
+
 if sys.version_info >= (3, 8):
     _SupportsFloatOrIndex: TypeAlias = SupportsFloat | SupportsIndex
 else:
@@ -26,6 +28,12 @@ def atanh(__x: _SupportsFloatOrIndex) -> float: ...
 if sys.version_info >= (3, 11):
     def cbrt(__x: _SupportsFloatOrIndex) -> float: ...
 
+class _SupportsCeil(Protocol[_T_co]):
+    def __ceil__(self) -> _T_co: ...
+
+@overload
+def ceil(__x: _SupportsCeil[_T]) -> _T: ...
+@overload
 def ceil(__x: _SupportsFloatOrIndex) -> int: ...
 
 if sys.version_info >= (3, 8):
@@ -55,6 +63,12 @@ if sys.version_info >= (3, 8):
 else:
     def factorial(__x: int) -> int: ...
 
+class _SupportsFloor(Protocol[_T_co]):
+    def __floor__(self) -> _T_co: ...
+
+@overload
+def floor(__x: _SupportsFloor[_T]) -> _T: ...
+@overload
 def floor(__x: _SupportsFloatOrIndex) -> int: ...
 def fmod(__x: _SupportsFloatOrIndex, __y: _SupportsFloatOrIndex) -> float: ...
 def frexp(__x: _SupportsFloatOrIndex) -> tuple[float, int]: ...
@@ -119,7 +133,12 @@ def sinh(__x: _SupportsFloatOrIndex) -> float: ...
 def sqrt(__x: _SupportsFloatOrIndex) -> float: ...
 def tan(__x: _SupportsFloatOrIndex) -> float: ...
 def tanh(__x: _SupportsFloatOrIndex) -> float: ...
-def trunc(__x: SupportsTrunc) -> int: ...
+
+# Is different from `_typeshed.SupportsTrunc`, which is not generic
+class _SupportsTrunc(Protocol[_T_co]):
+    def __trunc__(self) -> _T_co: ...
+
+def trunc(__x: _SupportsTrunc[_T]) -> _T: ...
 
 if sys.version_info >= (3, 9):
     def ulp(__x: _SupportsFloatOrIndex) -> float: ...
diff --git a/mypy/typeshed/stdlib/mmap.pyi b/mypy/typeshed/stdlib/mmap.pyi
index 8dbec23888387..30084b85bc512 100644
--- a/mypy/typeshed/stdlib/mmap.pyi
+++ b/mypy/typeshed/stdlib/mmap.pyi
@@ -67,8 +67,11 @@ class mmap(Iterable[int], Sized):
     def __setitem__(self, __index: int, __object: int) -> None: ...
     @overload
     def __setitem__(self, __index: slice, __object: ReadableBuffer) -> None: ...
-    # Doesn't actually exist, but the object is actually iterable because it has __getitem__ and
-    # __len__, so we claim that there is also an __iter__ to help type checkers.
+    # Doesn't actually exist, but the object actually supports "in" because it has __getitem__,
+    # so we claim that there is also a __contains__ to help type checkers.
+    def __contains__(self, __o: object) -> bool: ...
+    # Doesn't actually exist, but the object is actually iterable because it has __getitem__ and __len__,
+    # so we claim that there is also an __iter__ to help type checkers.
     def __iter__(self) -> Iterator[int]: ...
     def __enter__(self: Self) -> Self: ...
     def __exit__(self, *args: object) -> None: ...
diff --git a/mypy/typeshed/stdlib/msvcrt.pyi b/mypy/typeshed/stdlib/msvcrt.pyi
index 0bea8ce22b067..5849b9b00ca0c 100644
--- a/mypy/typeshed/stdlib/msvcrt.pyi
+++ b/mypy/typeshed/stdlib/msvcrt.pyi
@@ -21,8 +21,8 @@ if sys.platform == "win32":
     def getwch() -> str: ...
     def getche() -> bytes: ...
     def getwche() -> str: ...
-    def putch(__char: bytes) -> None: ...
+    def putch(__char: bytes | bytearray) -> None: ...
     def putwch(__unicode_char: str) -> None: ...
-    def ungetch(__char: bytes) -> None: ...
+    def ungetch(__char: bytes | bytearray) -> None: ...
     def ungetwch(__unicode_char: str) -> None: ...
     def heapmin() -> None: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/connection.pyi b/mypy/typeshed/stdlib/multiprocessing/connection.pyi
index cc9f5cf8f8900..5036f0ef222bb 100644
--- a/mypy/typeshed/stdlib/multiprocessing/connection.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/connection.pyi
@@ -1,7 +1,7 @@
 import socket
 import sys
 import types
-from _typeshed import Self
+from _typeshed import ReadableBuffer, Self
 from collections.abc import Iterable
 from typing import Any, Union
 from typing_extensions import SupportsIndex, TypeAlias
@@ -21,7 +21,7 @@ class _ConnectionBase:
     def writable(self) -> bool: ...  # undocumented
     def fileno(self) -> int: ...
     def close(self) -> None: ...
-    def send_bytes(self, buf: bytes, offset: int = ..., size: int | None = ...) -> None: ...
+    def send_bytes(self, buf: ReadableBuffer, offset: int = ..., size: int | None = ...) -> None: ...
     def send(self, obj: Any) -> None: ...
     def recv_bytes(self, maxlength: int | None = ...) -> bytes: ...
     def recv_bytes_into(self, buf: Any, offset: int = ...) -> int: ...
diff --git a/mypy/typeshed/stdlib/operator.pyi b/mypy/typeshed/stdlib/operator.pyi
index c3fc4b0a85037..a0e5df7977daf 100644
--- a/mypy/typeshed/stdlib/operator.pyi
+++ b/mypy/typeshed/stdlib/operator.pyi
@@ -1,5 +1,4 @@
 import sys
-
 from _operator import *
 
 __all__ = [
diff --git a/mypy/typeshed/stdlib/os/__init__.pyi b/mypy/typeshed/stdlib/os/__init__.pyi
index 6f51d4e7aa509..590d20576665e 100644
--- a/mypy/typeshed/stdlib/os/__init__.pyi
+++ b/mypy/typeshed/stdlib/os/__init__.pyi
@@ -503,11 +503,14 @@ if sys.platform != "win32":
     def getenvb(key: bytes) -> bytes | None: ...
     @overload
     def getenvb(key: bytes, default: _T) -> bytes | _T: ...
+    def putenv(__name: StrOrBytesPath, __value: StrOrBytesPath) -> None: ...
+    def unsetenv(__name: StrOrBytesPath) -> None: ...
 
-def putenv(__name: bytes | str, __value: bytes | str) -> None: ...
+else:
+    def putenv(__name: str, __value: str) -> None: ...
 
-if sys.platform != "win32" or sys.version_info >= (3, 9):
-    def unsetenv(__name: bytes | str) -> None: ...
+    if sys.version_info >= (3, 9):
+        def unsetenv(__name: str) -> None: ...
 
 _Opener: TypeAlias = Callable[[str, int], int]
 
@@ -622,7 +625,7 @@ if sys.platform != "win32":
         def posix_fadvise(__fd: int, __offset: int, __length: int, __advice: int) -> None: ...
 
     def pread(__fd: int, __length: int, __offset: int) -> bytes: ...
-    def pwrite(__fd: int, __buffer: bytes, __offset: int) -> int: ...
+    def pwrite(__fd: int, __buffer: ReadableBuffer, __offset: int) -> int: ...
     # In CI, stubtest sometimes reports that these are available on MacOS, sometimes not
     def preadv(__fd: int, __buffers: SupportsLenAndGetItem[WriteableBuffer], __offset: int, __flags: int = ...) -> int: ...
     def pwritev(__fd: int, __buffers: SupportsLenAndGetItem[ReadableBuffer], __offset: int, __flags: int = ...) -> int: ...
@@ -641,8 +644,8 @@ if sys.platform != "win32":
         in_fd: int,
         offset: int,
         count: int,
-        headers: Sequence[bytes] = ...,
-        trailers: Sequence[bytes] = ...,
+        headers: Sequence[ReadableBuffer] = ...,
+        trailers: Sequence[ReadableBuffer] = ...,
         flags: int = ...,
     ) -> int: ...  # FreeBSD and Mac OS X only
     def readv(__fd: int, __buffers: SupportsLenAndGetItem[WriteableBuffer]) -> int: ...
@@ -671,7 +674,7 @@ if sys.platform != "win32":
     def tcsetpgrp(__fd: int, __pgid: int) -> None: ...
     def ttyname(__fd: int) -> str: ...
 
-def write(__fd: int, __data: bytes) -> int: ...
+def write(__fd: int, __data: ReadableBuffer) -> int: ...
 def access(
     path: _FdOrAnyPath, mode: int, *, dir_fd: int | None = ..., effective_ids: bool = ..., follow_symlinks: bool = ...
 ) -> bool: ...
@@ -775,14 +778,19 @@ if sys.platform != "win32":
     ) -> Iterator[tuple[str, list[str], list[str], int]]: ...
     @overload
     def fwalk(
-        top: bytes, topdown: bool = ..., onerror: _OnError | None = ..., *, follow_symlinks: bool = ..., dir_fd: int | None = ...
+        top: BytesPath,
+        topdown: bool = ...,
+        onerror: _OnError | None = ...,
+        *,
+        follow_symlinks: bool = ...,
+        dir_fd: int | None = ...,
     ) -> Iterator[tuple[bytes, list[bytes], list[bytes], int]]: ...
     if sys.platform == "linux":
         def getxattr(path: _FdOrAnyPath, attribute: StrOrBytesPath, *, follow_symlinks: bool = ...) -> bytes: ...
         def listxattr(path: _FdOrAnyPath | None = ..., *, follow_symlinks: bool = ...) -> list[str]: ...
         def removexattr(path: _FdOrAnyPath, attribute: StrOrBytesPath, *, follow_symlinks: bool = ...) -> None: ...
         def setxattr(
-            path: _FdOrAnyPath, attribute: StrOrBytesPath, value: bytes, flags: int = ..., *, follow_symlinks: bool = ...
+            path: _FdOrAnyPath, attribute: StrOrBytesPath, value: ReadableBuffer, flags: int = ..., *, follow_symlinks: bool = ...
         ) -> None: ...
 
 def abort() -> NoReturn: ...
@@ -810,6 +818,10 @@ _ExecVArgs: TypeAlias = (
     | list[str | PathLike[Any]]
     | list[bytes | str | PathLike[Any]]
 )
+# Depending on the OS, the keys and values are passed either to
+# PyUnicode_FSDecoder (which accepts str | ReadableBuffer) or to
+# PyUnicode_FSConverter (which accepts StrOrBytesPath). For simplicity,
+# we limit to str | bytes.
 _ExecEnv: TypeAlias = Mapping[bytes, bytes | str] | Mapping[str, bytes | str]
 
 def execv(__path: StrOrBytesPath, __argv: _ExecVArgs) -> NoReturn: ...
diff --git a/mypy/typeshed/stdlib/pathlib.pyi b/mypy/typeshed/stdlib/pathlib.pyi
index 2a0f1760cae50..79c2352a0f85c 100644
--- a/mypy/typeshed/stdlib/pathlib.pyi
+++ b/mypy/typeshed/stdlib/pathlib.pyi
@@ -5,10 +5,12 @@ from _typeshed import (
     OpenBinaryModeUpdating,
     OpenBinaryModeWriting,
     OpenTextMode,
+    ReadableBuffer,
     Self,
+    StrOrBytesPath,
     StrPath,
 )
-from collections.abc import Generator, Sequence
+from collections.abc import Callable, Generator, Iterator, Sequence
 from io import BufferedRandom, BufferedReader, BufferedWriter, FileIO, TextIOWrapper
 from os import PathLike, stat_result
 from types import TracebackType
@@ -188,16 +190,20 @@ class Path(PurePath):
     def expanduser(self: Self) -> Self: ...
     def read_bytes(self) -> bytes: ...
     def read_text(self, encoding: str | None = ..., errors: str | None = ...) -> str: ...
-    def samefile(self, other_path: str | bytes | int | Path) -> bool: ...
-    def write_bytes(self, data: bytes) -> int: ...
+    def samefile(self, other_path: StrPath) -> bool: ...
+    def write_bytes(self, data: ReadableBuffer) -> int: ...
     if sys.version_info >= (3, 10):
         def write_text(
             self, data: str, encoding: str | None = ..., errors: str | None = ..., newline: str | None = ...
         ) -> int: ...
     else:
         def write_text(self, data: str, encoding: str | None = ..., errors: str | None = ...) -> int: ...
-    if sys.version_info >= (3, 8):
-        def link_to(self, target: StrPath | bytes) -> None: ...
+    if sys.version_info >= (3, 8) and sys.version_info < (3, 12):
+        def link_to(self, target: StrOrBytesPath) -> None: ...
+    if sys.version_info >= (3, 12):
+        def walk(
+            self: Self, top_down: bool = ..., on_error: Callable[[OSError], object] | None = ..., follow_symlinks: bool = ...
+        ) -> Iterator[tuple[Self, list[str], list[str]]]: ...
 
 class PosixPath(Path, PurePosixPath): ...
 class WindowsPath(Path, PureWindowsPath): ...
diff --git a/mypy/typeshed/stdlib/pickle.pyi b/mypy/typeshed/stdlib/pickle.pyi
index 9a94e9eced3c1..f393452069a36 100644
--- a/mypy/typeshed/stdlib/pickle.pyi
+++ b/mypy/typeshed/stdlib/pickle.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import ReadableBuffer
+from _typeshed import ReadableBuffer, SupportsWrite
 from collections.abc import Callable, Iterable, Iterator, Mapping
 from typing import Any, ClassVar, Protocol, SupportsBytes, Union
 from typing_extensions import SupportsIndex, TypeAlias, final
@@ -97,9 +97,6 @@ class _ReadableFileobj(Protocol):
     def read(self, __n: int) -> bytes: ...
     def readline(self) -> bytes: ...
 
-class _WritableFileobj(Protocol):
-    def write(self, __b: bytes) -> Any: ...
-
 if sys.version_info >= (3, 8):
     @final
     class PickleBuffer:
@@ -109,7 +106,7 @@ if sys.version_info >= (3, 8):
     _BufferCallback: TypeAlias = Callable[[PickleBuffer], Any] | None
     def dump(
         obj: Any,
-        file: _WritableFileobj,
+        file: SupportsWrite[bytes],
         protocol: int | None = ...,
         *,
         fix_imports: bool = ...,
@@ -136,7 +133,7 @@ if sys.version_info >= (3, 8):
     ) -> Any: ...
 
 else:
-    def dump(obj: Any, file: _WritableFileobj, protocol: int | None = ..., *, fix_imports: bool = ...) -> None: ...
+    def dump(obj: Any, file: SupportsWrite[bytes], protocol: int | None = ..., *, fix_imports: bool = ...) -> None: ...
     def dumps(obj: Any, protocol: int | None = ..., *, fix_imports: bool = ...) -> bytes: ...
     def load(file: _ReadableFileobj, *, fix_imports: bool = ..., encoding: str = ..., errors: str = ...) -> Any: ...
     def loads(data: ReadableBuffer, *, fix_imports: bool = ..., encoding: str = ..., errors: str = ...) -> Any: ...
@@ -162,7 +159,7 @@ class Pickler:
     if sys.version_info >= (3, 8):
         def __init__(
             self,
-            file: _WritableFileobj,
+            file: SupportsWrite[bytes],
             protocol: int | None = ...,
             *,
             fix_imports: bool = ...,
@@ -170,7 +167,7 @@ class Pickler:
         ) -> None: ...
         def reducer_override(self, obj: Any) -> Any: ...
     else:
-        def __init__(self, file: _WritableFileobj, protocol: int | None = ..., *, fix_imports: bool = ...) -> None: ...
+        def __init__(self, file: SupportsWrite[bytes], protocol: int | None = ..., *, fix_imports: bool = ...) -> None: ...
 
     def dump(self, __obj: Any) -> None: ...
     def clear_memo(self) -> None: ...
diff --git a/mypy/typeshed/stdlib/pickletools.pyi b/mypy/typeshed/stdlib/pickletools.pyi
index c78848464237c..2f0d5f12f8a39 100644
--- a/mypy/typeshed/stdlib/pickletools.pyi
+++ b/mypy/typeshed/stdlib/pickletools.pyi
@@ -156,10 +156,10 @@ class OpcodeInfo:
 
 opcodes: list[OpcodeInfo]
 
-def genops(pickle: bytes | IO[bytes]) -> Iterator[tuple[OpcodeInfo, Any | None, int | None]]: ...
-def optimize(p: bytes | IO[bytes]) -> bytes: ...
+def genops(pickle: bytes | bytearray | IO[bytes]) -> Iterator[tuple[OpcodeInfo, Any | None, int | None]]: ...
+def optimize(p: bytes | bytearray | IO[bytes]) -> bytes: ...
 def dis(
-    pickle: bytes | IO[bytes],
+    pickle: bytes | bytearray | IO[bytes],
     out: IO[str] | None = ...,
     memo: MutableMapping[int, Any] | None = ...,
     indentlevel: int = ...,
diff --git a/mypy/typeshed/stdlib/plistlib.pyi b/mypy/typeshed/stdlib/plistlib.pyi
index 9dcfcdb126cbc..4ec9cbd5a31c7 100644
--- a/mypy/typeshed/stdlib/plistlib.pyi
+++ b/mypy/typeshed/stdlib/plistlib.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import Self
+from _typeshed import ReadableBuffer, Self
 from collections.abc import Mapping, MutableMapping
 from datetime import datetime
 from enum import Enum
@@ -48,7 +48,9 @@ FMT_BINARY = PlistFormat.FMT_BINARY
 
 if sys.version_info >= (3, 9):
     def load(fp: IO[bytes], *, fmt: PlistFormat | None = ..., dict_type: type[MutableMapping[str, Any]] = ...) -> Any: ...
-    def loads(value: bytes, *, fmt: PlistFormat | None = ..., dict_type: type[MutableMapping[str, Any]] = ...) -> Any: ...
+    def loads(
+        value: ReadableBuffer, *, fmt: PlistFormat | None = ..., dict_type: type[MutableMapping[str, Any]] = ...
+    ) -> Any: ...
 
 else:
     def load(
@@ -59,7 +61,7 @@ else:
         dict_type: type[MutableMapping[str, Any]] = ...,
     ) -> Any: ...
     def loads(
-        value: bytes,
+        value: ReadableBuffer,
         *,
         fmt: PlistFormat | None = ...,
         use_builtin_types: bool = ...,
@@ -67,7 +69,7 @@ else:
     ) -> Any: ...
 
 def dump(
-    value: Mapping[str, Any] | list[Any] | tuple[Any, ...] | str | bool | float | bytes | datetime,
+    value: Mapping[str, Any] | list[Any] | tuple[Any, ...] | str | bool | float | bytes | bytearray | datetime,
     fp: IO[bytes],
     *,
     fmt: PlistFormat = ...,
@@ -75,7 +77,7 @@ def dump(
     skipkeys: bool = ...,
 ) -> None: ...
 def dumps(
-    value: Mapping[str, Any] | list[Any] | tuple[Any, ...] | str | bool | float | bytes | datetime,
+    value: Mapping[str, Any] | list[Any] | tuple[Any, ...] | str | bool | float | bytes | bytearray | datetime,
     *,
     fmt: PlistFormat = ...,
     skipkeys: bool = ...,
@@ -85,7 +87,7 @@ def dumps(
 if sys.version_info < (3, 9):
     def readPlist(pathOrFile: str | IO[bytes]) -> Any: ...
     def writePlist(value: Mapping[str, Any], pathOrFile: str | IO[bytes]) -> None: ...
-    def readPlistFromBytes(data: bytes) -> Any: ...
+    def readPlistFromBytes(data: ReadableBuffer) -> Any: ...
     def writePlistToBytes(value: Mapping[str, Any]) -> bytes: ...
 
 if sys.version_info < (3, 9):
diff --git a/mypy/typeshed/stdlib/pyexpat/__init__.pyi b/mypy/typeshed/stdlib/pyexpat/__init__.pyi
index 6a4ed891fe104..7e635c58c933d 100644
--- a/mypy/typeshed/stdlib/pyexpat/__init__.pyi
+++ b/mypy/typeshed/stdlib/pyexpat/__init__.pyi
@@ -1,7 +1,6 @@
-import pyexpat.errors as errors
-import pyexpat.model as model
-from _typeshed import SupportsRead
+from _typeshed import ReadableBuffer, SupportsRead
 from collections.abc import Callable
+from pyexpat import errors as errors, model as model
 from typing import Any
 from typing_extensions import TypeAlias, final
 
@@ -25,7 +24,7 @@ _Model: TypeAlias = tuple[int, int, str | None, tuple[Any, ...]]
 
 @final
 class XMLParserType:
-    def Parse(self, __data: str | bytes, __isfinal: bool = ...) -> int: ...
+    def Parse(self, __data: str | ReadableBuffer, __isfinal: bool = ...) -> int: ...
     def ParseFile(self, __file: SupportsRead[bytes]) -> int: ...
     def SetBase(self, __base: str) -> None: ...
     def GetBase(self) -> str | None: ...
diff --git a/mypy/typeshed/stdlib/quopri.pyi b/mypy/typeshed/stdlib/quopri.pyi
index b8dc0787fd1ae..549413226bdbc 100644
--- a/mypy/typeshed/stdlib/quopri.pyi
+++ b/mypy/typeshed/stdlib/quopri.pyi
@@ -1,8 +1,11 @@
-from typing import BinaryIO
+from _typeshed import ReadableBuffer, SupportsNoArgReadline, SupportsRead, SupportsWrite
+from typing import Protocol
 
 __all__ = ["encode", "decode", "encodestring", "decodestring"]
 
-def encode(input: BinaryIO, output: BinaryIO, quotetabs: int, header: int = ...) -> None: ...
-def encodestring(s: bytes, quotetabs: int = ..., header: int = ...) -> bytes: ...
-def decode(input: BinaryIO, output: BinaryIO, header: int = ...) -> None: ...
-def decodestring(s: bytes, header: int = ...) -> bytes: ...
+class _Input(SupportsRead[bytes], SupportsNoArgReadline[bytes], Protocol): ...
+
+def encode(input: _Input, output: SupportsWrite[bytes], quotetabs: int, header: int = ...) -> None: ...
+def encodestring(s: ReadableBuffer, quotetabs: int = ..., header: int = ...) -> bytes: ...
+def decode(input: _Input, output: SupportsWrite[bytes], header: int = ...) -> None: ...
+def decodestring(s: str | ReadableBuffer, header: int = ...) -> bytes: ...
diff --git a/mypy/typeshed/stdlib/smtplib.pyi b/mypy/typeshed/stdlib/smtplib.pyi
index 2d03b60e7bb4b..9fedd6f316d10 100644
--- a/mypy/typeshed/stdlib/smtplib.pyi
+++ b/mypy/typeshed/stdlib/smtplib.pyi
@@ -1,5 +1,6 @@
 import sys
-from _typeshed import Self
+from _socket import _Address as _SourceAddress
+from _typeshed import ReadableBuffer, Self, _BufferWithLen
 from collections.abc import Sequence
 from email.message import Message as _Message
 from re import Pattern
@@ -28,8 +29,6 @@ __all__ = [
 
 _Reply: TypeAlias = tuple[int, bytes]
 _SendErrs: TypeAlias = dict[str, _Reply]
-# Should match source_address for socket.create_connection
-_SourceAddress: TypeAlias = tuple[bytearray | bytes | str, int]
 
 SMTP_PORT: int
 SMTP_SSL_PORT: int
@@ -102,7 +101,7 @@ class SMTP:
     ) -> None: ...
     def set_debuglevel(self, debuglevel: int) -> None: ...
     def connect(self, host: str = ..., port: int = ..., source_address: _SourceAddress | None = ...) -> _Reply: ...
-    def send(self, s: bytes | str) -> None: ...
+    def send(self, s: ReadableBuffer | str) -> None: ...
     def putcmd(self, cmd: str, args: str = ...) -> None: ...
     def getreply(self) -> _Reply: ...
     def docmd(self, cmd: str, args: str = ...) -> _Reply: ...
@@ -114,7 +113,7 @@ class SMTP:
     def noop(self) -> _Reply: ...
     def mail(self, sender: str, options: Sequence[str] = ...) -> _Reply: ...
     def rcpt(self, recip: str, options: Sequence[str] = ...) -> _Reply: ...
-    def data(self, msg: bytes | str) -> _Reply: ...
+    def data(self, msg: ReadableBuffer | str) -> _Reply: ...
     def verify(self, address: str) -> _Reply: ...
     vrfy = verify
     def expn(self, address: str) -> _Reply: ...
@@ -125,16 +124,16 @@ class SMTP:
     @overload
     def auth_cram_md5(self, challenge: None = ...) -> None: ...
     @overload
-    def auth_cram_md5(self, challenge: bytes) -> str: ...
-    def auth_plain(self, challenge: bytes | None = ...) -> str: ...
-    def auth_login(self, challenge: bytes | None = ...) -> str: ...
+    def auth_cram_md5(self, challenge: ReadableBuffer) -> str: ...
+    def auth_plain(self, challenge: ReadableBuffer | None = ...) -> str: ...
+    def auth_login(self, challenge: ReadableBuffer | None = ...) -> str: ...
     def login(self, user: str, password: str, *, initial_response_ok: bool = ...) -> _Reply: ...
     def starttls(self, keyfile: str | None = ..., certfile: str | None = ..., context: SSLContext | None = ...) -> _Reply: ...
     def sendmail(
         self,
         from_addr: str,
         to_addrs: str | Sequence[str],
-        msg: bytes | str,
+        msg: _BufferWithLen | str,
         mail_options: Sequence[str] = ...,
         rcpt_options: Sequence[str] = ...,
     ) -> _SendErrs: ...
diff --git a/mypy/typeshed/stdlib/socket.pyi b/mypy/typeshed/stdlib/socket.pyi
index 89a6d059f1652..678bdafb25f0e 100644
--- a/mypy/typeshed/stdlib/socket.pyi
+++ b/mypy/typeshed/stdlib/socket.pyi
@@ -1,15 +1,8 @@
-import sys
-from _typeshed import ReadableBuffer, Self, WriteableBuffer
-from collections.abc import Iterable
-from enum import IntEnum, IntFlag
-from io import BufferedReader, BufferedRWPair, BufferedWriter, IOBase, RawIOBase, TextIOWrapper
-from typing import Any, Protocol, overload
-from typing_extensions import Literal
-
 # Ideally, we'd just do "from _socket import *". Unfortunately, socket
 # overrides some definitions from _socket incompatibly. mypy incorrectly
 # prefers the definitions from _socket over those defined here.
 import _socket
+import sys
 from _socket import (
     _FD,
     EAI_AGAIN as EAI_AGAIN,
@@ -119,6 +112,12 @@ from _socket import (
     setdefaulttimeout as setdefaulttimeout,
     timeout as timeout,
 )
+from _typeshed import ReadableBuffer, Self, WriteableBuffer
+from collections.abc import Iterable
+from enum import IntEnum, IntFlag
+from io import BufferedReader, BufferedRWPair, BufferedWriter, IOBase, RawIOBase, TextIOWrapper
+from typing import Any, Protocol, overload
+from typing_extensions import Literal
 
 if sys.platform != "darwin" or sys.version_info >= (3, 9):
     from _socket import (
@@ -738,7 +737,7 @@ if sys.platform != "win32":
     if sys.version_info >= (3, 9):
         # flags and address appear to be unused in send_fds and recv_fds
         def send_fds(
-            sock: socket, buffers: Iterable[bytes], fds: bytes | Iterable[int], flags: int = ..., address: None = ...
+            sock: socket, buffers: Iterable[ReadableBuffer], fds: Iterable[int], flags: int = ..., address: None = ...
         ) -> int: ...
         def recv_fds(sock: socket, bufsize: int, maxfds: int, flags: int = ...) -> tuple[bytes, list[int], int, Any]: ...
 
@@ -768,16 +767,14 @@ if sys.version_info >= (3, 11):
     def create_connection(
         address: tuple[str | None, int],
         timeout: float | None = ...,  # noqa: F811
-        source_address: tuple[bytearray | bytes | str, int] | None = ...,
+        source_address: _Address | None = ...,
         *,
         all_errors: bool = ...,
     ) -> socket: ...
 
 else:
     def create_connection(
-        address: tuple[str | None, int],
-        timeout: float | None = ...,  # noqa: F811
-        source_address: tuple[bytearray | bytes | str, int] | None = ...,
+        address: tuple[str | None, int], timeout: float | None = ..., source_address: _Address | None = ...  # noqa: F811
     ) -> socket: ...
 
 if sys.version_info >= (3, 8):
@@ -788,5 +785,10 @@ if sys.version_info >= (3, 8):
 
 # the 5th tuple item is an address
 def getaddrinfo(
-    host: bytes | str | None, port: str | int | None, family: int = ..., type: int = ..., proto: int = ..., flags: int = ...
+    host: bytes | str | None,
+    port: bytes | str | int | None,
+    family: int = ...,
+    type: int = ...,
+    proto: int = ...,
+    flags: int = ...,
 ) -> list[tuple[AddressFamily, SocketKind, int, str, tuple[str, int] | tuple[str, int, int, int]]]: ...
diff --git a/mypy/typeshed/stdlib/sqlite3/dbapi2.pyi b/mypy/typeshed/stdlib/sqlite3/dbapi2.pyi
index 189e796de109f..efda3b671ed54 100644
--- a/mypy/typeshed/stdlib/sqlite3/dbapi2.pyi
+++ b/mypy/typeshed/stdlib/sqlite3/dbapi2.pyi
@@ -1,6 +1,6 @@
 import sqlite3
 import sys
-from _typeshed import ReadableBuffer, Self, StrOrBytesPath, SupportsLenAndGetItem
+from _typeshed import Incomplete, ReadableBuffer, Self, StrOrBytesPath, SupportsLenAndGetItem
 from collections.abc import Callable, Generator, Iterable, Iterator, Mapping
 from datetime import date, datetime, time
 from types import TracebackType
@@ -227,9 +227,9 @@ else:
 
 if sys.version_info < (3, 8):
     class Cache:
-        def __init__(self, *args, **kwargs) -> None: ...
-        def display(self, *args, **kwargs) -> None: ...
-        def get(self, *args, **kwargs) -> None: ...
+        def __init__(self, *args: Incomplete, **kwargs: object) -> None: ...
+        def display(self, *args: Incomplete, **kwargs: Incomplete) -> None: ...
+        def get(self, *args: Incomplete, **kwargs: Incomplete) -> None: ...
 
 class _AggregateProtocol(Protocol):
     def step(self, __value: int) -> object: ...
@@ -437,7 +437,7 @@ if sys.version_info >= (3, 8):
 else:
     @final
     class Statement:
-        def __init__(self, *args, **kwargs): ...
+        def __init__(self, *args: Incomplete, **kwargs: Incomplete) -> None: ...
     _Statement: TypeAlias = Statement
 
 class Warning(Exception): ...
@@ -447,7 +447,7 @@ if sys.version_info >= (3, 11):
     class Blob:
         def close(self) -> None: ...
         def read(self, __length: int = ...) -> bytes: ...
-        def write(self, __data: bytes) -> None: ...
+        def write(self, __data: ReadableBuffer) -> None: ...
         def tell(self) -> int: ...
         # whence must be one of os.SEEK_SET, os.SEEK_CUR, os.SEEK_END
         def seek(self, __offset: int, __origin: int = ...) -> None: ...
diff --git a/mypy/typeshed/stdlib/ssl.pyi b/mypy/typeshed/stdlib/ssl.pyi
index 6443a6ea61ba2..543433f2fbd0a 100644
--- a/mypy/typeshed/stdlib/ssl.pyi
+++ b/mypy/typeshed/stdlib/ssl.pyi
@@ -11,7 +11,7 @@ _PCTRTTT: TypeAlias = tuple[_PCTRTT, ...]
 _PeerCertRetDictType: TypeAlias = dict[str, str | _PCTRTTT | _PCTRTT]
 _PeerCertRetType: TypeAlias = _PeerCertRetDictType | bytes | None
 _EnumRetType: TypeAlias = list[tuple[bytes, str, set[str] | bool]]
-_PasswordType: TypeAlias = Union[Callable[[], str | bytes], str, bytes]
+_PasswordType: TypeAlias = Union[Callable[[], str | bytes | bytearray], str, bytes, bytearray]
 
 _SrvnmeCbType: TypeAlias = Callable[[SSLSocket | SSLObject, str | None, SSLSocket], int | None]
 
@@ -61,7 +61,7 @@ def create_default_context(
     *,
     cafile: StrOrBytesPath | None = ...,
     capath: StrOrBytesPath | None = ...,
-    cadata: str | bytes | None = ...,
+    cadata: str | ReadableBuffer | None = ...,
 ) -> SSLContext: ...
 def _create_unverified_context(
     protocol: int = ...,
@@ -73,7 +73,7 @@ def _create_unverified_context(
     keyfile: StrOrBytesPath | None = ...,
     cafile: StrOrBytesPath | None = ...,
     capath: StrOrBytesPath | None = ...,
-    cadata: str | bytes | None = ...,
+    cadata: str | ReadableBuffer | None = ...,
 ) -> SSLContext: ...
 
 _create_default_https_context: Callable[..., SSLContext]
@@ -82,8 +82,11 @@ def RAND_bytes(__num: int) -> bytes: ...
 def RAND_pseudo_bytes(__num: int) -> tuple[bytes, bool]: ...
 def RAND_status() -> bool: ...
 def RAND_egd(path: str) -> None: ...
-def RAND_add(__s: bytes, __entropy: float) -> None: ...
-def match_hostname(cert: _PeerCertRetType, hostname: str) -> None: ...
+def RAND_add(__string: str | ReadableBuffer, __entropy: float) -> None: ...
+
+if sys.version_info < (3, 12):
+    def match_hostname(cert: _PeerCertRetDictType, hostname: str) -> None: ...
+
 def cert_time_to_seconds(cert_time: str) -> int: ...
 
 if sys.version_info >= (3, 10):
@@ -94,7 +97,7 @@ if sys.version_info >= (3, 10):
 else:
     def get_server_certificate(addr: tuple[str, int], ssl_version: int = ..., ca_certs: str | None = ...) -> str: ...
 
-def DER_cert_to_PEM_cert(der_cert_bytes: bytes) -> str: ...
+def DER_cert_to_PEM_cert(der_cert_bytes: ReadableBuffer) -> str: ...
 def PEM_cert_to_DER_cert(pem_cert_string: str) -> bytes: ...
 
 class DefaultVerifyPaths(NamedTuple):
@@ -290,8 +293,8 @@ class SSLSocket(socket.socket):
     @property
     def session_reused(self) -> bool | None: ...
     def __init__(self, *args: Any, **kwargs: Any) -> None: ...
-    def connect(self, addr: socket._Address | bytes) -> None: ...
-    def connect_ex(self, addr: socket._Address | bytes) -> int: ...
+    def connect(self, addr: socket._Address) -> None: ...
+    def connect_ex(self, addr: socket._Address) -> int: ...
     def recv(self, buflen: int = ..., flags: int = ...) -> bytes: ...
     def recv_into(self, buffer: WriteableBuffer, nbytes: int | None = ..., flags: int = ...) -> int: ...
     def recvfrom(self, buflen: int = ..., flags: int = ...) -> tuple[bytes, socket._RetAddress]: ...
@@ -301,12 +304,12 @@ class SSLSocket(socket.socket):
     def send(self, data: ReadableBuffer, flags: int = ...) -> int: ...
     def sendall(self, data: ReadableBuffer, flags: int = ...) -> None: ...
     @overload
-    def sendto(self, data: ReadableBuffer, flags_or_addr: socket._Address) -> int: ...
+    def sendto(self, data: ReadableBuffer, flags_or_addr: socket._Address, addr: None = ...) -> int: ...
     @overload
-    def sendto(self, data: ReadableBuffer, flags_or_addr: int | socket._Address, addr: socket._Address | None = ...) -> int: ...
+    def sendto(self, data: ReadableBuffer, flags_or_addr: int, addr: socket._Address) -> int: ...
     def shutdown(self, how: int) -> None: ...
     def read(self, len: int = ..., buffer: bytearray | None = ...) -> bytes: ...
-    def write(self, data: bytes) -> int: ...
+    def write(self, data: ReadableBuffer) -> int: ...
     def do_handshake(self, block: bool = ...) -> None: ...  # block is undocumented
     @overload
     def getpeercert(self, binary_form: Literal[False] = ...) -> _PeerCertRetDictType | None: ...
@@ -362,7 +365,7 @@ class SSLContext:
     ) -> None: ...
     def load_default_certs(self, purpose: Purpose = ...) -> None: ...
     def load_verify_locations(
-        self, cafile: StrOrBytesPath | None = ..., capath: StrOrBytesPath | None = ..., cadata: str | bytes | None = ...
+        self, cafile: StrOrBytesPath | None = ..., capath: StrOrBytesPath | None = ..., cadata: str | ReadableBuffer | None = ...
     ) -> None: ...
     @overload
     def get_ca_certs(self, binary_form: Literal[False] = ...) -> list[_PeerCertRetDictType]: ...
@@ -408,7 +411,7 @@ class SSLObject:
     def session_reused(self) -> bool: ...
     def __init__(self, *args: Any, **kwargs: Any) -> None: ...
     def read(self, len: int = ..., buffer: bytearray | None = ...) -> bytes: ...
-    def write(self, data: bytes) -> int: ...
+    def write(self, data: ReadableBuffer) -> int: ...
     @overload
     def getpeercert(self, binary_form: Literal[False] = ...) -> _PeerCertRetDictType | None: ...
     @overload
@@ -433,16 +436,21 @@ class MemoryBIO:
     pending: int
     eof: bool
     def read(self, __size: int = ...) -> bytes: ...
-    def write(self, __buf: bytes) -> int: ...
+    def write(self, __buf: ReadableBuffer) -> int: ...
     def write_eof(self) -> None: ...
 
 @final
 class SSLSession:
-    id: bytes
-    time: int
-    timeout: int
-    ticket_lifetime_hint: int
-    has_ticket: bool
+    @property
+    def has_ticket(self) -> bool: ...
+    @property
+    def id(self) -> bytes: ...
+    @property
+    def ticket_lifetime_hint(self) -> int: ...
+    @property
+    def time(self) -> int: ...
+    @property
+    def timeout(self) -> int: ...
 
 class SSLErrorNumber(enum.IntEnum):
     SSL_ERROR_EOF: int
diff --git a/mypy/typeshed/stdlib/struct.pyi b/mypy/typeshed/stdlib/struct.pyi
index 74afddd74262b..02097384e0f70 100644
--- a/mypy/typeshed/stdlib/struct.pyi
+++ b/mypy/typeshed/stdlib/struct.pyi
@@ -6,8 +6,8 @@ __all__ = ["calcsize", "pack", "pack_into", "unpack", "unpack_from", "iter_unpac
 
 class error(Exception): ...
 
-def pack(fmt: str | bytes, *v: Any) -> bytes: ...
-def pack_into(fmt: str | bytes, buffer: WriteableBuffer, offset: int, *v: Any) -> None: ...
+def pack(__fmt: str | bytes, *v: Any) -> bytes: ...
+def pack_into(__fmt: str | bytes, __buffer: WriteableBuffer, __offset: int, *v: Any) -> None: ...
 def unpack(__format: str | bytes, __buffer: ReadableBuffer) -> tuple[Any, ...]: ...
 def unpack_from(__format: str | bytes, buffer: ReadableBuffer, offset: int = ...) -> tuple[Any, ...]: ...
 def iter_unpack(__format: str | bytes, __buffer: ReadableBuffer) -> Iterator[tuple[Any, ...]]: ...
diff --git a/mypy/typeshed/stdlib/tarfile.pyi b/mypy/typeshed/stdlib/tarfile.pyi
index 8855e1a953dbd..5ad5af7f20bdc 100644
--- a/mypy/typeshed/stdlib/tarfile.pyi
+++ b/mypy/typeshed/stdlib/tarfile.pyi
@@ -346,7 +346,7 @@ class TarInfo:
     pax_headers: Mapping[str, str]
     def __init__(self, name: str = ...) -> None: ...
     @classmethod
-    def frombuf(cls: Type[Self], buf: bytes, encoding: str, errors: str) -> Self: ...
+    def frombuf(cls: Type[Self], buf: bytes | bytearray, encoding: str, errors: str) -> Self: ...
     @classmethod
     def fromtarfile(cls: Type[Self], tarfile: TarFile) -> Self: ...
     @property
diff --git a/mypy/typeshed/stdlib/termios.pyi b/mypy/typeshed/stdlib/termios.pyi
index 494162a49b389..bf8d7bee2473a 100644
--- a/mypy/typeshed/stdlib/termios.pyi
+++ b/mypy/typeshed/stdlib/termios.pyi
@@ -4,9 +4,9 @@ from typing import Any
 from typing_extensions import TypeAlias
 
 if sys.platform != "win32":
+    # Must be a list of length 7, containing 6 ints and a list of NCCS 1-character bytes or ints.
     _Attr: TypeAlias = list[int | list[bytes | int]]
 
-    # TODO constants not really documented
     B0: int
     B1000000: int
     B110: int
@@ -44,17 +44,22 @@ if sys.platform != "win32":
     BSDLY: int
     CBAUD: int
     CBAUDEX: int
+    CDEL: int
     CDSUSP: int
     CEOF: int
     CEOL: int
+    CEOL2: int
     CEOT: int
     CERASE: int
+    CESC: int
     CFLUSH: int
     CIBAUD: int
     CINTR: int
     CKILL: int
     CLNEXT: int
     CLOCAL: int
+    CNUL: int
+    COMMON: int
     CQUIT: int
     CR0: int
     CR1: int
@@ -73,6 +78,7 @@ if sys.platform != "win32":
     CSTOP: int
     CSTOPB: int
     CSUSP: int
+    CSWTCH: int
     CWERASE: int
     ECHO: int
     ECHOCTL: int
@@ -93,6 +99,7 @@ if sys.platform != "win32":
     FIONREAD: int
     FLUSHO: int
     HUPCL: int
+    IBSHIFT: int
     ICANON: int
     ICRNL: int
     IEXTEN: int
@@ -100,6 +107,7 @@ if sys.platform != "win32":
     IGNCR: int
     IGNPAR: int
     IMAXBEL: int
+    INIT_C_CC: int
     INLCR: int
     INPCK: int
     IOCSIZE_MASK: int
@@ -110,17 +118,18 @@ if sys.platform != "win32":
     IXANY: int
     IXOFF: int
     IXON: int
+    N_MOUSE: int
+    N_PPP: int
+    N_SLIP: int
+    N_STRIP: int
+    N_TTY: int
     NCC: int
     NCCS: int
     NL0: int
     NL1: int
     NLDLY: int
     NOFLSH: int
-    N_MOUSE: int
-    N_PPP: int
-    N_SLIP: int
-    N_STRIP: int
-    N_TTY: int
+    NSWTCH: int
     OCRNL: int
     OFDEL: int
     OFILL: int
@@ -151,6 +160,7 @@ if sys.platform != "win32":
     TCSADRAIN: int
     TCSAFLUSH: int
     TCSANOW: int
+    TCSASOFT: int
     TCSBRK: int
     TCSBRKP: int
     TCSETA: int
@@ -167,15 +177,11 @@ if sys.platform != "win32":
     TIOCGLCKTRMIOS: int
     TIOCGPGRP: int
     TIOCGSERIAL: int
+    TIOCGSIZE: int
     TIOCGSOFTCAR: int
     TIOCGWINSZ: int
     TIOCINQ: int
     TIOCLINUX: int
-    TIOCMBIC: int
-    TIOCMBIS: int
-    TIOCMGET: int
-    TIOCMIWAIT: int
-    TIOCMSET: int
     TIOCM_CAR: int
     TIOCM_CD: int
     TIOCM_CTS: int
@@ -187,10 +193,14 @@ if sys.platform != "win32":
     TIOCM_RTS: int
     TIOCM_SR: int
     TIOCM_ST: int
+    TIOCMBIC: int
+    TIOCMBIS: int
+    TIOCMGET: int
+    TIOCMIWAIT: int
+    TIOCMSET: int
     TIOCNOTTY: int
     TIOCNXCL: int
     TIOCOUTQ: int
-    TIOCPKT: int
     TIOCPKT_DATA: int
     TIOCPKT_DOSTOP: int
     TIOCPKT_FLUSHREAD: int
@@ -198,7 +208,9 @@ if sys.platform != "win32":
     TIOCPKT_NOSTOP: int
     TIOCPKT_START: int
     TIOCPKT_STOP: int
+    TIOCPKT: int
     TIOCSCTTY: int
+    TIOCSER_TEMT: int
     TIOCSERCONFIG: int
     TIOCSERGETLSR: int
     TIOCSERGETMULTI: int
@@ -206,14 +218,15 @@ if sys.platform != "win32":
     TIOCSERGWILD: int
     TIOCSERSETMULTI: int
     TIOCSERSWILD: int
-    TIOCSER_TEMT: int
     TIOCSETD: int
     TIOCSLCKTRMIOS: int
     TIOCSPGRP: int
     TIOCSSERIAL: int
+    TIOCSSIZE: int
     TIOCSSOFTCAR: int
     TIOCSTI: int
     TIOCSWINSZ: int
+    TIOCTTYGSTRUCT: int
     TOSTOP: int
     VDISCARD: int
     VEOF: int
@@ -238,7 +251,8 @@ if sys.platform != "win32":
     VWERASE: int
     XCASE: int
     XTABS: int
-    def tcgetattr(__fd: FileDescriptorLike) -> list[Any]: ...
+
+    def tcgetattr(__fd: FileDescriptorLike) -> list[Any]: ...  # Returns _Attr; we use Any to avoid a union in the return type
     def tcsetattr(__fd: FileDescriptorLike, __when: int, __attributes: _Attr) -> None: ...
     def tcsendbreak(__fd: FileDescriptorLike, __duration: int) -> None: ...
     def tcdrain(__fd: FileDescriptorLike) -> None: ...
diff --git a/mypy/typeshed/stdlib/tkinter/commondialog.pyi b/mypy/typeshed/stdlib/tkinter/commondialog.pyi
index 49101c7e60892..edae62582237e 100644
--- a/mypy/typeshed/stdlib/tkinter/commondialog.pyi
+++ b/mypy/typeshed/stdlib/tkinter/commondialog.pyi
@@ -10,5 +10,5 @@ class Dialog:
     command: ClassVar[str | None]
     master: Incomplete | None
     options: Mapping[str, Incomplete]
-    def __init__(self, master: Incomplete | None = ..., **options) -> None: ...
-    def show(self, **options): ...
+    def __init__(self, master: Incomplete | None = ..., **options: Incomplete) -> None: ...
+    def show(self, **options: Incomplete) -> Incomplete: ...
diff --git a/mypy/typeshed/stdlib/tkinter/dialog.pyi b/mypy/typeshed/stdlib/tkinter/dialog.pyi
index ef7713f409941..032dac2c15a27 100644
--- a/mypy/typeshed/stdlib/tkinter/dialog.pyi
+++ b/mypy/typeshed/stdlib/tkinter/dialog.pyi
@@ -12,5 +12,5 @@ DIALOG_ICON: str
 class Dialog(Widget):
     widgetName: str
     num: int
-    def __init__(self, master: Incomplete | None = ..., cnf: Mapping[str, Any] = ..., **kw) -> None: ...
+    def __init__(self, master: Incomplete | None = ..., cnf: Mapping[str, Any] = ..., **kw: Incomplete) -> None: ...
     def destroy(self) -> None: ...
diff --git a/mypy/typeshed/stdlib/tkinter/dnd.pyi b/mypy/typeshed/stdlib/tkinter/dnd.pyi
index e2cfc43f606a2..ad7972968f81b 100644
--- a/mypy/typeshed/stdlib/tkinter/dnd.pyi
+++ b/mypy/typeshed/stdlib/tkinter/dnd.pyi
@@ -16,4 +16,4 @@ class DndHandler:
     def on_motion(self, event: Event[Misc]) -> None: ...
     def on_release(self, event: Event[Misc]) -> None: ...
 
-def dnd_start(source, event) -> DndHandler | None: ...
+def dnd_start(source: _DndSource, event: Event[Misc]) -> DndHandler | None: ...
diff --git a/mypy/typeshed/stdlib/tkinter/scrolledtext.pyi b/mypy/typeshed/stdlib/tkinter/scrolledtext.pyi
index 72f6ca8c06870..4d8a7004c6b9d 100644
--- a/mypy/typeshed/stdlib/tkinter/scrolledtext.pyi
+++ b/mypy/typeshed/stdlib/tkinter/scrolledtext.pyi
@@ -1,3 +1,4 @@
+from _typeshed import Incomplete
 from tkinter import Frame, Misc, Scrollbar, Text
 
 __all__ = ["ScrolledText"]
@@ -6,4 +7,4 @@ __all__ = ["ScrolledText"]
 class ScrolledText(Text):
     frame: Frame
     vbar: Scrollbar
-    def __init__(self, master: Misc | None = ..., **kwargs) -> None: ...
+    def __init__(self, master: Misc | None = ..., **kwargs: Incomplete) -> None: ...
diff --git a/mypy/typeshed/stdlib/tokenize.pyi b/mypy/typeshed/stdlib/tokenize.pyi
index 6f242a6cd1efc..7c00b507a528b 100644
--- a/mypy/typeshed/stdlib/tokenize.pyi
+++ b/mypy/typeshed/stdlib/tokenize.pyi
@@ -122,8 +122,8 @@ class Untokenizer:
 # the docstring says "returns bytes" but is incorrect --
 # if the ENCODING token is missing, it skips the encode
 def untokenize(iterable: Iterable[_Token]) -> Any: ...
-def detect_encoding(readline: Callable[[], bytes]) -> tuple[str, Sequence[bytes]]: ...
-def tokenize(readline: Callable[[], bytes]) -> Generator[TokenInfo, None, None]: ...
+def detect_encoding(readline: Callable[[], bytes | bytearray]) -> tuple[str, Sequence[bytes]]: ...
+def tokenize(readline: Callable[[], bytes | bytearray]) -> Generator[TokenInfo, None, None]: ...
 def generate_tokens(readline: Callable[[], str]) -> Generator[TokenInfo, None, None]: ...  # undocumented
 def open(filename: StrOrBytesPath | int) -> TextIO: ...
 def group(*choices: str) -> str: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/types.pyi b/mypy/typeshed/stdlib/types.pyi
index 16fe096d31173..4047cf84593d3 100644
--- a/mypy/typeshed/stdlib/types.pyi
+++ b/mypy/typeshed/stdlib/types.pyi
@@ -585,13 +585,15 @@ if sys.version_info >= (3, 9):
         @property
         def __parameters__(self) -> tuple[Any, ...]: ...
         def __init__(self, origin: type, args: Any) -> None: ...
+        def __getitem__(self, __typeargs: Any) -> GenericAlias: ...
         if sys.version_info >= (3, 11):
             @property
             def __unpacked__(self) -> bool: ...
             @property
             def __typing_unpacked_tuple_args__(self) -> tuple[Any, ...] | None: ...
 
-        def __getattr__(self, name: str) -> Any: ...  # incomplete
+        # GenericAlias delegates attr access to `__origin__`
+        def __getattr__(self, name: str) -> Any: ...
 
 if sys.version_info >= (3, 10):
     @final
diff --git a/mypy/typeshed/stdlib/typing.pyi b/mypy/typeshed/stdlib/typing.pyi
index 954f47d145024..cc27ae7dbda2a 100644
--- a/mypy/typeshed/stdlib/typing.pyi
+++ b/mypy/typeshed/stdlib/typing.pyi
@@ -325,7 +325,7 @@ class SupportsRound(Protocol[_T_co]):
     def __round__(self, __ndigits: int) -> _T_co: ...
 
 @runtime_checkable
-class Sized(Protocol, metaclass=ABCMeta):
+class Sized(Protocol):
     @abstractmethod
     def __len__(self) -> int: ...
 
@@ -452,10 +452,7 @@ class Container(Protocol[_T_co]):
     def __contains__(self, __x: object) -> bool: ...
 
 @runtime_checkable
-class Collection(Iterable[_T_co], Container[_T_co], Protocol[_T_co]):
-    # Implement Sized (but don't have it as a base class).
-    @abstractmethod
-    def __len__(self) -> int: ...
+class Collection(Sized, Iterable[_T_co], Container[_T_co], Protocol[_T_co]): ...
 
 class Sequence(Collection[_T_co], Reversible[_T_co], Generic[_T_co]):
     @overload
@@ -566,7 +563,7 @@ class KeysView(MappingView, AbstractSet[_KT_co], Generic[_KT_co]):
     def __xor__(self, other: Iterable[_T]) -> set[_KT_co | _T]: ...
     def __rxor__(self, other: Iterable[_T]) -> set[_KT_co | _T]: ...
 
-class ValuesView(MappingView, Iterable[_VT_co], Generic[_VT_co]):
+class ValuesView(MappingView, Collection[_VT_co], Generic[_VT_co]):
     def __init__(self, mapping: Mapping[Any, _VT_co]) -> None: ...  # undocumented
     def __contains__(self, value: object) -> bool: ...
     def __iter__(self) -> Iterator[_VT_co]: ...
@@ -621,6 +618,8 @@ class MutableMapping(Mapping[_KT, _VT], Generic[_KT, _VT]):
     # -- os._Environ.__ior__
     # -- collections.UserDict.__ior__
     # -- collections.ChainMap.__ior__
+    # -- peewee.attrdict.__add__
+    # -- peewee.attrdict.__iadd__
     # -- weakref.WeakValueDictionary.__ior__
     # -- weakref.WeakKeyDictionary.__ior__
     @overload
@@ -638,7 +637,9 @@ TYPE_CHECKING: bool
 # This differs from runtime, but better reflects the fact that in reality
 # classes deriving from IO use different names for the arguments.
 class IO(Iterator[AnyStr], Generic[AnyStr]):
-    # TODO use abstract properties
+    # At runtime these are all abstract properties,
+    # but making them abstract in the stub is hugely disruptive, for not much gain.
+    # See #8726
     @property
     def mode(self) -> str: ...
     @property
@@ -691,7 +692,7 @@ class BinaryIO(IO[bytes]):
     def __enter__(self) -> BinaryIO: ...
 
 class TextIO(IO[str]):
-    # TODO use abstractproperty
+    # See comment regarding the @properties in the `IO` class
     @property
     def buffer(self) -> BinaryIO: ...
     @property
diff --git a/mypy/typeshed/stdlib/unicodedata.pyi b/mypy/typeshed/stdlib/unicodedata.pyi
index 7337ab8789b23..5a9aa0a3395f7 100644
--- a/mypy/typeshed/stdlib/unicodedata.pyi
+++ b/mypy/typeshed/stdlib/unicodedata.pyi
@@ -1,4 +1,5 @@
 import sys
+from _typeshed import ReadOnlyBuffer
 from typing import Any, TypeVar
 from typing_extensions import final
 
@@ -21,7 +22,7 @@ def east_asian_width(__chr: str) -> str: ...
 if sys.version_info >= (3, 8):
     def is_normalized(__form: str, __unistr: str) -> bool: ...
 
-def lookup(__name: str | bytes) -> str: ...
+def lookup(__name: str | ReadOnlyBuffer) -> str: ...
 def mirrored(__chr: str) -> int: ...
 def name(__chr: str, __default: _T = ...) -> str | _T: ...
 def normalize(__form: str, __unistr: str) -> str: ...
@@ -41,7 +42,7 @@ class UCD:
     if sys.version_info >= (3, 8):
         def is_normalized(self, __form: str, __unistr: str) -> bool: ...
 
-    def lookup(self, __name: str | bytes) -> str: ...
+    def lookup(self, __name: str | ReadOnlyBuffer) -> str: ...
     def mirrored(self, __chr: str) -> int: ...
     def name(self, __chr: str, __default: _T = ...) -> str | _T: ...
     def normalize(self, __form: str, __unistr: str) -> str: ...
diff --git a/mypy/typeshed/stdlib/unittest/case.pyi b/mypy/typeshed/stdlib/unittest/case.pyi
index 200f8dbaea233..c75539a97368c 100644
--- a/mypy/typeshed/stdlib/unittest/case.pyi
+++ b/mypy/typeshed/stdlib/unittest/case.pyi
@@ -157,18 +157,14 @@ class TestCase:
     def assertRaisesRegex(  # type: ignore[misc]
         self,
         expected_exception: type[BaseException] | tuple[type[BaseException], ...],
-        expected_regex: str | bytes | Pattern[str] | Pattern[bytes],
+        expected_regex: str | Pattern[str],
         callable: Callable[..., Any],
         *args: Any,
         **kwargs: Any,
     ) -> None: ...
     @overload
     def assertRaisesRegex(
-        self,
-        expected_exception: type[_E] | tuple[type[_E], ...],
-        expected_regex: str | bytes | Pattern[str] | Pattern[bytes],
-        *,
-        msg: Any = ...,
+        self, expected_exception: type[_E] | tuple[type[_E], ...], expected_regex: str | Pattern[str], *, msg: Any = ...
     ) -> _AssertRaisesContext[_E]: ...
     @overload
     def assertWarns(  # type: ignore[misc]
@@ -186,18 +182,14 @@ class TestCase:
     def assertWarnsRegex(  # type: ignore[misc]
         self,
         expected_warning: type[Warning] | tuple[type[Warning], ...],
-        expected_regex: str | bytes | Pattern[str] | Pattern[bytes],
+        expected_regex: str | Pattern[str],
         callable: Callable[_P, Any],
         *args: _P.args,
         **kwargs: _P.kwargs,
     ) -> None: ...
     @overload
     def assertWarnsRegex(
-        self,
-        expected_warning: type[Warning] | tuple[type[Warning], ...],
-        expected_regex: str | bytes | Pattern[str] | Pattern[bytes],
-        *,
-        msg: Any = ...,
+        self, expected_warning: type[Warning] | tuple[type[Warning], ...], expected_regex: str | Pattern[str], *, msg: Any = ...
     ) -> _AssertWarnsContext: ...
     def assertLogs(
         self, logger: str | logging.Logger | None = ..., level: int | str | None = ...
diff --git a/mypy/typeshed/stdlib/unittest/mock.pyi b/mypy/typeshed/stdlib/unittest/mock.pyi
index 133380fce334d..6c58f38a0d826 100644
--- a/mypy/typeshed/stdlib/unittest/mock.pyi
+++ b/mypy/typeshed/stdlib/unittest/mock.pyi
@@ -300,8 +300,8 @@ class _patcher:
         **kwargs: Any,
     ) -> _patch[_Mock]: ...
     @overload
+    @staticmethod
     def object(  # type: ignore[misc]
-        self,
         target: Any,
         attribute: str,
         new: _T,
@@ -313,8 +313,8 @@ class _patcher:
         **kwargs: Any,
     ) -> _patch[_T]: ...
     @overload
+    @staticmethod
     def object(
-        self,
         target: Any,
         attribute: str,
         *,
@@ -325,8 +325,8 @@ class _patcher:
         new_callable: Any | None = ...,
         **kwargs: Any,
     ) -> _patch[_Mock]: ...
+    @staticmethod
     def multiple(
-        self,
         target: Any,
         spec: Any | None = ...,
         create: bool = ...,
@@ -335,7 +335,8 @@ class _patcher:
         new_callable: Any | None = ...,
         **kwargs: Any,
     ) -> _patch[Any]: ...
-    def stopall(self) -> None: ...
+    @staticmethod
+    def stopall() -> None: ...
 
 patch: _patcher
 
diff --git a/mypy/typeshed/stdlib/urllib/parse.pyi b/mypy/typeshed/stdlib/urllib/parse.pyi
index 207a05e75a570..02e2774b3b8ed 100644
--- a/mypy/typeshed/stdlib/urllib/parse.pyi
+++ b/mypy/typeshed/stdlib/urllib/parse.pyi
@@ -1,6 +1,6 @@
 import sys
-from collections.abc import Callable, Mapping, Sequence
-from typing import Any, AnyStr, Generic, NamedTuple, overload
+from collections.abc import Callable, Iterable, Mapping, Sequence
+from typing import Any, AnyStr, Generic, NamedTuple, TypeVar, overload
 
 if sys.version_info >= (3, 9):
     from types import GenericAlias
@@ -132,14 +132,14 @@ def parse_qsl(
     separator: str = ...,
 ) -> list[tuple[AnyStr, AnyStr]]: ...
 @overload
-def quote(string: str, safe: str | bytes = ..., encoding: str | None = ..., errors: str | None = ...) -> str: ...
+def quote(string: str, safe: str | Iterable[int] = ..., encoding: str | None = ..., errors: str | None = ...) -> str: ...
 @overload
-def quote(string: bytes, safe: str | bytes = ...) -> str: ...
-def quote_from_bytes(bs: bytes, safe: str | bytes = ...) -> str: ...
+def quote(string: bytes | bytearray, safe: str | Iterable[int] = ...) -> str: ...
+def quote_from_bytes(bs: bytes | bytearray, safe: str | Iterable[int] = ...) -> str: ...
 @overload
-def quote_plus(string: str, safe: str | bytes = ..., encoding: str | None = ..., errors: str | None = ...) -> str: ...
+def quote_plus(string: str, safe: str | Iterable[int] = ..., encoding: str | None = ..., errors: str | None = ...) -> str: ...
 @overload
-def quote_plus(string: bytes, safe: str | bytes = ...) -> str: ...
+def quote_plus(string: bytes | bytearray, safe: str | Iterable[int] = ...) -> str: ...
 
 if sys.version_info >= (3, 9):
     def unquote(string: str | bytes, encoding: str = ..., errors: str = ...) -> str: ...
@@ -152,24 +152,27 @@ def unquote_plus(string: str, encoding: str = ..., errors: str = ...) -> str: ..
 @overload
 def urldefrag(url: str) -> DefragResult: ...
 @overload
-def urldefrag(url: bytes | None) -> DefragResultBytes: ...
+def urldefrag(url: bytes | bytearray | None) -> DefragResultBytes: ...
+
+_Q = TypeVar("_Q", bound=str | Iterable[int])
+
 def urlencode(
     query: Mapping[Any, Any] | Mapping[Any, Sequence[Any]] | Sequence[tuple[Any, Any]] | Sequence[tuple[Any, Sequence[Any]]],
     doseq: bool = ...,
-    safe: str | bytes = ...,
+    safe: _Q = ...,
     encoding: str = ...,
     errors: str = ...,
-    quote_via: Callable[[AnyStr, str | bytes, str, str], str] = ...,
+    quote_via: Callable[[AnyStr, _Q, str, str], str] = ...,
 ) -> str: ...
 def urljoin(base: AnyStr, url: AnyStr | None, allow_fragments: bool = ...) -> AnyStr: ...
 @overload
 def urlparse(url: str, scheme: str | None = ..., allow_fragments: bool = ...) -> ParseResult: ...
 @overload
-def urlparse(url: bytes | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> ParseResultBytes: ...
+def urlparse(url: bytes | bytearray | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> ParseResultBytes: ...
 @overload
 def urlsplit(url: str, scheme: str | None = ..., allow_fragments: bool = ...) -> SplitResult: ...
 @overload
-def urlsplit(url: bytes | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> SplitResultBytes: ...
+def urlsplit(url: bytes | bytearray | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> SplitResultBytes: ...
 @overload
 def urlunparse(
     components: tuple[AnyStr | None, AnyStr | None, AnyStr | None, AnyStr | None, AnyStr | None, AnyStr | None]
diff --git a/mypy/typeshed/stdlib/urllib/response.pyi b/mypy/typeshed/stdlib/urllib/response.pyi
index 8c9a600f3c486..ca9781dbfbb46 100644
--- a/mypy/typeshed/stdlib/urllib/response.pyi
+++ b/mypy/typeshed/stdlib/urllib/response.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import Self
+from _typeshed import ReadableBuffer, Self
 from collections.abc import Callable, Iterable
 from email.message import Message
 from types import TracebackType
@@ -33,8 +33,8 @@ class addbase(BinaryIO):
     def tell(self) -> int: ...
     def truncate(self, size: int | None = ...) -> int: ...
     def writable(self) -> bool: ...
-    def write(self, s: bytes) -> int: ...
-    def writelines(self, lines: Iterable[bytes]) -> None: ...
+    def write(self, s: ReadableBuffer) -> int: ...
+    def writelines(self, lines: Iterable[ReadableBuffer]) -> None: ...
 
 class addclosehook(addbase):
     closehook: Callable[..., object]
diff --git a/mypy/typeshed/stdlib/weakref.pyi b/mypy/typeshed/stdlib/weakref.pyi
index af960391e85d3..9a619235e689c 100644
--- a/mypy/typeshed/stdlib/weakref.pyi
+++ b/mypy/typeshed/stdlib/weakref.pyi
@@ -1,10 +1,5 @@
 import sys
 from _typeshed import Self, SupportsKeysAndGetItem
-from _weakrefset import WeakSet as WeakSet
-from collections.abc import Callable, Iterable, Iterator, Mapping, MutableMapping
-from typing import Any, Generic, TypeVar, overload
-from typing_extensions import ParamSpec
-
 from _weakref import (
     CallableProxyType as CallableProxyType,
     ProxyType as ProxyType,
@@ -14,6 +9,10 @@ from _weakref import (
     proxy as proxy,
     ref as ref,
 )
+from _weakrefset import WeakSet as WeakSet
+from collections.abc import Callable, Iterable, Iterator, Mapping, MutableMapping
+from typing import Any, Generic, TypeVar, overload
+from typing_extensions import ParamSpec
 
 __all__ = [
     "ref",
diff --git a/mypy/typeshed/stdlib/winsound.pyi b/mypy/typeshed/stdlib/winsound.pyi
index 588bd5969e98d..fd5a552cf9c17 100644
--- a/mypy/typeshed/stdlib/winsound.pyi
+++ b/mypy/typeshed/stdlib/winsound.pyi
@@ -1,4 +1,5 @@
 import sys
+from _typeshed import ReadableBuffer
 from typing import overload
 from typing_extensions import Literal
 
@@ -21,7 +22,7 @@ if sys.platform == "win32":
     def Beep(frequency: int, duration: int) -> None: ...
     # Can actually accept anything ORed with 4, and if not it's definitely str, but that's inexpressible
     @overload
-    def PlaySound(sound: bytes | None, flags: Literal[4]) -> None: ...
+    def PlaySound(sound: ReadableBuffer | None, flags: Literal[4]) -> None: ...
     @overload
-    def PlaySound(sound: str | bytes | None, flags: int) -> None: ...
+    def PlaySound(sound: str | ReadableBuffer | None, flags: int) -> None: ...
     def MessageBeep(type: int = ...) -> None: ...
diff --git a/mypy/typeshed/stdlib/xml/__init__.pyi b/mypy/typeshed/stdlib/xml/__init__.pyi
index c524ac2b1cfca..a487d2467f41b 100644
--- a/mypy/typeshed/stdlib/xml/__init__.pyi
+++ b/mypy/typeshed/stdlib/xml/__init__.pyi
@@ -1 +1 @@
-import xml.parsers as parsers
+from xml import parsers as parsers
diff --git a/mypy/typeshed/stdlib/xml/dom/expatbuilder.pyi b/mypy/typeshed/stdlib/xml/dom/expatbuilder.pyi
index 3ca885dbbaa04..e460d6b21afa5 100644
--- a/mypy/typeshed/stdlib/xml/dom/expatbuilder.pyi
+++ b/mypy/typeshed/stdlib/xml/dom/expatbuilder.pyi
@@ -1,4 +1,4 @@
-from _typeshed import Incomplete
+from _typeshed import Incomplete, ReadableBuffer, SupportsRead
 from typing import Any, NoReturn
 from xml.dom.minidom import Document, DOMImplementation, Node, TypeInfo
 from xml.dom.xmlbuilder import DOMBuilderFilter, Options
@@ -30,8 +30,8 @@ class ExpatBuilder:
     def getParser(self): ...
     def reset(self) -> None: ...
     def install(self, parser) -> None: ...
-    def parseFile(self, file) -> Document: ...
-    def parseString(self, string: str) -> Document: ...
+    def parseFile(self, file: SupportsRead[ReadableBuffer | str]) -> Document: ...
+    def parseString(self, string: str | ReadableBuffer) -> Document: ...
     def start_doctype_decl_handler(self, doctypeName, systemId, publicId, has_internal_subset) -> None: ...
     def end_doctype_decl_handler(self) -> None: ...
     def pi_handler(self, target, data) -> None: ...
@@ -87,14 +87,14 @@ class ParseEscape(Exception): ...
 class InternalSubsetExtractor(ExpatBuilder):
     subset: Any | None
     def getSubset(self) -> Any | None: ...
-    def parseFile(self, file) -> None: ...  # type: ignore[override]
-    def parseString(self, string: str) -> None: ...  # type: ignore[override]
+    def parseFile(self, file: SupportsRead[ReadableBuffer | str]) -> None: ...  # type: ignore[override]
+    def parseString(self, string: str | ReadableBuffer) -> None: ...  # type: ignore[override]
     def start_doctype_decl_handler(self, name, publicId, systemId, has_internal_subset) -> None: ...  # type: ignore[override]
     def end_doctype_decl_handler(self) -> NoReturn: ...
     def start_element_handler(self, name, attrs) -> NoReturn: ...
 
-def parse(file, namespaces: bool = ...): ...
-def parseString(string: str, namespaces: bool = ...): ...
+def parse(file: str | SupportsRead[ReadableBuffer | str], namespaces: bool = ...): ...
+def parseString(string: str | ReadableBuffer, namespaces: bool = ...): ...
 def parseFragment(file, context, namespaces: bool = ...): ...
 def parseFragmentString(string: str, context, namespaces: bool = ...): ...
 def makeBuilder(options: Options) -> ExpatBuilderNS | ExpatBuilder: ...
diff --git a/mypy/typeshed/stdlib/xml/dom/minidom.pyi b/mypy/typeshed/stdlib/xml/dom/minidom.pyi
index 04086fdc81b1f..5997e031fd73d 100644
--- a/mypy/typeshed/stdlib/xml/dom/minidom.pyi
+++ b/mypy/typeshed/stdlib/xml/dom/minidom.pyi
@@ -1,12 +1,12 @@
 import sys
 import xml.dom
-from _typeshed import Incomplete, Self, SupportsRead, SupportsWrite
+from _typeshed import Incomplete, ReadableBuffer, Self, SupportsRead, SupportsWrite
 from typing_extensions import Literal
 from xml.dom.xmlbuilder import DocumentLS, DOMImplementationLS
 from xml.sax.xmlreader import XMLReader
 
-def parse(file: str | SupportsRead[bytes] | SupportsRead[str], parser: XMLReader | None = ..., bufsize: int | None = ...): ...
-def parseString(string: str | bytes, parser: XMLReader | None = ...): ...
+def parse(file: str | SupportsRead[ReadableBuffer | str], parser: XMLReader | None = ..., bufsize: int | None = ...): ...
+def parseString(string: str | ReadableBuffer, parser: XMLReader | None = ...): ...
 def getDOMImplementation(features=...) -> DOMImplementation | None: ...
 
 class Node(xml.dom.Node):
@@ -213,7 +213,7 @@ class CDATASection(Text):
 
 class ReadOnlySequentialNamedNodeMap:
     def __init__(self, seq=...) -> None: ...
-    def __len__(self): ...
+    def __len__(self) -> int: ...
     def getNamedItem(self, name): ...
     def getNamedItemNS(self, namespaceURI: str, localName): ...
     def __getitem__(self, name_or_tuple): ...
diff --git a/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi b/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi
index 7bb78d0628ce7..3e3e3f2662065 100644
--- a/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi
+++ b/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi
@@ -1,4 +1,5 @@
 import sys
+from _typeshed import StrOrBytesPath
 from collections.abc import Callable
 from xml.etree.ElementTree import Element
 
@@ -11,7 +12,7 @@ if sys.version_info >= (3, 9):
 
 class FatalIncludeError(SyntaxError): ...
 
-def default_loader(href: str | bytes | int, parse: str, encoding: str | None = ...) -> str | Element: ...
+def default_loader(href: StrOrBytesPath | int, parse: str, encoding: str | None = ...) -> str | Element: ...
 
 # TODO: loader is of type default_loader ie it takes a callable that has the
 # same signature as default_loader. But default_loader has a keyword argument
diff --git a/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi b/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
index 84059bc21a879..c063c1fd34883 100644
--- a/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
+++ b/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
@@ -1,6 +1,6 @@
 import sys
 from _collections_abc import dict_keys
-from _typeshed import FileDescriptor, StrOrBytesPath, SupportsRead, SupportsWrite
+from _typeshed import FileDescriptor, ReadableBuffer, StrOrBytesPath, SupportsRead, SupportsWrite
 from collections.abc import Callable, Generator, ItemsView, Iterable, Iterator, Mapping, Sequence
 from typing import Any, TypeVar, overload
 from typing_extensions import Literal, SupportsIndex, TypeAlias, TypeGuard
@@ -54,7 +54,7 @@ def iselement(element: object) -> TypeGuard[Element]: ...
 if sys.version_info >= (3, 8):
     @overload
     def canonicalize(
-        xml_data: str | bytes | None = ...,
+        xml_data: str | ReadableBuffer | None = ...,
         *,
         out: None = ...,
         from_file: _FileRead | None = ...,
@@ -68,7 +68,7 @@ if sys.version_info >= (3, 8):
     ) -> str: ...
     @overload
     def canonicalize(
-        xml_data: str | bytes | None = ...,
+        xml_data: str | ReadableBuffer | None = ...,
         *,
         out: SupportsWrite[str],
         from_file: _FileRead | None = ...,
@@ -270,19 +270,19 @@ def iterparse(
 
 class XMLPullParser:
     def __init__(self, events: Sequence[str] | None = ..., *, _parser: XMLParser | None = ...) -> None: ...
-    def feed(self, data: str | bytes) -> None: ...
+    def feed(self, data: str | ReadableBuffer) -> None: ...
     def close(self) -> None: ...
     # Second element in the tuple could be `Element`, `tuple[str, str]` or `None`.
     # Use `Any` to avoid false-positive errors.
     def read_events(self) -> Iterator[tuple[str, Any]]: ...
 
-def XML(text: str | bytes, parser: XMLParser | None = ...) -> Element: ...
-def XMLID(text: str | bytes, parser: XMLParser | None = ...) -> tuple[Element, dict[str, Element]]: ...
+def XML(text: str | ReadableBuffer, parser: XMLParser | None = ...) -> Element: ...
+def XMLID(text: str | ReadableBuffer, parser: XMLParser | None = ...) -> tuple[Element, dict[str, Element]]: ...
 
 # This is aliased to XML in the source.
 fromstring = XML
 
-def fromstringlist(sequence: Sequence[str | bytes], parser: XMLParser | None = ...) -> Element: ...
+def fromstringlist(sequence: Sequence[str | ReadableBuffer], parser: XMLParser | None = ...) -> Element: ...
 
 # This type is both not precise enough and too precise. The TreeBuilder
 # requires the elementfactory to accept tag and attrs in its args and produce
@@ -313,9 +313,11 @@ class TreeBuilder:
         def __init__(self, element_factory: _ElementFactory | None = ...) -> None: ...
 
     def close(self) -> Element: ...
-    def data(self, __data: str | bytes) -> None: ...
-    def start(self, __tag: str | bytes, __attrs: dict[str | bytes, str | bytes]) -> Element: ...
-    def end(self, __tag: str | bytes) -> Element: ...
+    def data(self, __data: str) -> None: ...
+    # tag and attrs are passed to the element_factory, so they could be anything
+    # depending on what the particular factory supports.
+    def start(self, __tag: Any, __attrs: dict[Any, Any]) -> Element: ...
+    def end(self, __tag: str) -> Element: ...
     if sys.version_info >= (3, 8):
         # These two methods have pos-only parameters in the C implementation
         def comment(self, __text: str | None) -> Element: ...
@@ -355,4 +357,4 @@ class XMLParser:
         def doctype(self, __name: str, __pubid: str, __system: str) -> None: ...
 
     def close(self) -> Any: ...
-    def feed(self, __data: str | bytes) -> None: ...
+    def feed(self, __data: str | ReadableBuffer) -> None: ...
diff --git a/mypy/typeshed/stdlib/xml/parsers/__init__.pyi b/mypy/typeshed/stdlib/xml/parsers/__init__.pyi
index cac086235cbaf..cebdb6a30014b 100644
--- a/mypy/typeshed/stdlib/xml/parsers/__init__.pyi
+++ b/mypy/typeshed/stdlib/xml/parsers/__init__.pyi
@@ -1 +1 @@
-import xml.parsers.expat as expat
+from xml.parsers import expat as expat
diff --git a/mypy/typeshed/stdlib/xml/sax/__init__.pyi b/mypy/typeshed/stdlib/xml/sax/__init__.pyi
index af4ee052480f9..b8ab4d439e745 100644
--- a/mypy/typeshed/stdlib/xml/sax/__init__.pyi
+++ b/mypy/typeshed/stdlib/xml/sax/__init__.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import SupportsRead, _T_co
+from _typeshed import ReadableBuffer, SupportsRead, _T_co
 from collections.abc import Iterable
 from typing import Any, NoReturn, Protocol
 from xml.sax.handler import ContentHandler as ContentHandler, ErrorHandler as ErrorHandler
@@ -15,7 +15,7 @@ class SAXException(Exception):
     def __getitem__(self, ix: Any) -> NoReturn: ...
 
 class SAXParseException(SAXException):
-    def __init__(self, msg: str, exception: Exception, locator: Locator) -> None: ...
+    def __init__(self, msg: str, exception: Exception | None, locator: Locator) -> None: ...
     def getColumnNumber(self) -> int: ...
     def getLineNumber(self) -> int: ...
     def getPublicId(self): ...
@@ -36,5 +36,5 @@ else:
 def parse(
     source: str | _SupportsReadClose[bytes] | _SupportsReadClose[str], handler: ContentHandler, errorHandler: ErrorHandler = ...
 ) -> None: ...
-def parseString(string: bytes | str, handler: ContentHandler, errorHandler: ErrorHandler | None = ...) -> None: ...
+def parseString(string: ReadableBuffer | str, handler: ContentHandler, errorHandler: ErrorHandler | None = ...) -> None: ...
 def _create_parser(parser_name: str) -> XMLReader: ...
diff --git a/mypy/typeshed/stdlib/xml/sax/xmlreader.pyi b/mypy/typeshed/stdlib/xml/sax/xmlreader.pyi
index 517c17072b879..4480f40986355 100644
--- a/mypy/typeshed/stdlib/xml/sax/xmlreader.pyi
+++ b/mypy/typeshed/stdlib/xml/sax/xmlreader.pyi
@@ -53,7 +53,7 @@ class AttributesImpl:
     def getQNameByName(self, name): ...
     def getNames(self): ...
     def getQNames(self): ...
-    def __len__(self): ...
+    def __len__(self) -> int: ...
     def __getitem__(self, name): ...
     def keys(self): ...
     def __contains__(self, name): ...
diff --git a/mypy/typeshed/stdlib/zipfile.pyi b/mypy/typeshed/stdlib/zipfile.pyi
index da1710787252a..e964cd6eda871 100644
--- a/mypy/typeshed/stdlib/zipfile.pyi
+++ b/mypy/typeshed/stdlib/zipfile.pyi
@@ -1,6 +1,6 @@
 import io
 import sys
-from _typeshed import Self, StrOrBytesPath, StrPath
+from _typeshed import Self, StrOrBytesPath, StrPath, _BufferWithLen
 from collections.abc import Callable, Iterable, Iterator
 from os import PathLike
 from types import TracebackType
@@ -103,7 +103,7 @@ class ZipFile:
     compression: int  # undocumented
     compresslevel: int | None  # undocumented
     mode: _ZipFileMode  # undocumented
-    pwd: str | None  # undocumented
+    pwd: bytes | None  # undocumented
     if sys.version_info >= (3, 11):
         @overload
         def __init__(
@@ -173,7 +173,11 @@ class ZipFile:
         self, filename: StrPath, arcname: StrPath | None = ..., compress_type: int | None = ..., compresslevel: int | None = ...
     ) -> None: ...
     def writestr(
-        self, zinfo_or_arcname: str | ZipInfo, data: bytes | str, compress_type: int | None = ..., compresslevel: int | None = ...
+        self,
+        zinfo_or_arcname: str | ZipInfo,
+        data: _BufferWithLen | str,
+        compress_type: int | None = ...,
+        compresslevel: int | None = ...,
     ) -> None: ...
     if sys.version_info >= (3, 11):
         def mkdir(self, zinfo_or_directory_name: str | ZipInfo, mode: int = ...) -> None: ...
diff --git a/mypy/typeshed/stdlib/zipimport.pyi b/mypy/typeshed/stdlib/zipimport.pyi
index db06544138ca3..d3017f385c0c5 100644
--- a/mypy/typeshed/stdlib/zipimport.pyi
+++ b/mypy/typeshed/stdlib/zipimport.pyi
@@ -1,9 +1,8 @@
-import os
 import sys
+from _typeshed import StrOrBytesPath
 from importlib.abc import ResourceReader
 from importlib.machinery import ModuleSpec
 from types import CodeType, ModuleType
-from typing import Any
 
 if sys.version_info >= (3, 8):
     __all__ = ["ZipImportError", "zipimporter"]
@@ -13,7 +12,11 @@ class ZipImportError(ImportError): ...
 class zipimporter:
     archive: str
     prefix: str
-    def __init__(self, path: str | bytes | os.PathLike[Any]) -> None: ...
+    if sys.version_info >= (3, 11):
+        def __init__(self, path: str) -> None: ...
+    else:
+        def __init__(self, path: StrOrBytesPath) -> None: ...
+
     def find_loader(self, fullname: str, path: str | None = ...) -> tuple[zipimporter | None, list[str]]: ...  # undocumented
     def find_module(self, fullname: str, path: str | None = ...) -> zipimporter | None: ...
     def get_code(self, fullname: str) -> CodeType: ...
diff --git a/mypy/typeshed/stdlib/zlib.pyi b/mypy/typeshed/stdlib/zlib.pyi
index cfd6784bb7713..ea41567eefc57 100644
--- a/mypy/typeshed/stdlib/zlib.pyi
+++ b/mypy/typeshed/stdlib/zlib.pyi
@@ -1,6 +1,5 @@
 import sys
-from array import array
-from typing import Any
+from _typeshed import ReadableBuffer
 from typing_extensions import Literal
 
 DEFLATED: Literal[8]
@@ -29,7 +28,7 @@ Z_TREES: Literal[6]
 class error(Exception): ...
 
 class _Compress:
-    def compress(self, data: bytes) -> bytes: ...
+    def compress(self, data: ReadableBuffer) -> bytes: ...
     def flush(self, mode: int = ...) -> bytes: ...
     def copy(self) -> _Compress: ...
 
@@ -37,21 +36,26 @@ class _Decompress:
     unused_data: bytes
     unconsumed_tail: bytes
     eof: bool
-    def decompress(self, data: bytes, max_length: int = ...) -> bytes: ...
+    def decompress(self, data: ReadableBuffer, max_length: int = ...) -> bytes: ...
     def flush(self, length: int = ...) -> bytes: ...
     def copy(self) -> _Decompress: ...
 
-def adler32(__data: bytes, __value: int = ...) -> int: ...
+def adler32(__data: ReadableBuffer, __value: int = ...) -> int: ...
 
 if sys.version_info >= (3, 11):
-    def compress(__data: bytes, level: int = ..., wbits: int = ...) -> bytes: ...
+    def compress(__data: ReadableBuffer, level: int = ..., wbits: int = ...) -> bytes: ...
 
 else:
-    def compress(__data: bytes, level: int = ...) -> bytes: ...
+    def compress(__data: ReadableBuffer, level: int = ...) -> bytes: ...
 
 def compressobj(
-    level: int = ..., method: int = ..., wbits: int = ..., memLevel: int = ..., strategy: int = ..., zdict: bytes | None = ...
+    level: int = ...,
+    method: int = ...,
+    wbits: int = ...,
+    memLevel: int = ...,
+    strategy: int = ...,
+    zdict: ReadableBuffer | None = ...,
 ) -> _Compress: ...
-def crc32(__data: array[Any] | bytes, __value: int = ...) -> int: ...
-def decompress(__data: bytes, wbits: int = ..., bufsize: int = ...) -> bytes: ...
-def decompressobj(wbits: int = ..., zdict: bytes = ...) -> _Decompress: ...
+def crc32(__data: ReadableBuffer, __value: int = ...) -> int: ...
+def decompress(__data: ReadableBuffer, wbits: int = ..., bufsize: int = ...) -> bytes: ...
+def decompressobj(wbits: int = ..., zdict: ReadableBuffer = ...) -> _Decompress: ...
diff --git a/mypy/typeshed/stdlib/zoneinfo/__init__.pyi b/mypy/typeshed/stdlib/zoneinfo/__init__.pyi
index 7f22c07b32c08..8b9ba9e7023af 100644
--- a/mypy/typeshed/stdlib/zoneinfo/__init__.pyi
+++ b/mypy/typeshed/stdlib/zoneinfo/__init__.pyi
@@ -1,6 +1,6 @@
 from _typeshed import Self, StrPath
 from collections.abc import Iterable, Sequence
-from datetime import tzinfo
+from datetime import datetime, timedelta, tzinfo
 from typing import Any, Protocol
 
 __all__ = ["ZoneInfo", "reset_tzpath", "available_timezones", "TZPATH", "ZoneInfoNotFoundError", "InvalidTZPathWarning"]
@@ -19,6 +19,9 @@ class ZoneInfo(tzinfo):
     def from_file(cls: type[Self], __fobj: _IOBytes, key: str | None = ...) -> Self: ...
     @classmethod
     def clear_cache(cls, *, only_keys: Iterable[str] | None = ...) -> None: ...
+    def tzname(self, __dt: datetime | None) -> str | None: ...
+    def utcoffset(self, __dt: datetime | None) -> timedelta | None: ...
+    def dst(self, __dt: datetime | None) -> timedelta | None: ...
 
 # Note: Both here and in clear_cache, the types allow the use of `str` where
 # a sequence of strings is required. This should be remedied if a solution

From 0062994228fb62975c6cef4d2c80d00c7aa1c545 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 18 Nov 2022 01:08:36 -0800
Subject: [PATCH 056/231] Revert typeshed ctypes change (#14128)

Since the plugin provides superior type checking:
https://github.com/python/mypy/pull/13987#issuecomment-1310863427
---
 mypy/typeshed/stdlib/ctypes/__init__.pyi | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/mypy/typeshed/stdlib/ctypes/__init__.pyi b/mypy/typeshed/stdlib/ctypes/__init__.pyi
index 1851d3481ee2f..84e4ba07a02ad 100644
--- a/mypy/typeshed/stdlib/ctypes/__init__.pyi
+++ b/mypy/typeshed/stdlib/ctypes/__init__.pyi
@@ -266,11 +266,7 @@ class Array(Generic[_CT], _CData):
     def _type_(self) -> type[_CT]: ...
     @_type_.setter
     def _type_(self, value: type[_CT]) -> None: ...
-    # Note: only available if _CT == c_char
-    @property
-    def raw(self) -> bytes: ...
-    @raw.setter
-    def raw(self, value: ReadableBuffer) -> None: ...
+    raw: bytes  # Note: only available if _CT == c_char
     value: Any  # Note: bytes if _CT == c_char, str if _CT == c_wchar, unavailable otherwise
     # TODO These methods cannot be annotated correctly at the moment.
     # All of these "Any"s stand for the array's element type, but it's not possible to use _CT

From b650d9633d508005fc030e5e80097d74c3d24d0d Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 18 Nov 2022 01:49:39 -0800
Subject: [PATCH 057/231] Revert use of recursive alias in typeshed (#14130)

Easy crash to repro: `mypy --any-exprs-report=out -c 'pass' --show-traceback`
---
 mypy/typeshed/stdlib/_typeshed/__init__.pyi |  3 ++-
 mypy/typeshed/stdlib/builtins.pyi           | 14 ++++++++++----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/mypy/typeshed/stdlib/_typeshed/__init__.pyi b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
index 1b54284fe7274..3ae2fca1d19dc 100644
--- a/mypy/typeshed/stdlib/_typeshed/__init__.pyi
+++ b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
@@ -276,4 +276,5 @@ StrOrLiteralStr = TypeVar("StrOrLiteralStr", LiteralString, str)  # noqa: Y001
 ProfileFunction: TypeAlias = Callable[[FrameType, str, Any], object]
 
 # Objects suitable to be passed to sys.settrace, threading.settrace, and similar
-TraceFunction: TypeAlias = Callable[[FrameType, str, Any], TraceFunction | None]
+# TODO: Ideally this would be a recursive type alias
+TraceFunction: TypeAlias = Callable[[FrameType, str, Any], Callable[[FrameType, str, Any], Any] | None]
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index 00eac9e49cf0f..5482955eb0ab2 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -1232,13 +1232,19 @@ def iter(__function: Callable[[], _T | None], __sentinel: None) -> Iterator[_T]:
 @overload
 def iter(__function: Callable[[], _T], __sentinel: object) -> Iterator[_T]: ...
 
+# We need recursive types to express the type of the second argument to `isinstance` properly, hence the use of `Any`
 if sys.version_info >= (3, 10):
-    _ClassInfo: TypeAlias = type | types.UnionType | tuple[_ClassInfo, ...]
+    def isinstance(
+        __obj: object, __class_or_tuple: type | types.UnionType | tuple[type | types.UnionType | tuple[Any, ...], ...]
+    ) -> bool: ...
+    def issubclass(
+        __cls: type, __class_or_tuple: type | types.UnionType | tuple[type | types.UnionType | tuple[Any, ...], ...]
+    ) -> bool: ...
+
 else:
-    _ClassInfo: TypeAlias = type | tuple[_ClassInfo, ...]
+    def isinstance(__obj: object, __class_or_tuple: type | tuple[type | tuple[Any, ...], ...]) -> bool: ...
+    def issubclass(__cls: type, __class_or_tuple: type | tuple[type | tuple[Any, ...], ...]) -> bool: ...
 
-def isinstance(__obj: object, __class_or_tuple: _ClassInfo) -> bool: ...
-def issubclass(__cls: type, __class_or_tuple: _ClassInfo) -> bool: ...
 def len(__obj: Sized) -> int: ...
 def license() -> None: ...
 def locals() -> dict[str, Any]: ...

From 1d6a5b1d2abf617b149e8bf8ff435f64dc507fd3 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 18 Nov 2022 10:48:27 +0000
Subject: [PATCH 058/231] Fix daemon crash on malformed NamedTuple (#14119)

Fixes #14098

Having invalid statements in a NamedTuple is almost like a syntax error,
we can remove them after giving an error (without further analysis).
This PR does almost exactly the same as
https://github.com/python/mypy/pull/13963 did for TypedDicts.

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 mypy/nodes.py                              |  4 ++
 mypy/semanal_namedtuple.py                 | 19 ++++--
 mypy/semanal_typeddict.py                  |  2 +
 mypy/server/aststrip.py                    |  2 +
 test-data/unit/check-class-namedtuple.test |  2 -
 test-data/unit/fine-grained.test           | 72 ++++++++++++++++++++++
 6 files changed, 94 insertions(+), 7 deletions(-)

diff --git a/mypy/nodes.py b/mypy/nodes.py
index cf711c45f5871..ebf2f5cb271a4 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -1068,6 +1068,7 @@ class ClassDef(Statement):
         "analyzed",
         "has_incompatible_baseclass",
         "deco_line",
+        "removed_statements",
     )
 
     __match_args__ = ("name", "defs")
@@ -1086,6 +1087,8 @@ class ClassDef(Statement):
     keywords: dict[str, Expression]
     analyzed: Expression | None
     has_incompatible_baseclass: bool
+    # Used by special forms like NamedTuple and TypedDict to store invalid statements
+    removed_statements: list[Statement]
 
     def __init__(
         self,
@@ -1111,6 +1114,7 @@ def __init__(
         self.has_incompatible_baseclass = False
         # Used for error reporting (to keep backwad compatibility with pre-3.8)
         self.deco_line: int | None = None
+        self.removed_statements = []
 
     def accept(self, visitor: StatementVisitor[T]) -> T:
         return visitor.visit_class_def(self)
diff --git a/mypy/semanal_namedtuple.py b/mypy/semanal_namedtuple.py
index 04308db99e63f..ec5f13d0fce09 100644
--- a/mypy/semanal_namedtuple.py
+++ b/mypy/semanal_namedtuple.py
@@ -32,6 +32,7 @@
     NameExpr,
     PassStmt,
     RefExpr,
+    Statement,
     StrExpr,
     SymbolTable,
     SymbolTableNode,
@@ -111,7 +112,7 @@ def analyze_namedtuple_classdef(
                     if result is None:
                         # This is a valid named tuple, but some types are incomplete.
                         return True, None
-                    items, types, default_items = result
+                    items, types, default_items, statements = result
                     if is_func_scope and "@" not in defn.name:
                         defn.name += "@" + str(defn.line)
                     existing_info = None
@@ -123,6 +124,7 @@ def analyze_namedtuple_classdef(
                     defn.analyzed = NamedTupleExpr(info, is_typed=True)
                     defn.analyzed.line = defn.line
                     defn.analyzed.column = defn.column
+                    defn.defs.body = statements
                     # All done: this is a valid named tuple with all types known.
                     return True, info
         # This can't be a valid named tuple.
@@ -130,24 +132,27 @@ def analyze_namedtuple_classdef(
 
     def check_namedtuple_classdef(
         self, defn: ClassDef, is_stub_file: bool
-    ) -> tuple[list[str], list[Type], dict[str, Expression]] | None:
+    ) -> tuple[list[str], list[Type], dict[str, Expression], list[Statement]] | None:
         """Parse and validate fields in named tuple class definition.
 
-        Return a three tuple:
+        Return a four tuple:
           * field names
           * field types
           * field default values
+          * valid statements
         or None, if any of the types are not ready.
         """
         if self.options.python_version < (3, 6) and not is_stub_file:
             self.fail("NamedTuple class syntax is only supported in Python 3.6", defn)
-            return [], [], {}
+            return [], [], {}, []
         if len(defn.base_type_exprs) > 1:
             self.fail("NamedTuple should be a single base", defn)
         items: list[str] = []
         types: list[Type] = []
         default_items: dict[str, Expression] = {}
+        statements: list[Statement] = []
         for stmt in defn.defs.body:
+            statements.append(stmt)
             if not isinstance(stmt, AssignmentStmt):
                 # Still allow pass or ... (for empty namedtuples).
                 if isinstance(stmt, PassStmt) or (
@@ -160,9 +165,13 @@ def check_namedtuple_classdef(
                 # And docstrings.
                 if isinstance(stmt, ExpressionStmt) and isinstance(stmt.expr, StrExpr):
                     continue
+                statements.pop()
+                defn.removed_statements.append(stmt)
                 self.fail(NAMEDTUP_CLASS_ERROR, stmt)
             elif len(stmt.lvalues) > 1 or not isinstance(stmt.lvalues[0], NameExpr):
                 # An assignment, but an invalid one.
+                statements.pop()
+                defn.removed_statements.append(stmt)
                 self.fail(NAMEDTUP_CLASS_ERROR, stmt)
             else:
                 # Append name and type in this case...
@@ -199,7 +208,7 @@ def check_namedtuple_classdef(
                         )
                 else:
                     default_items[name] = stmt.rvalue
-        return items, types, default_items
+        return items, types, default_items, statements
 
     def check_namedtuple(
         self, node: Expression, var_name: str | None, is_func_scope: bool
diff --git a/mypy/semanal_typeddict.py b/mypy/semanal_typeddict.py
index e8be82bd41bef..fb45dcc0dfc4c 100644
--- a/mypy/semanal_typeddict.py
+++ b/mypy/semanal_typeddict.py
@@ -283,9 +283,11 @@ def analyze_typeddict_classdef_fields(
                 ):
                     statements.append(stmt)
                 else:
+                    defn.removed_statements.append(stmt)
                     self.fail(TPDICT_CLASS_ERROR, stmt)
             elif len(stmt.lvalues) > 1 or not isinstance(stmt.lvalues[0], NameExpr):
                 # An assignment, but an invalid one.
+                defn.removed_statements.append(stmt)
                 self.fail(TPDICT_CLASS_ERROR, stmt)
             else:
                 name = stmt.lvalues[0].name
diff --git a/mypy/server/aststrip.py b/mypy/server/aststrip.py
index 1bfd820efb211..87ce63e9d5433 100644
--- a/mypy/server/aststrip.py
+++ b/mypy/server/aststrip.py
@@ -140,6 +140,8 @@ def visit_class_def(self, node: ClassDef) -> None:
         ]
         with self.enter_class(node.info):
             super().visit_class_def(node)
+        node.defs.body.extend(node.removed_statements)
+        node.removed_statements = []
         TypeState.reset_subtype_caches_for(node.info)
         # Kill the TypeInfo, since there is none before semantic analysis.
         node.info = CLASSDEF_NO_INFO
diff --git a/test-data/unit/check-class-namedtuple.test b/test-data/unit/check-class-namedtuple.test
index 8e0545953bd84..8ae7f6555f9db 100644
--- a/test-data/unit/check-class-namedtuple.test
+++ b/test-data/unit/check-class-namedtuple.test
@@ -393,8 +393,6 @@ class X(typing.NamedTuple):
 [out]
 main:6: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
 main:7: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
-main:7: error: Type cannot be declared in assignment to non-self attribute
-main:7: error: "int" has no attribute "x"
 main:9: error: Non-default NamedTuple fields cannot follow default fields
 
 [builtins fixtures/list.pyi]
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index a6d8f206fbba0..c162f402486aa 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -10205,3 +10205,75 @@ C
 [builtins fixtures/dict.pyi]
 [out]
 ==
+
+[case testNamedTupleNestedCrash]
+import m
+[file m.py]
+from typing import NamedTuple
+
+class NT(NamedTuple):
+    class C: ...
+    x: int
+    y: int
+
+[file m.py.2]
+from typing import NamedTuple
+
+class NT(NamedTuple):
+    class C: ...
+    x: int
+    y: int
+# change
+[builtins fixtures/tuple.pyi]
+[out]
+m.py:4: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+==
+m.py:4: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+
+[case testNamedTupleNestedClassRecheck]
+import n
+[file n.py]
+import m
+x: m.NT
+[file m.py]
+from typing import NamedTuple
+from f import A
+
+class NT(NamedTuple):
+    class C: ...
+    x: int
+    y: A
+
+[file f.py]
+A = int
+[file f.py.2]
+A = str
+[builtins fixtures/tuple.pyi]
+[out]
+m.py:5: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+==
+m.py:5: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+
+[case testTypedDictNestedClassRecheck]
+import n
+[file n.py]
+import m
+x: m.TD
+[file m.py]
+from typing_extensions import TypedDict
+from f import A
+
+class TD(TypedDict):
+    class C: ...
+    x: int
+    y: A
+
+[file f.py]
+A = int
+[file f.py.2]
+A = str
+[builtins fixtures/dict.pyi]
+[out]
+m.py:5: error: Invalid statement in TypedDict definition; expected "field_name: field_type"
+==
+m.py:5: error: Invalid statement in TypedDict definition; expected "field_name: field_type"

From a206096050d87db65aa8fcd3ab3f3d0dc2302036 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 18 Nov 2022 19:22:40 +0000
Subject: [PATCH 059/231] Enable lxml tests on Python 3.11 (#14134)

Ref #12840
---
 test-requirements.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-requirements.txt b/test-requirements.txt
index 7fe486387f2f1..399785ce4c1c9 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -7,7 +7,7 @@ flake8==5.0.4           # must match version in .pre-commit-config.yaml
 flake8-bugbear==22.9.23 # must match version in .pre-commit-config.yaml
 flake8-noqa==1.2.9      # must match version in .pre-commit-config.yaml
 isort[colors]==5.10.1   # must match version in .pre-commit-config.yaml
-lxml>=4.4.0; python_version<'3.11'
+lxml>=4.9.1
 psutil>=4.0
 # pytest 6.2.3 does not support Python 3.10
 pytest>=6.2.4

From 1cc4a7d38daac2aa641c9355a27820beba3542e1 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 18 Nov 2022 11:23:28 -0800
Subject: [PATCH 060/231] Revert ctypes patch on an ongoing basis (#14129)

---
 misc/sync-typeshed.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/misc/sync-typeshed.py b/misc/sync-typeshed.py
index 878ffaa23bfbb..8eeb9be7f4f82 100644
--- a/misc/sync-typeshed.py
+++ b/misc/sync-typeshed.py
@@ -187,6 +187,7 @@ def main() -> None:
     commits_to_cherry_pick = [
         "780534b13722b7b0422178c049a1cbbf4ea4255b",  # LiteralString reverts
         "5319fa34a8004c1568bb6f032a07b8b14cc95bed",  # sum reverts
+        "0062994228fb62975c6cef4d2c80d00c7aa1c545",  # ctypes reverts
     ]
     for commit in commits_to_cherry_pick:
         subprocess.run(["git", "cherry-pick", commit], check=True)

From 05a3f7d8d61bc298809e5363d3a23aa16fe776d2 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 18 Nov 2022 19:37:58 +0000
Subject: [PATCH 061/231] Correctly handle Enum name on Python 3.11 (#14133)

Fixes #12483
Fixes https://github.com/python/typeshed/issues/7564
Ref #12841

The fix is straightforward. I can't use a unit test for this because
there are some builtins fixtures that don't have tuple, so I can't do
version check.
---
 mypy/semanal.py                |  8 +++++++-
 test-data/unit/pythoneval.test | 23 +++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 9b2b4ba44ccea..538e37c030a96 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1448,7 +1448,13 @@ def visit_decorator(self, dec: Decorator) -> None:
                 dec.var.is_classmethod = True
                 self.check_decorated_function_is_method("classmethod", dec)
             elif refers_to_fullname(
-                d, ("builtins.property", "abc.abstractproperty", "functools.cached_property")
+                d,
+                (
+                    "builtins.property",
+                    "abc.abstractproperty",
+                    "functools.cached_property",
+                    "enum.property",
+                ),
             ):
                 removed.append(i)
                 dec.func.is_property = True
diff --git a/test-data/unit/pythoneval.test b/test-data/unit/pythoneval.test
index f6336b48ee7b0..3f669246bb4e5 100644
--- a/test-data/unit/pythoneval.test
+++ b/test-data/unit/pythoneval.test
@@ -1712,3 +1712,26 @@ A = Type[int] | str
 B: TypeAlias = Type[int] | str
 [out]
 m.pyi:5: note: Revealed type is "typing._SpecialForm"
+
+[case testEnumNameWorkCorrectlyOn311]
+# flags: --python-version 3.11
+import enum
+
+class E(enum.Enum):
+    X = 1
+    Y = 2
+    @enum.property
+    def foo(self) -> int: ...
+
+e: E
+reveal_type(e.name)
+reveal_type(e.value)
+reveal_type(E.X.name)
+reveal_type(e.foo)
+reveal_type(E.Y.foo)
+[out]
+_testEnumNameWorkCorrectlyOn311.py:11: note: Revealed type is "builtins.str"
+_testEnumNameWorkCorrectlyOn311.py:12: note: Revealed type is "Union[Literal[1]?, Literal[2]?]"
+_testEnumNameWorkCorrectlyOn311.py:13: note: Revealed type is "Literal['X']?"
+_testEnumNameWorkCorrectlyOn311.py:14: note: Revealed type is "builtins.int"
+_testEnumNameWorkCorrectlyOn311.py:15: note: Revealed type is "builtins.int"

From a2477ff0d0cb751f27a2b38d27ce6572ead03451 Mon Sep 17 00:00:00 2001
From: ChristianWitzler <57713653+ChristianWitzler@users.noreply.github.com>
Date: Fri, 18 Nov 2022 21:00:08 +0100
Subject: [PATCH 062/231] Update code example in "Declaring decorators"
 (#14131)

- Added missing cast import
- Changed revealed type

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 docs/source/generics.rst | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/docs/source/generics.rst b/docs/source/generics.rst
index 59d4aa1a2dea1..9a13e2a955c41 100644
--- a/docs/source/generics.rst
+++ b/docs/source/generics.rst
@@ -635,7 +635,7 @@ Before parameter specifications, here's how one might have annotated the decorat
 
 .. code-block:: python
 
-   from typing import Callable, TypeVar
+   from typing import Any, Callable, TypeVar, cast
 
    F = TypeVar('F', bound=Callable[..., Any])
 
@@ -650,8 +650,8 @@ and that would enable the following type checks:
 
 .. code-block:: python
 
-   reveal_type(a)  # str
-   add_forty_two('x')    # Type check error: incompatible type "str"; expected "int"
+   reveal_type(a)  # Revealed type is "builtins.int"
+   add_forty_two('x')  # Argument 1 to "add_forty_two" has incompatible type "str"; expected "int"
 
 
 Note that the ``wrapper()`` function is not type-checked. Wrapper

From 6cd8e007923acef7a2899e85378bc4822472b848 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sat, 19 Nov 2022 02:00:33 +0000
Subject: [PATCH 063/231] Fix type query for recursive aliases (#14136)

See https://github.com/python/mypy/pull/14130 for context.

Btw it looks like these `Any` reports are quite broken in general. Some
issues I found:
* Many types are reported twice (even non-recursive)
* Explicit `Any` in alias r.h.s are not counted (because of reckless
`res = make_any_non_explicit(res)` in semanal.py)
* For generic aliases we count their r.h.s. as containing `Any` from
omitted generics

I tried to fix these things, but it is not trivial, so maybe we can do
it later in a separate PR.
---
 mypy/type_visitor.py        | 24 ++++++++----------------
 mypy/typeanal.py            |  2 +-
 test-data/unit/reports.test | 24 +++++++++++++++++++++++-
 3 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/mypy/type_visitor.py b/mypy/type_visitor.py
index fe404cda0becd..0f5ac05e68ac3 100644
--- a/mypy/type_visitor.py
+++ b/mypy/type_visitor.py
@@ -404,24 +404,16 @@ def visit_placeholder_type(self, t: PlaceholderType) -> T:
         return self.query_types(t.args)
 
     def visit_type_alias_type(self, t: TypeAliasType) -> T:
+        # Skip type aliases already visited types to avoid infinite recursion.
+        # TODO: Ideally we should fire subvisitors here (or use caching) if we care
+        #       about duplicates.
+        if t in self.seen_aliases:
+            return self.strategy([])
+        self.seen_aliases.add(t)
         if self.skip_alias_target:
             return self.query_types(t.args)
         return get_proper_type(t).accept(self)
 
     def query_types(self, types: Iterable[Type]) -> T:
-        """Perform a query for a list of types.
-
-        Use the strategy to combine the results.
-        Skip type aliases already visited types to avoid infinite recursion.
-        """
-        res: list[T] = []
-        for t in types:
-            if isinstance(t, TypeAliasType):
-                # Avoid infinite recursion for recursive type aliases.
-                # TODO: Ideally we should fire subvisitors here (or use caching) if we care
-                #       about duplicates.
-                if t in self.seen_aliases:
-                    continue
-                self.seen_aliases.add(t)
-            res.append(t.accept(self))
-        return self.strategy(res)
+        """Perform a query for a list of types using the strategy to combine the results."""
+        return self.strategy([t.accept(self) for t in types])
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 18a63011c5bf4..0dc1717d07249 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -450,7 +450,7 @@ def try_analyze_special_unbound_type(self, t: UnboundType, fullname: str) -> Typ
         if fullname == "builtins.None":
             return NoneType()
         elif fullname == "typing.Any" or fullname == "builtins.Any":
-            return AnyType(TypeOfAny.explicit)
+            return AnyType(TypeOfAny.explicit, line=t.line, column=t.column)
         elif fullname in FINAL_TYPE_NAMES:
             self.fail(
                 "Final can be only used as an outermost qualifier in a variable annotation",
diff --git a/test-data/unit/reports.test b/test-data/unit/reports.test
index a7ab6d754b2ca..50dabb1fdea9f 100644
--- a/test-data/unit/reports.test
+++ b/test-data/unit/reports.test
@@ -103,6 +103,28 @@ class A(object):
 </body>
 </html>
 
+[case testNoCrashRecursiveAliasInReport]
+# cmd: mypy --any-exprs-report report n.py
+
+[file n.py]
+from typing import Union, List, Any, TypeVar
+
+Nested = List[Union[Any, Nested]]
+T = TypeVar("T")
+NestedGen = List[Union[T, NestedGen[T]]]
+
+x: Nested
+y: NestedGen[int]
+z: NestedGen[Any]
+
+[file report/any-exprs.txt]
+[outfile report/types-of-anys.txt]
+ Name   Unannotated   Explicit   Unimported   Omitted Generics   Error   Special Form   Implementation Artifact
+-----------------------------------------------------------------------------------------------------------------
+    n             0          4            0                  8       0              0                         0
+-----------------------------------------------------------------------------------------------------------------
+Total             0          4            0                  8       0              0                         0
+
 [case testTypeVarTreatedAsEmptyLine]
 # cmd: mypy --html-report report n.py
 
@@ -480,7 +502,7 @@ namespace_packages = True
 <link rel="stylesheet" type="text/css" href="../../../mypy-html.css">
 </head>
 <body>
-<h2>folder.subfolder.something</h2>           
+<h2>folder.subfolder.something</h2>
 <table>
 <caption>folder/subfolder/something.py</caption>
 <tbody><tr>

From 56e9396e681d779cbb593d82d21c1fae76c6f430 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 18 Nov 2022 20:10:54 -0800
Subject: [PATCH 064/231] Make non-numeric non-empty FORCE_COLOR truthy
 (#14140)

Fixes #14139
---
 mypy/util.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mypy/util.py b/mypy/util.py
index e836aefb3c7ef..04ed616ade07d 100644
--- a/mypy/util.py
+++ b/mypy/util.py
@@ -520,7 +520,11 @@ def parse_gray_color(cup: bytes) -> str:
 
 
 def should_force_color() -> bool:
-    return bool(int(os.getenv("MYPY_FORCE_COLOR", os.getenv("FORCE_COLOR", "0"))))
+    env_var = os.getenv("MYPY_FORCE_COLOR", os.getenv("FORCE_COLOR", "0"))
+    try:
+        return bool(int(env_var))
+    except ValueError:
+        return bool(env_var)
 
 
 class FancyFormatter:

From e814c47a1950dba765207333cf91a61a2d9188ee Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sat, 19 Nov 2022 15:07:24 +0000
Subject: [PATCH 065/231] Fix incremental crash on generic function appearing
 in nested position (#14148)

Fixes #14137

Fix is trivial, I just forgot to call `super()` in one of my previous
PRs.
---
 mypy/checkmember.py                   |  1 +
 test-data/unit/check-incremental.test | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index 08d4ff412e4e0..554b49d3eda21 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -806,6 +806,7 @@ class FreezeTypeVarsVisitor(TypeTraverserVisitor):
     def visit_callable_type(self, t: CallableType) -> None:
         for v in t.variables:
             v.id.meta_level = 0
+        super().visit_callable_type(t)
 
 
 def lookup_member_var_or_accessor(info: TypeInfo, name: str, is_lvalue: bool) -> SymbolNode | None:
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index 5fca0f55a0d66..e5b69fb6fb9d4 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -6334,3 +6334,17 @@ reveal_type(D().meth)
 [out2]
 tmp/m.py:4: note: Revealed type is "def [Self <: lib.C] (self: Self`0, other: Self`0) -> Self`0"
 tmp/m.py:5: note: Revealed type is "def (other: m.D) -> m.D"
+
+[case testIncrementalNestedGenericCallableCrash]
+from typing import TypeVar, Callable
+
+T = TypeVar("T")
+
+class B:
+    def foo(self) -> Callable[[T], T]: ...
+
+class C(B):
+    def __init__(self) -> None:
+        self.x = self.foo()
+[out]
+[out2]

From f8d71f13d408198f81d55a6b57bf1d2c1b81a3c2 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sat, 19 Nov 2022 22:54:24 +0000
Subject: [PATCH 066/231] Make is_recursive and has_recursive_types() more
 consistent (#14147)

While working on another PR I noticed that current behavior of
`has_recursive_types()` is inconsistent, it returns `False` is there is
a recursive type nested as an argument to a generic non-recursive alias.
I wasn't able to find any situation where this actually matters, but I
think it is better if this function behaves consistently.
---
 mypy/test/testtypes.py   |  7 +++++++
 mypy/test/typefixture.py | 10 +++++++---
 mypy/types.py            | 26 +++++++++++++++++++-------
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/mypy/test/testtypes.py b/mypy/test/testtypes.py
index 31bdd6690a7af..18948ee7f6d6a 100644
--- a/mypy/test/testtypes.py
+++ b/mypy/test/testtypes.py
@@ -31,6 +31,7 @@
     UninhabitedType,
     UnionType,
     get_proper_type,
+    has_recursive_types,
 )
 
 
@@ -157,6 +158,12 @@ def test_type_alias_expand_all(self) -> None:
             [self.fx.a, self.fx.a], Instance(self.fx.std_tuplei, [self.fx.a])
         )
 
+    def test_recursive_nested_in_non_recursive(self) -> None:
+        A, _ = self.fx.def_alias_1(self.fx.a)
+        NA = self.fx.non_rec_alias(Instance(self.fx.gi, [UnboundType("T")]), ["T"], [A])
+        assert not NA.is_recursive
+        assert has_recursive_types(NA)
+
     def test_indirection_no_infinite_recursion(self) -> None:
         A, _ = self.fx.def_alias_1(self.fx.a)
         visitor = TypeIndirectionVisitor()
diff --git a/mypy/test/typefixture.py b/mypy/test/typefixture.py
index 380da909893a6..93e5e4b0b5ca0 100644
--- a/mypy/test/typefixture.py
+++ b/mypy/test/typefixture.py
@@ -339,9 +339,13 @@ def def_alias_2(self, base: Instance) -> tuple[TypeAliasType, Type]:
         A.alias = AN
         return A, target
 
-    def non_rec_alias(self, target: Type) -> TypeAliasType:
-        AN = TypeAlias(target, "__main__.A", -1, -1)
-        return TypeAliasType(AN, [])
+    def non_rec_alias(
+        self, target: Type, alias_tvars: list[str] | None = None, args: list[Type] | None = None
+    ) -> TypeAliasType:
+        AN = TypeAlias(target, "__main__.A", -1, -1, alias_tvars=alias_tvars)
+        if args is None:
+            args = []
+        return TypeAliasType(AN, args)
 
 
 class InterfaceTypeFixture(TypeFixture):
diff --git a/mypy/types.py b/mypy/types.py
index 1de294f9952d8..6c08b24afd80a 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -278,30 +278,42 @@ def _expand_once(self) -> Type:
             self.alias.target, self.alias.alias_tvars, self.args, self.line, self.column
         )
 
-    def _partial_expansion(self) -> tuple[ProperType, bool]:
+    def _partial_expansion(self, nothing_args: bool = False) -> tuple[ProperType, bool]:
         # Private method mostly for debugging and testing.
         unroller = UnrollAliasVisitor(set())
-        unrolled = self.accept(unroller)
+        if nothing_args:
+            alias = self.copy_modified(args=[UninhabitedType()] * len(self.args))
+        else:
+            alias = self
+        unrolled = alias.accept(unroller)
         assert isinstance(unrolled, ProperType)
         return unrolled, unroller.recursed
 
-    def expand_all_if_possible(self) -> ProperType | None:
+    def expand_all_if_possible(self, nothing_args: bool = False) -> ProperType | None:
         """Attempt a full expansion of the type alias (including nested aliases).
 
         If the expansion is not possible, i.e. the alias is (mutually-)recursive,
-        return None.
+        return None. If nothing_args is True, replace all type arguments with an
+        UninhabitedType() (used to detect recursively defined aliases).
         """
-        unrolled, recursed = self._partial_expansion()
+        unrolled, recursed = self._partial_expansion(nothing_args=nothing_args)
         if recursed:
             return None
         return unrolled
 
     @property
     def is_recursive(self) -> bool:
+        """Whether this type alias is recursive.
+
+        Note this doesn't check generic alias arguments, but only if this alias
+        *definition* is recursive. The property value thus can be cached on the
+        underlying TypeAlias node. If you want to include all nested types, use
+        has_recursive_types() function.
+        """
         assert self.alias is not None, "Unfixed type alias"
         is_recursive = self.alias._is_recursive
         if is_recursive is None:
-            is_recursive = self.expand_all_if_possible() is None
+            is_recursive = self.expand_all_if_possible(nothing_args=True) is None
             # We cache the value on the underlying TypeAlias node as an optimization,
             # since the value is the same for all instances of the same alias.
             self.alias._is_recursive = is_recursive
@@ -3259,7 +3271,7 @@ def __init__(self) -> None:
         super().__init__(any)
 
     def visit_type_alias_type(self, t: TypeAliasType) -> bool:
-        return t.is_recursive
+        return t.is_recursive or self.query_types(t.args)
 
 
 def has_recursive_types(typ: Type) -> bool:

From c660354846688ff8158d0f0178eb298171b74f5b Mon Sep 17 00:00:00 2001
From: Tom Schraitle <tomschr@users.noreply.github.com>
Date: Mon, 21 Nov 2022 09:00:36 +0100
Subject: [PATCH 067/231] Avoid use of implicit optional in decorator factory
 docs (#14156)

---
 docs/source/generics.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/source/generics.rst b/docs/source/generics.rst
index 9a13e2a955c41..a5c7b8accaa8f 100644
--- a/docs/source/generics.rst
+++ b/docs/source/generics.rst
@@ -724,7 +724,7 @@ achieved by combining with :py:func:`@overload <typing.overload>`:
 
 .. code-block:: python
 
-    from typing import Any, Callable, TypeVar, overload
+    from typing import Any, Callable, Optional, TypeVar, overload
 
     F = TypeVar('F', bound=Callable[..., Any])
 
@@ -736,7 +736,7 @@ achieved by combining with :py:func:`@overload <typing.overload>`:
     def atomic(*, savepoint: bool = True) -> Callable[[F], F]: ...
 
     # Implementation
-    def atomic(__func: Callable[..., Any] = None, *, savepoint: bool = True):
+    def atomic(__func: Optional[Callable[..., Any]] = None, *, savepoint: bool = True):
         def decorator(func: Callable[..., Any]):
             ...  # Code goes here
         if __func is not None:

From 3c5f368872413fae867bf4a2dff7781cbf547459 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 21 Nov 2022 18:42:13 +0000
Subject: [PATCH 068/231] Allow function arguments as base classes (#14135)

Fixes #5865

Looks quite easy and safe, unless I am missing something. Most changes
in the diff are just moving stuff around.

Previously we only applied argument types before type checking, but it
looks like we can totally do this in semantic analyzer. I also enable
variable annotated as `type` (or equivalently `Type[Any]`), this use
case was mentioned in the comments.

This PR also accidentally fixes two additional bugs, one related to type
variables with values vs walrus operator, another one for type variables
with values vs self types. I include test cases for those as well.
---
 mypy/checker.py                    | 29 +++--------------------------
 mypy/semanal.py                    | 25 +++++++++++++++++++++----
 mypy/stubtest.py                   |  2 +-
 mypy/treetransform.py              |  2 +-
 mypy/typeanal.py                   |  8 ++++++++
 mypy/types.py                      | 28 ++++++++++++++++++++++++++++
 test-data/unit/check-classes.test  | 15 +++++++++++++++
 test-data/unit/check-python38.test | 16 ++++++++++++++++
 test-data/unit/check-selftype.test | 13 +++++++++++++
 test-data/unit/semanal-types.test  |  2 ++
 10 files changed, 108 insertions(+), 32 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index c7de4911501a8..7a66a9408ee42 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -184,7 +184,6 @@
     LiteralType,
     NoneType,
     Overloaded,
-    ParamSpecType,
     PartialType,
     ProperType,
     StarType,
@@ -203,7 +202,6 @@
     UnboundType,
     UninhabitedType,
     UnionType,
-    UnpackType,
     flatten_nested_unions,
     get_proper_type,
     get_proper_types,
@@ -211,6 +209,7 @@
     is_named_instance,
     is_optional,
     remove_optional,
+    store_argument_type,
     strip_type,
 )
 from mypy.typetraverser import TypeTraverserVisitor
@@ -1174,30 +1173,8 @@ def check_func_def(
                             if ctx.line < 0:
                                 ctx = typ
                             self.fail(message_registry.FUNCTION_PARAMETER_CANNOT_BE_COVARIANT, ctx)
-                    if typ.arg_kinds[i] == nodes.ARG_STAR:
-                        if isinstance(arg_type, ParamSpecType):
-                            pass
-                        elif isinstance(arg_type, UnpackType):
-                            if isinstance(get_proper_type(arg_type.type), TupleType):
-                                # Instead of using Tuple[Unpack[Tuple[...]]], just use
-                                # Tuple[...]
-                                arg_type = arg_type.type
-                            else:
-                                arg_type = TupleType(
-                                    [arg_type],
-                                    fallback=self.named_generic_type(
-                                        "builtins.tuple", [self.named_type("builtins.object")]
-                                    ),
-                                )
-                        else:
-                            # builtins.tuple[T] is typing.Tuple[T, ...]
-                            arg_type = self.named_generic_type("builtins.tuple", [arg_type])
-                    elif typ.arg_kinds[i] == nodes.ARG_STAR2:
-                        if not isinstance(arg_type, ParamSpecType) and not typ.unpack_kwargs:
-                            arg_type = self.named_generic_type(
-                                "builtins.dict", [self.str_type(), arg_type]
-                            )
-                    item.arguments[i].variable.type = arg_type
+                    # Need to store arguments again for the expanded item.
+                    store_argument_type(item, i, typ, self.named_generic_type)
 
                 # Type check initialization expressions.
                 body_is_trivial = is_trivial_body(defn.body)
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 538e37c030a96..a5ddcc70eed63 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -273,6 +273,7 @@
     get_proper_types,
     invalid_recursive_alias,
     is_named_instance,
+    store_argument_type,
 )
 from mypy.typevars import fill_typevars
 from mypy.util import (
@@ -1315,7 +1316,10 @@ def analyze_function_body(self, defn: FuncItem) -> None:
             # Bind the type variables again to visit the body.
             if defn.type:
                 a = self.type_analyzer()
-                a.bind_function_type_variables(cast(CallableType, defn.type), defn)
+                typ = cast(CallableType, defn.type)
+                a.bind_function_type_variables(typ, defn)
+                for i in range(len(typ.arg_types)):
+                    store_argument_type(defn, i, typ, self.named_type)
             self.function_stack.append(defn)
             with self.enter(defn):
                 for arg in defn.arguments:
@@ -2018,7 +2022,9 @@ def analyze_base_classes(
                 continue
 
             try:
-                base = self.expr_to_analyzed_type(base_expr, allow_placeholder=True)
+                base = self.expr_to_analyzed_type(
+                    base_expr, allow_placeholder=True, allow_type_any=True
+                )
             except TypeTranslationError:
                 name = self.get_name_repr_of_expr(base_expr)
                 if isinstance(base_expr, CallExpr):
@@ -6139,7 +6145,11 @@ def accept(self, node: Node) -> None:
             report_internal_error(err, self.errors.file, node.line, self.errors, self.options)
 
     def expr_to_analyzed_type(
-        self, expr: Expression, report_invalid_types: bool = True, allow_placeholder: bool = False
+        self,
+        expr: Expression,
+        report_invalid_types: bool = True,
+        allow_placeholder: bool = False,
+        allow_type_any: bool = False,
     ) -> Type | None:
         if isinstance(expr, CallExpr):
             # This is a legacy syntax intended mostly for Python 2, we keep it for
@@ -6164,7 +6174,10 @@ def expr_to_analyzed_type(
             return TupleType(info.tuple_type.items, fallback=fallback)
         typ = self.expr_to_unanalyzed_type(expr)
         return self.anal_type(
-            typ, report_invalid_types=report_invalid_types, allow_placeholder=allow_placeholder
+            typ,
+            report_invalid_types=report_invalid_types,
+            allow_placeholder=allow_placeholder,
+            allow_type_any=allow_type_any,
         )
 
     def analyze_type_expr(self, expr: Expression) -> None:
@@ -6188,6 +6201,7 @@ def type_analyzer(
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
         prohibit_self_type: str | None = None,
+        allow_type_any: bool = False,
     ) -> TypeAnalyser:
         if tvar_scope is None:
             tvar_scope = self.tvar_scope
@@ -6204,6 +6218,7 @@ def type_analyzer(
             allow_required=allow_required,
             allow_param_spec_literals=allow_param_spec_literals,
             prohibit_self_type=prohibit_self_type,
+            allow_type_any=allow_type_any,
         )
         tpan.in_dynamic_func = bool(self.function_stack and self.function_stack[-1].is_dynamic())
         tpan.global_scope = not self.type and not self.function_stack
@@ -6224,6 +6239,7 @@ def anal_type(
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
         prohibit_self_type: str | None = None,
+        allow_type_any: bool = False,
         third_pass: bool = False,
     ) -> Type | None:
         """Semantically analyze a type.
@@ -6260,6 +6276,7 @@ def anal_type(
             allow_param_spec_literals=allow_param_spec_literals,
             report_invalid_types=report_invalid_types,
             prohibit_self_type=prohibit_self_type,
+            allow_type_any=allow_type_any,
         )
         tag = self.track_incomplete_refs()
         typ = typ.accept(a)
diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 87ccbd3176df4..74e57d9e5617b 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -354,7 +354,7 @@ def _verify_final(
 ) -> Iterator[Error]:
     try:
 
-        class SubClass(runtime):  # type: ignore[misc,valid-type]
+        class SubClass(runtime):  # type: ignore[misc]
             pass
 
     except TypeError:
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index c863db6b3dd56..2f678b89b1e6e 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -550,7 +550,7 @@ def visit_super_expr(self, node: SuperExpr) -> SuperExpr:
         return new
 
     def visit_assignment_expr(self, node: AssignmentExpr) -> AssignmentExpr:
-        return AssignmentExpr(node.target, node.value)
+        return AssignmentExpr(self.expr(node.target), self.expr(node.value))
 
     def visit_unary_expr(self, node: UnaryExpr) -> UnaryExpr:
         new = UnaryExpr(node.op, self.expr(node.expr))
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 0dc1717d07249..f22fa30706c4c 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -201,6 +201,7 @@ def __init__(
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
         prohibit_self_type: str | None = None,
+        allow_type_any: bool = False,
     ) -> None:
         self.api = api
         self.lookup_qualified = api.lookup_qualified
@@ -237,6 +238,8 @@ def __init__(
         # Names of type aliases encountered while analysing a type will be collected here.
         self.aliases_used: set[str] = set()
         self.prohibit_self_type = prohibit_self_type
+        # Allow variables typed as Type[Any] and type (useful for base classes).
+        self.allow_type_any = allow_type_any
 
     def visit_unbound_type(self, t: UnboundType, defining_literal: bool = False) -> Type:
         typ = self.visit_unbound_type_nonoptional(t, defining_literal)
@@ -730,6 +733,11 @@ def analyze_unbound_type_without_type_info(
                 return AnyType(
                     TypeOfAny.from_unimported_type, missing_import_name=typ.missing_import_name
                 )
+            elif self.allow_type_any:
+                if isinstance(typ, Instance) and typ.type.fullname == "builtins.type":
+                    return AnyType(TypeOfAny.special_form)
+                if isinstance(typ, TypeType) and isinstance(typ.item, AnyType):
+                    return AnyType(TypeOfAny.from_another_any, source_any=typ.item)
         # Option 2:
         # Unbound type variable. Currently these may be still valid,
         # for example when defining a generic type alias.
diff --git a/mypy/types.py b/mypy/types.py
index 6c08b24afd80a..78142d9003d9c 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -7,6 +7,7 @@
 from typing import (
     TYPE_CHECKING,
     Any,
+    Callable,
     ClassVar,
     Dict,
     Iterable,
@@ -29,6 +30,7 @@
     ArgKind,
     FakeInfo,
     FuncDef,
+    FuncItem,
     SymbolNode,
 )
 from mypy.state import state
@@ -3402,3 +3404,29 @@ def callable_with_ellipsis(any_type: AnyType, ret_type: Type, fallback: Instance
         fallback=fallback,
         is_ellipsis_args=True,
     )
+
+
+def store_argument_type(
+    defn: FuncItem, i: int, typ: CallableType, named_type: Callable[[str, list[Type]], Instance]
+) -> None:
+    arg_type = typ.arg_types[i]
+    if typ.arg_kinds[i] == ARG_STAR:
+        if isinstance(arg_type, ParamSpecType):
+            pass
+        elif isinstance(arg_type, UnpackType):
+            if isinstance(get_proper_type(arg_type.type), TupleType):
+                # Instead of using Tuple[Unpack[Tuple[...]]], just use
+                # Tuple[...]
+                arg_type = arg_type.type
+            else:
+                arg_type = TupleType(
+                    [arg_type],
+                    fallback=named_type("builtins.tuple", [named_type("builtins.object", [])]),
+                )
+        else:
+            # builtins.tuple[T] is typing.Tuple[T, ...]
+            arg_type = named_type("builtins.tuple", [arg_type])
+    elif typ.arg_kinds[i] == ARG_STAR2:
+        if not isinstance(arg_type, ParamSpecType) and not typ.unpack_kwargs:
+            arg_type = named_type("builtins.dict", [named_type("builtins.str", []), arg_type])
+    defn.arguments[i].variable.type = arg_type
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index 33208c081c28c..e3aea122ebe1b 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -7664,3 +7664,18 @@ class C(B):
     def foo(self) -> int:  # E: Signature of "foo" incompatible with supertype "B"
         ...
 [builtins fixtures/property.pyi]
+
+[case testAllowArgumentAsBaseClass]
+from typing import Any, Type
+
+def e(b) -> None:
+    class D(b): ...
+
+def f(b: Any) -> None:
+    class D(b): ...
+
+def g(b: Type[Any]) -> None:
+    class D(b): ...
+
+def h(b: type) -> None:
+    class D(b): ...
diff --git a/test-data/unit/check-python38.test b/test-data/unit/check-python38.test
index 1922192c2877a..30bdadf900c3a 100644
--- a/test-data/unit/check-python38.test
+++ b/test-data/unit/check-python38.test
@@ -718,3 +718,19 @@ def f1() -> None:
         y = x
     z = x
 [builtins fixtures/dict.pyi]
+
+[case testNarrowOnSelfInGeneric]
+# flags: --strict-optional
+from typing import Generic, TypeVar, Optional
+
+T = TypeVar("T", int, str)
+
+class C(Generic[T]):
+    x: Optional[T]
+    def meth(self) -> Optional[T]:
+        if (y := self.x) is not None:
+            reveal_type(y)
+        return None
+[out]
+main:10: note: Revealed type is "builtins.int"
+main:10: note: Revealed type is "builtins.str"
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index 494ae54400fbb..b002746a33972 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -1772,3 +1772,16 @@ class D(C): ...
 
 reveal_type(D.f)  # N: Revealed type is "def [T] (T`-1) -> T`-1"
 reveal_type(D().f)  # N: Revealed type is "def () -> __main__.D"
+
+[case testTypingSelfOnSuperTypeVarValues]
+from typing import Self, Generic, TypeVar
+
+T = TypeVar("T", int, str)
+
+class B:
+    def copy(self) -> Self: ...
+class C(B, Generic[T]):
+    def copy(self) -> Self:
+        inst = super().copy()
+        reveal_type(inst)  # N: Revealed type is "Self`0"
+        return inst
diff --git a/test-data/unit/semanal-types.test b/test-data/unit/semanal-types.test
index d832772f5f81e..8dc767e1abfcf 100644
--- a/test-data/unit/semanal-types.test
+++ b/test-data/unit/semanal-types.test
@@ -790,6 +790,7 @@ def f(x: int) -> None: pass
 def f(*args) -> None: pass
 
 x = f
+[builtins fixtures/tuple.pyi]
 [out]
 MypyFile:1(
   ImportFrom:1(typing, [overload])
@@ -1032,6 +1033,7 @@ MypyFile:1(
 
 [case testVarArgsAndKeywordArgs]
 def g(*x: int, y: str = ''): pass
+[builtins fixtures/tuple.pyi]
 [out]
 MypyFile:1(
   FuncDef:1(

From b83ac9cff3d38f868e45e4c4b011cbd2fdd37fc3 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Tue, 22 Nov 2022 16:28:55 +0000
Subject: [PATCH 069/231] Try empty context when assigning to union typed
 variables (#14151)

Fixes #4805
Fixes #13936

It is known that mypy can overuse outer type context sometimes
(especially when it is a union). This prevents a common use case for
narrowing types (see issue and test cases). This is a somewhat major
semantic change, but I think it should match better what a user would
expect.
---
 mypy/checker.py                             | 44 ++++++++++++++++
 test-data/unit/check-inference-context.test | 57 +++++++++++++++++++++
 test-data/unit/check-typeddict.test         |  2 +-
 3 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 7a66a9408ee42..b0fde94025b68 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -76,6 +76,7 @@
     AssignmentStmt,
     Block,
     BreakStmt,
+    BytesExpr,
     CallExpr,
     ClassDef,
     ComparisonExpr,
@@ -86,6 +87,7 @@
     EllipsisExpr,
     Expression,
     ExpressionStmt,
+    FloatExpr,
     ForStmt,
     FuncBase,
     FuncDef,
@@ -115,6 +117,7 @@
     ReturnStmt,
     StarExpr,
     Statement,
+    StrExpr,
     SymbolNode,
     SymbolTable,
     SymbolTableNode,
@@ -3826,6 +3829,23 @@ def inference_error_fallback_type(self, type: Type) -> Type:
         # we therefore need to erase them.
         return erase_typevars(fallback)
 
+    def simple_rvalue(self, rvalue: Expression) -> bool:
+        """Returns True for expressions for which inferred type should not depend on context.
+
+        Note that this function can still return False for some expressions where inferred type
+        does not depend on context. It only exists for performance optimizations.
+        """
+        if isinstance(rvalue, (IntExpr, StrExpr, BytesExpr, FloatExpr, RefExpr)):
+            return True
+        if isinstance(rvalue, CallExpr):
+            if isinstance(rvalue.callee, RefExpr) and isinstance(rvalue.callee.node, FuncBase):
+                typ = rvalue.callee.node.type
+                if isinstance(typ, CallableType):
+                    return not typ.variables
+                elif isinstance(typ, Overloaded):
+                    return not any(item.variables for item in typ.items)
+        return False
+
     def check_simple_assignment(
         self,
         lvalue_type: Type | None,
@@ -3847,6 +3867,30 @@ def check_simple_assignment(
             rvalue_type = self.expr_checker.accept(
                 rvalue, lvalue_type, always_allow_any=always_allow_any
             )
+            if (
+                isinstance(get_proper_type(lvalue_type), UnionType)
+                # Skip literal types, as they have special logic (for better errors).
+                and not isinstance(get_proper_type(rvalue_type), LiteralType)
+                and not self.simple_rvalue(rvalue)
+            ):
+                # Try re-inferring r.h.s. in empty context, and use that if it
+                # results in a narrower type. We don't do this always because this
+                # may cause some perf impact, plus we want to partially preserve
+                # the old behavior. This helps with various practical examples, see
+                # e.g. testOptionalTypeNarrowedByGenericCall.
+                with self.msg.filter_errors() as local_errors, self.local_type_map() as type_map:
+                    alt_rvalue_type = self.expr_checker.accept(
+                        rvalue, None, always_allow_any=always_allow_any
+                    )
+                if (
+                    not local_errors.has_new_errors()
+                    # Skip Any type, since it is special cased in binder.
+                    and not isinstance(get_proper_type(alt_rvalue_type), AnyType)
+                    and is_valid_inferred_type(alt_rvalue_type)
+                    and is_proper_subtype(alt_rvalue_type, rvalue_type)
+                ):
+                    rvalue_type = alt_rvalue_type
+                    self.store_types(type_map)
             if isinstance(rvalue_type, DeletedType):
                 self.msg.deleted_as_rvalue(rvalue_type, context)
             if isinstance(lvalue_type, DeletedType):
diff --git a/test-data/unit/check-inference-context.test b/test-data/unit/check-inference-context.test
index 2e26f54c6e93b..f80f93eb26159 100644
--- a/test-data/unit/check-inference-context.test
+++ b/test-data/unit/check-inference-context.test
@@ -1419,3 +1419,60 @@ def bar(x: Union[Mapping[Any, Any], Dict[Any, Sequence[Any]]]) -> None:
     ...
 bar({1: 2})
 [builtins fixtures/dict.pyi]
+
+[case testOptionalTypeNarrowedByGenericCall]
+# flags: --strict-optional
+from typing import Dict, Optional
+
+d: Dict[str, str] = {}
+
+def foo(arg: Optional[str] = None) -> None:
+    if arg is None:
+        arg = d.get("a", "b")
+    reveal_type(arg)  # N: Revealed type is "builtins.str"
+[builtins fixtures/dict.pyi]
+
+[case testOptionalTypeNarrowedByGenericCall2]
+# flags: --strict-optional
+from typing import Dict, Optional
+
+d: Dict[str, str] = {}
+x: Optional[str]
+if x:
+    reveal_type(x)  # N: Revealed type is "builtins.str"
+    x = d.get(x, x)
+    reveal_type(x)  # N: Revealed type is "builtins.str"
+[builtins fixtures/dict.pyi]
+
+[case testOptionalTypeNarrowedByGenericCall3]
+# flags: --strict-optional
+from typing import Generic, TypeVar, Union
+
+T = TypeVar("T")
+def bar(arg: Union[str, T]) -> Union[str, T]: ...
+
+def foo(arg: Union[str, int]) -> None:
+    if isinstance(arg, int):
+        arg = bar("default")
+    reveal_type(arg)  # N: Revealed type is "builtins.str"
+[builtins fixtures/isinstance.pyi]
+
+[case testOptionalTypeNarrowedByGenericCall4]
+# flags: --strict-optional
+from typing import Optional, List, Generic, TypeVar
+
+T = TypeVar("T", covariant=True)
+class C(Generic[T]): ...
+
+x: Optional[C[int]] = None
+y = x = C()
+reveal_type(y)  # N: Revealed type is "__main__.C[builtins.int]"
+
+[case testOptionalTypeNarrowedByGenericCall5]
+from typing import Any, Tuple, Union
+
+i: Union[Tuple[Any, ...], int]
+b: Any
+i = i if isinstance(i, int) else b
+reveal_type(i)  # N: Revealed type is "Union[Any, builtins.int]"
+[builtins fixtures/isinstance.pyi]
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index 24521062a5d45..fbef6157087c0 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -893,7 +893,7 @@ B = TypedDict('B', {'@type': Literal['b-type'], 'b': int})
 
 c: Union[A, B] = {'@type': 'a-type', 'a': 'Test'}
 reveal_type(c) # N: Revealed type is "Union[TypedDict('__main__.A', {'@type': Literal['a-type'], 'a': builtins.str}), TypedDict('__main__.B', {'@type': Literal['b-type'], 'b': builtins.int})]"
-[builtins fixtures/tuple.pyi]
+[builtins fixtures/dict.pyi]
 
 [case testTypedDictUnionAmbiguousCase]
 from typing import Union, Mapping, Any, cast

From 8fb482ff72f94b1f16e6c63746d4cb9cd111c76c Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <stas@dropbox.com>
Date: Tue, 22 Nov 2022 12:55:55 -0600
Subject: [PATCH 070/231] [partially defined] handle unreachable blocks
 (#14161)

This adds support for unreachable blocks in `partially-defined` check.

Currently, this only supports blocks that are detected as unreachable
during semantic analysis (so mostly stuff like python version, etc.).
This doesn't support more advanced cases (see #13926 for an example
what's not covered).

Closes #13929
---
 mypy/partially_defined.py                   |  9 +++++++-
 test-data/unit/check-partially-defined.test | 19 ++++++++++++++++
 test-data/unit/check-python310.test         | 24 +++++++++++++++++++++
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 7d87315c23ad3..5854036c0df3f 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -203,9 +203,13 @@ def visit_if_stmt(self, o: IfStmt) -> None:
             e.accept(self)
         self.tracker.start_branch_statement()
         for b in o.body:
+            if b.is_unreachable:
+                continue
             b.accept(self)
             self.tracker.next_branch()
         if o.else_body:
+            if o.else_body.is_unreachable:
+                self.tracker.skip_branch()
             o.else_body.accept(self)
         self.tracker.end_branch_statement()
 
@@ -218,7 +222,10 @@ def visit_match_stmt(self, o: MatchStmt) -> None:
             guard = o.guards[i]
             if guard is not None:
                 guard.accept(self)
-            o.bodies[i].accept(self)
+            if not o.bodies[i].is_unreachable:
+                o.bodies[i].accept(self)
+            else:
+                self.tracker.skip_branch()
             is_catchall = infer_pattern_value(pattern) == ALWAYS_TRUE
             if not is_catchall:
                 self.tracker.next_branch()
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index d456568c1131d..f6934fb142d18 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -367,3 +367,22 @@ def f() -> None:
     d = a
     d = b
 [builtins fixtures/tuple.pyi]
+
+[case testUnreachable]
+# flags: --enable-error-code partially-defined
+import typing
+
+if typing.TYPE_CHECKING:
+    x = 1
+elif int():
+    y = 1
+else:
+    y = 2
+a = x
+
+if not typing.TYPE_CHECKING:
+    pass
+else:
+    z = 1
+a = z
+[typing fixtures/typing-medium.pyi]
diff --git a/test-data/unit/check-python310.test b/test-data/unit/check-python310.test
index 3b90a910e943a..1967e7f4810b1 100644
--- a/test-data/unit/check-python310.test
+++ b/test-data/unit/check-python310.test
@@ -1789,6 +1789,30 @@ def f6(a: object) -> None:
             pass
 [builtins fixtures/tuple.pyi]
 
+[case testPartiallyDefinedMatchUnreachable]
+# flags: --enable-error-code partially-defined
+import typing
+
+def f0(x: int) -> int:
+    match x:
+        case 1 if not typing.TYPE_CHECKING:
+            pass
+        case 2:
+            y = 2
+        case _:
+            y = 3
+    return y # No error.
+
+def f1(x: int) -> int:
+    match x:
+        case 1 if not typing.TYPE_CHECKING:
+            pass
+        case 2:
+            y = 2
+    return y  # E: Name "y" may be undefined
+
+[typing fixtures/typing-medium.pyi]
+
 [case testTypeAliasWithNewUnionSyntaxAndNoneLeftOperand]
 from typing import overload
 class C:

From f656efc07c3d1e167d2d6873ffbfe254aa7225ff Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <stas@dropbox.com>
Date: Tue, 22 Nov 2022 15:57:02 -0600
Subject: [PATCH 071/231] Detect variables that are used before they're defined
 (#14163)

This implements a check when a variable is defined before use. Something
like:
```python
def foo() -> None:
    x = y
    y: int = 1
```

I've combined this check with the partially defined check but added a
separate error code. It's probably worth cleaning it up and making the
separation between the two checks a bit more clear. I can do this in a
follow-up PR.

Fixes #14124
---
 mypy/build.py                               |   4 +-
 mypy/errorcodes.py                          |   6 +
 mypy/messages.py                            |   3 +
 mypy/partially_defined.py                   | 129 +++++++++++++++-----
 test-data/unit/check-partially-defined.test |  46 +++++++
 5 files changed, 158 insertions(+), 30 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index 62367c35915e7..ba54c81845e04 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2341,7 +2341,9 @@ def type_check_second_pass(self) -> bool:
     def detect_partially_defined_vars(self, type_map: dict[Expression, Type]) -> None:
         assert self.tree is not None, "Internal error: method must be called on parsed file only"
         manager = self.manager
-        if manager.errors.is_error_code_enabled(codes.PARTIALLY_DEFINED):
+        if manager.errors.is_error_code_enabled(
+            codes.PARTIALLY_DEFINED
+        ) or manager.errors.is_error_code_enabled(codes.USE_BEFORE_DEF):
             manager.errors.set_file(self.xpath, self.tree.fullname, options=manager.options)
             self.tree.accept(
                 PartiallyDefinedVariableVisitor(
diff --git a/mypy/errorcodes.py b/mypy/errorcodes.py
index e1efc10b7a8bf..1c15407a955bc 100644
--- a/mypy/errorcodes.py
+++ b/mypy/errorcodes.py
@@ -192,6 +192,12 @@ def __str__(self) -> str:
     "General",
     default_enabled=False,
 )
+USE_BEFORE_DEF: Final[ErrorCode] = ErrorCode(
+    "use-before-def",
+    "Warn about variables that are used before they are defined",
+    "General",
+    default_enabled=False,
+)
 
 
 # Syntax errors are often blocking.
diff --git a/mypy/messages.py b/mypy/messages.py
index 2f487972d647e..85fa305125343 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -1231,6 +1231,9 @@ def undefined_in_superclass(self, member: str, context: Context) -> None:
     def variable_may_be_undefined(self, name: str, context: Context) -> None:
         self.fail(f'Name "{name}" may be undefined', context, code=codes.PARTIALLY_DEFINED)
 
+    def var_used_before_def(self, name: str, context: Context) -> None:
+        self.fail(f'Name "{name}" is used before definition', context, code=codes.USE_BEFORE_DEF)
+
     def first_argument_for_super_must_be_type(self, actual: Type, context: Context) -> None:
         actual = get_proper_type(actual)
         if isinstance(actual, Instance):
diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 5854036c0df3f..70a454beae9c3 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from mypy import checker
+from mypy import checker, errorcodes
 from mypy.messages import MessageBuilder
 from mypy.nodes import (
     AssertStmt,
@@ -93,10 +93,24 @@ def skip_branch(self) -> None:
         assert len(self.branches) > 0
         self.branches[-1].skipped = True
 
-    def is_possibly_undefined(self, name: str) -> bool:
+    def is_partially_defined(self, name: str) -> bool:
         assert len(self.branches) > 0
         return name in self.branches[-1].may_be_defined
 
+    def is_undefined(self, name: str) -> bool:
+        assert len(self.branches) > 0
+        branch = self.branches[-1]
+        return name not in branch.may_be_defined and name not in branch.must_be_defined
+
+    def is_defined_in_different_branch(self, name: str) -> bool:
+        assert len(self.branches) > 0
+        if not self.is_undefined(name):
+            return False
+        for b in self.branches[: len(self.branches) - 1]:
+            if name in b.must_be_defined or name in b.may_be_defined:
+                return True
+        return False
+
     def done(self) -> BranchState:
         branches = [b for b in self.branches if not b.skipped]
         if len(branches) == 0:
@@ -117,62 +131,102 @@ def done(self) -> BranchState:
         return BranchState(may_be_defined=may_be_defined, must_be_defined=must_be_defined)
 
 
+class Scope:
+    def __init__(self, stmts: list[BranchStatement]) -> None:
+        self.branch_stmts: list[BranchStatement] = stmts
+        self.undefined_refs: dict[str, set[NameExpr]] = {}
+
+    def record_undefined_ref(self, o: NameExpr) -> None:
+        if o.name not in self.undefined_refs:
+            self.undefined_refs[o.name] = set()
+        self.undefined_refs[o.name].add(o)
+
+    def pop_undefined_ref(self, name: str) -> set[NameExpr]:
+        return self.undefined_refs.pop(name, set())
+
+
 class DefinedVariableTracker:
     """DefinedVariableTracker manages the state and scope for the UndefinedVariablesVisitor."""
 
     def __init__(self) -> None:
         # There's always at least one scope. Within each scope, there's at least one "global" BranchingStatement.
-        self.scopes: list[list[BranchStatement]] = [[BranchStatement(BranchState())]]
+        self.scopes: list[Scope] = [Scope([BranchStatement(BranchState())])]
 
-    def _scope(self) -> list[BranchStatement]:
+    def _scope(self) -> Scope:
         assert len(self.scopes) > 0
         return self.scopes[-1]
 
     def enter_scope(self) -> None:
-        assert len(self._scope()) > 0
-        self.scopes.append([BranchStatement(self._scope()[-1].branches[-1])])
+        assert len(self._scope().branch_stmts) > 0
+        self.scopes.append(Scope([BranchStatement(self._scope().branch_stmts[-1].branches[-1])]))
 
     def exit_scope(self) -> None:
         self.scopes.pop()
 
     def start_branch_statement(self) -> None:
-        assert len(self._scope()) > 0
-        self._scope().append(BranchStatement(self._scope()[-1].branches[-1]))
+        assert len(self._scope().branch_stmts) > 0
+        self._scope().branch_stmts.append(
+            BranchStatement(self._scope().branch_stmts[-1].branches[-1])
+        )
 
     def next_branch(self) -> None:
-        assert len(self._scope()) > 1
-        self._scope()[-1].next_branch()
+        assert len(self._scope().branch_stmts) > 1
+        self._scope().branch_stmts[-1].next_branch()
 
     def end_branch_statement(self) -> None:
-        assert len(self._scope()) > 1
-        result = self._scope().pop().done()
-        self._scope()[-1].record_nested_branch(result)
+        assert len(self._scope().branch_stmts) > 1
+        result = self._scope().branch_stmts.pop().done()
+        self._scope().branch_stmts[-1].record_nested_branch(result)
 
     def skip_branch(self) -> None:
         # Only skip branch if we're outside of "root" branch statement.
-        if len(self._scope()) > 1:
-            self._scope()[-1].skip_branch()
+        if len(self._scope().branch_stmts) > 1:
+            self._scope().branch_stmts[-1].skip_branch()
 
-    def record_declaration(self, name: str) -> None:
+    def record_definition(self, name: str) -> None:
+        assert len(self.scopes) > 0
+        assert len(self.scopes[-1].branch_stmts) > 0
+        self._scope().branch_stmts[-1].record_definition(name)
+
+    def record_undefined_ref(self, o: NameExpr) -> None:
+        """Records an undefined reference. These can later be retrieved via `pop_undefined_ref`."""
+        assert len(self.scopes) > 0
+        self._scope().record_undefined_ref(o)
+
+    def pop_undefined_ref(self, name: str) -> set[NameExpr]:
+        """If name has previously been reported as undefined, the NameExpr that was called will be returned."""
         assert len(self.scopes) > 0
-        assert len(self.scopes[-1]) > 0
-        self._scope()[-1].record_definition(name)
+        return self._scope().pop_undefined_ref(name)
 
-    def is_possibly_undefined(self, name: str) -> bool:
-        assert len(self._scope()) > 0
+    def is_partially_defined(self, name: str) -> bool:
+        assert len(self._scope().branch_stmts) > 0
         # A variable is undefined if it's in a set of `may_be_defined` but not in `must_be_defined`.
-        # Cases where a variable is not defined altogether are handled by semantic analyzer.
-        return self._scope()[-1].is_possibly_undefined(name)
+        return self._scope().branch_stmts[-1].is_partially_defined(name)
+
+    def is_defined_in_different_branch(self, name: str) -> bool:
+        """This will return true if a variable is defined in a branch that's not the current branch."""
+        assert len(self._scope().branch_stmts) > 0
+        return self._scope().branch_stmts[-1].is_defined_in_different_branch(name)
+
+    def is_undefined(self, name: str) -> bool:
+        assert len(self._scope().branch_stmts) > 0
+        return self._scope().branch_stmts[-1].is_undefined(name)
 
 
 class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
-    """Detect variables that are defined only part of the time.
+    """Detects the following cases:
+    - A variable that's defined only part of the time.
+    - If a variable is used before definition
 
-    This visitor detects the following case:
+    An example of a partial definition:
     if foo():
         x = 1
     print(x)  # Error: "x" may be undefined.
 
+    Example of a use before definition:
+    x = y
+    y: int = 2
+
     Note that this code does not detect variables not defined in any of the branches -- that is
     handled by the semantic analyzer.
     """
@@ -184,7 +238,11 @@ def __init__(self, msg: MessageBuilder, type_map: dict[Expression, Type]) -> Non
 
     def process_lvalue(self, lvalue: Lvalue | None) -> None:
         if isinstance(lvalue, NameExpr):
-            self.tracker.record_declaration(lvalue.name)
+            # Was this name previously used? If yes, it's a use-before-definition error.
+            refs = self.tracker.pop_undefined_ref(lvalue.name)
+            for ref in refs:
+                self.msg.var_used_before_def(lvalue.name, ref)
+            self.tracker.record_definition(lvalue.name)
         elif isinstance(lvalue, (ListExpr, TupleExpr)):
             for item in lvalue.items:
                 self.process_lvalue(item)
@@ -239,7 +297,7 @@ def visit_func_def(self, o: FuncDef) -> None:
     def visit_func(self, o: FuncItem) -> None:
         if o.arguments is not None:
             for arg in o.arguments:
-                self.tracker.record_declaration(arg.variable.name)
+                self.tracker.record_definition(arg.variable.name)
         super().visit_func(o)
 
     def visit_generator_expr(self, o: GeneratorExpr) -> None:
@@ -314,10 +372,23 @@ def visit_starred_pattern(self, o: StarredPattern) -> None:
         super().visit_starred_pattern(o)
 
     def visit_name_expr(self, o: NameExpr) -> None:
-        if self.tracker.is_possibly_undefined(o.name):
-            self.msg.variable_may_be_undefined(o.name, o)
+        if self.tracker.is_partially_defined(o.name):
+            # A variable is only defined in some branches.
+            if self.msg.errors.is_error_code_enabled(errorcodes.PARTIALLY_DEFINED):
+                self.msg.variable_may_be_undefined(o.name, o)
             # We don't want to report the error on the same variable multiple times.
-            self.tracker.record_declaration(o.name)
+            self.tracker.record_definition(o.name)
+        elif self.tracker.is_defined_in_different_branch(o.name):
+            # A variable is defined in one branch but used in a different branch.
+            self.msg.var_used_before_def(o.name, o)
+        elif self.tracker.is_undefined(o.name):
+            # A variable is undefined. It could be due to two things:
+            # 1. A variable is just totally undefined
+            # 2. The variable is defined later in the code.
+            # Case (1) will be caught by semantic analyzer. Case (2) is a forward ref that should
+            # be caught by this visitor. Save the ref for later, so that if we see a definition,
+            # we know it's a use-before-definition scenario.
+            self.tracker.record_undefined_ref(o)
         super().visit_name_expr(o)
 
     def visit_with_stmt(self, o: WithStmt) -> None:
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index f6934fb142d18..c63023aa2746b 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -386,3 +386,49 @@ else:
     z = 1
 a = z
 [typing fixtures/typing-medium.pyi]
+
+[case testUseBeforeDef]
+# flags: --enable-error-code use-before-def
+
+def f0() -> None:
+    x = y  # E: Name "y" is used before definition
+    y: int = 1
+
+def f1() -> None:
+    if int():
+        x = 0
+    else:
+        y = x  # E: Name "x" is used before definition
+        z = x  # E: Name "x" is used before definition
+
+def f2() -> None:
+    x = 1
+    if int():
+        x = 0
+    else:
+        y = x  # No error.
+
+def f3() -> None:
+    if int():
+        pass
+    else:
+        # No use-before-def error.
+        y = z  # E: Name "z" is not defined
+
+    def inner2() -> None:
+        z = 0
+
+def f4() -> None:
+    if int():
+        pass
+    else:
+        y = z  # E: Name "z" is used before definition
+    z: int = 2
+
+def f5() -> None:
+    if int():
+        pass
+    else:
+        y = z  # E: Name "z" is used before definition
+        x = z  # E: Name "z" is used before definition
+    z: int = 2

From acbc40c50e0236a52bdd35583688fc391db1a410 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 23 Nov 2022 10:48:16 +0000
Subject: [PATCH 072/231] Don't install lxml on Windows on Python 3.11 (#14170)

Windows wheels for Python 3.11 are not included in the release, and
`cibuildwheels` cannot build them, this causes mypy wheel build failure
on Windows for Python 3.11, see e.g.
https://github.com/mypyc/mypy_mypyc-wheels/actions/runs/3527396237/jobs/5916408981

We need to do this until https://github.com/lxml/lxml/pull/360 is
released (hopefully in next few weeks).

cc @hauntsaninja @JukkaL
---
 test-requirements.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-requirements.txt b/test-requirements.txt
index 399785ce4c1c9..6f0c1b065ad45 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -7,7 +7,7 @@ flake8==5.0.4           # must match version in .pre-commit-config.yaml
 flake8-bugbear==22.9.23 # must match version in .pre-commit-config.yaml
 flake8-noqa==1.2.9      # must match version in .pre-commit-config.yaml
 isort[colors]==5.10.1   # must match version in .pre-commit-config.yaml
-lxml>=4.9.1
+lxml>=4.9.1; python_version<'3.11' or sys_platform!='win32'
 psutil>=4.0
 # pytest 6.2.3 does not support Python 3.10
 pytest>=6.2.4

From 07139ef8121fda39906e7a804ef599e61413c0c7 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 23 Nov 2022 14:29:52 +0000
Subject: [PATCH 073/231] Simplify callable overlap logic (#14174)

This gives around 1% speed-up on self check, and may give even more for
code that is heavy on overloads.
---
 mypy/meet.py     | 19 +++++++------------
 mypy/subtypes.py |  2 +-
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/mypy/meet.py b/mypy/meet.py
index f5cd4c1208da8..5c187eeb37d46 100644
--- a/mypy/meet.py
+++ b/mypy/meet.py
@@ -438,18 +438,13 @@ def _type_object_overlap(left: Type, right: Type) -> bool:
         return _type_object_overlap(left, right) or _type_object_overlap(right, left)
 
     if isinstance(left, CallableType) and isinstance(right, CallableType):
-
-        def _callable_overlap(left: CallableType, right: CallableType) -> bool:
-            return is_callable_compatible(
-                left,
-                right,
-                is_compat=_is_overlapping_types,
-                ignore_pos_arg_names=True,
-                allow_partial_overlap=True,
-            )
-
-        # Compare both directions to handle type objects.
-        return _callable_overlap(left, right) or _callable_overlap(right, left)
+        return is_callable_compatible(
+            left,
+            right,
+            is_compat=_is_overlapping_types,
+            ignore_pos_arg_names=True,
+            allow_partial_overlap=True,
+        )
     elif isinstance(left, CallableType):
         left = left.fallback
     elif isinstance(right, CallableType):
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 14109587191c6..a4b045cfa00cf 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -1361,7 +1361,7 @@ def g(x: int) -> int: ...
         ignore_pos_arg_names = True
 
     # Non-type cannot be a subtype of type.
-    if right.is_type_obj() and not left.is_type_obj():
+    if right.is_type_obj() and not left.is_type_obj() and not allow_partial_overlap:
         return False
 
     # A callable L is a subtype of a generic callable R if L is a

From 04d44c12cfbb3a469a96253d4656d16c21be41b9 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Wed, 23 Nov 2022 14:31:29 +0000
Subject: [PATCH 074/231] Add intenal flag for per-line type checking
 peformance (#14173)

This should help with the investigation of tricky performance
regressions like https://github.com/python/mypy/issues/13821.

I tried to implement in such a way that it will give minimal impact when
not used (since I am touching a hot method).
---
 mypy/build.py     | 30 ++++++++++++++++++++++++------
 mypy/checker.py   |  5 ++++-
 mypy/checkexpr.py | 29 ++++++++++++++++++++++++++---
 mypy/main.py      |  8 +++++++-
 mypy/options.py   |  1 +
 mypy/util.py      |  8 +++-----
 6 files changed, 65 insertions(+), 16 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index ba54c81845e04..b32276dd30208 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -12,6 +12,7 @@
 
 from __future__ import annotations
 
+import collections
 import contextlib
 import errno
 import gc
@@ -278,6 +279,8 @@ def _build(
             TypeState.reset_all_subtype_caches()
         if options.timing_stats is not None:
             dump_timing_stats(options.timing_stats, graph)
+        if options.line_checking_stats is not None:
+            dump_line_checking_stats(options.line_checking_stats, graph)
         return BuildResult(manager, graph)
     finally:
         t0 = time.time()
@@ -1889,6 +1892,10 @@ class State:
     # Cumulative time spent on this file, in microseconds (for profiling stats)
     time_spent_us: int = 0
 
+    # Per-line type-checking time (cumulative time spent type-checking expressions
+    # on a given source code line).
+    per_line_checking_time_ns: dict[int, int]
+
     def __init__(
         self,
         id: str | None,
@@ -1956,6 +1963,7 @@ def __init__(
             source = ""
         self.source = source
         self.add_ancestors()
+        self.per_line_checking_time_ns = collections.defaultdict(int)
         t0 = time.time()
         self.meta = validate_meta(self.meta, self.id, self.path, self.ignore_all, manager)
         self.manager.add_stats(validate_meta_time=time.time() - t0)
@@ -2320,6 +2328,7 @@ def type_checker(self) -> TypeChecker:
                 self.tree,
                 self.xpath,
                 manager.plugin,
+                self.per_line_checking_time_ns,
             )
         return self._type_checker
 
@@ -2945,13 +2954,22 @@ def dumps(self) -> str:
 
 
 def dump_timing_stats(path: str, graph: Graph) -> None:
-    """
-    Dump timing stats for each file in the given graph
-    """
+    """Dump timing stats for each file in the given graph."""
     with open(path, "w") as f:
-        for k in sorted(graph.keys()):
-            v = graph[k]
-            f.write(f"{v.id} {v.time_spent_us}\n")
+        for id in sorted(graph):
+            f.write(f"{id} {graph[id].time_spent_us}\n")
+
+
+def dump_line_checking_stats(path: str, graph: Graph) -> None:
+    """Dump per-line expression type checking stats."""
+    with open(path, "w") as f:
+        for id in sorted(graph):
+            if not graph[id].per_line_checking_time_ns:
+                continue
+            f.write(f"{id}:\n")
+            for line in sorted(graph[id].per_line_checking_time_ns):
+                line_time = graph[id].per_line_checking_time_ns[line]
+                f.write(f"{line:>5} {line_time/1000:8.1f}\n")
 
 
 def dump_graph(graph: Graph, stdout: TextIO | None = None) -> None:
diff --git a/mypy/checker.py b/mypy/checker.py
index b0fde94025b68..431fde299dc0f 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -364,6 +364,7 @@ def __init__(
         tree: MypyFile,
         path: str,
         plugin: Plugin,
+        per_line_checking_time_ns: dict[int, int],
     ) -> None:
         """Construct a type checker.
 
@@ -376,7 +377,9 @@ def __init__(
         self.path = path
         self.msg = MessageBuilder(errors, modules)
         self.plugin = plugin
-        self.expr_checker = mypy.checkexpr.ExpressionChecker(self, self.msg, self.plugin)
+        self.expr_checker = mypy.checkexpr.ExpressionChecker(
+            self, self.msg, self.plugin, per_line_checking_time_ns
+        )
         self.pattern_checker = PatternChecker(self, self.msg, self.plugin)
         self.tscope = Scope()
         self.scope = CheckerScope(tree)
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index b41a38825fb39..78ae412072f52 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import itertools
+import time
 from contextlib import contextmanager
 from typing import Callable, ClassVar, Iterator, List, Optional, Sequence, cast
 from typing_extensions import Final, TypeAlias as _TypeAlias, overload
@@ -263,11 +264,22 @@ class ExpressionChecker(ExpressionVisitor[Type]):
     strfrm_checker: StringFormatterChecker
     plugin: Plugin
 
-    def __init__(self, chk: mypy.checker.TypeChecker, msg: MessageBuilder, plugin: Plugin) -> None:
+    def __init__(
+        self,
+        chk: mypy.checker.TypeChecker,
+        msg: MessageBuilder,
+        plugin: Plugin,
+        per_line_checking_time_ns: dict[int, int],
+    ) -> None:
         """Construct an expression type checker."""
         self.chk = chk
         self.msg = msg
         self.plugin = plugin
+        self.per_line_checking_time_ns = per_line_checking_time_ns
+        self.collect_line_checking_stats = self.chk.options.line_checking_stats is not None
+        # Are we already visiting some expression? This is used to avoid double counting
+        # time for nested expressions.
+        self.in_expression = False
         self.type_context = [None]
 
         # Temporary overrides for expression types. This is currently
@@ -4727,7 +4739,14 @@ def accept(
         applies only to this expression and not any subexpressions.
         """
         if node in self.type_overrides:
+            # This branch is very fast, there is no point timing it.
             return self.type_overrides[node]
+        # We don't use context manager here to get most precise data (and avoid overhead).
+        record_time = False
+        if self.collect_line_checking_stats and not self.in_expression:
+            t0 = time.perf_counter_ns()
+            self.in_expression = True
+            record_time = True
         self.type_context.append(type_context)
         old_is_callee = self.is_callee
         self.is_callee = is_callee
@@ -4762,9 +4781,13 @@ def accept(
             self.msg.disallowed_any_type(typ, node)
 
         if not self.chk.in_checked_function() or self.chk.current_node_deferred:
-            return AnyType(TypeOfAny.unannotated)
+            result: Type = AnyType(TypeOfAny.unannotated)
         else:
-            return typ
+            result = typ
+        if record_time:
+            self.per_line_checking_time_ns[node.line] += time.perf_counter_ns() - t0
+            self.in_expression = False
+        return result
 
     def named_type(self, name: str) -> Instance:
         """Return an instance type with type given by the name and no type
diff --git a/mypy/main.py b/mypy/main.py
index 405596c209919..d0cb6ca4d505c 100644
--- a/mypy/main.py
+++ b/mypy/main.py
@@ -1082,8 +1082,14 @@ def add_invertible_flag(
         "--inferstats", action="store_true", dest="dump_inference_stats", help=argparse.SUPPRESS
     )
     parser.add_argument("--dump-build-stats", action="store_true", help=argparse.SUPPRESS)
-    # dump timing  stats for each processed file into the given output file
+    # Dump timing stats for each processed file into the given output file
     parser.add_argument("--timing-stats", dest="timing_stats", help=argparse.SUPPRESS)
+    # Dump per line type checking timing stats for each processed file into the given
+    # output file. Only total time spent in each top level expression will be shown.
+    # Times are show in microseconds.
+    parser.add_argument(
+        "--line-checking-stats", dest="line_checking_stats", help=argparse.SUPPRESS
+    )
     # --debug-cache will disable any cache-related compressions/optimizations,
     # which will make the cache writing process output pretty-printed JSON (which
     # is easier to debug).
diff --git a/mypy/options.py b/mypy/options.py
index 3a08ff9455ee7..ffb6b201e70be 100644
--- a/mypy/options.py
+++ b/mypy/options.py
@@ -283,6 +283,7 @@ def __init__(self) -> None:
         self.enable_incomplete_features = False  # deprecated
         self.enable_incomplete_feature: list[str] = []
         self.timing_stats: str | None = None
+        self.line_checking_stats: str | None = None
 
         # -- test options --
         # Stop after the semantic analysis phase
diff --git a/mypy/util.py b/mypy/util.py
index 04ed616ade07d..cced4db34fc91 100644
--- a/mypy/util.py
+++ b/mypy/util.py
@@ -807,13 +807,11 @@ def unnamed_function(name: str | None) -> bool:
     return name is not None and name == "_"
 
 
-# TODO: replace with uses of perf_counter_ns when support for py3.6 is dropped
-# (or when mypy properly handles alternate definitions based on python version check
-time_ref = time.perf_counter
+time_ref = time.perf_counter_ns
 
 
-def time_spent_us(t0: float) -> int:
-    return int((time.perf_counter() - t0) * 1e6)
+def time_spent_us(t0: int) -> int:
+    return int((time.perf_counter_ns() - t0) / 1000)
 
 
 def plural_s(s: int | Sized) -> str:

From 13bd201586e837962239dbdca8eda1f9966ebfc2 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Thu, 24 Nov 2022 11:22:10 +0000
Subject: [PATCH 075/231] Support ParamSpec variables in type aliases (#14159)

Fixes #11855
Fixes #7084
Fixes #10445
Should fix #4987

After thinking about this for some time, it looks like the best way to
implement this is by switching type aliases from unbound to bound type
variables. Then I can essentially simply share (or copy in one small
place, to avoid cyclic imports) all the logic that currently exists for
`ParamSpec` and `Concatenate` in `expand_type()` etc.

This will also address a big piece of tech debt, and will get some
benefits (almost) for free, such as checking bounds/values for alias
type variables, and much tighter handling of unbound type variables.

Note that in this PR I change logic for emitting some errors, I try to
avoid showing multiple errors for the same location/reason. But this is
not an essential part of this PR (it is just some test cases would
otherwise fail with even more error messages), I can reconsider if there
are objections.
---
 docs/source/generics.rst                      |   8 +-
 mypy/checker.py                               |   2 +-
 mypy/checkexpr.py                             |   6 +-
 mypy/erasetype.py                             |   4 +-
 mypy/expandtype.py                            |  34 +---
 mypy/fixup.py                                 |   2 +
 mypy/mixedtraverser.py                        |   5 +
 mypy/nodes.py                                 |  31 ++--
 mypy/semanal.py                               |  94 +++++++----
 mypy/semanal_typeargs.py                      |  90 ++++++++---
 mypy/semanal_typeddict.py                     |   4 +-
 mypy/server/astdiff.py                        |   2 +-
 mypy/server/astmerge.py                       |   2 +
 mypy/subtypes.py                              |  22 ++-
 mypy/test/testtypes.py                        |   3 +-
 mypy/test/typefixture.py                      |   5 +-
 mypy/typeanal.py                              | 135 +++++++++-------
 mypy/types.py                                 |  83 ++++++++--
 mypy/typetraverser.py                         |   3 +
 test-data/unit/check-generics.test            |  30 +++-
 test-data/unit/check-isinstance.test          |   5 -
 test-data/unit/check-literal.test             |  25 +--
 .../unit/check-parameter-specification.test   | 152 +++++++++++++++++-
 test-data/unit/check-type-aliases.test        |  35 ++++
 24 files changed, 554 insertions(+), 228 deletions(-)

diff --git a/docs/source/generics.rst b/docs/source/generics.rst
index a5c7b8accaa8f..a867bc863c839 100644
--- a/docs/source/generics.rst
+++ b/docs/source/generics.rst
@@ -916,9 +916,5 @@ defeating the purpose of using aliases.  Example:
 
     OIntVec = Optional[Vec[int]]
 
-.. note::
-
-    A type alias does not define a new type. For generic type aliases
-    this means that variance of type variables used for alias definition does not
-    apply to aliases. A parameterized generic alias is treated simply as an original
-    type with the corresponding type variables substituted.
+Using type variable bounds or values in generic aliases, has the same effect
+as in generic classes/functions.
diff --git a/mypy/checker.py b/mypy/checker.py
index 431fde299dc0f..f9acc9766140f 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -7115,7 +7115,7 @@ def visit_uninhabited_type(self, t: UninhabitedType) -> Type:
         return t
 
     def visit_type_alias_type(self, t: TypeAliasType) -> Type:
-        # Target of the alias cannot by an ambiguous <nothing>, so we just
+        # Target of the alias cannot be an ambiguous <nothing>, so we just
         # replace the arguments.
         return t.copy_modified(args=[a.accept(self) for a in t.args])
 
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 78ae412072f52..362ef1eeb7f8a 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -3854,10 +3854,8 @@ def visit_type_application(self, tapp: TypeApplication) -> Type:
 
         There are two different options here, depending on whether expr refers
         to a type alias or directly to a generic class. In the first case we need
-        to use a dedicated function typeanal.expand_type_aliases. This
-        is due to the fact that currently type aliases machinery uses
-        unbound type variables, while normal generics use bound ones;
-        see TypeAlias docstring for more details.
+        to use a dedicated function typeanal.expand_type_alias(). This
+        is due to some differences in how type arguments are applied and checked.
         """
         if isinstance(tapp.expr, RefExpr) and isinstance(tapp.expr.node, TypeAlias):
             # Subscription of a (generic) alias in runtime context, expand the alias.
diff --git a/mypy/erasetype.py b/mypy/erasetype.py
index 89c07186f44a3..6533d0c4e0f91 100644
--- a/mypy/erasetype.py
+++ b/mypy/erasetype.py
@@ -176,8 +176,8 @@ def visit_param_spec(self, t: ParamSpecType) -> Type:
         return t
 
     def visit_type_alias_type(self, t: TypeAliasType) -> Type:
-        # Type alias target can't contain bound type variables, so
-        # it is safe to just erase the arguments.
+        # Type alias target can't contain bound type variables (not bound by the type
+        # alias itself), so it is safe to just erase the arguments.
         return t.copy_modified(args=[a.accept(self) for a in t.args])
 
 
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 43f4e6bcd75b5..d3286480e3169 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -15,7 +15,6 @@
     NoneType,
     Overloaded,
     Parameters,
-    ParamSpecFlavor,
     ParamSpecType,
     PartialType,
     ProperType,
@@ -34,6 +33,7 @@
     UninhabitedType,
     UnionType,
     UnpackType,
+    expand_param_spec,
     get_proper_type,
 )
 from mypy.typevartuples import (
@@ -212,32 +212,8 @@ def visit_param_spec(self, t: ParamSpecType) -> Type:
             # TODO: what does prefix mean in this case?
             # TODO: why does this case even happen? Instances aren't plural.
             return repl
-        elif isinstance(repl, ParamSpecType):
-            return repl.copy_modified(
-                flavor=t.flavor,
-                prefix=t.prefix.copy_modified(
-                    arg_types=t.prefix.arg_types + repl.prefix.arg_types,
-                    arg_kinds=t.prefix.arg_kinds + repl.prefix.arg_kinds,
-                    arg_names=t.prefix.arg_names + repl.prefix.arg_names,
-                ),
-            )
-        elif isinstance(repl, Parameters) or isinstance(repl, CallableType):
-            # if the paramspec is *P.args or **P.kwargs:
-            if t.flavor != ParamSpecFlavor.BARE:
-                assert isinstance(repl, CallableType), "Should not be able to get here."
-                # Is this always the right thing to do?
-                param_spec = repl.param_spec()
-                if param_spec:
-                    return param_spec.with_flavor(t.flavor)
-                else:
-                    return repl
-            else:
-                return Parameters(
-                    t.prefix.arg_types + repl.arg_types,
-                    t.prefix.arg_kinds + repl.arg_kinds,
-                    t.prefix.arg_names + repl.arg_names,
-                    variables=[*t.prefix.variables, *repl.variables],
-                )
+        elif isinstance(repl, (ParamSpecType, Parameters, CallableType)):
+            return expand_param_spec(t, repl)
         else:
             # TODO: should this branch be removed? better not to fail silently
             return repl
@@ -446,8 +422,8 @@ def visit_type_type(self, t: TypeType) -> Type:
         return TypeType.make_normalized(item)
 
     def visit_type_alias_type(self, t: TypeAliasType) -> Type:
-        # Target of the type alias cannot contain type variables,
-        # so we just expand the arguments.
+        # Target of the type alias cannot contain type variables (not bound by the type
+        # alias itself), so we just expand the arguments.
         return t.copy_modified(args=self.expand_types(t.args))
 
     def expand_types(self, types: Iterable[Type]) -> list[Type]:
diff --git a/mypy/fixup.py b/mypy/fixup.py
index b3a2d43d6b4d6..3593e4faa184e 100644
--- a/mypy/fixup.py
+++ b/mypy/fixup.py
@@ -180,6 +180,8 @@ def visit_var(self, v: Var) -> None:
 
     def visit_type_alias(self, a: TypeAlias) -> None:
         a.target.accept(self.type_fixer)
+        for v in a.alias_tvars:
+            v.accept(self.type_fixer)
 
 
 class TypeFixer(TypeVisitor[None]):
diff --git a/mypy/mixedtraverser.py b/mypy/mixedtraverser.py
index d25e9b9b0137e..771f87fc6bd65 100644
--- a/mypy/mixedtraverser.py
+++ b/mypy/mixedtraverser.py
@@ -25,6 +25,9 @@
 class MixedTraverserVisitor(TraverserVisitor, TypeTraverserVisitor):
     """Recursive traversal of both Node and Type objects."""
 
+    def __init__(self) -> None:
+        self.in_type_alias_expr = False
+
     # Symbol nodes
 
     def visit_var(self, var: Var) -> None:
@@ -45,7 +48,9 @@ def visit_class_def(self, o: ClassDef) -> None:
 
     def visit_type_alias_expr(self, o: TypeAliasExpr) -> None:
         super().visit_type_alias_expr(o)
+        self.in_type_alias_expr = True
         o.type.accept(self)
+        self.in_type_alias_expr = False
 
     def visit_type_var_expr(self, o: TypeVarExpr) -> None:
         super().visit_type_var_expr(o)
diff --git a/mypy/nodes.py b/mypy/nodes.py
index ebf2f5cb271a4..f0fc13dad7804 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -12,6 +12,7 @@
     Callable,
     Dict,
     Iterator,
+    List,
     Optional,
     Sequence,
     Tuple,
@@ -2546,7 +2547,7 @@ class TypeAliasExpr(Expression):
 
     # The target type.
     type: mypy.types.Type
-    # Names of unbound type variables used to define the alias
+    # Names of type variables used to define the alias
     tvars: list[str]
     # Whether this alias was defined in bare form. Used to distinguish
     # between
@@ -2559,7 +2560,7 @@ class TypeAliasExpr(Expression):
     def __init__(self, node: TypeAlias) -> None:
         super().__init__()
         self.type = node.target
-        self.tvars = node.alias_tvars
+        self.tvars = [v.name for v in node.alias_tvars]
         self.no_args = node.no_args
         self.node = node
 
@@ -3309,10 +3310,9 @@ class TypeAlias(SymbolNode):
     class-valued attributes. See SemanticAnalyzerPass2.check_and_set_up_type_alias
     for details.
 
-    Aliases can be generic. Currently, mypy uses unbound type variables for
-    generic aliases and identifies them by name. Essentially, type aliases
-    work as macros that expand textually. The definition and expansion rules are
-    following:
+    Aliases can be generic. We use bound type variables for generic aliases, similar
+    to classes. Essentially, type aliases work as macros that expand textually.
+    The definition and expansion rules are following:
 
         1. An alias targeting a generic class without explicit variables act as
         the given class (this doesn't apply to TypedDict, Tuple and Callable, which
@@ -3363,11 +3363,11 @@ def f(x: B[T]) -> T: ...  # without T, Any would be used here
 
     Meaning of other fields:
 
-    target: The target type. For generic aliases contains unbound type variables
-        as nested types.
+    target: The target type. For generic aliases contains bound type variables
+        as nested types (currently TypeVar and ParamSpec are supported).
     _fullname: Qualified name of this type alias. This is used in particular
         to track fine grained dependencies from aliases.
-    alias_tvars: Names of unbound type variables used to define this alias.
+    alias_tvars: Type variables used to define this alias.
     normalized: Used to distinguish between `A = List`, and `A = list`. Both
         are internally stored using `builtins.list` (because `typing.List` is
         itself an alias), while the second cannot be subscripted because of
@@ -3396,7 +3396,7 @@ def __init__(
         line: int,
         column: int,
         *,
-        alias_tvars: list[str] | None = None,
+        alias_tvars: list[mypy.types.TypeVarLikeType] | None = None,
         no_args: bool = False,
         normalized: bool = False,
         eager: bool = False,
@@ -3446,12 +3446,16 @@ def name(self) -> str:
     def fullname(self) -> str:
         return self._fullname
 
+    @property
+    def has_param_spec_type(self) -> bool:
+        return any(isinstance(v, mypy.types.ParamSpecType) for v in self.alias_tvars)
+
     def serialize(self) -> JsonDict:
         data: JsonDict = {
             ".class": "TypeAlias",
             "fullname": self._fullname,
             "target": self.target.serialize(),
-            "alias_tvars": self.alias_tvars,
+            "alias_tvars": [v.serialize() for v in self.alias_tvars],
             "no_args": self.no_args,
             "normalized": self.normalized,
             "line": self.line,
@@ -3466,7 +3470,8 @@ def accept(self, visitor: NodeVisitor[T]) -> T:
     def deserialize(cls, data: JsonDict) -> TypeAlias:
         assert data[".class"] == "TypeAlias"
         fullname = data["fullname"]
-        alias_tvars = data["alias_tvars"]
+        alias_tvars = [mypy.types.deserialize_type(v) for v in data["alias_tvars"]]
+        assert all(isinstance(t, mypy.types.TypeVarLikeType) for t in alias_tvars)
         target = mypy.types.deserialize_type(data["target"])
         no_args = data["no_args"]
         normalized = data["normalized"]
@@ -3477,7 +3482,7 @@ def deserialize(cls, data: JsonDict) -> TypeAlias:
             fullname,
             line,
             column,
-            alias_tvars=alias_tvars,
+            alias_tvars=cast(List[mypy.types.TypeVarLikeType], alias_tvars),
             no_args=no_args,
             normalized=normalized,
         )
diff --git a/mypy/semanal.py b/mypy/semanal.py
index a5ddcc70eed63..74ab1c1c6f308 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -50,7 +50,7 @@
 
 from __future__ import annotations
 
-from contextlib import contextmanager
+from contextlib import contextmanager, nullcontext
 from typing import Any, Callable, Collection, Iterable, Iterator, List, TypeVar, cast
 from typing_extensions import Final, TypeAlias as _TypeAlias
 
@@ -459,6 +459,11 @@ def __init__(
         # rvalues while temporarily setting this to True.
         self.basic_type_applications = False
 
+        # Used to temporarily enable unbound type variables in some contexts. Namely,
+        # in base class expressions, and in right hand sides of type aliases. Do not add
+        # new uses of this, as this may cause leaking `UnboundType`s to type checking.
+        self.allow_unbound_tvars = False
+
     # mypyc doesn't properly handle implementing an abstractproperty
     # with a regular attribute so we make them properties
     @property
@@ -477,6 +482,15 @@ def is_typeshed_stub_file(self) -> bool:
     def final_iteration(self) -> bool:
         return self._final_iteration
 
+    @contextmanager
+    def allow_unbound_tvars_set(self) -> Iterator[None]:
+        old = self.allow_unbound_tvars
+        self.allow_unbound_tvars = True
+        try:
+            yield
+        finally:
+            self.allow_unbound_tvars = old
+
     #
     # Preparing module (performed before semantic analysis)
     #
@@ -1599,7 +1613,7 @@ def setup_type_vars(self, defn: ClassDef, tvar_defs: list[TypeVarLikeType]) -> N
 
     def setup_alias_type_vars(self, defn: ClassDef) -> None:
         assert defn.info.special_alias is not None
-        defn.info.special_alias.alias_tvars = list(defn.info.type_vars)
+        defn.info.special_alias.alias_tvars = list(defn.type_vars)
         target = defn.info.special_alias.target
         assert isinstance(target, ProperType)
         if isinstance(target, TypedDictType):
@@ -2631,7 +2645,10 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
         # when analysing any type applications there) thus preventing the further analysis.
         # To break the tie, we first analyse rvalue partially, if it can be a type alias.
         with self.basic_type_applications_set(s):
-            s.rvalue.accept(self)
+            with self.allow_unbound_tvars_set() if self.can_possibly_be_index_alias(
+                s
+            ) else nullcontext():
+                s.rvalue.accept(self)
         if self.found_incomplete_ref(tag) or self.should_wait_rhs(s.rvalue):
             # Initializer couldn't be fully analyzed. Defer the current node and give up.
             # Make sure that if we skip the definition of some local names, they can't be
@@ -2642,7 +2659,8 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
         if self.can_possibly_be_index_alias(s):
             # Now re-visit those rvalues that were we skipped type applications above.
             # This should be safe as generally semantic analyzer is idempotent.
-            s.rvalue.accept(self)
+            with self.allow_unbound_tvars_set():
+                s.rvalue.accept(self)
 
         # The r.h.s. is now ready to be classified, first check if it is a special form:
         special_form = False
@@ -3272,42 +3290,56 @@ def analyze_simple_literal_type(self, rvalue: Expression, is_final: bool) -> Typ
         return None
 
     def analyze_alias(
-        self, rvalue: Expression, allow_placeholder: bool = False
-    ) -> tuple[Type | None, list[str], set[str], list[str]]:
+        self, name: str, rvalue: Expression, allow_placeholder: bool = False
+    ) -> tuple[Type | None, list[TypeVarLikeType], set[str], list[str]]:
         """Check if 'rvalue' is a valid type allowed for aliasing (e.g. not a type variable).
 
         If yes, return the corresponding type, a list of
         qualified type variable names for generic aliases, a set of names the alias depends on,
         and a list of type variables if the alias is generic.
-        An schematic example for the dependencies:
+        A schematic example for the dependencies:
             A = int
             B = str
             analyze_alias(Dict[A, B])[2] == {'__main__.A', '__main__.B'}
         """
         dynamic = bool(self.function_stack and self.function_stack[-1].is_dynamic())
         global_scope = not self.type and not self.function_stack
-        res = analyze_type_alias(
-            rvalue,
-            self,
-            self.tvar_scope,
-            self.plugin,
-            self.options,
-            self.is_typeshed_stub_file,
-            allow_placeholder=allow_placeholder,
-            in_dynamic_func=dynamic,
-            global_scope=global_scope,
-        )
-        typ: Type | None = None
+        try:
+            typ = expr_to_unanalyzed_type(rvalue, self.options, self.is_stub_file)
+        except TypeTranslationError:
+            self.fail(
+                "Invalid type alias: expression is not a valid type", rvalue, code=codes.VALID_TYPE
+            )
+            return None, [], set(), []
+
+        found_type_vars = typ.accept(TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope))
+        tvar_defs: list[TypeVarLikeType] = []
+        namespace = self.qualified_name(name)
+        with self.tvar_scope_frame(self.tvar_scope.class_frame(namespace)):
+            for name, tvar_expr in found_type_vars:
+                tvar_def = self.tvar_scope.bind_new(name, tvar_expr)
+                tvar_defs.append(tvar_def)
+
+            res = analyze_type_alias(
+                typ,
+                self,
+                self.tvar_scope,
+                self.plugin,
+                self.options,
+                self.is_typeshed_stub_file,
+                allow_placeholder=allow_placeholder,
+                in_dynamic_func=dynamic,
+                global_scope=global_scope,
+                allowed_alias_tvars=tvar_defs,
+            )
+        analyzed: Type | None = None
         if res:
-            typ, depends_on = res
-            found_type_vars = typ.accept(TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope))
-            alias_tvars = [name for (name, node) in found_type_vars]
+            analyzed, depends_on = res
             qualified_tvars = [node.fullname for (name, node) in found_type_vars]
         else:
-            alias_tvars = []
             depends_on = set()
             qualified_tvars = []
-        return typ, alias_tvars, depends_on, qualified_tvars
+        return analyzed, tvar_defs, depends_on, qualified_tvars
 
     def is_pep_613(self, s: AssignmentStmt) -> bool:
         if s.unanalyzed_type is not None and isinstance(s.unanalyzed_type, UnboundType):
@@ -3387,13 +3419,13 @@ def check_and_set_up_type_alias(self, s: AssignmentStmt) -> bool:
         res: Type | None = None
         if self.is_none_alias(rvalue):
             res = NoneType()
-            alias_tvars: list[str] = []
+            alias_tvars: list[TypeVarLikeType] = []
             depends_on: set[str] = set()
             qualified_tvars: list[str] = []
         else:
             tag = self.track_incomplete_refs()
             res, alias_tvars, depends_on, qualified_tvars = self.analyze_alias(
-                rvalue, allow_placeholder=True
+                lvalue.name, rvalue, allow_placeholder=True
             )
             if not res:
                 return False
@@ -4978,12 +5010,12 @@ def analyze_type_application_args(self, expr: IndexExpr) -> list[Type] | None:
             except TypeTranslationError:
                 self.fail("Type expected within [...]", expr)
                 return None
-            # We always allow unbound type variables in IndexExpr, since we
-            # may be analysing a type alias definition rvalue. The error will be
-            # reported elsewhere if it is not the case.
             analyzed = self.anal_type(
                 typearg,
-                allow_unbound_tvars=True,
+                # The type application may appear in base class expression,
+                # where type variables are not bound yet. Or when accepting
+                # r.h.s. of type alias before we figured out it is a type alias.
+                allow_unbound_tvars=self.allow_unbound_tvars,
                 allow_placeholder=True,
                 allow_param_spec_literals=has_param_spec,
             )
@@ -6187,7 +6219,7 @@ def analyze_type_expr(self, expr: Expression) -> None:
         # them semantically analyzed, however, if they need to treat it as an expression
         # and not a type. (Which is to say, mypyc needs to do this.) Do the analysis
         # in a fresh tvar scope in order to suppress any errors about using type variables.
-        with self.tvar_scope_frame(TypeVarLikeScope()):
+        with self.tvar_scope_frame(TypeVarLikeScope()), self.allow_unbound_tvars_set():
             expr.accept(self)
 
     def type_analyzer(
diff --git a/mypy/semanal_typeargs.py b/mypy/semanal_typeargs.py
index 72903423116fc..b9965236c3790 100644
--- a/mypy/semanal_typeargs.py
+++ b/mypy/semanal_typeargs.py
@@ -7,23 +7,27 @@
 
 from __future__ import annotations
 
+from typing import Sequence
+
 from mypy import errorcodes as codes, message_registry
 from mypy.errorcodes import ErrorCode
 from mypy.errors import Errors
 from mypy.messages import format_type
 from mypy.mixedtraverser import MixedTraverserVisitor
-from mypy.nodes import Block, ClassDef, Context, FakeInfo, FuncItem, MypyFile, TypeInfo
+from mypy.nodes import Block, ClassDef, Context, FakeInfo, FuncItem, MypyFile
 from mypy.options import Options
 from mypy.scope import Scope
 from mypy.subtypes import is_same_type, is_subtype
 from mypy.types import (
     AnyType,
     Instance,
+    Parameters,
     ParamSpecType,
     TupleType,
     Type,
     TypeAliasType,
     TypeOfAny,
+    TypeVarLikeType,
     TypeVarTupleType,
     TypeVarType,
     UnboundType,
@@ -35,6 +39,7 @@
 
 class TypeArgumentAnalyzer(MixedTraverserVisitor):
     def __init__(self, errors: Errors, options: Options, is_typeshed_file: bool) -> None:
+        super().__init__()
         self.errors = errors
         self.options = options
         self.is_typeshed_file = is_typeshed_file
@@ -77,7 +82,12 @@ def visit_type_alias_type(self, t: TypeAliasType) -> None:
         # correct aliases.
         if t.alias and len(t.args) != len(t.alias.alias_tvars):
             t.args = [AnyType(TypeOfAny.from_error) for _ in t.alias.alias_tvars]
-        get_proper_type(t).accept(self)
+        assert t.alias is not None, f"Unfixed type alias {t.type_ref}"
+        is_error = self.validate_args(t.alias.name, t.args, t.alias.alias_tvars, t)
+        if not is_error:
+            # If there was already an error for the alias itself, there is no point in checking
+            # the expansion, most likely it will result in the same kind of error.
+            get_proper_type(t).accept(self)
 
     def visit_instance(self, t: Instance) -> None:
         # Type argument counts were checked in the main semantic analyzer pass. We assume
@@ -85,36 +95,67 @@ def visit_instance(self, t: Instance) -> None:
         info = t.type
         if isinstance(info, FakeInfo):
             return  # https://github.com/python/mypy/issues/11079
-        for (i, arg), tvar in zip(enumerate(t.args), info.defn.type_vars):
+        self.validate_args(info.name, t.args, info.defn.type_vars, t)
+        super().visit_instance(t)
+
+    def validate_args(
+        self, name: str, args: Sequence[Type], type_vars: list[TypeVarLikeType], ctx: Context
+    ) -> bool:
+        is_error = False
+        for (i, arg), tvar in zip(enumerate(args), type_vars):
             if isinstance(tvar, TypeVarType):
                 if isinstance(arg, ParamSpecType):
                     # TODO: Better message
-                    self.fail(f'Invalid location for ParamSpec "{arg.name}"', t)
+                    is_error = True
+                    self.fail(f'Invalid location for ParamSpec "{arg.name}"', ctx)
+                    self.note(
+                        "You can use ParamSpec as the first argument to Callable, e.g., "
+                        "'Callable[{}, int]'".format(arg.name),
+                        ctx,
+                    )
                     continue
                 if tvar.values:
                     if isinstance(arg, TypeVarType):
+                        if self.in_type_alias_expr:
+                            # Type aliases are allowed to use unconstrained type variables
+                            # error will be checked at substitution point.
+                            continue
                         arg_values = arg.values
                         if not arg_values:
+                            is_error = True
                             self.fail(
-                                message_registry.INVALID_TYPEVAR_AS_TYPEARG.format(
-                                    arg.name, info.name
-                                ),
-                                t,
+                                message_registry.INVALID_TYPEVAR_AS_TYPEARG.format(arg.name, name),
+                                ctx,
                                 code=codes.TYPE_VAR,
                             )
                             continue
                     else:
                         arg_values = [arg]
-                    self.check_type_var_values(info, arg_values, tvar.name, tvar.values, i + 1, t)
+                    if self.check_type_var_values(name, arg_values, tvar.name, tvar.values, ctx):
+                        is_error = True
                 if not is_subtype(arg, tvar.upper_bound):
+                    if self.in_type_alias_expr and isinstance(arg, TypeVarType):
+                        # Type aliases are allowed to use unconstrained type variables
+                        # error will be checked at substitution point.
+                        continue
+                    is_error = True
                     self.fail(
                         message_registry.INVALID_TYPEVAR_ARG_BOUND.format(
-                            format_type(arg), info.name, format_type(tvar.upper_bound)
+                            format_type(arg), name, format_type(tvar.upper_bound)
                         ),
-                        t,
+                        ctx,
                         code=codes.TYPE_VAR,
                     )
-        super().visit_instance(t)
+            elif isinstance(tvar, ParamSpecType):
+                if not isinstance(
+                    get_proper_type(arg), (ParamSpecType, Parameters, AnyType, UnboundType)
+                ):
+                    self.fail(
+                        "Can only replace ParamSpec with a parameter types list or"
+                        f" another ParamSpec, got {format_type(arg)}",
+                        ctx,
+                    )
+        return is_error
 
     def visit_unpack_type(self, typ: UnpackType) -> None:
         proper_type = get_proper_type(typ.type)
@@ -132,28 +173,25 @@ def visit_unpack_type(self, typ: UnpackType) -> None:
         self.fail(message_registry.INVALID_UNPACK.format(proper_type), typ)
 
     def check_type_var_values(
-        self,
-        type: TypeInfo,
-        actuals: list[Type],
-        arg_name: str,
-        valids: list[Type],
-        arg_number: int,
-        context: Context,
-    ) -> None:
+        self, name: str, actuals: list[Type], arg_name: str, valids: list[Type], context: Context
+    ) -> bool:
+        is_error = False
         for actual in get_proper_types(actuals):
-            # TODO: bind type variables in class bases/alias targets
-            # so we can safely check this, currently we miss some errors.
+            # We skip UnboundType here, since they may appear in defn.bases,
+            # the error will be caught when visiting info.bases, that have bound type
+            # variables.
             if not isinstance(actual, (AnyType, UnboundType)) and not any(
                 is_same_type(actual, value) for value in valids
             ):
+                is_error = True
                 if len(actuals) > 1 or not isinstance(actual, Instance):
                     self.fail(
-                        message_registry.INVALID_TYPEVAR_ARG_VALUE.format(type.name),
+                        message_registry.INVALID_TYPEVAR_ARG_VALUE.format(name),
                         context,
                         code=codes.TYPE_VAR,
                     )
                 else:
-                    class_name = f'"{type.name}"'
+                    class_name = f'"{name}"'
                     actual_type_name = f'"{actual.type.name}"'
                     self.fail(
                         message_registry.INCOMPATIBLE_TYPEVAR_VALUE.format(
@@ -162,6 +200,10 @@ def check_type_var_values(
                         context,
                         code=codes.TYPE_VAR,
                     )
+        return is_error
 
     def fail(self, msg: str, context: Context, *, code: ErrorCode | None = None) -> None:
         self.errors.report(context.line, context.column, msg, code=code)
+
+    def note(self, msg: str, context: Context, *, code: ErrorCode | None = None) -> None:
+        self.errors.report(context.line, context.column, msg, severity="note", code=code)
diff --git a/mypy/semanal_typeddict.py b/mypy/semanal_typeddict.py
index fb45dcc0dfc4c..cd3d02bc6bb8b 100644
--- a/mypy/semanal_typeddict.py
+++ b/mypy/semanal_typeddict.py
@@ -189,7 +189,7 @@ def add_keys_and_types_from_base(
         valid_items = base_items.copy()
 
         # Always fix invalid bases to avoid crashes.
-        tvars = info.type_vars
+        tvars = info.defn.type_vars
         if len(base_args) != len(tvars):
             any_kind = TypeOfAny.from_omitted_generics
             if base_args:
@@ -235,7 +235,7 @@ def analyze_base_args(self, base: IndexExpr, ctx: Context) -> list[Type] | None:
         return base_args
 
     def map_items_to_base(
-        self, valid_items: dict[str, Type], tvars: list[str], base_args: list[Type]
+        self, valid_items: dict[str, Type], tvars: list[TypeVarLikeType], base_args: list[Type]
     ) -> dict[str, Type]:
         """Map item types to how they would look in their base with type arguments applied.
 
diff --git a/mypy/server/astdiff.py b/mypy/server/astdiff.py
index 41a79db480c92..97f811384d370 100644
--- a/mypy/server/astdiff.py
+++ b/mypy/server/astdiff.py
@@ -187,7 +187,7 @@ def snapshot_symbol_table(name_prefix: str, table: SymbolTable) -> dict[str, Sna
         elif isinstance(node, TypeAlias):
             result[name] = (
                 "TypeAlias",
-                node.alias_tvars,
+                snapshot_types(node.alias_tvars),
                 node.normalized,
                 node.no_args,
                 snapshot_optional_type(node.target),
diff --git a/mypy/server/astmerge.py b/mypy/server/astmerge.py
index a14335acca7e7..04422036b67b0 100644
--- a/mypy/server/astmerge.py
+++ b/mypy/server/astmerge.py
@@ -331,6 +331,8 @@ def visit_var(self, node: Var) -> None:
 
     def visit_type_alias(self, node: TypeAlias) -> None:
         self.fixup_type(node.target)
+        for v in node.alias_tvars:
+            self.fixup_type(v)
         super().visit_type_alias(node)
 
     # Helpers
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index a4b045cfa00cf..e4667c45fbc5f 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -631,6 +631,8 @@ def visit_param_spec(self, left: ParamSpecType) -> bool:
             and right.flavor == left.flavor
         ):
             return True
+        if isinstance(right, Parameters) and are_trivial_parameters(right):
+            return True
         return self._is_subtype(left.upper_bound, self.right)
 
     def visit_type_var_tuple(self, left: TypeVarTupleType) -> bool:
@@ -1415,6 +1417,18 @@ def g(x: int) -> int: ...
     )
 
 
+def are_trivial_parameters(param: Parameters | NormalizedCallableType) -> bool:
+    param_star = param.var_arg()
+    param_star2 = param.kw_arg()
+    return (
+        param.arg_kinds == [ARG_STAR, ARG_STAR2]
+        and param_star is not None
+        and isinstance(get_proper_type(param_star.typ), AnyType)
+        and param_star2 is not None
+        and isinstance(get_proper_type(param_star2.typ), AnyType)
+    )
+
+
 def are_parameters_compatible(
     left: Parameters | NormalizedCallableType,
     right: Parameters | NormalizedCallableType,
@@ -1435,13 +1449,7 @@ def are_parameters_compatible(
     right_star2 = right.kw_arg()
 
     # Treat "def _(*a: Any, **kw: Any) -> X" similarly to "Callable[..., X]"
-    if (
-        right.arg_kinds == [ARG_STAR, ARG_STAR2]
-        and right_star
-        and isinstance(get_proper_type(right_star.typ), AnyType)
-        and right_star2
-        and isinstance(get_proper_type(right_star2.typ), AnyType)
-    ):
+    if are_trivial_parameters(right):
         return True
 
     # Match up corresponding arguments and check them for compatibility. In
diff --git a/mypy/test/testtypes.py b/mypy/test/testtypes.py
index 18948ee7f6d6a..ee0256e2057a3 100644
--- a/mypy/test/testtypes.py
+++ b/mypy/test/testtypes.py
@@ -160,7 +160,8 @@ def test_type_alias_expand_all(self) -> None:
 
     def test_recursive_nested_in_non_recursive(self) -> None:
         A, _ = self.fx.def_alias_1(self.fx.a)
-        NA = self.fx.non_rec_alias(Instance(self.fx.gi, [UnboundType("T")]), ["T"], [A])
+        T = TypeVarType("T", "T", -1, [], self.fx.o)
+        NA = self.fx.non_rec_alias(Instance(self.fx.gi, [T]), [T], [A])
         assert not NA.is_recursive
         assert has_recursive_types(NA)
 
diff --git a/mypy/test/typefixture.py b/mypy/test/typefixture.py
index 93e5e4b0b5ca0..bd8351171208f 100644
--- a/mypy/test/typefixture.py
+++ b/mypy/test/typefixture.py
@@ -340,7 +340,10 @@ def def_alias_2(self, base: Instance) -> tuple[TypeAliasType, Type]:
         return A, target
 
     def non_rec_alias(
-        self, target: Type, alias_tvars: list[str] | None = None, args: list[Type] | None = None
+        self,
+        target: Type,
+        alias_tvars: list[TypeVarLikeType] | None = None,
+        args: list[Type] | None = None,
     ) -> TypeAliasType:
         AN = TypeAlias(target, "__main__.A", -1, -1, alias_tvars=alias_tvars)
         if args is None:
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index f22fa30706c4c..f34f6ef49f6c6 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -10,7 +10,6 @@
 
 from mypy import errorcodes as codes, message_registry, nodes
 from mypy.errorcodes import ErrorCode
-from mypy.exprtotype import TypeTranslationError, expr_to_unanalyzed_type
 from mypy.messages import MessageBuilder, format_type_bare, quote_type_string, wrong_type_arg_count
 from mypy.nodes import (
     ARG_NAMED,
@@ -23,7 +22,6 @@
     ArgKind,
     Context,
     Decorator,
-    Expression,
     MypyFile,
     ParamSpecExpr,
     PlaceholderNode,
@@ -87,6 +85,7 @@
     callable_with_ellipsis,
     flatten_nested_unions,
     get_proper_type,
+    has_type_vars,
 )
 from mypy.typetraverser import TypeTraverserVisitor
 from mypy.typevars import fill_typevars
@@ -122,7 +121,7 @@
 
 
 def analyze_type_alias(
-    node: Expression,
+    type: Type,
     api: SemanticAnalyzerCoreInterface,
     tvar_scope: TypeVarLikeScope,
     plugin: Plugin,
@@ -131,6 +130,7 @@ def analyze_type_alias(
     allow_placeholder: bool = False,
     in_dynamic_func: bool = False,
     global_scope: bool = True,
+    allowed_alias_tvars: list[TypeVarLikeType] | None = None,
 ) -> tuple[Type, set[str]] | None:
     """Analyze r.h.s. of a (potential) type alias definition.
 
@@ -138,11 +138,6 @@ def analyze_type_alias(
     full names of type aliases it depends on (directly or indirectly).
     Return None otherwise. 'node' must have been semantically analyzed.
     """
-    try:
-        type = expr_to_unanalyzed_type(node, options, api.is_stub_file)
-    except TypeTranslationError:
-        api.fail("Invalid type alias: expression is not a valid type", node, code=codes.VALID_TYPE)
-        return None
     analyzer = TypeAnalyser(
         api,
         tvar_scope,
@@ -152,6 +147,7 @@ def analyze_type_alias(
         defining_alias=True,
         allow_placeholder=allow_placeholder,
         prohibit_self_type="type alias target",
+        allowed_alias_tvars=allowed_alias_tvars,
     )
     analyzer.in_dynamic_func = in_dynamic_func
     analyzer.global_scope = global_scope
@@ -201,6 +197,7 @@ def __init__(
         allow_param_spec_literals: bool = False,
         report_invalid_types: bool = True,
         prohibit_self_type: str | None = None,
+        allowed_alias_tvars: list[TypeVarLikeType] | None = None,
         allow_type_any: bool = False,
     ) -> None:
         self.api = api
@@ -219,8 +216,12 @@ def __init__(
         self.always_allow_new_syntax = self.api.is_stub_file or self.api.is_future_flag_set(
             "annotations"
         )
-        # Should we accept unbound type variables (always OK in aliases)?
-        self.allow_unbound_tvars = allow_unbound_tvars or defining_alias
+        # Should we accept unbound type variables? This is currently used for class bases,
+        # and alias right hand sides (before they are analyzed as type aliases).
+        self.allow_unbound_tvars = allow_unbound_tvars
+        if allowed_alias_tvars is None:
+            allowed_alias_tvars = []
+        self.allowed_alias_tvars = allowed_alias_tvars
         # If false, record incomplete ref if we generate PlaceholderType.
         self.allow_placeholder = allow_placeholder
         # Are we in a context where Required[] is allowed?
@@ -263,7 +264,12 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                         self.api.defer()
                     else:
                         self.api.record_incomplete_ref()
-                    return PlaceholderType(node.fullname, self.anal_array(t.args), t.line)
+                    # Always allow ParamSpec for placeholders, if they are actually not valid,
+                    # they will be reported later, after we resolve placeholders.
+                    with self.set_allow_param_spec_literals(True):
+                        return PlaceholderType(
+                            node.fullname, self.anal_array(t.args, allow_param_spec=True), t.line
+                        )
                 else:
                     if self.api.final_iteration:
                         self.cannot_resolve_type(t)
@@ -290,6 +296,8 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
             tvar_def = self.tvar_scope.get_binding(sym)
             if isinstance(sym.node, ParamSpecExpr):
                 if tvar_def is None:
+                    if self.allow_unbound_tvars:
+                        return t
                     self.fail(f'ParamSpec "{t.name}" is unbound', t, code=codes.VALID_TYPE)
                     return AnyType(TypeOfAny.from_error)
                 assert isinstance(tvar_def, ParamSpecType)
@@ -307,7 +315,12 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                     line=t.line,
                     column=t.column,
                 )
-            if isinstance(sym.node, TypeVarExpr) and tvar_def is not None and self.defining_alias:
+            if (
+                isinstance(sym.node, TypeVarExpr)
+                and self.defining_alias
+                and not defining_literal
+                and (tvar_def is None or tvar_def not in self.allowed_alias_tvars)
+            ):
                 self.fail(
                     f'Can\'t use bound type variable "{t.name}" to define generic alias',
                     t,
@@ -332,7 +345,9 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                     column=t.column,
                 )
             if isinstance(sym.node, TypeVarTupleExpr) and (
-                tvar_def is not None and self.defining_alias
+                tvar_def is not None
+                and self.defining_alias
+                and tvar_def not in self.allowed_alias_tvars
             ):
                 self.fail(
                     f'Can\'t use bound type variable "{t.name}" to define generic alias',
@@ -363,7 +378,11 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                 return special
             if isinstance(node, TypeAlias):
                 self.aliases_used.add(fullname)
-                an_args = self.anal_array(t.args)
+                with self.set_allow_param_spec_literals(node.has_param_spec_type):
+                    an_args = self.anal_array(t.args, allow_param_spec=True)
+                    if node.has_param_spec_type and len(node.alias_tvars) == 1:
+                        an_args = self.pack_paramspec_args(an_args)
+
                 disallow_any = self.options.disallow_any_generics and not self.is_typeshed_stub
                 res = expand_type_alias(
                     node,
@@ -406,6 +425,17 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
         else:  # sym is None
             return AnyType(TypeOfAny.special_form)
 
+    def pack_paramspec_args(self, an_args: Sequence[Type]) -> list[Type]:
+        # "Aesthetic" ParamSpec literals for single ParamSpec: C[int, str] -> C[[int, str]].
+        # These do not support mypy_extensions VarArgs, etc. as they were already analyzed
+        # TODO: should these be re-analyzed to get rid of this inconsistency?
+        count = len(an_args)
+        if count > 0:
+            first_arg = get_proper_type(an_args[0])
+            if not (count == 1 and isinstance(first_arg, (Parameters, ParamSpecType, AnyType))):
+                return [Parameters(an_args, [ARG_POS] * count, [None] * count)]
+        return list(an_args)
+
     def cannot_resolve_type(self, t: UnboundType) -> None:
         # TODO: Move error message generation to messages.py. We'd first
         #       need access to MessageBuilder here. Also move the similar
@@ -422,6 +452,10 @@ def apply_concatenate_operator(self, t: UnboundType) -> Type:
         # last argument has to be ParamSpec
         ps = self.anal_type(t.args[-1], allow_param_spec=True)
         if not isinstance(ps, ParamSpecType):
+            if isinstance(ps, UnboundType) and self.allow_unbound_tvars:
+                sym = self.lookup_qualified(ps.name, t)
+                if sym is not None and isinstance(sym.node, ParamSpecExpr):
+                    return ps
             self.api.fail(
                 "The last parameter to Concatenate needs to be a ParamSpec",
                 t,
@@ -633,25 +667,8 @@ def analyze_type_with_type_info(
             instance = Instance(
                 info, self.anal_array(args, allow_param_spec=True), ctx.line, ctx.column
             )
-
-        # "aesthetic" paramspec literals
-        # these do not support mypy_extensions VarArgs, etc. as they were already analyzed
-        #   TODO: should these be re-analyzed to get rid of this inconsistency?
-        # another inconsistency is with empty type args (Z[] is more possibly an error imo)
-        if len(info.type_vars) == 1 and info.has_param_spec_type and len(instance.args) > 0:
-            first_arg = get_proper_type(instance.args[0])
-
-            # TODO: can I use tuple syntax to isinstance multiple in 3.6?
-            if not (
-                len(instance.args) == 1
-                and (
-                    isinstance(first_arg, Parameters)
-                    or isinstance(first_arg, ParamSpecType)
-                    or isinstance(first_arg, AnyType)
-                )
-            ):
-                args = instance.args
-                instance.args = (Parameters(args, [ARG_POS] * len(args), [None] * len(args)),)
+        if len(info.type_vars) == 1 and info.has_param_spec_type:
+            instance.args = tuple(self.pack_paramspec_args(instance.args))
 
         if info.has_type_var_tuple_type:
             # - 1 to allow for the empty type var tuple case.
@@ -676,6 +693,7 @@ def analyze_type_with_type_info(
             if info.special_alias:
                 return expand_type_alias(
                     info.special_alias,
+                    # TODO: should we allow NamedTuples generic in ParamSpec?
                     self.anal_array(args),
                     self.fail,
                     False,
@@ -690,6 +708,7 @@ def analyze_type_with_type_info(
             if info.special_alias:
                 return expand_type_alias(
                     info.special_alias,
+                    # TODO: should we allow TypedDicts generic in ParamSpec?
                     self.anal_array(args),
                     self.fail,
                     False,
@@ -810,9 +829,11 @@ def analyze_unbound_type_without_type_info(
             )
         else:
             message = 'Cannot interpret reference "{}" as a type'
-        self.fail(message.format(name), t, code=codes.VALID_TYPE)
-        for note in notes:
-            self.note(note, t, code=codes.VALID_TYPE)
+        if not defining_literal:
+            # Literal check already gives a custom error. Avoid duplicating errors.
+            self.fail(message.format(name), t, code=codes.VALID_TYPE)
+            for note in notes:
+                self.note(note, t, code=codes.VALID_TYPE)
 
         # TODO: Would it be better to always return Any instead of UnboundType
         # in case of an error? On one hand, UnboundType has a name so error messages
@@ -1102,6 +1123,16 @@ def analyze_callable_args_for_paramspec(
             return None
         tvar_def = self.tvar_scope.get_binding(sym)
         if not isinstance(tvar_def, ParamSpecType):
+            if (
+                tvar_def is None
+                and self.allow_unbound_tvars
+                and isinstance(sym.node, ParamSpecExpr)
+            ):
+                # We are analyzing this type in runtime context (e.g. as type application).
+                # If it is not valid as a type in this position an error will be given later.
+                return callable_with_ellipsis(
+                    AnyType(TypeOfAny.explicit), ret_type=ret_type, fallback=fallback
+                )
             return None
 
         return CallableType(
@@ -1137,6 +1168,14 @@ def analyze_callable_args_for_concatenate(
 
         tvar_def = self.anal_type(callable_args, allow_param_spec=True)
         if not isinstance(tvar_def, ParamSpecType):
+            if self.allow_unbound_tvars and isinstance(tvar_def, UnboundType):
+                sym = self.lookup_qualified(tvar_def.name, callable_args)
+                if sym is not None and isinstance(sym.node, ParamSpecExpr):
+                    # We are analyzing this type in runtime context (e.g. as type application).
+                    # If it is not valid as a type in this position an error will be given later.
+                    return callable_with_ellipsis(
+                        AnyType(TypeOfAny.explicit), ret_type=ret_type, fallback=fallback
+                    )
             return None
 
         # ick, CallableType should take ParamSpecType
@@ -1637,12 +1676,12 @@ def expand_type_alias(
     """Expand a (generic) type alias target following the rules outlined in TypeAlias docstring.
 
     Here:
-        target: original target type (contains unbound type variables)
-        alias_tvars: type variable names
+        target: original target type
         args: types to be substituted in place of type variables
         fail: error reporter callback
         no_args: whether original definition used a bare generic `A = List`
         ctx: context where expansion happens
+        unexpanded_type, disallow_any, use_standard_error: used to customize error messages
     """
     exp_len = len(node.alias_tvars)
     act_len = len(args)
@@ -1682,6 +1721,9 @@ def expand_type_alias(
             msg = f"Bad number of arguments for type alias, expected: {exp_len}, given: {act_len}"
         fail(msg, ctx, code=codes.TYPE_ARG)
         return set_any_tvars(node, ctx.line, ctx.column, from_error=True)
+    # TODO: we need to check args validity w.r.t alias.alias_tvars.
+    # Otherwise invalid instantiations will be allowed in runtime context.
+    # Note: in type context, these will be still caught by semanal_typeargs.
     typ = TypeAliasType(node, args, ctx.line, ctx.column)
     assert typ.alias is not None
     # HACK: Implement FlexibleAlias[T, typ] by expanding it to typ here.
@@ -1822,26 +1864,11 @@ def __init__(
         self.scope = scope
         self.diverging = False
 
-    def is_alias_tvar(self, t: Type) -> bool:
-        # Generic type aliases use unbound type variables.
-        if not isinstance(t, UnboundType) or t.args:
-            return False
-        node = self.lookup(t.name, t)
-        if (
-            node
-            and isinstance(node.node, TypeVarLikeExpr)
-            and self.scope.get_binding(node) is None
-        ):
-            return True
-        return False
-
     def visit_type_alias_type(self, t: TypeAliasType) -> Type:
         assert t.alias is not None, f"Unfixed type alias {t.type_ref}"
         if t.alias in self.seen_nodes:
             for arg in t.args:
-                if not self.is_alias_tvar(arg) and bool(
-                    arg.accept(TypeVarLikeQuery(self.lookup, self.scope))
-                ):
+                if not isinstance(arg, TypeVarLikeType) and has_type_vars(arg):
                     self.diverging = True
                     return t
             # All clear for this expansion chain.
diff --git a/mypy/types.py b/mypy/types.py
index 78142d9003d9c..7d2ac9911bef3 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3202,24 +3202,45 @@ def is_named_instance(t: Type, fullnames: str | tuple[str, ...]) -> TypeGuard[In
 
 
 class InstantiateAliasVisitor(TrivialSyntheticTypeTranslator):
-    def __init__(self, vars: list[str], subs: list[Type]) -> None:
-        self.replacements = {v: s for (v, s) in zip(vars, subs)}
+    def __init__(self, vars: list[TypeVarLikeType], subs: list[Type]) -> None:
+        self.replacements = {v.id: s for (v, s) in zip(vars, subs)}
 
     def visit_type_alias_type(self, typ: TypeAliasType) -> Type:
         return typ.copy_modified(args=[t.accept(self) for t in typ.args])
 
-    def visit_unbound_type(self, typ: UnboundType) -> Type:
-        # TODO: stop using unbound type variables for type aliases.
-        # Now that type aliases are very similar to TypeInfos we should
-        # make type variable tracking similar as well. Maybe we can even support
-        # upper bounds etc. for generic type aliases.
-        if typ.name in self.replacements:
-            return self.replacements[typ.name]
+    def visit_type_var(self, typ: TypeVarType) -> Type:
+        if typ.id in self.replacements:
+            return self.replacements[typ.id]
         return typ
 
-    def visit_type_var(self, typ: TypeVarType) -> Type:
-        if typ.name in self.replacements:
-            return self.replacements[typ.name]
+    def visit_callable_type(self, t: CallableType) -> Type:
+        param_spec = t.param_spec()
+        if param_spec is not None:
+            # TODO: this branch duplicates the one in expand_type(), find a way to reuse it
+            # without import cycle types <-> typeanal <-> expandtype.
+            repl = get_proper_type(self.replacements.get(param_spec.id))
+            if isinstance(repl, CallableType) or isinstance(repl, Parameters):
+                prefix = param_spec.prefix
+                t = t.expand_param_spec(repl, no_prefix=True)
+                return t.copy_modified(
+                    arg_types=[t.accept(self) for t in prefix.arg_types] + t.arg_types,
+                    arg_kinds=prefix.arg_kinds + t.arg_kinds,
+                    arg_names=prefix.arg_names + t.arg_names,
+                    ret_type=t.ret_type.accept(self),
+                    type_guard=(t.type_guard.accept(self) if t.type_guard is not None else None),
+                )
+        return super().visit_callable_type(t)
+
+    def visit_param_spec(self, typ: ParamSpecType) -> Type:
+        if typ.id in self.replacements:
+            repl = get_proper_type(self.replacements[typ.id])
+            # TODO: all the TODOs from same logic in expand_type() apply here.
+            if isinstance(repl, Instance):
+                return repl
+            elif isinstance(repl, (ParamSpecType, Parameters, CallableType)):
+                return expand_param_spec(typ, repl)
+            else:
+                return repl
         return typ
 
 
@@ -3236,7 +3257,7 @@ def visit_instance(self, typ: Instance) -> None:
 
 
 def replace_alias_tvars(
-    tp: Type, vars: list[str], subs: list[Type], newline: int, newcolumn: int
+    tp: Type, vars: list[TypeVarLikeType], subs: list[Type], newline: int, newcolumn: int
 ) -> Type:
     """Replace type variables in a generic type alias tp with substitutions subs
     resetting context. Length of subs should be already checked.
@@ -3252,6 +3273,7 @@ def replace_alias_tvars(
 class HasTypeVars(TypeQuery[bool]):
     def __init__(self) -> None:
         super().__init__(any)
+        self.skip_alias_target = True
 
     def visit_type_var(self, t: TypeVarType) -> bool:
         return True
@@ -3406,6 +3428,41 @@ def callable_with_ellipsis(any_type: AnyType, ret_type: Type, fallback: Instance
     )
 
 
+def expand_param_spec(
+    t: ParamSpecType, repl: ParamSpecType | Parameters | CallableType
+) -> ProperType:
+    """This is shared part of the logic w.r.t. ParamSpec instantiation.
+
+    It is shared between type aliases and proper types, that currently use somewhat different
+    logic for instantiation."""
+    if isinstance(repl, ParamSpecType):
+        return repl.copy_modified(
+            flavor=t.flavor,
+            prefix=t.prefix.copy_modified(
+                arg_types=t.prefix.arg_types + repl.prefix.arg_types,
+                arg_kinds=t.prefix.arg_kinds + repl.prefix.arg_kinds,
+                arg_names=t.prefix.arg_names + repl.prefix.arg_names,
+            ),
+        )
+    else:
+        # if the paramspec is *P.args or **P.kwargs:
+        if t.flavor != ParamSpecFlavor.BARE:
+            assert isinstance(repl, CallableType), "Should not be able to get here."
+            # Is this always the right thing to do?
+            param_spec = repl.param_spec()
+            if param_spec:
+                return param_spec.with_flavor(t.flavor)
+            else:
+                return repl
+        else:
+            return Parameters(
+                t.prefix.arg_types + repl.arg_types,
+                t.prefix.arg_kinds + repl.arg_kinds,
+                t.prefix.arg_names + repl.arg_names,
+                variables=[*t.prefix.variables, *repl.variables],
+            )
+
+
 def store_argument_type(
     defn: FuncItem, i: int, typ: CallableType, named_type: Callable[[str, list[Type]], Instance]
 ) -> None:
diff --git a/mypy/typetraverser.py b/mypy/typetraverser.py
index afe77efff78df..9c4a9157ad6a2 100644
--- a/mypy/typetraverser.py
+++ b/mypy/typetraverser.py
@@ -131,6 +131,9 @@ def visit_raw_expression_type(self, t: RawExpressionType) -> None:
         pass
 
     def visit_type_alias_type(self, t: TypeAliasType) -> None:
+        # TODO: sometimes we want to traverse target as well
+        # We need to find a way to indicate explicitly the intent,
+        # maybe make this method abstract (like for TypeTranslator)?
         self.traverse_types(t.args)
 
     def visit_unpack_type(self, t: UnpackType) -> None:
diff --git a/test-data/unit/check-generics.test b/test-data/unit/check-generics.test
index 04108dded7234..dd7e31528a4fe 100644
--- a/test-data/unit/check-generics.test
+++ b/test-data/unit/check-generics.test
@@ -655,7 +655,7 @@ a: other.Array[float]
 reveal_type(a) # N: Revealed type is "other.array[Any, other.dtype[builtins.float]]"
 
 [out]
-main:3: error: Type argument "float" of "dtype" must be a subtype of "generic"  [type-var]
+main:3: error: Type argument "float" of "Array" must be a subtype of "generic"  [type-var]
     a: other.Array[float]
        ^
 [file other.py]
@@ -1031,8 +1031,9 @@ IntNode[int](1, 1)
 IntNode[int](1, 'a')  # E: Argument 2 to "Node" has incompatible type "str"; expected "int"
 
 SameNode = Node[T, T]
-# TODO: fix https://github.com/python/mypy/issues/7084.
-ff = SameNode[T](1, 1)
+ff = SameNode[T](1, 1)  # E: Type variable "__main__.T" is unbound \
+        # N: (Hint: Use "Generic[T]" or "Protocol[T]" base class to bind "T" inside a class) \
+        # N: (Hint: Use "T" in function signature to bind "T" inside a function)
 a = SameNode(1, 'x')
 reveal_type(a) # N: Revealed type is "__main__.Node[Any, Any]"
 b = SameNode[int](1, 1)
@@ -1101,13 +1102,12 @@ BadA = A[str, T]  # One error here
 SameA = A[T, T]
 
 x = None # type: SameA[int]
-y = None # type: SameA[str] # Two errors here, for both args of A
+y = None # type: SameA[str] # Another error here
 
 [builtins fixtures/list.pyi]
 [out]
 main:9:8: error: Value of type variable "T" of "A" cannot be "str"
-main:13:1: error: Value of type variable "T" of "A" cannot be "str"
-main:13:1: error: Value of type variable "S" of "A" cannot be "str"
+main:13:1: error: Value of type variable "T" of "SameA" cannot be "str"
 
 [case testGenericTypeAliasesIgnoredPotentialAlias]
 class A: ...
@@ -2645,3 +2645,21 @@ class C(Generic[T]):
 
 def foo(x: C[T]) -> T:
     return x.x(42).y  # OK
+
+[case testNestedGenericFunctionTypeApplication]
+from typing import TypeVar, Generic, List
+
+A = TypeVar("A")
+B = TypeVar("B")
+
+class C(Generic[A]):
+    x: A
+
+def foo(x: A) -> A:
+    def bar() -> List[A]:
+        y = C[List[A]]()
+        z = C[List[B]]()  # E: Type variable "__main__.B" is unbound \
+                # N: (Hint: Use "Generic[B]" or "Protocol[B]" base class to bind "B" inside a class) \
+                # N: (Hint: Use "B" in function signature to bind "B" inside a function)
+        return y.x
+    return bar()[0]
diff --git a/test-data/unit/check-isinstance.test b/test-data/unit/check-isinstance.test
index 6eddcd866cabe..0722ee8d91e5a 100644
--- a/test-data/unit/check-isinstance.test
+++ b/test-data/unit/check-isinstance.test
@@ -1750,11 +1750,8 @@ def f(cls: Type[object]) -> None:
 [case testIsinstanceTypeArgs]
 from typing import Iterable, TypeVar
 x = 1
-T = TypeVar('T')
-
 isinstance(x, Iterable)
 isinstance(x, Iterable[int])  # E: Parameterized generics cannot be used with class or instance checks
-isinstance(x, Iterable[T])  # E: Parameterized generics cannot be used with class or instance checks
 isinstance(x, (int, Iterable[int]))  # E: Parameterized generics cannot be used with class or instance checks
 isinstance(x, (int, (str, Iterable[int])))  # E: Parameterized generics cannot be used with class or instance checks
 [builtins fixtures/isinstancelist.pyi]
@@ -1783,10 +1780,8 @@ isinstance(x, It2)  # E: Parameterized generics cannot be used with class or ins
 [case testIssubclassTypeArgs]
 from typing import Iterable, TypeVar
 x = int
-T = TypeVar('T')
 issubclass(x, Iterable)
 issubclass(x, Iterable[int])  # E: Parameterized generics cannot be used with class or instance checks
-issubclass(x, Iterable[T])  # E: Parameterized generics cannot be used with class or instance checks
 issubclass(x, (int, Iterable[int]))  # E: Parameterized generics cannot be used with class or instance checks
 [builtins fixtures/isinstance.pyi]
 [typing fixtures/typing-full.pyi]
diff --git a/test-data/unit/check-literal.test b/test-data/unit/check-literal.test
index ef8c9095e58aa..d523e5c08af83 100644
--- a/test-data/unit/check-literal.test
+++ b/test-data/unit/check-literal.test
@@ -2437,23 +2437,10 @@ b: Final = 3
 c: Final[Literal[3]] = 3
 d: Literal[3]
 
-# TODO: Consider if we want to support cases 'b' and 'd' or not.
-# Probably not: we want to mostly keep the 'types' and 'value' worlds distinct.
-# However, according to final semantics, we ought to be able to substitute "b" with
-# "3" wherever it's used and get the same behavior -- so maybe we do need to support
-# at least case "b" for consistency?
-a_wrap: Literal[4, a]  # E: Parameter 2 of Literal[...] is invalid \
-                       # E: Variable "__main__.a" is not valid as a type \
-                       # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
-b_wrap: Literal[4, b]  # E: Parameter 2 of Literal[...] is invalid \
-                       # E: Variable "__main__.b" is not valid as a type \
-                       # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
-c_wrap: Literal[4, c]  # E: Parameter 2 of Literal[...] is invalid \
-                       # E: Variable "__main__.c" is not valid as a type \
-                       # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
-d_wrap: Literal[4, d]  # E: Parameter 2 of Literal[...] is invalid \
-                       # E: Variable "__main__.d" is not valid as a type \
-                       # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
+a_wrap: Literal[4, a]  # E: Parameter 2 of Literal[...] is invalid
+b_wrap: Literal[4, b]  # E: Parameter 2 of Literal[...] is invalid
+c_wrap: Literal[4, c]  # E: Parameter 2 of Literal[...] is invalid
+d_wrap: Literal[4, d]  # E: Parameter 2 of Literal[...] is invalid
 [builtins fixtures/tuple.pyi]
 [out]
 
@@ -2517,9 +2504,7 @@ r: Literal[Color.RED]
 g: Literal[Color.GREEN]
 b: Literal[Color.BLUE]
 bad1: Literal[Color]         # E: Parameter 1 of Literal[...] is invalid
-bad2: Literal[Color.func]    # E: Function "__main__.Color.func" is not valid as a type \
-                             # N: Perhaps you need "Callable[...]" or a callback protocol? \
-                             # E: Parameter 1 of Literal[...] is invalid
+bad2: Literal[Color.func]    # E: Parameter 1 of Literal[...] is invalid
 bad3: Literal[Color.func()]  # E: Invalid type: Literal[...] cannot contain arbitrary expressions
 
 def expects_color(x: Color) -> None: pass
diff --git a/test-data/unit/check-parameter-specification.test b/test-data/unit/check-parameter-specification.test
index b13f74bc3729b..4a5dd0c1b04ea 100644
--- a/test-data/unit/check-parameter-specification.test
+++ b/test-data/unit/check-parameter-specification.test
@@ -429,7 +429,6 @@ class Z(Generic[P]): ...
 # literals can be applied
 n: Z[[int]]
 
-# TODO: type aliases too
 nt1 = Z[[int]]
 nt2: TypeAlias = Z[[int]]
 
@@ -506,8 +505,7 @@ def f2(x: X[int, Concatenate[int, P_2]]) -> str: ...  # Accepted
 def f3(x: X[int, [int, bool]]) -> str: ...            # Accepted
 # ellipsis only show up here, but I can assume it works like Callable[..., R]
 def f4(x: X[int, ...]) -> str: ...                    # Accepted
-# TODO: this is not rejected:
-# def f5(x: X[int, int]) -> str: ...                    # Rejected
+def f5(x: X[int, int]) -> str: ...  # E: Can only replace ParamSpec with a parameter types list or another ParamSpec, got "int"
 
 # CASE 3
 def bar(x: int, *args: bool) -> int: ...
@@ -844,9 +842,7 @@ class A:
         ...
 
 reveal_type(A.func)  # N: Revealed type is "def [_P, _R] (self: __main__.A, action: def (*_P.args, **_P.kwargs) -> _R`-2, *_P.args, **_P.kwargs) -> _R`-2"
-
-# TODO: _R`<n> keeps flip-flopping between 5 (?), 13, 14, 15. Spooky.
-# reveal_type(A().func)  $ N: Revealed type is "def [_P, _R] (action: def (*_P.args, **_P.kwargs) -> _R`13, *_P.args, **_P.kwargs) -> _R`13"
+reveal_type(A().func)  # N: Revealed type is "def [_P, _R] (action: def (*_P.args, **_P.kwargs) -> _R`5, *_P.args, **_P.kwargs) -> _R`5"
 
 def f(x: int) -> int:
     ...
@@ -879,8 +875,7 @@ class A:
         ...
 
 reveal_type(A.func)  # N: Revealed type is "def [_P] (self: __main__.A, action: __main__.Job[_P`-1, None]) -> __main__.Job[_P`-1, None]"
-# TODO: flakey, _P`4 alternates around.
-# reveal_type(A().func)  $ N: Revealed type is "def [_P] (action: __main__.Job[_P`4, None]) -> __main__.Job[_P`4, None]"
+reveal_type(A().func)  # N: Revealed type is "def [_P] (action: __main__.Job[_P`3, None]) -> __main__.Job[_P`3, None]"
 reveal_type(A().func(Job(lambda x: x)))  # N: Revealed type is "__main__.Job[[x: Any], None]"
 
 def f(x: int, y: int) -> None: ...
@@ -1296,3 +1291,144 @@ class C(Generic[P]):
 
 reveal_type(bar(C(fn=foo, x=1)))  # N: Revealed type is "__main__.C[[x: builtins.int]]"
 [builtins fixtures/paramspec.pyi]
+
+[case testParamSpecInTypeAliasBasic]
+from typing import ParamSpec, Callable
+
+P = ParamSpec("P")
+C = Callable[P, int]
+def f(n: C[P]) -> C[P]: ...
+
+@f
+def bar(x: int) -> int: ...
+@f    # E: Argument 1 to "f" has incompatible type "Callable[[int], str]"; expected "Callable[[int], int]"
+def foo(x: int) -> str: ...
+
+x: C[[int, str]]
+reveal_type(x)  # N: Revealed type is "def (builtins.int, builtins.str) -> builtins.int"
+y: C[int, str]
+reveal_type(y)  # N: Revealed type is "def (builtins.int, builtins.str) -> builtins.int"
+[builtins fixtures/paramspec.pyi]
+
+[case testParamSpecInTypeAliasConcatenate]
+from typing import ParamSpec, Callable
+from typing_extensions import Concatenate
+
+P = ParamSpec("P")
+C = Callable[Concatenate[int, P], int]
+def f(n: C[P]) -> C[P]: ...
+
+@f  # E: Argument 1 to "f" has incompatible type "Callable[[], int]"; expected "Callable[[int], int]"
+def bad() -> int: ...
+
+@f
+def bar(x: int) -> int: ...
+
+@f
+def bar2(x: int, y: str) -> int: ...
+reveal_type(bar2)  # N: Revealed type is "def (builtins.int, y: builtins.str) -> builtins.int"
+
+@f  # E: Argument 1 to "f" has incompatible type "Callable[[int], str]"; expected "Callable[[int], int]" \
+    # N: This is likely because "foo" has named arguments: "x". Consider marking them positional-only
+def foo(x: int) -> str: ...
+
+@f  # E: Argument 1 to "f" has incompatible type "Callable[[str, int], int]"; expected "Callable[[int, int], int]" \
+    # N: This is likely because "foo2" has named arguments: "x". Consider marking them positional-only
+def foo2(x: str, y: int) -> int: ...
+
+x: C[[int, str]]
+reveal_type(x)  # N: Revealed type is "def (builtins.int, builtins.int, builtins.str) -> builtins.int"
+y: C[int, str]
+reveal_type(y)  # N: Revealed type is "def (builtins.int, builtins.int, builtins.str) -> builtins.int"
+[builtins fixtures/paramspec.pyi]
+
+[case testParamSpecInTypeAliasRecursive]
+from typing import ParamSpec, Callable, Union
+
+P = ParamSpec("P")
+C = Callable[P, Union[int, C[P]]]
+def f(n: C[P]) -> C[P]: ...
+
+@f
+def bar(x: int) -> int: ...
+
+@f
+def bar2(__x: int) -> Callable[[int], int]: ...
+
+@f  # E: Argument 1 to "f" has incompatible type "Callable[[int], str]"; expected "C[[int]]"
+def foo(x: int) -> str: ...
+
+@f  # E: Argument 1 to "f" has incompatible type "Callable[[int], Callable[[int], str]]"; expected "C[[int]]"
+def foo2(__x: int) -> Callable[[int], str]: ...
+
+x: C[[int, str]]
+reveal_type(x)  # N: Revealed type is "def (builtins.int, builtins.str) -> Union[builtins.int, ...]"
+y: C[int, str]
+reveal_type(y)  # N: Revealed type is "def (builtins.int, builtins.str) -> Union[builtins.int, ...]"
+[builtins fixtures/paramspec.pyi]
+
+[case testParamSpecAliasInRuntimeContext]
+from typing import ParamSpec, Generic
+
+P = ParamSpec("P")
+class C(Generic[P]): ...
+
+c = C[int, str]()
+reveal_type(c)  # N: Revealed type is "__main__.C[[builtins.int, builtins.str]]"
+
+A = C[P]
+a = A[int, str]()
+reveal_type(a)  # N: Revealed type is "__main__.C[[builtins.int, builtins.str]]"
+[builtins fixtures/paramspec.pyi]
+
+[case testParamSpecAliasInvalidLocations]
+from typing import ParamSpec, Generic, List, TypeVar, Callable
+
+P = ParamSpec("P")
+T = TypeVar("T")
+A = List[T]
+def f(x: A[[int, str]]) -> None: ...  # E: Bracketed expression "[...]" is not valid as a type \
+                                      # N: Did you mean "List[...]"?
+def g(x: A[P]) -> None: ...  # E: Invalid location for ParamSpec "P" \
+                             # N: You can use ParamSpec as the first argument to Callable, e.g., 'Callable[P, int]'
+
+C = Callable[P, T]
+x: C[int]  # E: Bad number of arguments for type alias, expected: 2, given: 1
+y: C[int, str]  # E: Can only replace ParamSpec with a parameter types list or another ParamSpec, got "int"
+z: C[int, str, bytes]  # E: Bad number of arguments for type alias, expected: 2, given: 3
+[builtins fixtures/paramspec.pyi]
+
+[case testTrivialParametersHandledCorrectly]
+from typing import ParamSpec, Generic, TypeVar, Callable, Any
+from typing_extensions import Concatenate
+
+P = ParamSpec("P")
+T = TypeVar("T")
+S = TypeVar("S")
+
+class C(Generic[S, P, T]): ...
+
+def foo(f: Callable[P, int]) -> None:
+    x: C[Any, ..., Any]
+    x1: C[int, Concatenate[int, str, P], str]
+    x = x1  # OK
+[builtins fixtures/paramspec.pyi]
+
+[case testParamSpecAliasNested]
+from typing import ParamSpec, Callable, List, TypeVar, Generic
+from typing_extensions import Concatenate
+
+P = ParamSpec("P")
+A = List[Callable[P, None]]
+B = List[Callable[Concatenate[int, P], None]]
+
+fs: A[int, str]
+reveal_type(fs)  # N: Revealed type is "builtins.list[def (builtins.int, builtins.str)]"
+gs: B[int, str]
+reveal_type(gs)  # N: Revealed type is "builtins.list[def (builtins.int, builtins.int, builtins.str)]"
+
+T = TypeVar("T")
+class C(Generic[T]): ...
+C[Callable[P, int]]()  # E: The first argument to Callable must be a list of types, parameter specification, or "..." \
+                       # N: See https://mypy.readthedocs.io/en/stable/kinds_of_types.html#callable-types-and-lambdas
+[builtins fixtures/paramspec.pyi]
diff --git a/test-data/unit/check-type-aliases.test b/test-data/unit/check-type-aliases.test
index fab372976ab27..121be34f03391 100644
--- a/test-data/unit/check-type-aliases.test
+++ b/test-data/unit/check-type-aliases.test
@@ -947,3 +947,38 @@ c.SpecialImplicit = 4
 c.SpecialExplicit = 4
 [builtins fixtures/tuple.pyi]
 [typing fixtures/typing-medium.pyi]
+
+[case testValidTypeAliasValues]
+from typing import TypeVar, Generic, List
+
+T = TypeVar("T", int, str)
+S = TypeVar("S", int, bytes)
+
+class C(Generic[T]): ...
+class D(C[S]): ...  # E: Invalid type argument value for "C"
+
+U = TypeVar("U")
+A = List[C[U]]
+x: A[bytes]  # E: Value of type variable "T" of "C" cannot be "bytes"
+
+V = TypeVar("V", bound=int)
+class E(Generic[V]): ...
+B = List[E[U]]
+y: B[str]  # E: Type argument "str" of "E" must be a subtype of "int"
+
+[case testValidTypeAliasValuesMoreRestrictive]
+from typing import TypeVar, Generic, List
+
+T = TypeVar("T")
+S = TypeVar("S", int, str)
+U = TypeVar("U", bound=int)
+
+class C(Generic[T]): ...
+
+A = List[C[S]]
+x: A[int]
+x_bad: A[bytes]  # E: Value of type variable "S" of "A" cannot be "bytes"
+
+B = List[C[U]]
+y: B[int]
+y_bad: B[str]  # E: Type argument "str" of "B" must be a subtype of "int"

From 4471c7e76f27ee51eb8d47a4803097ec15c62128 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Thu, 24 Nov 2022 16:52:22 +0000
Subject: [PATCH 076/231] Proposal: don't simplify unions in expand_type()
 (#14178)

Fixes #6730

Currently `expand_type()` is inherently recursive, going through
`expand_type` -> `make_simplified_union` -> `is_proper_subtype` ->
`map_instance_to_supertype` -> `expand_type`. TBH I never liked this, so
I propose that we don't do this. One one hand, this is a significant
change in semantics, but on the other hand:
* This fixes a crash (actually a whole class of crashes) that can happen
even without recursive aliases
* This removes an ugly import and simplifies an import cycle in mypy
code
* This makes mypy 2% faster (measured on self-check)

To make transition smoother, I propose to make trivial simplifications,
like removing `<nothing>` (and `None` without strict optional), removing
everything else if there is an `object` type, and remove strict
duplicates. Notably, with these few things _all existing tests pass_
(and even without it, only half a dozen tests fail on `reveal_type()`).
---
 mypy/expandtype.py                        | 14 ++++++----
 mypy/types.py                             | 30 ++++++++++++++++++++
 test-data/unit/check-recursive-types.test | 34 +++++++++++++++++++++++
 test-data/unit/pythoneval.test            | 16 +++++++++++
 4 files changed, 89 insertions(+), 5 deletions(-)

diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index d3286480e3169..96d556121fd4f 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -34,7 +34,9 @@
     UnionType,
     UnpackType,
     expand_param_spec,
+    flatten_nested_unions,
     get_proper_type,
+    remove_trivial,
 )
 from mypy.typevartuples import (
     find_unpack_in_list,
@@ -405,11 +407,13 @@ def visit_literal_type(self, t: LiteralType) -> Type:
         return t
 
     def visit_union_type(self, t: UnionType) -> Type:
-        # After substituting for type variables in t.items,
-        # some of the resulting types might be subtypes of others.
-        from mypy.typeops import make_simplified_union  # asdf
-
-        return make_simplified_union(self.expand_types(t.items), t.line, t.column)
+        expanded = self.expand_types(t.items)
+        # After substituting for type variables in t.items, some resulting types
+        # might be subtypes of others, however calling  make_simplified_union()
+        # can cause recursion, so we just remove strict duplicates.
+        return UnionType.make_union(
+            remove_trivial(flatten_nested_unions(expanded)), t.line, t.column
+        )
 
     def visit_partial_type(self, t: PartialType) -> Type:
         return t
diff --git a/mypy/types.py b/mypy/types.py
index 7d2ac9911bef3..326727310a1b1 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3487,3 +3487,33 @@ def store_argument_type(
         if not isinstance(arg_type, ParamSpecType) and not typ.unpack_kwargs:
             arg_type = named_type("builtins.dict", [named_type("builtins.str", []), arg_type])
     defn.arguments[i].variable.type = arg_type
+
+
+def remove_trivial(types: Iterable[Type]) -> list[Type]:
+    """Make trivial simplifications on a list of types without calling is_subtype().
+
+    This makes following simplifications:
+        * Remove bottom types (taking into account strict optional setting)
+        * Remove everything else if there is an `object`
+        * Remove strict duplicate types
+    """
+    removed_none = False
+    new_types = []
+    all_types = set()
+    for t in types:
+        p_t = get_proper_type(t)
+        if isinstance(p_t, UninhabitedType):
+            continue
+        if isinstance(p_t, NoneType) and not state.strict_optional:
+            removed_none = True
+            continue
+        if isinstance(p_t, Instance) and p_t.type.fullname == "builtins.object":
+            return [p_t]
+        if p_t not in all_types:
+            new_types.append(t)
+            all_types.add(p_t)
+    if new_types:
+        return new_types
+    if removed_none:
+        return [NoneType()]
+    return [UninhabitedType()]
diff --git a/test-data/unit/check-recursive-types.test b/test-data/unit/check-recursive-types.test
index 95b0918866f12..0aa3c4c18be30 100644
--- a/test-data/unit/check-recursive-types.test
+++ b/test-data/unit/check-recursive-types.test
@@ -837,3 +837,37 @@ def foo(x: T) -> C: ...
 
 Nested = Union[C, Sequence[Nested]]
 x: Nested = foo(42)
+
+[case testNoRecursiveExpandInstanceUnionCrash]
+from typing import List, Union
+
+class Tag(List[Union[Tag, List[Tag]]]): ...
+Tag()
+
+[case testNoRecursiveExpandInstanceUnionCrashGeneric]
+from typing import Generic, Iterable, TypeVar, Union
+
+ValueT = TypeVar("ValueT")
+class Recursive(Iterable[Union[ValueT, Recursive[ValueT]]]):
+    pass
+
+class Base(Generic[ValueT]):
+    def __init__(self, element: ValueT):
+        pass
+class Sub(Base[Union[ValueT, Recursive[ValueT]]]):
+    pass
+
+x: Iterable[str]
+reveal_type(Sub)  # N: Revealed type is "def [ValueT] (element: Union[ValueT`1, __main__.Recursive[ValueT`1]]) -> __main__.Sub[ValueT`1]"
+reveal_type(Sub(x))  # N: Revealed type is "__main__.Sub[typing.Iterable[builtins.str]]"
+
+[case testNoRecursiveExpandInstanceUnionCrashInference]
+from typing import TypeVar, Union, Generic, List
+
+T = TypeVar("T")
+InList = Union[T, InListRecurse[T]]
+class InListRecurse(Generic[T], List[InList[T]]): ...
+
+def list_thing(transforming: InList[T]) -> T:
+    ...
+reveal_type(list_thing([5]))  # N: Revealed type is "builtins.list[builtins.int]"
diff --git a/test-data/unit/pythoneval.test b/test-data/unit/pythoneval.test
index 3f669246bb4e5..d89a66d1c5448 100644
--- a/test-data/unit/pythoneval.test
+++ b/test-data/unit/pythoneval.test
@@ -1735,3 +1735,19 @@ _testEnumNameWorkCorrectlyOn311.py:12: note: Revealed type is "Union[Literal[1]?
 _testEnumNameWorkCorrectlyOn311.py:13: note: Revealed type is "Literal['X']?"
 _testEnumNameWorkCorrectlyOn311.py:14: note: Revealed type is "builtins.int"
 _testEnumNameWorkCorrectlyOn311.py:15: note: Revealed type is "builtins.int"
+
+[case testTypedDictUnionGetFull]
+from typing import Dict
+from typing_extensions import TypedDict
+
+class TD(TypedDict, total=False):
+    x: int
+    y: int
+
+A = Dict[str, TD]
+x: A
+def foo(k: str) -> TD:
+    reveal_type(x.get(k, {}))
+    return x.get(k, {})
+[out]
+_testTypedDictUnionGetFull.py:11: note: Revealed type is "TypedDict('_testTypedDictUnionGetFull.TD', {'x'?: builtins.int, 'y'?: builtins.int})"

From 7ea5ff6c1476d425b6434405add819f0e1abec67 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Fri, 25 Nov 2022 10:06:54 +0000
Subject: [PATCH 077/231] Fix issues with type aliases and new style unions
 (#14181)

Fix aliases like this and other aliases involving new-style unions:
```
A = type[int] | str
```

Fixes #12392. Fixes #14158.
---
 mypy/checker.py                        | 21 +-------
 mypy/checkexpr.py                      |  3 ++
 mypy/nodes.py                          | 23 +++++++--
 mypy/semanal.py                        |  6 ++-
 mypy/server/aststrip.py                |  5 ++
 mypy/strconv.py                        |  2 +
 mypy/traverser.py                      |  2 +
 mypy/treetransform.py                  |  7 ++-
 test-data/unit/check-type-aliases.test | 11 ++++
 test-data/unit/fine-grained.test       | 31 ++++++++++++
 test-data/unit/pythoneval.test         | 69 +++++++++++++++++++++++++-
 11 files changed, 152 insertions(+), 28 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index f9acc9766140f..80f7e19c65f0f 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -2668,26 +2668,7 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
             self.msg.annotation_in_unchecked_function(context=s)
 
     def check_type_alias_rvalue(self, s: AssignmentStmt) -> None:
-        if not (self.is_stub and isinstance(s.rvalue, OpExpr) and s.rvalue.op == "|"):
-            # We do this mostly for compatibility with old semantic analyzer.
-            # TODO: should we get rid of this?
-            alias_type = self.expr_checker.accept(s.rvalue)
-        else:
-            # Avoid type checking 'X | Y' in stubs, since there can be errors
-            # on older Python targets.
-            alias_type = AnyType(TypeOfAny.special_form)
-
-            def accept_items(e: Expression) -> None:
-                if isinstance(e, OpExpr) and e.op == "|":
-                    accept_items(e.left)
-                    accept_items(e.right)
-                else:
-                    # Nested union types have been converted to type context
-                    # in semantic analysis (such as in 'list[int | str]'),
-                    # so we don't need to deal with them here.
-                    self.expr_checker.accept(e)
-
-            accept_items(s.rvalue)
+        alias_type = self.expr_checker.accept(s.rvalue)
         self.store_type(s.lvalues[-1], alias_type)
 
     def check_assignment(
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 362ef1eeb7f8a..ad0f42f1e32a2 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -2847,6 +2847,9 @@ def visit_ellipsis(self, e: EllipsisExpr) -> Type:
 
     def visit_op_expr(self, e: OpExpr) -> Type:
         """Type check a binary operator expression."""
+        if e.analyzed:
+            # It's actually a type expression X | Y.
+            return self.accept(e.analyzed)
         if e.op == "and" or e.op == "or":
             return self.check_boolean_op(e, e)
         if e.op == "*" and isinstance(e.left, ListExpr):
diff --git a/mypy/nodes.py b/mypy/nodes.py
index f0fc13dad7804..c02e21e88b446 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -1969,10 +1969,20 @@ def accept(self, visitor: ExpressionVisitor[T]) -> T:
 
 
 class OpExpr(Expression):
-    """Binary operation (other than . or [] or comparison operators,
-    which have specific nodes)."""
+    """Binary operation.
 
-    __slots__ = ("op", "left", "right", "method_type", "right_always", "right_unreachable")
+    The dot (.), [] and comparison operators have more specific nodes.
+    """
+
+    __slots__ = (
+        "op",
+        "left",
+        "right",
+        "method_type",
+        "right_always",
+        "right_unreachable",
+        "analyzed",
+    )
 
     __match_args__ = ("left", "op", "right")
 
@@ -1985,8 +1995,12 @@ class OpExpr(Expression):
     right_always: bool
     # Per static analysis only: Is the right side unreachable?
     right_unreachable: bool
+    # Used for expressions that represent a type "X | Y" in some contexts
+    analyzed: TypeAliasExpr | None
 
-    def __init__(self, op: str, left: Expression, right: Expression) -> None:
+    def __init__(
+        self, op: str, left: Expression, right: Expression, analyzed: TypeAliasExpr | None = None
+    ) -> None:
         super().__init__()
         self.op = op
         self.left = left
@@ -1994,6 +2008,7 @@ def __init__(self, op: str, left: Expression, right: Expression) -> None:
         self.method_type = None
         self.right_always = False
         self.right_unreachable = False
+        self.analyzed = analyzed
 
     def accept(self, visitor: ExpressionVisitor[T]) -> T:
         return visitor.visit_op_expr(self)
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 74ab1c1c6f308..698959ca1bdff 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -3472,7 +3472,11 @@ def check_and_set_up_type_alias(self, s: AssignmentStmt) -> bool:
             no_args=no_args,
             eager=eager,
         )
-        if isinstance(s.rvalue, (IndexExpr, CallExpr)):  # CallExpr is for `void = type(None)`
+        if isinstance(s.rvalue, (IndexExpr, CallExpr, OpExpr)) and (
+            not isinstance(rvalue, OpExpr)
+            or (self.options.python_version >= (3, 10) or self.is_stub_file)
+        ):
+            # Note: CallExpr is for "void = type(None)" and OpExpr is for "X | Y" union syntax.
             s.rvalue.analyzed = TypeAliasExpr(alias_node)
             s.rvalue.analyzed.line = s.line
             # we use the column from resulting target, to get better location for errors
diff --git a/mypy/server/aststrip.py b/mypy/server/aststrip.py
index 87ce63e9d5433..83d90f31e8c43 100644
--- a/mypy/server/aststrip.py
+++ b/mypy/server/aststrip.py
@@ -54,6 +54,7 @@
     MypyFile,
     NameExpr,
     Node,
+    OpExpr,
     OverloadedFuncDef,
     RefExpr,
     StarExpr,
@@ -222,6 +223,10 @@ def visit_index_expr(self, node: IndexExpr) -> None:
         node.analyzed = None  # May have been an alias or type application.
         super().visit_index_expr(node)
 
+    def visit_op_expr(self, node: OpExpr) -> None:
+        node.analyzed = None  # May have been an alias
+        super().visit_op_expr(node)
+
     def strip_ref_expr(self, node: RefExpr) -> None:
         node.kind = None
         node.node = None
diff --git a/mypy/strconv.py b/mypy/strconv.py
index f1aa6819e2b72..861a7c9b7fa08 100644
--- a/mypy/strconv.py
+++ b/mypy/strconv.py
@@ -413,6 +413,8 @@ def visit_call_expr(self, o: mypy.nodes.CallExpr) -> str:
         return self.dump(a + extra, o)
 
     def visit_op_expr(self, o: mypy.nodes.OpExpr) -> str:
+        if o.analyzed:
+            return o.analyzed.accept(self)
         return self.dump([o.op, o.left, o.right], o)
 
     def visit_comparison_expr(self, o: mypy.nodes.ComparisonExpr) -> str:
diff --git a/mypy/traverser.py b/mypy/traverser.py
index 3c4f21601b880..378d44c67f47a 100644
--- a/mypy/traverser.py
+++ b/mypy/traverser.py
@@ -262,6 +262,8 @@ def visit_call_expr(self, o: CallExpr) -> None:
     def visit_op_expr(self, o: OpExpr) -> None:
         o.left.accept(self)
         o.right.accept(self)
+        if o.analyzed is not None:
+            o.analyzed.accept(self)
 
     def visit_comparison_expr(self, o: ComparisonExpr) -> None:
         for operand in o.operands:
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index 2f678b89b1e6e..432baf7d73b78 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -519,7 +519,12 @@ def visit_call_expr(self, node: CallExpr) -> CallExpr:
         )
 
     def visit_op_expr(self, node: OpExpr) -> OpExpr:
-        new = OpExpr(node.op, self.expr(node.left), self.expr(node.right))
+        new = OpExpr(
+            node.op,
+            self.expr(node.left),
+            self.expr(node.right),
+            cast(Optional[TypeAliasExpr], self.optional_expr(node.analyzed)),
+        )
         new.method_type = self.optional_type(node.method_type)
         return new
 
diff --git a/test-data/unit/check-type-aliases.test b/test-data/unit/check-type-aliases.test
index 121be34f03391..e9b5e3e4d9665 100644
--- a/test-data/unit/check-type-aliases.test
+++ b/test-data/unit/check-type-aliases.test
@@ -948,6 +948,17 @@ c.SpecialExplicit = 4
 [builtins fixtures/tuple.pyi]
 [typing fixtures/typing-medium.pyi]
 
+[case testNewStyleUnionInTypeAliasWithMalformedInstance]
+# flags: --python-version 3.10
+from typing import List
+
+A = List[int, str] | int  # E: "list" expects 1 type argument, but 2 given
+B = int | list[int, str]  # E: "list" expects 1 type argument, but 2 given
+a: A
+b: B
+reveal_type(a)  # N: Revealed type is "Union[builtins.list[Any], builtins.int]"
+reveal_type(b)  # N: Revealed type is "Union[builtins.int, builtins.list[Any]]"
+
 [case testValidTypeAliasValues]
 from typing import TypeVar, Generic, List
 
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index c162f402486aa..1a318b52a0823 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -10277,3 +10277,34 @@ A = str
 m.py:5: error: Invalid statement in TypedDict definition; expected "field_name: field_type"
 ==
 m.py:5: error: Invalid statement in TypedDict definition; expected "field_name: field_type"
+
+[case testTypeAliasWithNewStyleUnionChangedToVariable]
+# flags: --python-version 3.10
+import a
+
+[file a.py]
+from b import C, D
+A = C | D
+a: A
+reveal_type(a)
+
+[file b.py]
+C = int
+D = str
+
+[file b.py.2]
+C = "x"
+D = "y"
+
+[file b.py.3]
+C = str
+D = int
+[out]
+a.py:4: note: Revealed type is "Union[builtins.int, builtins.str]"
+==
+a.py:2: error: Unsupported left operand type for | ("str")
+a.py:3: error: Variable "a.A" is not valid as a type
+a.py:3: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
+a.py:4: note: Revealed type is "A?"
+==
+a.py:4: note: Revealed type is "Union[builtins.str, builtins.int]"
diff --git a/test-data/unit/pythoneval.test b/test-data/unit/pythoneval.test
index d89a66d1c5448..acaaf5f21cf07 100644
--- a/test-data/unit/pythoneval.test
+++ b/test-data/unit/pythoneval.test
@@ -1663,7 +1663,7 @@ _testNarrowTypeForDictKeys.py:16: note: Revealed type is "Union[builtins.str, No
 
 [case testTypeAliasWithNewStyleUnion]
 # flags: --python-version 3.10
-from typing import Literal, Type, TypeAlias
+from typing import Literal, Type, TypeAlias, TypeVar
 
 Foo = Literal[1, 2]
 reveal_type(Foo)
@@ -1682,15 +1682,44 @@ Opt4 = float | None
 
 A = Type[int] | str
 B: TypeAlias = Type[int] | str
+C = type[int] | str
+
+D = type[int] | str
+x: D
+reveal_type(x)
+E: TypeAlias = type[int] | str
+y: E
+reveal_type(y)
+F = list[type[int] | str]
+
+T = TypeVar("T", int, str)
+def foo(x: T) -> T:
+    A = type[int] | str
+    a: A
+    return x
 [out]
 _testTypeAliasWithNewStyleUnion.py:5: note: Revealed type is "typing._SpecialForm"
+_testTypeAliasWithNewStyleUnion.py:25: note: Revealed type is "Union[Type[builtins.int], builtins.str]"
+_testTypeAliasWithNewStyleUnion.py:28: note: Revealed type is "Union[Type[builtins.int], builtins.str]"
 
 [case testTypeAliasWithNewStyleUnionInStub]
 # flags: --python-version 3.7
 import m
+a: m.A
+reveal_type(a)
+b: m.B
+reveal_type(b)
+c: m.C
+reveal_type(c)
+d: m.D
+reveal_type(d)
+e: m.E
+reveal_type(e)
+f: m.F
+reveal_type(f)
 
 [file m.pyi]
-from typing import Type
+from typing import Type, Callable
 from typing_extensions import Literal, TypeAlias
 
 Foo = Literal[1, 2]
@@ -1710,8 +1739,27 @@ Opt4 = float | None
 
 A = Type[int] | str
 B: TypeAlias = Type[int] | str
+C = type[int] | str
+reveal_type(C)
+D: TypeAlias = type[int] | str
+E = str | type[int]
+F: TypeAlias = str | type[int]
+G = list[type[int] | str]
+H = list[str | type[int]]
+
+CU1 = int | Callable[[], str | bool]
+CU2: TypeAlias = int | Callable[[], str | bool]
+CU3 = int | Callable[[str | bool], str]
+CU4: TypeAlias = int | Callable[[str | bool], str]
 [out]
 m.pyi:5: note: Revealed type is "typing._SpecialForm"
+m.pyi:22: note: Revealed type is "typing._SpecialForm"
+_testTypeAliasWithNewStyleUnionInStub.py:4: note: Revealed type is "Union[Type[builtins.int], builtins.str]"
+_testTypeAliasWithNewStyleUnionInStub.py:6: note: Revealed type is "Union[Type[builtins.int], builtins.str]"
+_testTypeAliasWithNewStyleUnionInStub.py:8: note: Revealed type is "Union[Type[builtins.int], builtins.str]"
+_testTypeAliasWithNewStyleUnionInStub.py:10: note: Revealed type is "Union[Type[builtins.int], builtins.str]"
+_testTypeAliasWithNewStyleUnionInStub.py:12: note: Revealed type is "Union[builtins.str, Type[builtins.int]]"
+_testTypeAliasWithNewStyleUnionInStub.py:14: note: Revealed type is "Union[builtins.str, Type[builtins.int]]"
 
 [case testEnumNameWorkCorrectlyOn311]
 # flags: --python-version 3.11
@@ -1736,6 +1784,23 @@ _testEnumNameWorkCorrectlyOn311.py:13: note: Revealed type is "Literal['X']?"
 _testEnumNameWorkCorrectlyOn311.py:14: note: Revealed type is "builtins.int"
 _testEnumNameWorkCorrectlyOn311.py:15: note: Revealed type is "builtins.int"
 
+[case testTypeAliasNotSupportedWithNewStyleUnion]
+# flags: --python-version 3.9
+from typing_extensions import TypeAlias
+A = type[int] | str
+B = str | type[int]
+C = str | int
+D: TypeAlias = str | int
+[out]
+_testTypeAliasNotSupportedWithNewStyleUnion.py:3: error: Invalid type alias: expression is not a valid type
+_testTypeAliasNotSupportedWithNewStyleUnion.py:3: error: Value of type "Type[type]" is not indexable
+_testTypeAliasNotSupportedWithNewStyleUnion.py:4: error: Invalid type alias: expression is not a valid type
+_testTypeAliasNotSupportedWithNewStyleUnion.py:4: error: Value of type "Type[type]" is not indexable
+_testTypeAliasNotSupportedWithNewStyleUnion.py:5: error: Invalid type alias: expression is not a valid type
+_testTypeAliasNotSupportedWithNewStyleUnion.py:5: error: Unsupported left operand type for | ("Type[str]")
+_testTypeAliasNotSupportedWithNewStyleUnion.py:6: error: Invalid type alias: expression is not a valid type
+_testTypeAliasNotSupportedWithNewStyleUnion.py:6: error: Unsupported left operand type for | ("Type[str]")
+
 [case testTypedDictUnionGetFull]
 from typing import Dict
 from typing_extensions import TypedDict

From a9024a801b2fe11f1e67ea62d55b22f4dc913076 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Fri, 25 Nov 2022 12:58:26 +0000
Subject: [PATCH 078/231] Fix type aliases with fixed-length tuples (#14184)

Fix type aliases like these:
```
T = tuple[int, str]
```
Type applications involving fixed-length tuples still don't fully work.
The inferred type is a variable-length tuple when constructing a tuple
using a type application, e.g. `tuple[int, str]((1, ""))`. This seems a
pretty low-priority issue, whereas the type alias use case seems common.

Most of the work was by @sobolevn originally in #12134. I just finished
it up.

Fixes #11098.
---
 mypy/checkexpr.py                      |  3 ++
 test-data/unit/check-type-aliases.test | 32 ++++++++++++++++++++
 test-data/unit/pythoneval.test         | 42 ++++++++++++++++++++++++++
 3 files changed, 77 insertions(+)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index ad0f42f1e32a2..eb585aba42dfc 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -3969,6 +3969,9 @@ def apply_type_arguments_to_callable(
 
         if isinstance(tp, CallableType):
             if len(tp.variables) != len(args):
+                if tp.is_type_obj() and tp.type_object().fullname == "builtins.tuple":
+                    # TODO: Specialize the callable for the type arguments
+                    return tp
                 self.msg.incompatible_type_application(len(tp.variables), len(args), ctx)
                 return AnyType(TypeOfAny.from_error)
             return self.apply_generic_arguments(tp, args, ctx)
diff --git a/test-data/unit/check-type-aliases.test b/test-data/unit/check-type-aliases.test
index e9b5e3e4d9665..e5d9bf94873ad 100644
--- a/test-data/unit/check-type-aliases.test
+++ b/test-data/unit/check-type-aliases.test
@@ -993,3 +993,35 @@ x_bad: A[bytes]  # E: Value of type variable "S" of "A" cannot be "bytes"
 B = List[C[U]]
 y: B[int]
 y_bad: B[str]  # E: Type argument "str" of "B" must be a subtype of "int"
+
+[case testTupleWithDifferentArgsPy38]
+# flags: --python-version 3.8
+NotYet1 = tuple[float]  # E: "tuple" is not subscriptable
+NotYet2 = tuple[float, float]  # E: "tuple" is not subscriptable
+NotYet3 = tuple[float, ...]  # E: Unexpected "..." \
+                             # E: "tuple" is not subscriptable
+NotYet4 = tuple[float, float, ...]  # E: Unexpected "..." \
+                                    # E: "tuple" is not subscriptable
+[builtins fixtures/tuple.pyi]
+
+[case testTupleWithDifferentArgsStub]
+# https://github.com/python/mypy/issues/11098
+import tup
+
+[file tup.pyi]
+Correct1 = str | tuple[float, float, str]
+Correct2 = tuple[float] | str
+Correct3 = tuple[float, ...] | str
+Correct4 = tuple[float, str] | str
+Correct5 = tuple[int, str]
+Correct6 = tuple[int, ...]
+
+RHSAlias1: type = tuple[int, int]
+RHSAlias2: type = tuple[int]
+RHSAlias3: type = tuple[int, ...]
+
+# Wrong:
+
+WrongTypeElement = str | tuple[float, 1]  # E: Invalid type: try using Literal[1] instead?
+WrongEllipsis = str | tuple[float, float, ...]  # E: Unexpected "..."
+[builtins fixtures/tuple.pyi]
diff --git a/test-data/unit/pythoneval.test b/test-data/unit/pythoneval.test
index acaaf5f21cf07..3520b58740187 100644
--- a/test-data/unit/pythoneval.test
+++ b/test-data/unit/pythoneval.test
@@ -1816,3 +1816,45 @@ def foo(k: str) -> TD:
     return x.get(k, {})
 [out]
 _testTypedDictUnionGetFull.py:11: note: Revealed type is "TypedDict('_testTypedDictUnionGetFull.TD', {'x'?: builtins.int, 'y'?: builtins.int})"
+
+[case testTupleWithDifferentArgsPy310]
+# https://github.com/python/mypy/issues/11098
+# flags: --python-version 3.10
+Correct1 = str | tuple[float, float, str]
+Correct2 = tuple[float] | str
+Correct3 = tuple[float, ...] | str
+Correct4 = tuple[float, str]
+Correct5 = tuple[float, ...]
+Correct6 = list[tuple[int, str]]
+c1: Correct1
+c2: Correct2
+c3: Correct3
+c4: Correct4
+c5: Correct5
+c6: Correct6
+reveal_type(c1)
+reveal_type(c2)
+reveal_type(c3)
+reveal_type(c4)
+reveal_type(c5)
+reveal_type(c6)
+
+RHSAlias1: type = tuple[int, int]
+RHSAlias2: type = tuple[int]
+RHSAlias3: type = tuple[int, ...]
+
+WrongTypeElement = str | tuple[float, 1]  # Error
+WrongEllipsis = tuple[float, float, ...] | str  # Error
+
+# TODO: This should produce a fixed-length tuple
+reveal_type(tuple[int, str]((1, "x")))
+[out]
+_testTupleWithDifferentArgsPy310.py:15: note: Revealed type is "Union[builtins.str, Tuple[builtins.float, builtins.float, builtins.str]]"
+_testTupleWithDifferentArgsPy310.py:16: note: Revealed type is "Union[Tuple[builtins.float], builtins.str]"
+_testTupleWithDifferentArgsPy310.py:17: note: Revealed type is "Union[builtins.tuple[builtins.float, ...], builtins.str]"
+_testTupleWithDifferentArgsPy310.py:18: note: Revealed type is "Tuple[builtins.float, builtins.str]"
+_testTupleWithDifferentArgsPy310.py:19: note: Revealed type is "builtins.tuple[builtins.float, ...]"
+_testTupleWithDifferentArgsPy310.py:20: note: Revealed type is "builtins.list[Tuple[builtins.int, builtins.str]]"
+_testTupleWithDifferentArgsPy310.py:26: error: Invalid type: try using Literal[1] instead?
+_testTupleWithDifferentArgsPy310.py:27: error: Unexpected "..."
+_testTupleWithDifferentArgsPy310.py:30: note: Revealed type is "builtins.tuple[builtins.object, ...]"

From 278a09537ac51a131b1298e4d1ba015bac3fc8c5 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 25 Nov 2022 17:27:37 +0000
Subject: [PATCH 079/231] Fix crash on overriding with frozen attrs (#14186)

Fixes #6715

Fix is straightforward, currently we assume that if we have a variable
in MRO, and its name appears in current class, it is from this class,
which in fact may not be the case when a variable is overridden with a
property or method.

I also add a test case for a crash that was previously reported in the
same issue but is already (accidentally?) fixed.
---
 mypy/plugins/attrs.py          |  6 ++++-
 test-data/unit/check-attr.test | 46 ++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/mypy/plugins/attrs.py b/mypy/plugins/attrs.py
index 17f1794d8c75d..ce0f45967152c 100644
--- a/mypy/plugins/attrs.py
+++ b/mypy/plugins/attrs.py
@@ -736,7 +736,11 @@ def _make_frozen(ctx: mypy.plugin.ClassDefContext, attributes: list[Attribute])
         if attribute.name in ctx.cls.info.names:
             # This variable belongs to this class so we can modify it.
             node = ctx.cls.info.names[attribute.name].node
-            assert isinstance(node, Var)
+            if not isinstance(node, Var):
+                # The superclass attribute was overridden with a non-variable.
+                # No need to do anything here, override will be verified during
+                # type checking.
+                continue
             node.is_property = True
         else:
             # This variable belongs to a super class so create new Var so we
diff --git a/test-data/unit/check-attr.test b/test-data/unit/check-attr.test
index fe123acfa0016..4d27d5f39d1e7 100644
--- a/test-data/unit/check-attr.test
+++ b/test-data/unit/check-attr.test
@@ -1788,3 +1788,49 @@ class C:
 c = C(x=[C.D()])
 reveal_type(c.x)  # N: Revealed type is "builtins.list[__main__.C.D]"
 [builtins fixtures/list.pyi]
+
+[case testRedefinitionInFrozenClassNoCrash]
+import attr
+
+@attr.s
+class MyData:
+    is_foo: bool = attr.ib()
+
+    @staticmethod  # E: Name "is_foo" already defined on line 5
+    def is_foo(string: str) -> bool: ...
+[builtins fixtures/classmethod.pyi]
+
+[case testOverrideWithPropertyInFrozenClassNoCrash]
+from attrs import frozen
+
+@frozen(kw_only=True)
+class Base:
+    name: str
+
+@frozen(kw_only=True)
+class Sub(Base):
+    first_name: str
+    last_name: str
+
+    @property
+    def name(self) -> str: ...
+[builtins fixtures/property.pyi]
+
+[case testOverrideWithPropertyInFrozenClassChecked]
+from attrs import frozen
+
+@frozen(kw_only=True)
+class Base:
+    name: str
+
+@frozen(kw_only=True)
+class Sub(Base):
+    first_name: str
+    last_name: str
+
+    @property
+    def name(self) -> int: ...  # E: Signature of "name" incompatible with supertype "Base"
+
+# This matches runtime semantics
+reveal_type(Sub)  # N: Revealed type is "def (*, name: builtins.str, first_name: builtins.str, last_name: builtins.str) -> __main__.Sub"
+[builtins fixtures/property.pyi]

From db0beb1014d8367221d47d3b11e2b49e757fa2fa Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <stas@dropbox.com>
Date: Fri, 25 Nov 2022 14:03:39 -0600
Subject: [PATCH 080/231] Switch error code used to report vars defined in
 different branch (#14176)

We previously used `use-before-def` code here but this commit switched
it to use `partially-defined`. This particular check generates a lot of
false positives, in particular around loops of the form:
```python
for i in range(2)
  if i == 0:
    x = 1
  else:
    y = x
```

While in an ideal world mypy has no false positives, it's not feasible
for us to handle this correctly in the short-term. Moving this to
partially-defined error code makes the `use-before-def` have a much
lower false positive rate, which is a plus. Unfortunately,
`partially-defined` will always have a higher false positive rate. This
means that if we enable it by default, lots of people will disable this
check. We want to avoid the same thing happening to use-before-def
check.

See [this
PR](https://github.com/python/mypy/pull/14166#issuecomment-1325709734)
for further discussion.
---
 mypy/partially_defined.py                   | 10 +++-
 test-data/unit/check-partially-defined.test | 60 +++++++++++++++------
 2 files changed, 53 insertions(+), 17 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 70a454beae9c3..7e71af4044edd 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -234,6 +234,7 @@ class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
     def __init__(self, msg: MessageBuilder, type_map: dict[Expression, Type]) -> None:
         self.msg = msg
         self.type_map = type_map
+        self.loop_depth = 0
         self.tracker = DefinedVariableTracker()
 
     def process_lvalue(self, lvalue: Lvalue | None) -> None:
@@ -319,10 +320,12 @@ def visit_for_stmt(self, o: ForStmt) -> None:
         self.process_lvalue(o.index)
         o.index.accept(self)
         self.tracker.start_branch_statement()
+        self.loop_depth += 1
         o.body.accept(self)
         self.tracker.next_branch()
         if o.else_body:
             o.else_body.accept(self)
+        self.loop_depth -= 1
         self.tracker.end_branch_statement()
 
     def visit_return_stmt(self, o: ReturnStmt) -> None:
@@ -354,7 +357,9 @@ def visit_expression_stmt(self, o: ExpressionStmt) -> None:
     def visit_while_stmt(self, o: WhileStmt) -> None:
         o.expr.accept(self)
         self.tracker.start_branch_statement()
+        self.loop_depth += 1
         o.body.accept(self)
+        self.loop_depth -= 1
         if not checker.is_true_literal(o.expr):
             self.tracker.next_branch()
             if o.else_body:
@@ -380,7 +385,10 @@ def visit_name_expr(self, o: NameExpr) -> None:
             self.tracker.record_definition(o.name)
         elif self.tracker.is_defined_in_different_branch(o.name):
             # A variable is defined in one branch but used in a different branch.
-            self.msg.var_used_before_def(o.name, o)
+            if self.loop_depth > 0:
+                self.msg.variable_may_be_undefined(o.name, o)
+            else:
+                self.msg.var_used_before_def(o.name, o)
         elif self.tracker.is_undefined(o.name):
             # A variable is undefined. It could be due to two things:
             # 1. A variable is just totally undefined
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index c63023aa2746b..2028362cedbeb 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -206,6 +206,48 @@ def f5() -> int:
         return 3
     return 1
 
+[case testDefinedDifferentBranchUseBeforeDef]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+
+def f0() -> None:
+    if int():
+        x = 0
+    else:
+        y = x  # E: Name "x" is used before definition
+        z = x  # E: Name "x" is used before definition
+
+def f1() -> None:
+    x = 1
+    if int():
+        x = 0
+    else:
+        y = x  # No error.
+
+
+[case testDefinedDifferentBranchPartiallyDefined]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+
+def f0() -> None:
+    first_iter = True
+    for i in [0, 1]:
+        if first_iter:
+            first_iter = False
+            x = 0
+        else:
+            # This is technically a false positive but mypy isn't smart enough for this yet.
+            y = x  # E: Name "x" may be undefined
+            z = x  # E: Name "x" may be undefined
+
+
+def f1() -> None:
+    while True:
+        if int():
+            x = 0
+        else:
+            y = x  # E: Name "x" may be undefined
+            z = x  # E: Name "x" may be undefined
+
+
 [case testAssert]
 # flags: --enable-error-code partially-defined
 def f1() -> int:
@@ -394,21 +436,7 @@ def f0() -> None:
     x = y  # E: Name "y" is used before definition
     y: int = 1
 
-def f1() -> None:
-    if int():
-        x = 0
-    else:
-        y = x  # E: Name "x" is used before definition
-        z = x  # E: Name "x" is used before definition
-
 def f2() -> None:
-    x = 1
-    if int():
-        x = 0
-    else:
-        y = x  # No error.
-
-def f3() -> None:
     if int():
         pass
     else:
@@ -418,14 +446,14 @@ def f3() -> None:
     def inner2() -> None:
         z = 0
 
-def f4() -> None:
+def f3() -> None:
     if int():
         pass
     else:
         y = z  # E: Name "z" is used before definition
     z: int = 2
 
-def f5() -> None:
+def f4() -> None:
     if int():
         pass
     else:

From d58a851463fca5f2512c66e3db7ecee0d26d1eae Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Fri, 25 Nov 2022 15:02:56 -0600
Subject: [PATCH 081/231] Implement miscellaneous fixes for partially-defined
 check (#14175)

These are the issues that I've found using mypy-primer.

You should be able to review this PR commit-by-commit. Each commit
includes the relevant tests:
- Process imports correctly
- Support for function names
- Skip stub files (this change has no tests)
- Handle builtins and implicit module attrs (e.g. `str` and `__doc__`)
- Improved support for lambdas.
---
 mypy/build.py                               |   3 +
 mypy/partially_defined.py                   |  43 +++++++
 test-data/unit/check-partially-defined.test | 121 ++++++++++++++++++++
 3 files changed, 167 insertions(+)

diff --git a/mypy/build.py b/mypy/build.py
index b32276dd30208..8df5e480791d6 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2349,6 +2349,9 @@ def type_check_second_pass(self) -> bool:
 
     def detect_partially_defined_vars(self, type_map: dict[Expression, Type]) -> None:
         assert self.tree is not None, "Internal error: method must be called on parsed file only"
+        if self.tree.is_stub:
+            # We skip stub files because they aren't actually executed.
+            return
         manager = self.manager
         if manager.errors.is_error_code_enabled(
             codes.PARTIALLY_DEFINED
diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 7e71af4044edd..4ca083f5e4c50 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -16,15 +16,21 @@
     FuncItem,
     GeneratorExpr,
     IfStmt,
+    Import,
+    ImportFrom,
+    LambdaExpr,
     ListExpr,
     Lvalue,
     MatchStmt,
     NameExpr,
     RaiseStmt,
+    RefExpr,
     ReturnStmt,
+    StarExpr,
     TupleExpr,
     WhileStmt,
     WithStmt,
+    implicit_module_attrs,
 )
 from mypy.patterns import AsPattern, StarredPattern
 from mypy.reachability import ALWAYS_TRUE, infer_pattern_value
@@ -213,6 +219,10 @@ def is_undefined(self, name: str) -> bool:
         return self._scope().branch_stmts[-1].is_undefined(name)
 
 
+def refers_to_builtin(o: RefExpr) -> bool:
+    return o.fullname is not None and o.fullname.startswith("builtins.")
+
+
 class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
     """Detects the following cases:
     - A variable that's defined only part of the time.
@@ -236,6 +246,8 @@ def __init__(self, msg: MessageBuilder, type_map: dict[Expression, Type]) -> Non
         self.type_map = type_map
         self.loop_depth = 0
         self.tracker = DefinedVariableTracker()
+        for name in implicit_module_attrs:
+            self.tracker.record_definition(name)
 
     def process_lvalue(self, lvalue: Lvalue | None) -> None:
         if isinstance(lvalue, NameExpr):
@@ -244,6 +256,8 @@ def process_lvalue(self, lvalue: Lvalue | None) -> None:
             for ref in refs:
                 self.msg.var_used_before_def(lvalue.name, ref)
             self.tracker.record_definition(lvalue.name)
+        elif isinstance(lvalue, StarExpr):
+            self.process_lvalue(lvalue.expr)
         elif isinstance(lvalue, (ListExpr, TupleExpr)):
             for item in lvalue.items:
                 self.process_lvalue(item)
@@ -291,6 +305,7 @@ def visit_match_stmt(self, o: MatchStmt) -> None:
         self.tracker.end_branch_statement()
 
     def visit_func_def(self, o: FuncDef) -> None:
+        self.tracker.record_definition(o.name)
         self.tracker.enter_scope()
         super().visit_func_def(o)
         self.tracker.exit_scope()
@@ -332,6 +347,11 @@ def visit_return_stmt(self, o: ReturnStmt) -> None:
         super().visit_return_stmt(o)
         self.tracker.skip_branch()
 
+    def visit_lambda_expr(self, o: LambdaExpr) -> None:
+        self.tracker.enter_scope()
+        super().visit_lambda_expr(o)
+        self.tracker.exit_scope()
+
     def visit_assert_stmt(self, o: AssertStmt) -> None:
         super().visit_assert_stmt(o)
         if checker.is_false_literal(o.expr):
@@ -377,6 +397,8 @@ def visit_starred_pattern(self, o: StarredPattern) -> None:
         super().visit_starred_pattern(o)
 
     def visit_name_expr(self, o: NameExpr) -> None:
+        if refers_to_builtin(o):
+            return
         if self.tracker.is_partially_defined(o.name):
             # A variable is only defined in some branches.
             if self.msg.errors.is_error_code_enabled(errorcodes.PARTIALLY_DEFINED):
@@ -404,3 +426,24 @@ def visit_with_stmt(self, o: WithStmt) -> None:
             expr.accept(self)
             self.process_lvalue(idx)
         o.body.accept(self)
+
+    def visit_import(self, o: Import) -> None:
+        for mod, alias in o.ids:
+            if alias is not None:
+                self.tracker.record_definition(alias)
+            else:
+                # When you do `import x.y`, only `x` becomes defined.
+                names = mod.split(".")
+                if len(names) > 0:
+                    # `names` should always be nonempty, but we don't want mypy
+                    # to crash on invalid code.
+                    self.tracker.record_definition(names[0])
+        super().visit_import(o)
+
+    def visit_import_from(self, o: ImportFrom) -> None:
+        for mod, alias in o.names:
+            name = alias
+            if name is None:
+                name = mod
+            self.tracker.record_definition(name)
+        super().visit_import_from(o)
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index 2028362cedbeb..85bf08079f793 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -90,6 +90,16 @@ else:
 a = y + x  # E: Name "x" may be undefined
 a = y + z  # E: Name "z" may be undefined
 
+[case testIndexExpr]
+# flags: --enable-error-code partially-defined
+
+if int():
+    *x, y = (1, 2)
+else:
+    x = [1, 2]
+a = x  # No error.
+b = y  # E: Name "y" may be undefined
+
 [case testRedefined]
 # flags: --enable-error-code partially-defined
 y = 3
@@ -104,6 +114,32 @@ else:
 
 x = y + 2
 
+[case testFunction]
+# flags: --enable-error-code partially-defined
+def f0() -> None:
+    if int():
+        def some_func() -> None:
+            pass
+
+    some_func()  # E: Name "some_func" may be undefined
+
+def f1() -> None:
+    if int():
+        def some_func() -> None:
+            pass
+    else:
+        def some_func() -> None:
+            pass
+
+    some_func()  # No error.
+
+[case testLambda]
+# flags: --enable-error-code partially-defined
+def f0(b: bool) -> None:
+    if b:
+        fn = lambda: 2
+    y = fn   # E: Name "fn" may be undefined
+
 [case testGenerator]
 # flags: --enable-error-code partially-defined
 if int():
@@ -460,3 +496,88 @@ def f4() -> None:
         y = z  # E: Name "z" is used before definition
         x = z  # E: Name "z" is used before definition
     z: int = 2
+
+[case testUseBeforeDefImportsBasic]
+# flags: --enable-error-code use-before-def
+import foo  # type: ignore
+import x.y  # type: ignore
+
+def f0() -> None:
+    a = foo  # No error.
+    foo: int = 1
+
+def f1() -> None:
+    a = y  # E: Name "y" is used before definition
+    y: int = 1
+
+def f2() -> None:
+    a = x  # No error.
+    x: int = 1
+
+def f3() -> None:
+    a = x.y  # No error.
+    x: int = 1
+
+[case testUseBeforeDefImportBasicRename]
+# flags: --enable-error-code use-before-def
+import x.y as z  # type: ignore
+from typing import Any
+
+def f0() -> None:
+    a = z  # No error.
+    z: int = 1
+
+def f1() -> None:
+    a = x  # E: Name "x" is used before definition
+    x: int = 1
+
+def f2() -> None:
+    a = x.y  # E: Name "x" is used before definition
+    x: Any = 1
+
+def f3() -> None:
+    a = y  # E: Name "y" is used before definition
+    y: int = 1
+
+[case testUseBeforeDefImportFrom]
+# flags: --enable-error-code use-before-def
+from foo import x  # type: ignore
+
+def f0() -> None:
+    a = x  # No error.
+    x: int = 1
+
+[case testUseBeforeDefImportFromRename]
+# flags: --enable-error-code use-before-def
+from foo import x as y  # type: ignore
+
+def f0() -> None:
+    a = y  # No error.
+    y: int = 1
+
+def f1() -> None:
+    a = x  # E: Name "x" is used before definition
+    x: int = 1
+
+[case testUseBeforeDefFunctionDeclarations]
+# flags: --enable-error-code use-before-def
+
+def f0() -> None:
+    def inner() -> None:
+        pass
+
+    inner()  # No error.
+    inner = lambda: None
+
+[case testUseBeforeDefBuiltins]
+# flags: --enable-error-code use-before-def
+
+def f0() -> None:
+    s = type(123)
+    type = "abc"
+    a = type
+
+[case testUseBeforeDefImplicitModuleAttrs]
+# flags: --enable-error-code use-before-def
+a = __name__  # No error.
+__name__ = "abc"

From a9c62c5f82f34a923b8117a5394983aefce37b63 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Fri, 25 Nov 2022 14:57:08 -0800
Subject: [PATCH 082/231] stubtest: if a default is present in the stub, check
 that it is correct (#14085)

Helps with python/typeshed#8988.
---
 mypy/evalexpr.py          | 204 ++++++++++++++++++++++++++++++++++++++
 mypy/stubtest.py          |  19 ++++
 mypy/test/teststubtest.py |  55 +++++++++-
 3 files changed, 277 insertions(+), 1 deletion(-)
 create mode 100644 mypy/evalexpr.py

diff --git a/mypy/evalexpr.py b/mypy/evalexpr.py
new file mode 100644
index 0000000000000..2bc6966fa2fac
--- /dev/null
+++ b/mypy/evalexpr.py
@@ -0,0 +1,204 @@
+"""
+
+Evaluate an expression.
+
+Used by stubtest; in a separate file because things break if we don't
+put it in a mypyc-compiled file.
+
+"""
+import ast
+from typing_extensions import Final
+
+import mypy.nodes
+from mypy.visitor import ExpressionVisitor
+
+UNKNOWN = object()
+
+
+class _NodeEvaluator(ExpressionVisitor[object]):
+    def visit_int_expr(self, o: mypy.nodes.IntExpr) -> int:
+        return o.value
+
+    def visit_str_expr(self, o: mypy.nodes.StrExpr) -> str:
+        return o.value
+
+    def visit_bytes_expr(self, o: mypy.nodes.BytesExpr) -> object:
+        # The value of a BytesExpr is a string created from the repr()
+        # of the bytes object. Get the original bytes back.
+        try:
+            return ast.literal_eval(f"b'{o.value}'")
+        except SyntaxError:
+            return ast.literal_eval(f'b"{o.value}"')
+
+    def visit_float_expr(self, o: mypy.nodes.FloatExpr) -> float:
+        return o.value
+
+    def visit_complex_expr(self, o: mypy.nodes.ComplexExpr) -> object:
+        return o.value
+
+    def visit_ellipsis(self, o: mypy.nodes.EllipsisExpr) -> object:
+        return Ellipsis
+
+    def visit_star_expr(self, o: mypy.nodes.StarExpr) -> object:
+        return UNKNOWN
+
+    def visit_name_expr(self, o: mypy.nodes.NameExpr) -> object:
+        if o.name == "True":
+            return True
+        elif o.name == "False":
+            return False
+        elif o.name == "None":
+            return None
+        # TODO: Handle more names by figuring out a way to hook into the
+        # symbol table.
+        return UNKNOWN
+
+    def visit_member_expr(self, o: mypy.nodes.MemberExpr) -> object:
+        return UNKNOWN
+
+    def visit_yield_from_expr(self, o: mypy.nodes.YieldFromExpr) -> object:
+        return UNKNOWN
+
+    def visit_yield_expr(self, o: mypy.nodes.YieldExpr) -> object:
+        return UNKNOWN
+
+    def visit_call_expr(self, o: mypy.nodes.CallExpr) -> object:
+        return UNKNOWN
+
+    def visit_op_expr(self, o: mypy.nodes.OpExpr) -> object:
+        return UNKNOWN
+
+    def visit_comparison_expr(self, o: mypy.nodes.ComparisonExpr) -> object:
+        return UNKNOWN
+
+    def visit_cast_expr(self, o: mypy.nodes.CastExpr) -> object:
+        return o.expr.accept(self)
+
+    def visit_assert_type_expr(self, o: mypy.nodes.AssertTypeExpr) -> object:
+        return o.expr.accept(self)
+
+    def visit_reveal_expr(self, o: mypy.nodes.RevealExpr) -> object:
+        return UNKNOWN
+
+    def visit_super_expr(self, o: mypy.nodes.SuperExpr) -> object:
+        return UNKNOWN
+
+    def visit_unary_expr(self, o: mypy.nodes.UnaryExpr) -> object:
+        operand = o.expr.accept(self)
+        if operand is UNKNOWN:
+            return UNKNOWN
+        if o.op == "-":
+            if isinstance(operand, (int, float, complex)):
+                return -operand
+        elif o.op == "+":
+            if isinstance(operand, (int, float, complex)):
+                return +operand
+        elif o.op == "~":
+            if isinstance(operand, int):
+                return ~operand
+        elif o.op == "not":
+            if isinstance(operand, (bool, int, float, str, bytes)):
+                return not operand
+        return UNKNOWN
+
+    def visit_assignment_expr(self, o: mypy.nodes.AssignmentExpr) -> object:
+        return o.value.accept(self)
+
+    def visit_list_expr(self, o: mypy.nodes.ListExpr) -> object:
+        items = [item.accept(self) for item in o.items]
+        if all(item is not UNKNOWN for item in items):
+            return items
+        return UNKNOWN
+
+    def visit_dict_expr(self, o: mypy.nodes.DictExpr) -> object:
+        items = [
+            (UNKNOWN if key is None else key.accept(self), value.accept(self))
+            for key, value in o.items
+        ]
+        if all(key is not UNKNOWN and value is not None for key, value in items):
+            return dict(items)
+        return UNKNOWN
+
+    def visit_tuple_expr(self, o: mypy.nodes.TupleExpr) -> object:
+        items = [item.accept(self) for item in o.items]
+        if all(item is not UNKNOWN for item in items):
+            return tuple(items)
+        return UNKNOWN
+
+    def visit_set_expr(self, o: mypy.nodes.SetExpr) -> object:
+        items = [item.accept(self) for item in o.items]
+        if all(item is not UNKNOWN for item in items):
+            return set(items)
+        return UNKNOWN
+
+    def visit_index_expr(self, o: mypy.nodes.IndexExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_application(self, o: mypy.nodes.TypeApplication) -> object:
+        return UNKNOWN
+
+    def visit_lambda_expr(self, o: mypy.nodes.LambdaExpr) -> object:
+        return UNKNOWN
+
+    def visit_list_comprehension(self, o: mypy.nodes.ListComprehension) -> object:
+        return UNKNOWN
+
+    def visit_set_comprehension(self, o: mypy.nodes.SetComprehension) -> object:
+        return UNKNOWN
+
+    def visit_dictionary_comprehension(self, o: mypy.nodes.DictionaryComprehension) -> object:
+        return UNKNOWN
+
+    def visit_generator_expr(self, o: mypy.nodes.GeneratorExpr) -> object:
+        return UNKNOWN
+
+    def visit_slice_expr(self, o: mypy.nodes.SliceExpr) -> object:
+        return UNKNOWN
+
+    def visit_conditional_expr(self, o: mypy.nodes.ConditionalExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_var_expr(self, o: mypy.nodes.TypeVarExpr) -> object:
+        return UNKNOWN
+
+    def visit_paramspec_expr(self, o: mypy.nodes.ParamSpecExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_var_tuple_expr(self, o: mypy.nodes.TypeVarTupleExpr) -> object:
+        return UNKNOWN
+
+    def visit_type_alias_expr(self, o: mypy.nodes.TypeAliasExpr) -> object:
+        return UNKNOWN
+
+    def visit_namedtuple_expr(self, o: mypy.nodes.NamedTupleExpr) -> object:
+        return UNKNOWN
+
+    def visit_enum_call_expr(self, o: mypy.nodes.EnumCallExpr) -> object:
+        return UNKNOWN
+
+    def visit_typeddict_expr(self, o: mypy.nodes.TypedDictExpr) -> object:
+        return UNKNOWN
+
+    def visit_newtype_expr(self, o: mypy.nodes.NewTypeExpr) -> object:
+        return UNKNOWN
+
+    def visit__promote_expr(self, o: mypy.nodes.PromoteExpr) -> object:
+        return UNKNOWN
+
+    def visit_await_expr(self, o: mypy.nodes.AwaitExpr) -> object:
+        return UNKNOWN
+
+    def visit_temp_node(self, o: mypy.nodes.TempNode) -> object:
+        return UNKNOWN
+
+
+_evaluator: Final = _NodeEvaluator()
+
+
+def evaluate_expression(expr: mypy.nodes.Expression) -> object:
+    """Evaluate an expression at runtime.
+
+    Return the result of the expression, or UNKNOWN if the expression cannot be
+    evaluated.
+    """
+    return expr.accept(_evaluator)
diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 74e57d9e5617b..8add8178823aa 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -29,11 +29,13 @@
 
 import mypy.build
 import mypy.modulefinder
+import mypy.nodes
 import mypy.state
 import mypy.types
 import mypy.version
 from mypy import nodes
 from mypy.config_parser import parse_config_file
+from mypy.evalexpr import UNKNOWN, evaluate_expression
 from mypy.options import Options
 from mypy.util import FancyFormatter, bytes_to_human_readable_repr, is_dunder, plural_s
 
@@ -573,6 +575,23 @@ def _verify_arg_default_value(
                     f"has a default value of type {runtime_type}, "
                     f"which is incompatible with stub argument type {stub_type}"
                 )
+            if stub_arg.initializer is not None:
+                stub_default = evaluate_expression(stub_arg.initializer)
+                if (
+                    stub_default is not UNKNOWN
+                    and stub_default is not ...
+                    and (
+                        stub_default != runtime_arg.default
+                        # We want the types to match exactly, e.g. in case the stub has
+                        # True and the runtime has 1 (or vice versa).
+                        or type(stub_default) is not type(runtime_arg.default)  # noqa: E721
+                    )
+                ):
+                    yield (
+                        f'runtime argument "{runtime_arg.name}" '
+                        f"has a default value of {runtime_arg.default!r}, "
+                        f"which is different from stub argument default {stub_default!r}"
+                    )
     else:
         if stub_arg.kind.is_optional():
             yield (
diff --git a/mypy/test/teststubtest.py b/mypy/test/teststubtest.py
index 5a6904bfaaf4a..e863f4f575688 100644
--- a/mypy/test/teststubtest.py
+++ b/mypy/test/teststubtest.py
@@ -302,7 +302,7 @@ def test_arg_kind(self) -> Iterator[Case]:
             )
 
     @collect_cases
-    def test_default_value(self) -> Iterator[Case]:
+    def test_default_presence(self) -> Iterator[Case]:
         yield Case(
             stub="def f1(text: str = ...) -> None: ...",
             runtime="def f1(text = 'asdf'): pass",
@@ -336,6 +336,59 @@ def f6(text: _T = ...) -> None: ...
             error="f6",
         )
 
+    @collect_cases
+    def test_default_value(self) -> Iterator[Case]:
+        yield Case(
+            stub="def f1(text: str = 'x') -> None: ...",
+            runtime="def f1(text = 'y'): pass",
+            error="f1",
+        )
+        yield Case(
+            stub='def f2(text: bytes = b"x\'") -> None: ...',
+            runtime='def f2(text = b"x\'"): pass',
+            error=None,
+        )
+        yield Case(
+            stub='def f3(text: bytes = b"y\'") -> None: ...',
+            runtime='def f3(text = b"x\'"): pass',
+            error="f3",
+        )
+        yield Case(
+            stub="def f4(text: object = 1) -> None: ...",
+            runtime="def f4(text = 1.0): pass",
+            error="f4",
+        )
+        yield Case(
+            stub="def f5(text: object = True) -> None: ...",
+            runtime="def f5(text = 1): pass",
+            error="f5",
+        )
+        yield Case(
+            stub="def f6(text: object = True) -> None: ...",
+            runtime="def f6(text = True): pass",
+            error=None,
+        )
+        yield Case(
+            stub="def f7(text: object = not True) -> None: ...",
+            runtime="def f7(text = False): pass",
+            error=None,
+        )
+        yield Case(
+            stub="def f8(text: object = not True) -> None: ...",
+            runtime="def f8(text = True): pass",
+            error="f8",
+        )
+        yield Case(
+            stub="def f9(text: object = {1: 2}) -> None: ...",
+            runtime="def f9(text = {1: 3}): pass",
+            error="f9",
+        )
+        yield Case(
+            stub="def f10(text: object = [1, 2]) -> None: ...",
+            runtime="def f10(text = [1, 2]): pass",
+            error=None,
+        )
+
     @collect_cases
     def test_static_class_method(self) -> Iterator[Case]:
         yield Case(

From 5795488903f807211d267d3319d153c30e74b77e Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Sun, 27 Nov 2022 09:40:05 -0600
Subject: [PATCH 083/231] [partially defined] fix gating by error code (#14194)

This was incorrect for a few callsites. I refactored the code to make it
harder to make a mistake like this.

This wasn't visible before because we only run the
PartillyDefinedVisitor if either of the error codes reported by it are
enabled.
---
 mypy/partially_defined.py | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 4ca083f5e4c50..9a8c397c0c28a 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -7,6 +7,7 @@
     AssignmentExpr,
     AssignmentStmt,
     BreakStmt,
+    Context,
     ContinueStmt,
     DictionaryComprehension,
     Expression,
@@ -249,12 +250,20 @@ def __init__(self, msg: MessageBuilder, type_map: dict[Expression, Type]) -> Non
         for name in implicit_module_attrs:
             self.tracker.record_definition(name)
 
+    def var_used_before_def(self, name: str, context: Context) -> None:
+        if self.msg.errors.is_error_code_enabled(errorcodes.USE_BEFORE_DEF):
+            self.msg.var_used_before_def(name, context)
+
+    def variable_may_be_undefined(self, name: str, context: Context) -> None:
+        if self.msg.errors.is_error_code_enabled(errorcodes.PARTIALLY_DEFINED):
+            self.msg.variable_may_be_undefined(name, context)
+
     def process_lvalue(self, lvalue: Lvalue | None) -> None:
         if isinstance(lvalue, NameExpr):
             # Was this name previously used? If yes, it's a use-before-definition error.
             refs = self.tracker.pop_undefined_ref(lvalue.name)
             for ref in refs:
-                self.msg.var_used_before_def(lvalue.name, ref)
+                self.var_used_before_def(lvalue.name, ref)
             self.tracker.record_definition(lvalue.name)
         elif isinstance(lvalue, StarExpr):
             self.process_lvalue(lvalue.expr)
@@ -401,16 +410,15 @@ def visit_name_expr(self, o: NameExpr) -> None:
             return
         if self.tracker.is_partially_defined(o.name):
             # A variable is only defined in some branches.
-            if self.msg.errors.is_error_code_enabled(errorcodes.PARTIALLY_DEFINED):
-                self.msg.variable_may_be_undefined(o.name, o)
+            self.variable_may_be_undefined(o.name, o)
             # We don't want to report the error on the same variable multiple times.
             self.tracker.record_definition(o.name)
         elif self.tracker.is_defined_in_different_branch(o.name):
             # A variable is defined in one branch but used in a different branch.
             if self.loop_depth > 0:
-                self.msg.variable_may_be_undefined(o.name, o)
+                self.variable_may_be_undefined(o.name, o)
             else:
-                self.msg.var_used_before_def(o.name, o)
+                self.var_used_before_def(o.name, o)
         elif self.tracker.is_undefined(o.name):
             # A variable is undefined. It could be due to two things:
             # 1. A variable is just totally undefined

From a82c288890e80ec85cc8d84985a65d6c4b7f9ffe Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Sun, 27 Nov 2022 12:06:01 -0600
Subject: [PATCH 084/231] [partially defined] rework handling of else in loops
 (#14191)

`else` in loops is executed if the loop didn't exit via a raise, return,
or a break. Therefore, we should treat it execution as unconditional if
there is not a break statement.

This PR also improves error messages in `else`, reporting them as "may
be undefined" instead of "used before definition"

Fixes #14097

Co-authored-by: Ivan Levkivskyi <levkivskyi@gmail.com>
---
 mypy/partially_defined.py                   | 49 +++++++++++++----
 test-data/unit/check-partially-defined.test | 59 ++++++++++++++++-----
 2 files changed, 86 insertions(+), 22 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 9a8c397c0c28a..0005282d92a9d 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -224,6 +224,11 @@ def refers_to_builtin(o: RefExpr) -> bool:
     return o.fullname is not None and o.fullname.startswith("builtins.")
 
 
+class Loop:
+    def __init__(self) -> None:
+        self.has_break = False
+
+
 class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
     """Detects the following cases:
     - A variable that's defined only part of the time.
@@ -245,7 +250,7 @@ class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
     def __init__(self, msg: MessageBuilder, type_map: dict[Expression, Type]) -> None:
         self.msg = msg
         self.type_map = type_map
-        self.loop_depth = 0
+        self.loops: list[Loop] = []
         self.tracker = DefinedVariableTracker()
         for name in implicit_module_attrs:
             self.tracker.record_definition(name)
@@ -344,13 +349,23 @@ def visit_for_stmt(self, o: ForStmt) -> None:
         self.process_lvalue(o.index)
         o.index.accept(self)
         self.tracker.start_branch_statement()
-        self.loop_depth += 1
+        loop = Loop()
+        self.loops.append(loop)
         o.body.accept(self)
         self.tracker.next_branch()
-        if o.else_body:
-            o.else_body.accept(self)
-        self.loop_depth -= 1
         self.tracker.end_branch_statement()
+        if o.else_body is not None:
+            # If the loop has a `break` inside, `else` is executed conditionally.
+            # If the loop doesn't have a `break` either the function will return or
+            # execute the `else`.
+            has_break = loop.has_break
+            if has_break:
+                self.tracker.start_branch_statement()
+                self.tracker.next_branch()
+            o.else_body.accept(self)
+            if has_break:
+                self.tracker.end_branch_statement()
+        self.loops.pop()
 
     def visit_return_stmt(self, o: ReturnStmt) -> None:
         super().visit_return_stmt(o)
@@ -376,6 +391,8 @@ def visit_continue_stmt(self, o: ContinueStmt) -> None:
 
     def visit_break_stmt(self, o: BreakStmt) -> None:
         super().visit_break_stmt(o)
+        if self.loops:
+            self.loops[-1].has_break = True
         self.tracker.skip_branch()
 
     def visit_expression_stmt(self, o: ExpressionStmt) -> None:
@@ -386,14 +403,28 @@ def visit_expression_stmt(self, o: ExpressionStmt) -> None:
     def visit_while_stmt(self, o: WhileStmt) -> None:
         o.expr.accept(self)
         self.tracker.start_branch_statement()
-        self.loop_depth += 1
+        loop = Loop()
+        self.loops.append(loop)
         o.body.accept(self)
-        self.loop_depth -= 1
+        has_break = loop.has_break
         if not checker.is_true_literal(o.expr):
+            # If this is a loop like `while True`, we can consider the body to be
+            # a single branch statement (we're guaranteed that the body is executed at least once).
+            # If not, call next_branch() to make all variables defined there conditional.
             self.tracker.next_branch()
+        self.tracker.end_branch_statement()
+        if o.else_body is not None:
+            # If the loop has a `break` inside, `else` is executed conditionally.
+            # If the loop doesn't have a `break` either the function will return or
+            # execute the `else`.
+            if has_break:
+                self.tracker.start_branch_statement()
+                self.tracker.next_branch()
             if o.else_body:
                 o.else_body.accept(self)
-        self.tracker.end_branch_statement()
+            if has_break:
+                self.tracker.end_branch_statement()
+        self.loops.pop()
 
     def visit_as_pattern(self, o: AsPattern) -> None:
         if o.name is not None:
@@ -415,7 +446,7 @@ def visit_name_expr(self, o: NameExpr) -> None:
             self.tracker.record_definition(o.name)
         elif self.tracker.is_defined_in_different_branch(o.name):
             # A variable is defined in one branch but used in a different branch.
-            if self.loop_depth > 0:
+            if self.loops:
                 self.variable_may_be_undefined(o.name, o)
             else:
                 self.var_used_before_def(o.name, o)
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index 85bf08079f793..e91e7aa65e7b3 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -167,22 +167,49 @@ def foo(a: int) -> None:
 [case testWhile]
 # flags: --enable-error-code partially-defined
 while int():
-    x = 1
+    a = 1
 
-y = x  # E: Name "x" may be undefined
+x = a  # E: Name "a" may be undefined
 
 while int():
-    z = 1
+    b = 1
 else:
-    z = 2
+    b = 2
 
-y = z  # No error.
+y = b  # No error.
 
 while True:
-    k = 1
+    c = 1
     if int():
         break
-y = k # No error.
+y = c  # No error.
+
+# This while loop doesn't have a `break` inside, so we know that the else must always get executed.
+while int():
+    pass
+else:
+    d = 1
+y = d  # No error.
+
+while int():
+    if int():
+        break
+else:
+    e = 1
+# If a while loop has a `break`, it's possible that the else didn't get executed.
+y = e  # E: Name "e" may be undefined
+
+while int():
+    while int():
+        if int():
+            break
+    else:
+        f = 1
+else:
+    g = 2
+
+y = f  # E: Name "f" may be undefined
+y = g
 
 [case testForLoop]
 # flags: --enable-error-code partially-defined
@@ -190,7 +217,6 @@ for x in [1, 2, 3]:
     if x:
         x = 1
     y = x
-    z = 1
 else:
     z = 2
 
@@ -283,6 +309,17 @@ def f1() -> None:
             y = x  # E: Name "x" may be undefined
             z = x  # E: Name "x" may be undefined
 
+def f2() -> None:
+    for i in [0, 1]:
+        x = i
+    else:
+        y = x  # E: Name "x" may be undefined
+
+def f3() -> None:
+    while int():
+        x = 1
+    else:
+        y = x  # E: Name "x" may be undefined
 
 [case testAssert]
 # flags: --enable-error-code partially-defined
@@ -338,16 +375,12 @@ def f2() -> int:
     while int():
         if int():
             x = 1
-            z = 1
         elif int():
             pass
         else:
             continue
         y = x  # E: Name "x" may be undefined
-    else:
-        x = 2
-        z = 2
-    return z  # E: Name "z" may be undefined
+    return x  # E: Name "x" may be undefined
 
 def f3() -> None:
     while True:

From 5c3d306fddd900a2eb66437af05dd36851b221a4 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Sun, 27 Nov 2022 16:06:21 -0600
Subject: [PATCH 085/231] [partially defined] use correct error code in nested
 if statements (#14193)

In order to know to use `partially-defined` code vs `use-before-def`, we
had to check if a variable is defined in any branches, not just in the
current one.
This would cause an error to be reported as a `use-before-def` and not
`partially-defined` code.
---
 mypy/partially_defined.py                   | 14 +++++++-----
 test-data/unit/check-partially-defined.test | 25 ++++++++++++++++++---
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 0005282d92a9d..3c9dec13af704 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -109,11 +109,9 @@ def is_undefined(self, name: str) -> bool:
         branch = self.branches[-1]
         return name not in branch.may_be_defined and name not in branch.must_be_defined
 
-    def is_defined_in_different_branch(self, name: str) -> bool:
+    def is_defined_in_a_branch(self, name: str) -> bool:
         assert len(self.branches) > 0
-        if not self.is_undefined(name):
-            return False
-        for b in self.branches[: len(self.branches) - 1]:
+        for b in self.branches:
             if name in b.must_be_defined or name in b.may_be_defined:
                 return True
         return False
@@ -213,7 +211,13 @@ def is_partially_defined(self, name: str) -> bool:
     def is_defined_in_different_branch(self, name: str) -> bool:
         """This will return true if a variable is defined in a branch that's not the current branch."""
         assert len(self._scope().branch_stmts) > 0
-        return self._scope().branch_stmts[-1].is_defined_in_different_branch(name)
+        stmt = self._scope().branch_stmts[-1]
+        if not stmt.is_undefined(name):
+            return False
+        for stmt in self._scope().branch_stmts:
+            if stmt.is_defined_in_a_branch(name):
+                return True
+        return False
 
     def is_undefined(self, name: str) -> bool:
         assert len(self._scope().branch_stmts) > 0
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index e91e7aa65e7b3..11aa30642314c 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -285,6 +285,19 @@ def f1() -> None:
     else:
         y = x  # No error.
 
+def f2() -> None:
+    if int():
+        x = 0
+    elif int():
+        y = x  # E: Name "x" is used before definition
+    else:
+        y = x  # E: Name "x" is used before definition
+        if int():
+            z = x  # E: Name "x" is used before definition
+            x = 1
+        else:
+            x = 2
+        w = x  # No error.
 
 [case testDefinedDifferentBranchPartiallyDefined]
 # flags: --enable-error-code partially-defined --enable-error-code use-before-def
@@ -295,11 +308,17 @@ def f0() -> None:
         if first_iter:
             first_iter = False
             x = 0
-        else:
+        elif int():
             # This is technically a false positive but mypy isn't smart enough for this yet.
             y = x  # E: Name "x" may be undefined
-            z = x  # E: Name "x" may be undefined
-
+        else:
+            y = x  # E: Name "x" may be undefined
+            if int():
+                z = x  # E: Name "x" may be undefined
+                x = 1
+            else:
+                x = 2
+            w = x  # No error.
 
 def f1() -> None:
     while True:

From 71288c749f1507feab0b2ffcc312f1fb7c33cc46 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Sun, 27 Nov 2022 16:07:29 -0600
Subject: [PATCH 086/231] [partially defined] respect check-untyped-defs flag
 (#14204)

We should not check untyped functions unless --check-untyped-defs is
set.

This is part of the reason why #14166 saw so many new errors reported in
open source projects.
---
 mypy/build.py                               |  2 +-
 mypy/partially_defined.py                   |  8 +++++++-
 test-data/unit/check-partially-defined.test | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index 8df5e480791d6..b85b49483739d 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2359,7 +2359,7 @@ def detect_partially_defined_vars(self, type_map: dict[Expression, Type]) -> Non
             manager.errors.set_file(self.xpath, self.tree.fullname, options=manager.options)
             self.tree.accept(
                 PartiallyDefinedVariableVisitor(
-                    MessageBuilder(manager.errors, manager.modules), type_map
+                    MessageBuilder(manager.errors, manager.modules), type_map, manager.options
                 )
             )
 
diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 3c9dec13af704..c8db4bc5960c8 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -33,6 +33,7 @@
     WithStmt,
     implicit_module_attrs,
 )
+from mypy.options import Options
 from mypy.patterns import AsPattern, StarredPattern
 from mypy.reachability import ALWAYS_TRUE, infer_pattern_value
 from mypy.traverser import ExtendedTraverserVisitor
@@ -251,9 +252,12 @@ class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
     handled by the semantic analyzer.
     """
 
-    def __init__(self, msg: MessageBuilder, type_map: dict[Expression, Type]) -> None:
+    def __init__(
+        self, msg: MessageBuilder, type_map: dict[Expression, Type], options: Options
+    ) -> None:
         self.msg = msg
         self.type_map = type_map
+        self.options = options
         self.loops: list[Loop] = []
         self.tracker = DefinedVariableTracker()
         for name in implicit_module_attrs:
@@ -329,6 +333,8 @@ def visit_func_def(self, o: FuncDef) -> None:
         self.tracker.exit_scope()
 
     def visit_func(self, o: FuncItem) -> None:
+        if o.is_dynamic() and not self.options.check_untyped_defs:
+            return
         if o.arguments is not None:
             for arg in o.arguments:
                 self.tracker.record_definition(arg.variable.name)
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index 11aa30642314c..52822f98ab534 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -633,3 +633,21 @@ def f0() -> None:
 # flags: --enable-error-code use-before-def
 a = __name__  # No error.
 __name__ = "abc"
+
+[case testUntypedDef]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+
+def f():
+    if int():
+        x = 0
+    z = y  # No use-before-def error because def is untyped.
+    y = x  # No partially-defined error because def is untyped.
+
+[case testUntypedDefCheckUntypedDefs]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def --check-untyped-defs
+
+def f():
+    if int():
+        x = 0
+    z = y  # E: Name "y" is used before definition
+    y: int = x  # E: Name "x" may be undefined

From 00ee7d5137854f9ae09060f834a6e988ee04e342 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 28 Nov 2022 01:05:22 +0000
Subject: [PATCH 087/231] Fix a crash when incorrect super() is used outside a
 method (#14208)

Ref #14201
---
 mypy/checkexpr.py               | 7 ++++---
 test-data/unit/check-super.test | 7 +++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index eb585aba42dfc..b97c78cba2fcd 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -4390,13 +4390,14 @@ def visit_super_expr(self, e: SuperExpr) -> Type:
             index = mro.index(type_info)
         else:
             method = self.chk.scope.top_function()
-            assert method is not None
             # Mypy explicitly allows supertype upper bounds (and no upper bound at all)
             # for annotating self-types. However, if such an annotation is used for
             # checking super() we will still get an error. So to be consistent, we also
             # allow such imprecise annotations for use with super(), where we fall back
-            # to the current class MRO instead.
-            if is_self_type_like(instance_type, is_classmethod=method.is_class):
+            # to the current class MRO instead. This works only from inside a method.
+            if method is not None and is_self_type_like(
+                instance_type, is_classmethod=method.is_class
+            ):
                 if e.info and type_info in e.info.mro:
                     mro = e.info.mro
                     index = mro.index(type_info)
diff --git a/test-data/unit/check-super.test b/test-data/unit/check-super.test
index 0913f4f251262..6537f563a99c1 100644
--- a/test-data/unit/check-super.test
+++ b/test-data/unit/check-super.test
@@ -409,3 +409,10 @@ class B(A):
         reveal_type(super().foo())  # N: Revealed type is "T`-1"
         return super().foo()
 [builtins fixtures/classmethod.pyi]
+
+[case testWrongSuperOutsideMethodNoCrash]
+class B:
+    x: int
+class C1(B): ...
+class C2(B): ...
+super(C1, C2).x  # E: Argument 2 for "super" not an instance of argument 1

From 365297c5240af67acb4798a18135dc87b734477b Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 28 Nov 2022 04:21:34 +0000
Subject: [PATCH 088/231] Fix crash in Self type on forward reference in upper
 bound (#14206)

Fixes #14199

This is straightforward, just use the same logic as for regular (user
defined) type variables.
---
 mypy/semanal.py                       |  6 +++++-
 test-data/unit/check-classes.test     | 15 +++++++++++++++
 test-data/unit/check-dataclasses.test | 20 ++++++++++++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 698959ca1bdff..3e1e1a1e5d611 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1047,7 +1047,11 @@ def setup_self_type(self) -> None:
         assert self.type is not None
         info = self.type
         if info.self_type is not None:
-            return
+            if has_placeholder(info.self_type.upper_bound):
+                # Similar to regular (user defined) type variables.
+                self.defer(force_progress=True)
+            else:
+                return
         info.self_type = TypeVarType("Self", f"{info.fullname}.Self", 0, [], fill_typevars(info))
 
     def visit_overloaded_func_def(self, defn: OverloadedFuncDef) -> None:
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index e3aea122ebe1b..8784c73c5b175 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -7679,3 +7679,18 @@ def g(b: Type[Any]) -> None:
 
 def h(b: type) -> None:
     class D(b): ...
+
+[case testNoCrashOnSelfWithForwardRefGenericClass]
+from typing import Generic, Sequence, TypeVar, Self
+
+_T = TypeVar('_T', bound="Foo")
+
+class Foo:
+    foo: int
+
+class Element(Generic[_T]):
+    elements: Sequence[Self]
+
+class Bar(Foo): ...
+e: Element[Bar]
+reveal_type(e.elements)  # N: Revealed type is "typing.Sequence[__main__.Element[__main__.Bar]]"
diff --git a/test-data/unit/check-dataclasses.test b/test-data/unit/check-dataclasses.test
index d289ec5a8e58d..c248f8db85854 100644
--- a/test-data/unit/check-dataclasses.test
+++ b/test-data/unit/check-dataclasses.test
@@ -1981,3 +1981,23 @@ def const_two(x: T) -> str:
 c = Cont(Box(const_two))
 reveal_type(c)  # N: Revealed type is "__main__.Cont[builtins.str]"
 [builtins fixtures/dataclasses.pyi]
+
+[case testNoCrashOnSelfWithForwardRefGenericDataclass]
+from typing import Generic, Sequence, TypeVar, Self
+from dataclasses import dataclass
+
+_T = TypeVar('_T', bound="Foo")
+
+@dataclass
+class Foo:
+    foo: int
+
+@dataclass
+class Element(Generic[_T]):
+    elements: Sequence[Self]
+
+@dataclass
+class Bar(Foo): ...
+e: Element[Bar]
+reveal_type(e.elements)  # N: Revealed type is "typing.Sequence[__main__.Element[__main__.Bar]]"
+[builtins fixtures/dataclasses.pyi]

From 19c7fd3815ca68074da317f8f63627194831dcfe Mon Sep 17 00:00:00 2001
From: Vincent Vanlaer <13833860+VincentVanlaer@users.noreply.github.com>
Date: Mon, 28 Nov 2022 10:02:54 +0100
Subject: [PATCH 089/231] Fix ParamSpec constraint for types as callable
 (#14153)

Most types can be considered as callables, constructing the type itself.
When a constraint was created for a ParamSpec variable, the return type
would be set to NoneType, which conflicts with assumptions that
CallableType makes when it is the constructor of another type, crashing
mypy. This patch replaces the return type by UninhabitedType instead,
which stops CallableType from considering itself as a constructor.
---
 mypy/constraints.py                           |  2 +-
 .../unit/check-parameter-specification.test   | 24 +++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index 4e78e5ff11176..6efb9997d36f1 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -954,7 +954,7 @@ def visit_callable_type(self, template: CallableType) -> list[Constraint]:
                                 arg_types=cactual.arg_types[prefix_len:],
                                 arg_kinds=cactual.arg_kinds[prefix_len:],
                                 arg_names=cactual.arg_names[prefix_len:],
-                                ret_type=NoneType(),
+                                ret_type=UninhabitedType(),
                             ),
                         )
                     )
diff --git a/test-data/unit/check-parameter-specification.test b/test-data/unit/check-parameter-specification.test
index 4a5dd0c1b04ea..463ba3e654662 100644
--- a/test-data/unit/check-parameter-specification.test
+++ b/test-data/unit/check-parameter-specification.test
@@ -1292,6 +1292,30 @@ class C(Generic[P]):
 reveal_type(bar(C(fn=foo, x=1)))  # N: Revealed type is "__main__.C[[x: builtins.int]]"
 [builtins fixtures/paramspec.pyi]
 
+[case testParamSpecClassConstructor]
+# flags: --strict-optional
+from typing import ParamSpec, Callable
+
+P = ParamSpec("P")
+
+class SomeClass:
+    def __init__(self, a: str) -> None:
+        pass
+
+def func(t: Callable[P, SomeClass], val: Callable[P, SomeClass]) -> None:
+    pass
+
+def constructor(a: str) -> SomeClass:
+    return SomeClass(a)
+
+def wrong_constructor(a: bool) -> SomeClass:
+    return SomeClass("a")
+
+func(SomeClass, constructor)
+func(SomeClass, wrong_constructor)  # E: Argument 1 to "func" has incompatible type "Type[SomeClass]"; expected "Callable[[VarArg(<nothing>), KwArg(<nothing>)], SomeClass]" \
+				    # E: Argument 2 to "func" has incompatible type "Callable[[bool], SomeClass]"; expected "Callable[[VarArg(<nothing>), KwArg(<nothing>)], SomeClass]"
+[builtins fixtures/paramspec.pyi]
+
 [case testParamSpecInTypeAliasBasic]
 from typing import ParamSpec, Callable
 

From 8ab0ef1bbcbae730ce94d59b19f024e968cab1dc Mon Sep 17 00:00:00 2001
From: Jonathan Daniel <36337649+jond01@users.noreply.github.com>
Date: Mon, 28 Nov 2022 15:47:23 +0200
Subject: [PATCH 090/231] [docs] Update `running_mypy.rst` - fix typo (#14212)

Fix typo - remove an unneeded period


https://mypy.readthedocs.io/en/stable/running_mypy.html#ignore-missing-imports

![image](https://user-images.githubusercontent.com/36337649/204286512-34a07d28-5417-4857-87a6-f910b33fb81f.png)
---
 docs/source/running_mypy.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/source/running_mypy.rst b/docs/source/running_mypy.rst
index 3deaf26023fcf..4a7b5dcf40930 100644
--- a/docs/source/running_mypy.rst
+++ b/docs/source/running_mypy.rst
@@ -250,7 +250,7 @@ If you are getting this error, try:
 1.  Upgrading the version of the library you're using, in case a newer version
     has started to include type hints.
 
-2.  Searching to see if there is a :ref:`PEP 561 compliant stub package <installed-packages>`.
+2.  Searching to see if there is a :ref:`PEP 561 compliant stub package <installed-packages>`
     corresponding to your third party library. Stub packages let you install
     type hints independently from the library itself.
 

From d094c381277b7bec3c3b9956a53395e989347112 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Mon, 28 Nov 2022 19:00:13 -0600
Subject: [PATCH 091/231] [use before def] handle class and function
 definitions (#14203)

Previously, we would ignore any class definitions and would fail to
detect undefined classes and functions. This updates the logic to handle
them.

Closes #686
---
 mypy/partially_defined.py                   | 22 +++++++++----
 test-data/unit/check-partially-defined.test | 34 +++++++++++++++++++++
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index c8db4bc5960c8..c2c925e0477c2 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -7,6 +7,7 @@
     AssignmentExpr,
     AssignmentStmt,
     BreakStmt,
+    ClassDef,
     Context,
     ContinueStmt,
     DictionaryComprehension,
@@ -271,13 +272,16 @@ def variable_may_be_undefined(self, name: str, context: Context) -> None:
         if self.msg.errors.is_error_code_enabled(errorcodes.PARTIALLY_DEFINED):
             self.msg.variable_may_be_undefined(name, context)
 
+    def process_definition(self, name: str) -> None:
+        # Was this name previously used? If yes, it's a use-before-definition error.
+        refs = self.tracker.pop_undefined_ref(name)
+        for ref in refs:
+            self.var_used_before_def(name, ref)
+        self.tracker.record_definition(name)
+
     def process_lvalue(self, lvalue: Lvalue | None) -> None:
         if isinstance(lvalue, NameExpr):
-            # Was this name previously used? If yes, it's a use-before-definition error.
-            refs = self.tracker.pop_undefined_ref(lvalue.name)
-            for ref in refs:
-                self.var_used_before_def(lvalue.name, ref)
-            self.tracker.record_definition(lvalue.name)
+            self.process_definition(lvalue.name)
         elif isinstance(lvalue, StarExpr):
             self.process_lvalue(lvalue.expr)
         elif isinstance(lvalue, (ListExpr, TupleExpr)):
@@ -327,7 +331,7 @@ def visit_match_stmt(self, o: MatchStmt) -> None:
         self.tracker.end_branch_statement()
 
     def visit_func_def(self, o: FuncDef) -> None:
-        self.tracker.record_definition(o.name)
+        self.process_definition(o.name)
         self.tracker.enter_scope()
         super().visit_func_def(o)
         self.tracker.exit_scope()
@@ -476,6 +480,12 @@ def visit_with_stmt(self, o: WithStmt) -> None:
             self.process_lvalue(idx)
         o.body.accept(self)
 
+    def visit_class_def(self, o: ClassDef) -> None:
+        self.process_definition(o.name)
+        self.tracker.enter_scope()
+        super().visit_class_def(o)
+        self.tracker.exit_scope()
+
     def visit_import(self, o: Import) -> None:
         for mod, alias in o.ids:
             if alias is not None:
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index 52822f98ab534..7c10306684ca8 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -140,6 +140,40 @@ def f0(b: bool) -> None:
         fn = lambda: 2
     y = fn   # E: Name "fn" may be undefined
 
+[case testUseBeforeDefClass]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def f(x: A):  # No error here.
+    pass
+y = A()  # E: Name "A" is used before definition
+class A: pass
+
+[case testClassScope]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+class C:
+    x = 0
+    def f0(self) -> None: pass
+
+    def f2(self) -> None:
+        f0()  # No error.
+        self.f0()  # No error.
+
+f0()  # E: Name "f0" is used before definition
+def f0() -> None: pass
+y = x  # E: Name "x" is used before definition
+x = 1
+
+[case testClassInsideFunction]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def f() -> None:
+    class C: pass
+
+c = C()  # E: Name "C" is used before definition
+class C: pass
+
+[case testUseBeforeDefFunc]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+foo() # E: Name "foo" is used before definition
+def foo(): pass
 [case testGenerator]
 # flags: --enable-error-code partially-defined
 if int():

From 3a3cf412b278ee7bf710742b168beed41c1c02f2 Mon Sep 17 00:00:00 2001
From: Nikita Sobolev <mail@sobolevn.me>
Date: Tue, 29 Nov 2022 16:43:54 +0300
Subject: [PATCH 092/231] [stubtest] Add `__warningregistry__` to the list of
 ignored module dunders (#14218)

We have multiple of these in `typeshed`:
https://github.com/python/typeshed/search?q=__warningregistry__
---
 mypy/stubtest.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 8add8178823aa..5e7f9cf331b28 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -1243,6 +1243,8 @@ def verify_typealias(
         "__annotations__",
         "__path__",  # mypy adds __path__ to packages, but C packages don't have it
         "__getattr__",  # resulting behaviour might be typed explicitly
+        # Created by `warnings.warn`, does not make much sense to have in stubs:
+        "__warningregistry__",
         # TODO: remove the following from this list
         "__author__",
         "__version__",

From 98f1b00a3b41b3734f7a20adbd755c13e37beb43 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Tue, 29 Nov 2022 16:07:17 -0600
Subject: [PATCH 093/231] [partially defined] fix false positive with
 global/nonlocal vars (#14222)

This is a workaround until we implement better handling for variables
undefined in global scope (see #14213).

We treat `global/nonlocal` as a variable declaration. I've included test
cases that should fail in the future once we implement the check
properly.
---
 mypy/partially_defined.py                   | 12 ++++++
 test-data/unit/check-partially-defined.test | 43 +++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index c2c925e0477c2..1a38501e9f677 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -17,6 +17,7 @@
     FuncDef,
     FuncItem,
     GeneratorExpr,
+    GlobalDecl,
     IfStmt,
     Import,
     ImportFrom,
@@ -25,6 +26,7 @@
     Lvalue,
     MatchStmt,
     NameExpr,
+    NonlocalDecl,
     RaiseStmt,
     RefExpr,
     ReturnStmt,
@@ -279,6 +281,16 @@ def process_definition(self, name: str) -> None:
             self.var_used_before_def(name, ref)
         self.tracker.record_definition(name)
 
+    def visit_global_decl(self, o: GlobalDecl) -> None:
+        for name in o.names:
+            self.process_definition(name)
+        super().visit_global_decl(o)
+
+    def visit_nonlocal_decl(self, o: NonlocalDecl) -> None:
+        for name in o.names:
+            self.process_definition(name)
+        super().visit_nonlocal_decl(o)
+
     def process_lvalue(self, lvalue: Lvalue | None) -> None:
         if isinstance(lvalue, NameExpr):
             self.process_definition(lvalue.name)
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index 7c10306684ca8..3359702b60bc5 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -191,6 +191,49 @@ if int():
     y = 3
 x = y  # E: Name "y" may be undefined
 
+[case testVarDefinedInOuterScopeUpdated]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def f0() -> None:
+    global x
+    y = x
+    x = 1  # No error.
+
+x = 2
+
+[case testNonlocalVar]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def f0() -> None:
+    x = 2
+
+    def inner() -> None:
+        nonlocal x
+        y = x
+        x = 1  # No error.
+
+
+[case testGlobalDeclarationAfterUsage]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def f0() -> None:
+    y = x  # E: Name "x" is used before definition
+    global x
+    x = 1  # No error.
+
+x = 2
+[case testVarDefinedInOuterScope]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def f0() -> None:
+  global x
+  y = x  # We do not detect such errors right now.
+
+f0()
+x = 1
+[case testDefinedInOuterScopeNoError]
+# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+def foo() -> None:
+    bar()
+
+def bar() -> None:
+    foo()
 [case testFuncParams]
 # flags: --enable-error-code partially-defined
 def foo(a: int) -> None:

From d3427c1ad5064afb6bddee459a24a91fdc036b76 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Wed, 30 Nov 2022 06:44:08 -0600
Subject: [PATCH 094/231] [partially defined] fix a false-negative with
 variable defined in a skipped branch (#14221)

The goal of partially-defined check is to detect variables that could be
undefined but semantic analyzer doesn't detect them as undefined. In
this case, a variable was defined in a branch that returns, so semantic
analyzer considered it defined when it was not.

I've discovered this when testing support for try/except statements
(#14114).
---
 mypy/partially_defined.py                   | 32 ++++++++++++---------
 test-data/unit/check-partially-defined.test |  6 ++++
 2 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 1a38501e9f677..3ec8db3665cd7 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -121,23 +121,29 @@ def is_defined_in_a_branch(self, name: str) -> bool:
         return False
 
     def done(self) -> BranchState:
-        branches = [b for b in self.branches if not b.skipped]
-        if len(branches) == 0:
-            return BranchState(skipped=True)
-        if len(branches) == 1:
-            return branches[0]
-
-        # must_be_defined is a union of must_be_defined of all branches.
-        must_be_defined = set(branches[0].must_be_defined)
-        for b in branches[1:]:
-            must_be_defined.intersection_update(b.must_be_defined)
-        # may_be_defined are all variables that are not must be defined.
+        # First, compute all vars, including skipped branches. We include skipped branches
+        # because our goal is to capture all variables that semantic analyzer would
+        # consider defined.
         all_vars = set()
-        for b in branches:
+        for b in self.branches:
             all_vars.update(b.may_be_defined)
             all_vars.update(b.must_be_defined)
+        # For the rest of the things, we only care about branches that weren't skipped.
+        non_skipped_branches = [b for b in self.branches if not b.skipped]
+        if len(non_skipped_branches) > 0:
+            must_be_defined = non_skipped_branches[0].must_be_defined
+            for b in non_skipped_branches[1:]:
+                must_be_defined.intersection_update(b.must_be_defined)
+        else:
+            must_be_defined = set()
+        # Everything that wasn't defined in all branches but was defined
+        # in at least one branch should be in `may_be_defined`!
         may_be_defined = all_vars.difference(must_be_defined)
-        return BranchState(may_be_defined=may_be_defined, must_be_defined=must_be_defined)
+        return BranchState(
+            must_be_defined=must_be_defined,
+            may_be_defined=may_be_defined,
+            skipped=len(non_skipped_branches) == 0,
+        )
 
 
 class Scope:
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-partially-defined.test
index 3359702b60bc5..623e897e865d4 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-partially-defined.test
@@ -345,6 +345,12 @@ def f5() -> int:
         return 3
     return 1
 
+def f6() -> int:
+    if int():
+        x = 0
+        return x
+    return x  # E: Name "x" may be undefined
+
 [case testDefinedDifferentBranchUseBeforeDef]
 # flags: --enable-error-code partially-defined --enable-error-code use-before-def
 

From 6e9227a8cedf268799d2f0442ec855db46414778 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 30 Nov 2022 19:43:29 -0800
Subject: [PATCH 095/231] Sync typeshed (#14228)

Sync typeshed

Source commit:

https://github.com/python/typeshed/commit/87d2683ef974ef6d6d8b38313f73e9ef0acad06c
---
 mypy/typeshed/stdlib/_typeshed/__init__.pyi   | 26 ++++++++-
 mypy/typeshed/stdlib/abc.pyi                  |  4 +-
 mypy/typeshed/stdlib/asyncio/base_events.pyi  | 28 +++++-----
 mypy/typeshed/stdlib/asyncio/events.pyi       | 32 +++++------
 mypy/typeshed/stdlib/builtins.pyi             | 53 ++++++++++++-------
 mypy/typeshed/stdlib/marshal.pyi              | 30 +++++++++--
 .../stdlib/multiprocessing/reduction.pyi      | 37 ++++++++-----
 mypy/typeshed/stdlib/ssl.pyi                  |  4 ++
 mypy/typeshed/stdlib/string.pyi               | 11 +++-
 mypy/typeshed/stdlib/unicodedata.pyi          |  9 ++--
 mypy/typeshed/stdlib/unittest/mock.pyi        |  2 +-
 mypy/typeshed/stdlib/urllib/parse.pyi         | 19 +++++--
 mypy/typeshed/stdlib/urllib/request.pyi       | 48 +++++++++--------
 mypy/typeshed/stdlib/xmlrpc/client.pyi        | 45 +++++++++++-----
 mypy/typeshed/stdlib/xmlrpc/server.pyi        |  6 +--
 15 files changed, 234 insertions(+), 120 deletions(-)

diff --git a/mypy/typeshed/stdlib/_typeshed/__init__.pyi b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
index 3ae2fca1d19dc..f01db74caf40a 100644
--- a/mypy/typeshed/stdlib/_typeshed/__init__.pyi
+++ b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
@@ -236,6 +236,29 @@ else:
 ReadableBuffer: TypeAlias = ReadOnlyBuffer | WriteableBuffer  # stable
 _BufferWithLen: TypeAlias = ReadableBuffer  # not stable  # noqa: Y047
 
+# Anything that implements the read-write buffer interface, and can be sliced/indexed.
+SliceableBuffer: TypeAlias = bytes | bytearray | memoryview | array.array[Any] | mmap.mmap
+IndexableBuffer: TypeAlias = bytes | bytearray | memoryview | array.array[Any] | mmap.mmap
+# https://github.com/python/typeshed/pull/9115#issuecomment-1304905864
+# Post PEP 688, they should be rewritten as such:
+# from collections.abc import Sequence
+# from typing import Sized, overload
+# class SliceableBuffer(Protocol):
+#     def __buffer__(self, __flags: int) -> memoryview: ...
+#     def __getitem__(self, __slice: slice) -> Sequence[int]: ...
+# class IndexableBuffer(Protocol):
+#     def __buffer__(self, __flags: int) -> memoryview: ...
+#     def __getitem__(self, __i: int) -> int: ...
+# class SupportsGetItemBuffer(SliceableBuffer, IndexableBuffer, Protocol):
+#     def __buffer__(self, __flags: int) -> memoryview: ...
+#     def __contains__(self, __x: Any) -> bool: ...
+#     @overload
+#     def __getitem__(self, __slice: slice) -> Sequence[int]: ...
+#     @overload
+#     def __getitem__(self, __i: int) -> int: ...
+# class SizedBuffer(Sized, Protocol):  # instead of _BufferWithLen
+#     def __buffer__(self, __flags: int) -> memoryview: ...
+
 ExcInfo: TypeAlias = tuple[type[BaseException], BaseException, TracebackType]
 OptExcInfo: TypeAlias = Union[ExcInfo, tuple[None, None, None]]
 
@@ -276,5 +299,4 @@ StrOrLiteralStr = TypeVar("StrOrLiteralStr", LiteralString, str)  # noqa: Y001
 ProfileFunction: TypeAlias = Callable[[FrameType, str, Any], object]
 
 # Objects suitable to be passed to sys.settrace, threading.settrace, and similar
-# TODO: Ideally this would be a recursive type alias
-TraceFunction: TypeAlias = Callable[[FrameType, str, Any], Callable[[FrameType, str, Any], Any] | None]
+TraceFunction: TypeAlias = Callable[[FrameType, str, Any], TraceFunction | None]
diff --git a/mypy/typeshed/stdlib/abc.pyi b/mypy/typeshed/stdlib/abc.pyi
index 110eba24a9cae..7b39c88ed3948 100644
--- a/mypy/typeshed/stdlib/abc.pyi
+++ b/mypy/typeshed/stdlib/abc.pyi
@@ -18,8 +18,8 @@ class ABCMeta(type):
     else:
         def __new__(mcls: type[Self], name: str, bases: tuple[type, ...], namespace: dict[str, Any], **kwargs: Any) -> Self: ...
 
-    def __instancecheck__(cls: ABCMeta, instance: Any) -> Any: ...
-    def __subclasscheck__(cls: ABCMeta, subclass: Any) -> Any: ...
+    def __instancecheck__(cls: ABCMeta, instance: Any) -> bool: ...
+    def __subclasscheck__(cls: ABCMeta, subclass: type) -> bool: ...
     def _dump_registry(cls: ABCMeta, file: SupportsWrite[str] | None = ...) -> None: ...
     def register(cls: ABCMeta, subclass: type[_T]) -> type[_T]: ...
 
diff --git a/mypy/typeshed/stdlib/asyncio/base_events.pyi b/mypy/typeshed/stdlib/asyncio/base_events.pyi
index c1ab114b6036e..83576ab6455e7 100644
--- a/mypy/typeshed/stdlib/asyncio/base_events.pyi
+++ b/mypy/typeshed/stdlib/asyncio/base_events.pyi
@@ -5,7 +5,7 @@ from asyncio.events import AbstractEventLoop, AbstractServer, Handle, TimerHandl
 from asyncio.futures import Future
 from asyncio.protocols import BaseProtocol
 from asyncio.tasks import Task
-from asyncio.transports import BaseTransport, ReadTransport, SubprocessTransport, WriteTransport
+from asyncio.transports import BaseTransport, DatagramTransport, ReadTransport, SubprocessTransport, Transport, WriteTransport
 from collections.abc import Awaitable, Callable, Coroutine, Generator, Iterable, Sequence
 from contextvars import Context
 from socket import AddressFamily, SocketKind, _Address, _RetAddress, socket
@@ -129,7 +129,7 @@ class BaseEventLoop(AbstractEventLoop):
             ssl_shutdown_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
         @overload
         async def create_connection(
             self,
@@ -148,7 +148,7 @@ class BaseEventLoop(AbstractEventLoop):
             ssl_shutdown_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     elif sys.version_info >= (3, 8):
         @overload
         async def create_connection(
@@ -167,7 +167,7 @@ class BaseEventLoop(AbstractEventLoop):
             ssl_handshake_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
         @overload
         async def create_connection(
             self,
@@ -185,7 +185,7 @@ class BaseEventLoop(AbstractEventLoop):
             ssl_handshake_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     else:
         @overload
         async def create_connection(
@@ -202,7 +202,7 @@ class BaseEventLoop(AbstractEventLoop):
             local_addr: tuple[str, int] | None = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
         @overload
         async def create_connection(
             self,
@@ -218,7 +218,7 @@ class BaseEventLoop(AbstractEventLoop):
             local_addr: None = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     if sys.version_info >= (3, 11):
         @overload
         async def create_server(
@@ -266,7 +266,7 @@ class BaseEventLoop(AbstractEventLoop):
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
             ssl_shutdown_timeout: float | None = ...,
-        ) -> BaseTransport: ...
+        ) -> Transport: ...
         async def connect_accepted_socket(
             self,
             protocol_factory: Callable[[], _ProtocolT],
@@ -275,7 +275,7 @@ class BaseEventLoop(AbstractEventLoop):
             ssl: _SSLContext = ...,
             ssl_handshake_timeout: float | None = ...,
             ssl_shutdown_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     else:
         @overload
         async def create_server(
@@ -320,7 +320,7 @@ class BaseEventLoop(AbstractEventLoop):
             server_side: bool = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> BaseTransport: ...
+        ) -> Transport: ...
         async def connect_accepted_socket(
             self,
             protocol_factory: Callable[[], _ProtocolT],
@@ -328,13 +328,13 @@ class BaseEventLoop(AbstractEventLoop):
             *,
             ssl: _SSLContext = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
 
     async def sock_sendfile(
         self, sock: socket, file: IO[bytes], offset: int = ..., count: int | None = ..., *, fallback: bool | None = ...
     ) -> int: ...
     async def sendfile(
-        self, transport: BaseTransport, file: IO[bytes], offset: int = ..., count: int | None = ..., *, fallback: bool = ...
+        self, transport: WriteTransport, file: IO[bytes], offset: int = ..., count: int | None = ..., *, fallback: bool = ...
     ) -> int: ...
     if sys.version_info >= (3, 11):
         async def create_datagram_endpoint(  # type: ignore[override]
@@ -349,7 +349,7 @@ class BaseEventLoop(AbstractEventLoop):
             reuse_port: bool | None = ...,
             allow_broadcast: bool | None = ...,
             sock: socket | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[DatagramTransport, _ProtocolT]: ...
     else:
         async def create_datagram_endpoint(
             self,
@@ -364,7 +364,7 @@ class BaseEventLoop(AbstractEventLoop):
             reuse_port: bool | None = ...,
             allow_broadcast: bool | None = ...,
             sock: socket | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[DatagramTransport, _ProtocolT]: ...
     # Pipes and subprocesses.
     async def connect_read_pipe(
         self, protocol_factory: Callable[[], _ProtocolT], pipe: Any
diff --git a/mypy/typeshed/stdlib/asyncio/events.pyi b/mypy/typeshed/stdlib/asyncio/events.pyi
index 280be4ab5ba98..7241d5a29f8df 100644
--- a/mypy/typeshed/stdlib/asyncio/events.pyi
+++ b/mypy/typeshed/stdlib/asyncio/events.pyi
@@ -12,7 +12,7 @@ from .base_events import Server
 from .futures import Future
 from .protocols import BaseProtocol
 from .tasks import Task
-from .transports import BaseTransport, ReadTransport, SubprocessTransport, WriteTransport
+from .transports import BaseTransport, DatagramTransport, ReadTransport, SubprocessTransport, Transport, WriteTransport
 from .unix_events import AbstractChildWatcher
 
 if sys.version_info >= (3, 8):
@@ -223,7 +223,7 @@ class AbstractEventLoop:
             ssl_shutdown_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
         @overload
         @abstractmethod
         async def create_connection(
@@ -243,7 +243,7 @@ class AbstractEventLoop:
             ssl_shutdown_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     elif sys.version_info >= (3, 8):
         @overload
         @abstractmethod
@@ -263,7 +263,7 @@ class AbstractEventLoop:
             ssl_handshake_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
         @overload
         @abstractmethod
         async def create_connection(
@@ -282,7 +282,7 @@ class AbstractEventLoop:
             ssl_handshake_timeout: float | None = ...,
             happy_eyeballs_delay: float | None = ...,
             interleave: int | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     else:
         @overload
         @abstractmethod
@@ -300,7 +300,7 @@ class AbstractEventLoop:
             local_addr: tuple[str, int] | None = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
         @overload
         @abstractmethod
         async def create_connection(
@@ -317,7 +317,7 @@ class AbstractEventLoop:
             local_addr: None = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     if sys.version_info >= (3, 11):
         @overload
         @abstractmethod
@@ -360,7 +360,7 @@ class AbstractEventLoop:
         @abstractmethod
         async def start_tls(
             self,
-            transport: BaseTransport,
+            transport: WriteTransport,
             protocol: BaseProtocol,
             sslcontext: ssl.SSLContext,
             *,
@@ -368,7 +368,7 @@ class AbstractEventLoop:
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
             ssl_shutdown_timeout: float | None = ...,
-        ) -> BaseTransport: ...
+        ) -> Transport: ...
         async def create_unix_server(
             self,
             protocol_factory: _ProtocolFactory,
@@ -428,7 +428,7 @@ class AbstractEventLoop:
             server_side: bool = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> BaseTransport: ...
+        ) -> Transport: ...
         async def create_unix_server(
             self,
             protocol_factory: _ProtocolFactory,
@@ -449,7 +449,7 @@ class AbstractEventLoop:
             ssl: _SSLContext = ...,
             ssl_handshake_timeout: float | None = ...,
             ssl_shutdown_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     elif sys.version_info >= (3, 10):
         async def connect_accepted_socket(
             self,
@@ -458,7 +458,7 @@ class AbstractEventLoop:
             *,
             ssl: _SSLContext = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     if sys.version_info >= (3, 11):
         async def create_unix_connection(
             self,
@@ -470,7 +470,7 @@ class AbstractEventLoop:
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
             ssl_shutdown_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
     else:
         async def create_unix_connection(
             self,
@@ -481,7 +481,7 @@ class AbstractEventLoop:
             sock: socket | None = ...,
             server_hostname: str | None = ...,
             ssl_handshake_timeout: float | None = ...,
-        ) -> tuple[BaseTransport, _ProtocolT]: ...
+        ) -> tuple[Transport, _ProtocolT]: ...
 
     @abstractmethod
     async def sock_sendfile(
@@ -489,7 +489,7 @@ class AbstractEventLoop:
     ) -> int: ...
     @abstractmethod
     async def sendfile(
-        self, transport: BaseTransport, file: IO[bytes], offset: int = ..., count: int | None = ..., *, fallback: bool = ...
+        self, transport: WriteTransport, file: IO[bytes], offset: int = ..., count: int | None = ..., *, fallback: bool = ...
     ) -> int: ...
     @abstractmethod
     async def create_datagram_endpoint(
@@ -505,7 +505,7 @@ class AbstractEventLoop:
         reuse_port: bool | None = ...,
         allow_broadcast: bool | None = ...,
         sock: socket | None = ...,
-    ) -> tuple[BaseTransport, _ProtocolT]: ...
+    ) -> tuple[DatagramTransport, _ProtocolT]: ...
     # Pipes and subprocesses.
     @abstractmethod
     async def connect_read_pipe(
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index 5482955eb0ab2..a47d774467ddd 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -1232,19 +1232,13 @@ def iter(__function: Callable[[], _T | None], __sentinel: None) -> Iterator[_T]:
 @overload
 def iter(__function: Callable[[], _T], __sentinel: object) -> Iterator[_T]: ...
 
-# We need recursive types to express the type of the second argument to `isinstance` properly, hence the use of `Any`
 if sys.version_info >= (3, 10):
-    def isinstance(
-        __obj: object, __class_or_tuple: type | types.UnionType | tuple[type | types.UnionType | tuple[Any, ...], ...]
-    ) -> bool: ...
-    def issubclass(
-        __cls: type, __class_or_tuple: type | types.UnionType | tuple[type | types.UnionType | tuple[Any, ...], ...]
-    ) -> bool: ...
-
+    _ClassInfo: TypeAlias = type | types.UnionType | tuple[_ClassInfo, ...]
 else:
-    def isinstance(__obj: object, __class_or_tuple: type | tuple[type | tuple[Any, ...], ...]) -> bool: ...
-    def issubclass(__cls: type, __class_or_tuple: type | tuple[type | tuple[Any, ...], ...]) -> bool: ...
+    _ClassInfo: TypeAlias = type | tuple[_ClassInfo, ...]
 
+def isinstance(__obj: object, __class_or_tuple: _ClassInfo) -> bool: ...
+def issubclass(__cls: type, __class_or_tuple: _ClassInfo) -> bool: ...
 def len(__obj: Sized) -> int: ...
 def license() -> None: ...
 def locals() -> dict[str, Any]: ...
@@ -1852,6 +1846,7 @@ if sys.version_info >= (3, 11):
     _ExceptionT_co = TypeVar("_ExceptionT_co", bound=Exception, covariant=True)
     _ExceptionT = TypeVar("_ExceptionT", bound=Exception)
 
+    # See `check_exception_group.py` for use-cases and comments.
     class BaseExceptionGroup(BaseException, Generic[_BaseExceptionT_co]):
         def __new__(cls: type[Self], __message: str, __exceptions: Sequence[_BaseExceptionT_co]) -> Self: ...
         @property
@@ -1859,18 +1854,34 @@ if sys.version_info >= (3, 11):
         @property
         def exceptions(self) -> tuple[_BaseExceptionT_co | BaseExceptionGroup[_BaseExceptionT_co], ...]: ...
         @overload
+        def subgroup(
+            self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+        ) -> ExceptionGroup[_ExceptionT] | None: ...
+        @overload
         def subgroup(
             self, __condition: type[_BaseExceptionT] | tuple[type[_BaseExceptionT], ...]
         ) -> BaseExceptionGroup[_BaseExceptionT] | None: ...
         @overload
-        def subgroup(self: Self, __condition: Callable[[_BaseExceptionT_co], bool]) -> Self | None: ...
+        def subgroup(
+            self: Self, __condition: Callable[[_BaseExceptionT_co | Self], bool]
+        ) -> BaseExceptionGroup[_BaseExceptionT_co] | None: ...
+        @overload
+        def split(
+            self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+        ) -> tuple[ExceptionGroup[_ExceptionT] | None, BaseExceptionGroup[_BaseExceptionT_co] | None]: ...
+        @overload
+        def split(
+            self, __condition: type[_BaseExceptionT] | tuple[type[_BaseExceptionT], ...]
+        ) -> tuple[BaseExceptionGroup[_BaseExceptionT] | None, BaseExceptionGroup[_BaseExceptionT_co] | None]: ...
         @overload
         def split(
-            self: Self, __condition: type[_BaseExceptionT] | tuple[type[_BaseExceptionT], ...]
-        ) -> tuple[BaseExceptionGroup[_BaseExceptionT] | None, Self | None]: ...
+            self: Self, __condition: Callable[[_BaseExceptionT_co | Self], bool]
+        ) -> tuple[BaseExceptionGroup[_BaseExceptionT_co] | None, BaseExceptionGroup[_BaseExceptionT_co] | None]: ...
+        # In reality it is `NonEmptySequence`:
         @overload
-        def split(self: Self, __condition: Callable[[_BaseExceptionT_co], bool]) -> tuple[Self | None, Self | None]: ...
-        def derive(self: Self, __excs: Sequence[_BaseExceptionT_co]) -> Self: ...
+        def derive(self, __excs: Sequence[_ExceptionT]) -> ExceptionGroup[_ExceptionT]: ...
+        @overload
+        def derive(self, __excs: Sequence[_BaseExceptionT]) -> BaseExceptionGroup[_BaseExceptionT]: ...
         def __class_getitem__(cls, __item: Any) -> GenericAlias: ...
 
     class ExceptionGroup(BaseExceptionGroup[_ExceptionT_co], Exception):
@@ -1883,10 +1894,14 @@ if sys.version_info >= (3, 11):
             self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
         ) -> ExceptionGroup[_ExceptionT] | None: ...
         @overload
-        def subgroup(self: Self, __condition: Callable[[_ExceptionT_co], bool]) -> Self | None: ...
+        def subgroup(
+            self: Self, __condition: Callable[[_ExceptionT_co | Self], bool]
+        ) -> ExceptionGroup[_ExceptionT_co] | None: ...
         @overload  # type: ignore[override]
         def split(
-            self: Self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
-        ) -> tuple[ExceptionGroup[_ExceptionT] | None, Self | None]: ...
+            self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+        ) -> tuple[ExceptionGroup[_ExceptionT] | None, ExceptionGroup[_ExceptionT_co] | None]: ...
         @overload
-        def split(self: Self, __condition: Callable[[_ExceptionT_co], bool]) -> tuple[Self | None, Self | None]: ...
+        def split(
+            self: Self, __condition: Callable[[_ExceptionT_co | Self], bool]
+        ) -> tuple[ExceptionGroup[_ExceptionT_co] | None, ExceptionGroup[_ExceptionT_co] | None]: ...
diff --git a/mypy/typeshed/stdlib/marshal.pyi b/mypy/typeshed/stdlib/marshal.pyi
index d68cdd1431090..d46d9c10483d7 100644
--- a/mypy/typeshed/stdlib/marshal.pyi
+++ b/mypy/typeshed/stdlib/marshal.pyi
@@ -1,9 +1,33 @@
+import builtins
+import types
 from _typeshed import ReadableBuffer, SupportsRead, SupportsWrite
-from typing import Any
+from typing import Any, Union
+from typing_extensions import TypeAlias
 
 version: int
 
-def dump(__value: Any, __file: SupportsWrite[bytes], __version: int = ...) -> None: ...
+_Marshallable: TypeAlias = Union[
+    # handled in w_object() in marshal.c
+    None,
+    type[StopIteration],
+    builtins.ellipsis,
+    bool,
+    # handled in w_complex_object() in marshal.c
+    int,
+    float,
+    complex,
+    bytes,
+    str,
+    tuple[_Marshallable, ...],
+    list[Any],
+    dict[Any, Any],
+    set[Any],
+    frozenset[_Marshallable],
+    types.CodeType,
+    ReadableBuffer,
+]
+
+def dump(__value: _Marshallable, __file: SupportsWrite[bytes], __version: int = ...) -> None: ...
 def load(__file: SupportsRead[bytes]) -> Any: ...
-def dumps(__value: Any, __version: int = ...) -> bytes: ...
+def dumps(__value: _Marshallable, __version: int = ...) -> bytes: ...
 def loads(__bytes: ReadableBuffer) -> Any: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/reduction.pyi b/mypy/typeshed/stdlib/multiprocessing/reduction.pyi
index cab86d866babc..d6b70aefa48d5 100644
--- a/mypy/typeshed/stdlib/multiprocessing/reduction.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/reduction.pyi
@@ -1,9 +1,14 @@
 import pickle
 import sys
-from _typeshed import HasFileno, Incomplete
+from _typeshed import HasFileno, SupportsWrite
 from abc import ABCMeta
+from builtins import type as Type  # alias to avoid name clash
+from collections.abc import Callable
 from copyreg import _DispatchTableType
+from multiprocessing import connection
+from pickle import _ReducedType
 from socket import socket
+from typing import Any
 from typing_extensions import Literal
 
 if sys.platform == "win32":
@@ -11,18 +16,20 @@ if sys.platform == "win32":
 else:
     __all__ = ["send_handle", "recv_handle", "ForkingPickler", "register", "dump", "DupFd", "sendfds", "recvfds"]
 
+HAVE_SEND_HANDLE: bool
+
 class ForkingPickler(pickle.Pickler):
     dispatch_table: _DispatchTableType
-    def __init__(self, *args) -> None: ...
+    def __init__(self, file: SupportsWrite[bytes], protocol: int | None = ...) -> None: ...
     @classmethod
-    def register(cls, type, reduce) -> None: ...
+    def register(cls, type: Type, reduce: Callable[[Any], _ReducedType]) -> None: ...
     @classmethod
-    def dumps(cls, obj, protocol: Incomplete | None = ...): ...
+    def dumps(cls, obj: Any, protocol: int | None = ...) -> memoryview: ...
     loads = pickle.loads
 
 register = ForkingPickler.register
 
-def dump(obj, file, protocol: Incomplete | None = ...) -> None: ...
+def dump(obj: Any, file: SupportsWrite[bytes], protocol: int | None = ...) -> None: ...
 
 if sys.platform == "win32":
     if sys.version_info >= (3, 8):
@@ -32,13 +39,13 @@ if sys.platform == "win32":
     else:
         def duplicate(handle: int, target_process: int | None = ..., inheritable: bool = ...) -> int: ...
 
-    def steal_handle(source_pid, handle): ...
-    def send_handle(conn, handle, destination_pid) -> None: ...
-    def recv_handle(conn): ...
+    def steal_handle(source_pid: int, handle: int) -> int: ...
+    def send_handle(conn: connection.PipeConnection, handle: int, destination_pid: int) -> None: ...
+    def recv_handle(conn: connection.PipeConnection) -> int: ...
 
     class DupHandle:
-        def __init__(self, handle, access, pid: Incomplete | None = ...) -> None: ...
-        def detach(self): ...
+        def __init__(self, handle: int, access: int, pid: int | None = ...) -> None: ...
+        def detach(self) -> int: ...
 
 else:
     if sys.platform == "darwin":
@@ -47,10 +54,11 @@ else:
         ACKNOWLEDGE: Literal[False]
 
     def recvfds(sock: socket, size: int) -> list[int]: ...
-    def send_handle(conn, handle, destination_pid) -> None: ...
+    # destination_pid is unused
+    def send_handle(conn: HasFileno, handle: int, destination_pid: object) -> None: ...
     def recv_handle(conn: HasFileno) -> int: ...
-    def sendfds(sock, fds) -> None: ...
-    def DupFd(fd): ...
+    def sendfds(sock: socket, fds: list[int]) -> None: ...
+    def DupFd(fd: int) -> Any: ...  # Return type is really hard to get right
 
 # These aliases are to work around pyright complaints.
 # Pyright doesn't like it when a class object is defined as an alias
@@ -84,4 +92,5 @@ class AbstractReducer(metaclass=ABCMeta):
         sendfds = _sendfds
         recvfds = _recvfds
         DupFd = _DupFd
-    def __init__(self, *args) -> None: ...
+    # *args are unused
+    def __init__(self, *args: object) -> None: ...
diff --git a/mypy/typeshed/stdlib/ssl.pyi b/mypy/typeshed/stdlib/ssl.pyi
index 543433f2fbd0a..91844e8369df3 100644
--- a/mypy/typeshed/stdlib/ssl.pyi
+++ b/mypy/typeshed/stdlib/ssl.pyi
@@ -180,6 +180,8 @@ class Options(enum.IntFlag):
     OP_NO_RENEGOTIATION: int
     if sys.version_info >= (3, 8):
         OP_ENABLE_MIDDLEBOX_COMPAT: int
+        if sys.platform == "linux":
+            OP_IGNORE_UNEXPECTED_EOF: int
 
 OP_ALL: Options
 OP_NO_SSLv2: Options
@@ -196,6 +198,8 @@ OP_NO_TICKET: Options
 OP_NO_RENEGOTIATION: Options
 if sys.version_info >= (3, 8):
     OP_ENABLE_MIDDLEBOX_COMPAT: Options
+    if sys.platform == "linux":
+        OP_IGNORE_UNEXPECTED_EOF: Options
 
 HAS_NEVER_CHECK_COMMON_NAME: bool
 HAS_SSLv2: bool
diff --git a/mypy/typeshed/stdlib/string.pyi b/mypy/typeshed/stdlib/string.pyi
index 6fb803fe53be3..49802ce81019a 100644
--- a/mypy/typeshed/stdlib/string.pyi
+++ b/mypy/typeshed/stdlib/string.pyi
@@ -64,11 +64,20 @@ class Formatter:
     ) -> LiteralString: ...
     @overload
     def vformat(self, format_string: str, args: Sequence[Any], kwargs: Mapping[str, Any]) -> str: ...
+    def _vformat(  # undocumented
+        self,
+        format_string: str,
+        args: Sequence[Any],
+        kwargs: Mapping[str, Any],
+        used_args: set[int | str],
+        recursion_depth: int,
+        auto_arg_index: int = ...,
+    ) -> tuple[str, int]: ...
     def parse(
         self, format_string: StrOrLiteralStr
     ) -> Iterable[tuple[StrOrLiteralStr, StrOrLiteralStr | None, StrOrLiteralStr | None, StrOrLiteralStr | None]]: ...
     def get_field(self, field_name: str, args: Sequence[Any], kwargs: Mapping[str, Any]) -> Any: ...
     def get_value(self, key: int | str, args: Sequence[Any], kwargs: Mapping[str, Any]) -> Any: ...
-    def check_unused_args(self, used_args: Sequence[int | str], args: Sequence[Any], kwargs: Mapping[str, Any]) -> None: ...
+    def check_unused_args(self, used_args: set[int | str], args: Sequence[Any], kwargs: Mapping[str, Any]) -> None: ...
     def format_field(self, value: Any, format_spec: str) -> Any: ...
     def convert_field(self, value: Any, conversion: str) -> Any: ...
diff --git a/mypy/typeshed/stdlib/unicodedata.pyi b/mypy/typeshed/stdlib/unicodedata.pyi
index 5a9aa0a3395f7..4569d6584fd6e 100644
--- a/mypy/typeshed/stdlib/unicodedata.pyi
+++ b/mypy/typeshed/stdlib/unicodedata.pyi
@@ -1,7 +1,7 @@
 import sys
 from _typeshed import ReadOnlyBuffer
 from typing import Any, TypeVar
-from typing_extensions import final
+from typing_extensions import Literal, TypeAlias, final
 
 ucd_3_2_0: UCD
 unidata_version: str
@@ -17,7 +17,10 @@ def combining(__chr: str) -> int: ...
 def decimal(__chr: str, __default: _T = ...) -> int | _T: ...
 def decomposition(__chr: str) -> str: ...
 def digit(__chr: str, __default: _T = ...) -> int | _T: ...
-def east_asian_width(__chr: str) -> str: ...
+
+_EastAsianWidth: TypeAlias = Literal["F", "H", "W", "Na", "A", "N"]
+
+def east_asian_width(__chr: str) -> _EastAsianWidth: ...
 
 if sys.version_info >= (3, 8):
     def is_normalized(__form: str, __unistr: str) -> bool: ...
@@ -38,7 +41,7 @@ class UCD:
     def decimal(self, __chr: str, __default: _T = ...) -> int | _T: ...
     def decomposition(self, __chr: str) -> str: ...
     def digit(self, __chr: str, __default: _T = ...) -> int | _T: ...
-    def east_asian_width(self, __chr: str) -> str: ...
+    def east_asian_width(self, __chr: str) -> _EastAsianWidth: ...
     if sys.version_info >= (3, 8):
         def is_normalized(self, __form: str, __unistr: str) -> bool: ...
 
diff --git a/mypy/typeshed/stdlib/unittest/mock.pyi b/mypy/typeshed/stdlib/unittest/mock.pyi
index 6c58f38a0d826..e4cedef1b4256 100644
--- a/mypy/typeshed/stdlib/unittest/mock.pyi
+++ b/mypy/typeshed/stdlib/unittest/mock.pyi
@@ -82,7 +82,7 @@ class _Call(tuple[Any, ...]):
     def __eq__(self, other: object) -> bool: ...
     def __ne__(self, __other: object) -> bool: ...
     def __call__(self, *args: Any, **kwargs: Any) -> _Call: ...
-    def __getattr__(self, attr: Any) -> Any: ...
+    def __getattr__(self, attr: str) -> Any: ...
     def __getattribute__(self, attr: str) -> Any: ...
     if sys.version_info >= (3, 8):
         @property
diff --git a/mypy/typeshed/stdlib/urllib/parse.pyi b/mypy/typeshed/stdlib/urllib/parse.pyi
index 02e2774b3b8ed..efb91a4b34fff 100644
--- a/mypy/typeshed/stdlib/urllib/parse.pyi
+++ b/mypy/typeshed/stdlib/urllib/parse.pyi
@@ -147,7 +147,7 @@ if sys.version_info >= (3, 9):
 else:
     def unquote(string: str, encoding: str = ..., errors: str = ...) -> str: ...
 
-def unquote_to_bytes(string: str | bytes) -> bytes: ...
+def unquote_to_bytes(string: str | bytes | bytearray) -> bytes: ...
 def unquote_plus(string: str, encoding: str = ..., errors: str = ...) -> str: ...
 @overload
 def urldefrag(url: str) -> DefragResult: ...
@@ -168,11 +168,22 @@ def urljoin(base: AnyStr, url: AnyStr | None, allow_fragments: bool = ...) -> An
 @overload
 def urlparse(url: str, scheme: str | None = ..., allow_fragments: bool = ...) -> ParseResult: ...
 @overload
-def urlparse(url: bytes | bytearray | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> ParseResultBytes: ...
+def urlparse(
+    url: bytes | bytearray | None, scheme: bytes | bytearray | None = ..., allow_fragments: bool = ...
+) -> ParseResultBytes: ...
 @overload
 def urlsplit(url: str, scheme: str | None = ..., allow_fragments: bool = ...) -> SplitResult: ...
-@overload
-def urlsplit(url: bytes | bytearray | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> SplitResultBytes: ...
+
+if sys.version_info >= (3, 11):
+    @overload
+    def urlsplit(url: bytes | None, scheme: bytes | None = ..., allow_fragments: bool = ...) -> SplitResultBytes: ...
+
+else:
+    @overload
+    def urlsplit(
+        url: bytes | bytearray | None, scheme: bytes | bytearray | None = ..., allow_fragments: bool = ...
+    ) -> SplitResultBytes: ...
+
 @overload
 def urlunparse(
     components: tuple[AnyStr | None, AnyStr | None, AnyStr | None, AnyStr | None, AnyStr | None, AnyStr | None]
diff --git a/mypy/typeshed/stdlib/urllib/request.pyi b/mypy/typeshed/stdlib/urllib/request.pyi
index 3cd5fc740fca6..00c1602937628 100644
--- a/mypy/typeshed/stdlib/urllib/request.pyi
+++ b/mypy/typeshed/stdlib/urllib/request.pyi
@@ -1,6 +1,6 @@
 import ssl
 import sys
-from _typeshed import StrOrBytesPath, SupportsRead
+from _typeshed import ReadableBuffer, StrOrBytesPath, SupportsRead
 from collections.abc import Callable, Iterable, Mapping, MutableMapping, Sequence
 from email.message import Message
 from http.client import HTTPConnection, HTTPMessage, HTTPResponse
@@ -50,7 +50,7 @@ __all__ = [
 
 _T = TypeVar("_T")
 _UrlopenRet: TypeAlias = Any
-_DataType: TypeAlias = bytes | SupportsRead[bytes] | Iterable[bytes] | None
+_DataType: TypeAlias = ReadableBuffer | SupportsRead[bytes] | Iterable[bytes] | None
 
 def urlopen(
     url: str | Request,
@@ -214,7 +214,7 @@ class AbstractDigestAuthHandler:
     def get_cnonce(self, nonce: str) -> str: ...
     def get_authorization(self, req: Request, chal: Mapping[str, str]) -> str: ...
     def get_algorithm_impls(self, algorithm: str) -> tuple[Callable[[str], str], Callable[[str, str], str]]: ...
-    def get_entity_digest(self, data: bytes | None, chal: Mapping[str, str]) -> str | None: ...
+    def get_entity_digest(self, data: ReadableBuffer | None, chal: Mapping[str, str]) -> str | None: ...
 
 class HTTPDigestAuthHandler(BaseHandler, AbstractDigestAuthHandler):
     auth_header: ClassVar[str]  # undocumented
@@ -301,14 +301,14 @@ def urlcleanup() -> None: ...
 class URLopener:
     version: ClassVar[str]
     def __init__(self, proxies: dict[str, str] | None = ..., **x509: str) -> None: ...
-    def open(self, fullurl: str, data: bytes | None = ...) -> _UrlopenRet: ...
-    def open_unknown(self, fullurl: str, data: bytes | None = ...) -> _UrlopenRet: ...
+    def open(self, fullurl: str, data: ReadableBuffer | None = ...) -> _UrlopenRet: ...
+    def open_unknown(self, fullurl: str, data: ReadableBuffer | None = ...) -> _UrlopenRet: ...
     def retrieve(
         self,
         url: str,
         filename: str | None = ...,
         reporthook: Callable[[int, int, int], object] | None = ...,
-        data: bytes | None = ...,
+        data: ReadableBuffer | None = ...,
     ) -> tuple[str, Message | None]: ...
     def addheader(self, *args: tuple[str, str]) -> None: ...  # undocumented
     def cleanup(self) -> None: ...  # undocumented
@@ -319,32 +319,32 @@ class URLopener:
     def http_error_default(
         self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage
     ) -> _UrlopenRet: ...  # undocumented
-    def open_data(self, url: str, data: bytes | None = ...) -> addinfourl: ...  # undocumented
+    def open_data(self, url: str, data: ReadableBuffer | None = ...) -> addinfourl: ...  # undocumented
     def open_file(self, url: str) -> addinfourl: ...  # undocumented
     def open_ftp(self, url: str) -> addinfourl: ...  # undocumented
-    def open_http(self, url: str, data: bytes | None = ...) -> _UrlopenRet: ...  # undocumented
-    def open_https(self, url: str, data: bytes | None = ...) -> _UrlopenRet: ...  # undocumented
+    def open_http(self, url: str, data: ReadableBuffer | None = ...) -> _UrlopenRet: ...  # undocumented
+    def open_https(self, url: str, data: ReadableBuffer | None = ...) -> _UrlopenRet: ...  # undocumented
     def open_local_file(self, url: str) -> addinfourl: ...  # undocumented
-    def open_unknown_proxy(self, proxy: str, fullurl: str, data: bytes | None = ...) -> None: ...  # undocumented
+    def open_unknown_proxy(self, proxy: str, fullurl: str, data: ReadableBuffer | None = ...) -> None: ...  # undocumented
 
 class FancyURLopener(URLopener):
     def prompt_user_passwd(self, host: str, realm: str) -> tuple[str, str]: ...
     def get_user_passwd(self, host: str, realm: str, clear_cache: int = ...) -> tuple[str, str]: ...  # undocumented
     def http_error_301(
-        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: bytes | None = ...
+        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | addinfourl | None: ...  # undocumented
     def http_error_302(
-        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: bytes | None = ...
+        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | addinfourl | None: ...  # undocumented
     def http_error_303(
-        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: bytes | None = ...
+        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | addinfourl | None: ...  # undocumented
     def http_error_307(
-        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: bytes | None = ...
+        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | addinfourl | None: ...  # undocumented
     if sys.version_info >= (3, 11):
         def http_error_308(
-            self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: bytes | None = ...
+            self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: ReadableBuffer | None = ...
         ) -> _UrlopenRet | addinfourl | None: ...  # undocumented
 
     def http_error_401(
@@ -354,7 +354,7 @@ class FancyURLopener(URLopener):
         errcode: int,
         errmsg: str,
         headers: HTTPMessage,
-        data: bytes | None = ...,
+        data: ReadableBuffer | None = ...,
         retry: bool = ...,
     ) -> _UrlopenRet | None: ...  # undocumented
     def http_error_407(
@@ -364,20 +364,24 @@ class FancyURLopener(URLopener):
         errcode: int,
         errmsg: str,
         headers: HTTPMessage,
-        data: bytes | None = ...,
+        data: ReadableBuffer | None = ...,
         retry: bool = ...,
     ) -> _UrlopenRet | None: ...  # undocumented
     def http_error_default(
         self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage
     ) -> addinfourl: ...  # undocumented
     def redirect_internal(
-        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: bytes | None
+        self, url: str, fp: IO[bytes], errcode: int, errmsg: str, headers: HTTPMessage, data: ReadableBuffer | None
+    ) -> _UrlopenRet | None: ...  # undocumented
+    def retry_http_basic_auth(
+        self, url: str, realm: str, data: ReadableBuffer | None = ...
+    ) -> _UrlopenRet | None: ...  # undocumented
+    def retry_https_basic_auth(
+        self, url: str, realm: str, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | None: ...  # undocumented
-    def retry_http_basic_auth(self, url: str, realm: str, data: bytes | None = ...) -> _UrlopenRet | None: ...  # undocumented
-    def retry_https_basic_auth(self, url: str, realm: str, data: bytes | None = ...) -> _UrlopenRet | None: ...  # undocumented
     def retry_proxy_http_basic_auth(
-        self, url: str, realm: str, data: bytes | None = ...
+        self, url: str, realm: str, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | None: ...  # undocumented
     def retry_proxy_https_basic_auth(
-        self, url: str, realm: str, data: bytes | None = ...
+        self, url: str, realm: str, data: ReadableBuffer | None = ...
     ) -> _UrlopenRet | None: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/xmlrpc/client.pyi b/mypy/typeshed/stdlib/xmlrpc/client.pyi
index 150291009f54a..0e048f57844de 100644
--- a/mypy/typeshed/stdlib/xmlrpc/client.pyi
+++ b/mypy/typeshed/stdlib/xmlrpc/client.pyi
@@ -2,7 +2,7 @@ import gzip
 import http.client
 import sys
 import time
-from _typeshed import Self, SupportsRead, SupportsWrite
+from _typeshed import ReadableBuffer, Self, SupportsRead, SupportsWrite, _BufferWithLen
 from collections.abc import Callable, Iterable, Mapping
 from datetime import datetime
 from io import BytesIO
@@ -15,7 +15,20 @@ class _SupportsTimeTuple(Protocol):
 
 _DateTimeComparable: TypeAlias = DateTime | datetime | str | _SupportsTimeTuple
 _Marshallable: TypeAlias = (
-    bool | int | float | str | bytes | None | tuple[Any, ...] | list[Any] | dict[Any, Any] | datetime | DateTime | Binary
+    bool
+    | int
+    | float
+    | str
+    | bytes
+    | bytearray
+    | None
+    | tuple[_Marshallable, ...]
+    # Ideally we'd use _Marshallable for list and dict, but invariance makes that impractical
+    | list[Any]
+    | dict[str, Any]
+    | datetime
+    | DateTime
+    | Binary
 )
 _XMLDate: TypeAlias = int | datetime | tuple[int, ...] | time.struct_time
 _HostType: TypeAlias = Union[tuple[str, dict[str, str]], str]
@@ -83,18 +96,18 @@ def _datetime_type(data: str) -> datetime: ...  # undocumented
 class Binary:
 
     data: bytes
-    def __init__(self, data: bytes | None = ...) -> None: ...
-    def decode(self, data: bytes) -> None: ...
+    def __init__(self, data: bytes | bytearray | None = ...) -> None: ...
+    def decode(self, data: ReadableBuffer) -> None: ...
     def encode(self, out: SupportsWrite[str]) -> None: ...
     def __eq__(self, other: object) -> bool: ...
 
-def _binary(data: bytes) -> Binary: ...  # undocumented
+def _binary(data: ReadableBuffer) -> Binary: ...  # undocumented
 
 WRAPPERS: tuple[type[DateTime], type[Binary]]  # undocumented
 
 class ExpatParser:  # undocumented
     def __init__(self, target: Unmarshaller) -> None: ...
-    def feed(self, data: str | bytes) -> None: ...
+    def feed(self, data: str | ReadableBuffer) -> None: ...
     def close(self) -> None: ...
 
 _WriteCallback: TypeAlias = Callable[[str], object]
@@ -115,7 +128,7 @@ class Marshaller:
     def dump_int(self, value: int, write: _WriteCallback) -> None: ...
     def dump_double(self, value: float, write: _WriteCallback) -> None: ...
     def dump_unicode(self, value: str, write: _WriteCallback, escape: Callable[[str], str] = ...) -> None: ...
-    def dump_bytes(self, value: bytes, write: _WriteCallback) -> None: ...
+    def dump_bytes(self, value: ReadableBuffer, write: _WriteCallback) -> None: ...
     def dump_array(self, value: Iterable[_Marshallable], write: _WriteCallback) -> None: ...
     def dump_struct(
         self, value: Mapping[str, _Marshallable], write: _WriteCallback, escape: Callable[[str], str] = ...
@@ -196,13 +209,13 @@ def dumps(
     allow_none: bool = ...,
 ) -> str: ...
 def loads(data: str, use_datetime: bool = ..., use_builtin_types: bool = ...) -> tuple[tuple[_Marshallable, ...], str | None]: ...
-def gzip_encode(data: bytes) -> bytes: ...  # undocumented
-def gzip_decode(data: bytes, max_decode: int = ...) -> bytes: ...  # undocumented
+def gzip_encode(data: ReadableBuffer) -> bytes: ...  # undocumented
+def gzip_decode(data: ReadableBuffer, max_decode: int = ...) -> bytes: ...  # undocumented
 
 class GzipDecodedResponse(gzip.GzipFile):  # undocumented
 
     io: BytesIO
-    def __init__(self, response: SupportsRead[bytes]) -> None: ...
+    def __init__(self, response: SupportsRead[ReadableBuffer]) -> None: ...
 
 class _Method:  # undocumented
 
@@ -231,17 +244,21 @@ class Transport:
     else:
         def __init__(self, use_datetime: bool = ..., use_builtin_types: bool = ...) -> None: ...
 
-    def request(self, host: _HostType, handler: str, request_body: bytes, verbose: bool = ...) -> tuple[_Marshallable, ...]: ...
+    def request(
+        self, host: _HostType, handler: str, request_body: _BufferWithLen, verbose: bool = ...
+    ) -> tuple[_Marshallable, ...]: ...
     def single_request(
-        self, host: _HostType, handler: str, request_body: bytes, verbose: bool = ...
+        self, host: _HostType, handler: str, request_body: _BufferWithLen, verbose: bool = ...
     ) -> tuple[_Marshallable, ...]: ...
     def getparser(self) -> tuple[ExpatParser, Unmarshaller]: ...
     def get_host_info(self, host: _HostType) -> tuple[str, list[tuple[str, str]], dict[str, str]]: ...
     def make_connection(self, host: _HostType) -> http.client.HTTPConnection: ...
     def close(self) -> None: ...
-    def send_request(self, host: _HostType, handler: str, request_body: bytes, debug: bool) -> http.client.HTTPConnection: ...
+    def send_request(
+        self, host: _HostType, handler: str, request_body: _BufferWithLen, debug: bool
+    ) -> http.client.HTTPConnection: ...
     def send_headers(self, connection: http.client.HTTPConnection, headers: list[tuple[str, str]]) -> None: ...
-    def send_content(self, connection: http.client.HTTPConnection, request_body: bytes) -> None: ...
+    def send_content(self, connection: http.client.HTTPConnection, request_body: _BufferWithLen) -> None: ...
     def parse_response(self, response: http.client.HTTPResponse) -> tuple[_Marshallable, ...]: ...
 
 class SafeTransport(Transport):
diff --git a/mypy/typeshed/stdlib/xmlrpc/server.pyi b/mypy/typeshed/stdlib/xmlrpc/server.pyi
index c11d8d8e7a143..4d28974cbbeda 100644
--- a/mypy/typeshed/stdlib/xmlrpc/server.pyi
+++ b/mypy/typeshed/stdlib/xmlrpc/server.pyi
@@ -2,14 +2,10 @@ import http.server
 import pydoc
 import socketserver
 from collections.abc import Callable, Iterable, Mapping
-from datetime import datetime
 from re import Pattern
 from typing import Any, ClassVar, Protocol
 from typing_extensions import TypeAlias
-from xmlrpc.client import Fault
-
-# TODO: Recursive type on tuple, list, dict
-_Marshallable: TypeAlias = None | bool | int | float | str | bytes | tuple[Any, ...] | list[Any] | dict[Any, Any] | datetime
+from xmlrpc.client import Fault, _Marshallable
 
 # The dispatch accepts anywhere from 0 to N arguments, no easy way to allow this in mypy
 class _DispatchArity0(Protocol):

From 3c71548c0bc7955c462211985859c273bd9224bc Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 1 Dec 2022 02:14:28 -0800
Subject: [PATCH 096/231] Fix false negatives involving Unions and generators
 or coroutines (#14224)

Fixes #14223
---
 mypy/checker.py                       | 12 ++++++++++++
 test-data/unit/check-async-await.test | 18 ++++++++++++++++++
 test-data/unit/check-statements.test  |  9 +++++++++
 3 files changed, 39 insertions(+)

diff --git a/mypy/checker.py b/mypy/checker.py
index 80f7e19c65f0f..1c8956ae6722a 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -848,6 +848,10 @@ def get_generator_yield_type(self, return_type: Type, is_coroutine: bool) -> Typ
 
         if isinstance(return_type, AnyType):
             return AnyType(TypeOfAny.from_another_any, source_any=return_type)
+        elif isinstance(return_type, UnionType):
+            return make_simplified_union(
+                [self.get_generator_yield_type(item, is_coroutine) for item in return_type.items]
+            )
         elif not self.is_generator_return_type(
             return_type, is_coroutine
         ) and not self.is_async_generator_return_type(return_type):
@@ -878,6 +882,10 @@ def get_generator_receive_type(self, return_type: Type, is_coroutine: bool) -> T
 
         if isinstance(return_type, AnyType):
             return AnyType(TypeOfAny.from_another_any, source_any=return_type)
+        elif isinstance(return_type, UnionType):
+            return make_simplified_union(
+                [self.get_generator_receive_type(item, is_coroutine) for item in return_type.items]
+            )
         elif not self.is_generator_return_type(
             return_type, is_coroutine
         ) and not self.is_async_generator_return_type(return_type):
@@ -917,6 +925,10 @@ def get_generator_return_type(self, return_type: Type, is_coroutine: bool) -> Ty
 
         if isinstance(return_type, AnyType):
             return AnyType(TypeOfAny.from_another_any, source_any=return_type)
+        elif isinstance(return_type, UnionType):
+            return make_simplified_union(
+                [self.get_generator_return_type(item, is_coroutine) for item in return_type.items]
+            )
         elif not self.is_generator_return_type(return_type, is_coroutine):
             # If the function doesn't have a proper Generator (or
             # Awaitable) return type, anything is permissible.
diff --git a/test-data/unit/check-async-await.test b/test-data/unit/check-async-await.test
index 195e70cf58806..d53cba2fc642b 100644
--- a/test-data/unit/check-async-await.test
+++ b/test-data/unit/check-async-await.test
@@ -925,3 +925,21 @@ async def f() -> AsyncGenerator[int, None]:
 
 [builtins fixtures/async_await.pyi]
 [typing fixtures/typing-async.pyi]
+
+[case testAwaitUnion]
+from typing import overload, Union
+
+class A: ...
+class B: ...
+
+@overload
+async def foo(x: A) -> B: ...
+@overload
+async def foo(x: B) -> A: ...
+async def foo(x): ...
+
+async def bar(x: Union[A, B]) -> None:
+    reveal_type(await foo(x))  # N: Revealed type is "Union[__main__.B, __main__.A]"
+
+[builtins fixtures/async_await.pyi]
+[typing fixtures/typing-async.pyi]
diff --git a/test-data/unit/check-statements.test b/test-data/unit/check-statements.test
index 4be5060996e28..3450f8593d27d 100644
--- a/test-data/unit/check-statements.test
+++ b/test-data/unit/check-statements.test
@@ -2206,3 +2206,12 @@ def foo():
     x: int = "no"  # N: By default the bodies of untyped functions are not checked, consider using --check-untyped-defs
     y = "no"  # type: int  # N: By default the bodies of untyped functions are not checked, consider using --check-untyped-defs
     z: int  # N: By default the bodies of untyped functions are not checked, consider using --check-untyped-defs
+
+[case testGeneratorUnion]
+from typing import Generator, Union
+
+class A: pass
+class B: pass
+
+def foo(x: int) -> Union[Generator[A, None, None], Generator[B, None, None]]:
+    yield x  # E: Incompatible types in "yield" (actual type "int", expected type "Union[A, B]")

From 8da17d71e156140e67057703a46805637ab869cf Mon Sep 17 00:00:00 2001
From: jhance <jhance@users.noreply.github.com>
Date: Thu, 1 Dec 2022 09:35:41 -0800
Subject: [PATCH 097/231] Give TypeVarTupleType a fallback (#14231)

We want to eventually decomission the use of TypeList for
constraints/expanded values of TypeVarTupleTypes. In order to do that we
will need a reference to the tuple fallback. All the places we currently
construct these TypeLists for the use in variadic generics have access
to a TypeVarTupleType, so putting the tuple fallback into the typevar
type is a reasonable way to make that information accessible where we
need it.

In order to get it into the type, we first put it into the expr by
making a symbol table lookup in semanal.
---
 mypy/copytype.py                   |  2 +-
 mypy/nodes.py                      | 17 ++++++++++++++++-
 mypy/semanal.py                    |  3 ++-
 mypy/test/typefixture.py           | 25 +++++++++++++------------
 mypy/treetransform.py              |  6 +++++-
 mypy/tvar_scope.py                 |  1 +
 mypy/typeanal.py                   |  2 ++
 mypy/types.py                      | 22 +++++++++++++++++++++-
 mypy/typevars.py                   | 10 +++++++++-
 test-data/unit/semanal-errors.test |  1 +
 test-data/unit/semanal-types.test  |  1 +
 11 files changed, 72 insertions(+), 18 deletions(-)

diff --git a/mypy/copytype.py b/mypy/copytype.py
index baa1ba34cbacf..6024e527705bb 100644
--- a/mypy/copytype.py
+++ b/mypy/copytype.py
@@ -94,7 +94,7 @@ def visit_parameters(self, t: Parameters) -> ProperType:
         return self.copy_common(t, dup)
 
     def visit_type_var_tuple(self, t: TypeVarTupleType) -> ProperType:
-        dup = TypeVarTupleType(t.name, t.fullname, t.id, t.upper_bound)
+        dup = TypeVarTupleType(t.name, t.fullname, t.id, t.upper_bound, t.tuple_fallback)
         return self.copy_common(t, dup)
 
     def visit_unpack_type(self, t: UnpackType) -> ProperType:
diff --git a/mypy/nodes.py b/mypy/nodes.py
index c02e21e88b446..80ab787f4a9cf 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -2526,10 +2526,23 @@ def deserialize(cls, data: JsonDict) -> ParamSpecExpr:
 class TypeVarTupleExpr(TypeVarLikeExpr):
     """Type variable tuple expression TypeVarTuple(...)."""
 
-    __slots__ = ()
+    __slots__ = "tuple_fallback"
+
+    tuple_fallback: mypy.types.Instance
 
     __match_args__ = ("name", "upper_bound")
 
+    def __init__(
+        self,
+        name: str,
+        fullname: str,
+        upper_bound: mypy.types.Type,
+        tuple_fallback: mypy.types.Instance,
+        variance: int = INVARIANT,
+    ) -> None:
+        super().__init__(name, fullname, upper_bound, variance)
+        self.tuple_fallback = tuple_fallback
+
     def accept(self, visitor: ExpressionVisitor[T]) -> T:
         return visitor.visit_type_var_tuple_expr(self)
 
@@ -2539,6 +2552,7 @@ def serialize(self) -> JsonDict:
             "name": self._name,
             "fullname": self._fullname,
             "upper_bound": self.upper_bound.serialize(),
+            "tuple_fallback": self.tuple_fallback.serialize(),
             "variance": self.variance,
         }
 
@@ -2549,6 +2563,7 @@ def deserialize(cls, data: JsonDict) -> TypeVarTupleExpr:
             data["name"],
             data["fullname"],
             mypy.types.deserialize_type(data["upper_bound"]),
+            mypy.types.Instance.deserialize(data["tuple_fallback"]),
             data["variance"],
         )
 
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 3e1e1a1e5d611..266dc891b6979 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -4119,8 +4119,9 @@ def process_typevartuple_declaration(self, s: AssignmentStmt) -> bool:
 
         # PEP 646 does not specify the behavior of variance, constraints, or bounds.
         if not call.analyzed:
+            tuple_fallback = self.named_type("builtins.tuple", [self.object_type()])
             typevartuple_var = TypeVarTupleExpr(
-                name, self.qualified_name(name), self.object_type(), INVARIANT
+                name, self.qualified_name(name), self.object_type(), tuple_fallback, INVARIANT
             )
             typevartuple_var.line = call.line
             call.analyzed = typevartuple_var
diff --git a/mypy/test/typefixture.py b/mypy/test/typefixture.py
index bd8351171208f..d12e7abab0e25 100644
--- a/mypy/test/typefixture.py
+++ b/mypy/test/typefixture.py
@@ -56,9 +56,6 @@ def make_type_var(
         ) -> TypeVarType:
             return TypeVarType(name, name, id, values, upper_bound, variance)
 
-        def make_type_var_tuple(name: str, id: int, upper_bound: Type) -> TypeVarTupleType:
-            return TypeVarTupleType(name, name, id, upper_bound)
-
         self.t = make_type_var("T", 1, [], self.o, variance)  # T`1 (type variable)
         self.tf = make_type_var("T", -1, [], self.o, variance)  # T`-1 (type variable)
         self.tf2 = make_type_var("T", -2, [], self.o, variance)  # T`-2 (type variable)
@@ -68,10 +65,6 @@ def make_type_var_tuple(name: str, id: int, upper_bound: Type) -> TypeVarTupleTy
         self.sf1 = make_type_var("S", -1, [], self.o, variance)  # S`-1 (type variable)
         self.u = make_type_var("U", 3, [], self.o, variance)  # U`3 (type variable)
 
-        self.ts = make_type_var_tuple("Ts", 1, self.o)  # Ts`1 (type var tuple)
-        self.ss = make_type_var_tuple("Ss", 2, self.o)  # Ss`2 (type var tuple)
-        self.us = make_type_var_tuple("Us", 3, self.o)  # Us`3 (type var tuple)
-
         # Simple types
         self.anyt = AnyType(TypeOfAny.special_form)
         self.nonet = NoneType()
@@ -133,10 +126,6 @@ def make_type_var_tuple(name: str, id: int, upper_bound: Type) -> TypeVarTupleTy
             bases=[Instance(self.gi, [self.s1])],
         )
 
-        self.gvi = self.make_type_info("GV", mro=[self.oi], typevars=["Ts"], typevar_tuple_index=0)
-        self.gv2i = self.make_type_info(
-            "GV2", mro=[self.oi], typevars=["T", "Ts", "S"], typevar_tuple_index=1
-        )
         # list[T]
         self.std_listi = self.make_type_info(
             "builtins.list", mro=[self.oi], typevars=["T"], variances=[variance]
@@ -218,6 +207,18 @@ def make_type_var_tuple(name: str, id: int, upper_bound: Type) -> TypeVarTupleTy
         self._add_bool_dunder(self.bool_type_info)
         self._add_bool_dunder(self.ai)
 
+        def make_type_var_tuple(name: str, id: int, upper_bound: Type) -> TypeVarTupleType:
+            return TypeVarTupleType(name, name, id, upper_bound, self.std_tuple)
+
+        self.ts = make_type_var_tuple("Ts", 1, self.o)  # Ts`1 (type var tuple)
+        self.ss = make_type_var_tuple("Ss", 2, self.o)  # Ss`2 (type var tuple)
+        self.us = make_type_var_tuple("Us", 3, self.o)  # Us`3 (type var tuple)
+
+        self.gvi = self.make_type_info("GV", mro=[self.oi], typevars=["Ts"], typevar_tuple_index=0)
+        self.gv2i = self.make_type_info(
+            "GV2", mro=[self.oi], typevars=["T", "Ts", "S"], typevar_tuple_index=1
+        )
+
     def _add_bool_dunder(self, type_info: TypeInfo) -> None:
         signature = CallableType([], [], [], Instance(self.bool_type_info, []), self.function)
         bool_func = FuncDef("__bool__", [], Block([]))
@@ -296,7 +297,7 @@ def make_type_info(
             v: list[TypeVarLikeType] = []
             for id, n in enumerate(typevars, 1):
                 if typevar_tuple_index is not None and id - 1 == typevar_tuple_index:
-                    v.append(TypeVarTupleType(n, n, id, self.o))
+                    v.append(TypeVarTupleType(n, n, id, self.o, self.std_tuple))
                 else:
                     if variances:
                         variance = variances[id - 1]
diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index 432baf7d73b78..535f50d5cf5e1 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -653,7 +653,11 @@ def visit_paramspec_expr(self, node: ParamSpecExpr) -> ParamSpecExpr:
 
     def visit_type_var_tuple_expr(self, node: TypeVarTupleExpr) -> TypeVarTupleExpr:
         return TypeVarTupleExpr(
-            node.name, node.fullname, self.type(node.upper_bound), variance=node.variance
+            node.name,
+            node.fullname,
+            self.type(node.upper_bound),
+            node.tuple_fallback,
+            variance=node.variance,
         )
 
     def visit_type_alias_expr(self, node: TypeAliasExpr) -> TypeAliasExpr:
diff --git a/mypy/tvar_scope.py b/mypy/tvar_scope.py
index f926d0dfb8838..db83768bf68ab 100644
--- a/mypy/tvar_scope.py
+++ b/mypy/tvar_scope.py
@@ -115,6 +115,7 @@ def bind_new(self, name: str, tvar_expr: TypeVarLikeExpr) -> TypeVarLikeType:
                 tvar_expr.fullname,
                 i,
                 upper_bound=tvar_expr.upper_bound,
+                tuple_fallback=tvar_expr.tuple_fallback,
                 line=tvar_expr.line,
                 column=tvar_expr.column,
             )
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index f34f6ef49f6c6..468b10fc98474 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -364,12 +364,14 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                     self.fail(
                         f'Type variable "{t.name}" used with arguments', t, code=codes.VALID_TYPE
                     )
+
                 # Change the line number
                 return TypeVarTupleType(
                     tvar_def.name,
                     tvar_def.fullname,
                     tvar_def.id,
                     tvar_def.upper_bound,
+                    sym.node.tuple_fallback,
                     line=t.line,
                     column=t.column,
                 )
diff --git a/mypy/types.py b/mypy/types.py
index 326727310a1b1..b5a4f90d5ec3a 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -720,6 +720,20 @@ class TypeVarTupleType(TypeVarLikeType):
     See PEP646 for more information.
     """
 
+    def __init__(
+        self,
+        name: str,
+        fullname: str,
+        id: TypeVarId | int,
+        upper_bound: Type,
+        tuple_fallback: Instance,
+        *,
+        line: int = -1,
+        column: int = -1,
+    ) -> None:
+        super().__init__(name, fullname, id, upper_bound, line=line, column=column)
+        self.tuple_fallback = tuple_fallback
+
     def serialize(self) -> JsonDict:
         assert not self.id.is_meta_var()
         return {
@@ -728,13 +742,18 @@ def serialize(self) -> JsonDict:
             "fullname": self.fullname,
             "id": self.id.raw_id,
             "upper_bound": self.upper_bound.serialize(),
+            "tuple_fallback": self.tuple_fallback.serialize(),
         }
 
     @classmethod
     def deserialize(cls, data: JsonDict) -> TypeVarTupleType:
         assert data[".class"] == "TypeVarTupleType"
         return TypeVarTupleType(
-            data["name"], data["fullname"], data["id"], deserialize_type(data["upper_bound"])
+            data["name"],
+            data["fullname"],
+            data["id"],
+            deserialize_type(data["upper_bound"]),
+            Instance.deserialize(data["tuple_fallback"]),
         )
 
     def accept(self, visitor: TypeVisitor[T]) -> T:
@@ -759,6 +778,7 @@ def copy_modified(self, id: Bogus[TypeVarId | int] = _dummy) -> TypeVarTupleType
             self.fullname,
             self.id if id is _dummy else id,
             self.upper_bound,
+            self.tuple_fallback,
             line=self.line,
             column=self.column,
         )
diff --git a/mypy/typevars.py b/mypy/typevars.py
index 9c813550d5ea0..69c2eed37fa4f 100644
--- a/mypy/typevars.py
+++ b/mypy/typevars.py
@@ -39,7 +39,15 @@ def fill_typevars(typ: TypeInfo) -> Instance | TupleType:
             )
         elif isinstance(tv, TypeVarTupleType):
             tv = UnpackType(
-                TypeVarTupleType(tv.name, tv.fullname, tv.id, tv.upper_bound, line=-1, column=-1)
+                TypeVarTupleType(
+                    tv.name,
+                    tv.fullname,
+                    tv.id,
+                    tv.upper_bound,
+                    tv.tuple_fallback,
+                    line=-1,
+                    column=-1,
+                )
             )
         else:
             assert isinstance(tv, ParamSpecType)
diff --git a/test-data/unit/semanal-errors.test b/test-data/unit/semanal-errors.test
index 2b10beacbf97e..5697d473414ec 100644
--- a/test-data/unit/semanal-errors.test
+++ b/test-data/unit/semanal-errors.test
@@ -1474,3 +1474,4 @@ y: Unpack[TVariadic]  # E: TypeVarTuple "TVariadic" is unbound
 
 class Variadic(Generic[Unpack[TVariadic], Unpack[TVariadic2]]):  # E: Can only use one type var tuple in a class def
     pass
+[builtins fixtures/tuple.pyi]
diff --git a/test-data/unit/semanal-types.test b/test-data/unit/semanal-types.test
index 8dc767e1abfcf..77ef10a26b133 100644
--- a/test-data/unit/semanal-types.test
+++ b/test-data/unit/semanal-types.test
@@ -1560,3 +1560,4 @@ MypyFile:1(
   AssignmentStmt:2(
     NameExpr(TV* [__main__.TV])
     TypeVarTupleExpr:2()))
+[builtins fixtures/tuple.pyi]

From ceb976f1b9bc4c3ae7cd07a5222ec076f6c7ab72 Mon Sep 17 00:00:00 2001
From: Nikita Sobolev <mail@sobolevn.me>
Date: Thu, 1 Dec 2022 23:36:00 +0300
Subject: [PATCH 098/231] [stubtest] associate exported symbol error with
 __all__ object_path (#14217)

---
 mypy/stubtest.py          | 4 ++--
 mypy/test/teststubtest.py | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 5e7f9cf331b28..5e39b996076b5 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -261,10 +261,10 @@ def _verify_exported_names(
     if not (names_in_runtime_not_stub or names_in_stub_not_runtime):
         return
     yield Error(
-        object_path,
+        object_path + ["__all__"],
         (
             "names exported from the stub do not correspond to the names exported at runtime. "
-            "This is probably due to an inaccurate `__all__` in the stub or things being missing from the stub."
+            "This is probably due to things being missing from the stub, or if present, an inaccurate `__all__` in the stub"
         ),
         # Pass in MISSING instead of the stub and runtime objects, as the line numbers aren't very
         # relevant here, and it makes for a prettier error message
diff --git a/mypy/test/teststubtest.py b/mypy/test/teststubtest.py
index e863f4f575688..812333e3feb49 100644
--- a/mypy/test/teststubtest.py
+++ b/mypy/test/teststubtest.py
@@ -1028,7 +1028,7 @@ def test_all_in_stub_not_at_runtime(self) -> Iterator[Case]:
 
     @collect_cases
     def test_all_in_stub_different_to_all_at_runtime(self) -> Iterator[Case]:
-        # We *should* emit an error with the module name itself,
+        # We *should* emit an error with the module name itself + __all__,
         # if the stub *does* define __all__,
         # but the stub's __all__ is inconsistent with the runtime's __all__
         yield Case(
@@ -1040,7 +1040,7 @@ def test_all_in_stub_different_to_all_at_runtime(self) -> Iterator[Case]:
             __all__ = []
             foo = 'foo'
             """,
-            error="",
+            error="__all__",
         )
 
     @collect_cases

From 740b36428d8817d276e46f817ac11b18cea4d766 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Fri, 2 Dec 2022 00:06:34 +0000
Subject: [PATCH 099/231] Fix --fast-exit argument (#14229)

Previously --fast-exit would actually disable the fast_exit option. Now
it behaves as expected (a no-op, since fast exit is enabled by default).
---
 mypy/main.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mypy/main.py b/mypy/main.py
index d0cb6ca4d505c..8f60d13074a08 100644
--- a/mypy/main.py
+++ b/mypy/main.py
@@ -1008,7 +1008,10 @@ def add_invertible_flag(
         help="When encountering SOURCE_FILE, read and type check "
         "the contents of SHADOW_FILE instead.",
     )
-    add_invertible_flag("--fast-exit", default=True, help=argparse.SUPPRESS, group=internals_group)
+    internals_group.add_argument("--fast-exit", action="store_true", help=argparse.SUPPRESS)
+    internals_group.add_argument(
+        "--no-fast-exit", action="store_false", dest="fast_exit", help=argparse.SUPPRESS
+    )
     # This flag is useful for mypy tests, where function bodies may be omitted. Plugin developers
     # may want to use this as well in their tests.
     add_invertible_flag(

From d5e96e381f72ad3fafaae8707b688b3da320587d Mon Sep 17 00:00:00 2001
From: dosisod <39638017+dosisod@users.noreply.github.com>
Date: Fri, 2 Dec 2022 07:42:28 -0800
Subject: [PATCH 100/231] [mypyc] Add `match` statement support (#13953)

Closes https://github.com/mypyc/mypyc/issues/911

Like the title says, this PR adds support for compiling `match`
statements in mypyc. Most of the work has been done, but there are some
things which are still a WIP.

A todo list of what has been done, and the (small) number of things that
need to be worked out:

- [x] Or patterns: `1 | 2 | 3`
- [x] Value patterns: `123`, `x.y.z`, etc.
- [x] Singleton patterns: `True`, `False`, and `None`
- [x] Sequence patterns:
  - [x] Fixed length patterns `[1, 2, 3]`
  - [x] Starred patterns `[*prev, 4, 5, 6]`, `[1, 2, 3, *rest]`, etc:
    - [x] `[*rest]` is currently not working, but should be an easy fix
- [x] Support any object which supports the [Sequence
Protocol](https://docs.python.org/3/c-api/sequence.html) (need help with
this)
- [x] Mapping Pattern (`{"key": value}`):
  - [x] General support
  - [x] Starred patterns: `{"key": value, **rest}`
- [x] Support any object which supports the [Mapping
Protocol](https://docs.python.org/3/c-api/mapping.html) (need help with
this)
- [x] Class patterns:
  - [x] Basic class `isinstance()` check
  - [x] Positional args: `Class(1, 2, 3)`
  - [x] Keyword args: `Class(x=1, y=2, z=3)`
  - [x] Shortcut for built-in datatypes: `int(x)` -> `int() as x`
- [x] Capture patterns:
  - [x] Wildcard pattern: `_`
  - [x] As pattern: `123 as num`
  - [x] Capture pattern: `x`

Some features which I was unsure how to implement are:

* Fix `*rest` and `**rest` star patterns name collisions. Basically, you
cannot use `rest` (or any other name) twice in the same match statement
if `rest` is a different type (ie, `dict` vs `list`). If it was defined
as `object` instead of `dict`/`list` everything would be fine.

Also some operations on native classes and primitive types could be
optimized.
---
 mypyc/irbuild/classdef.py          |    2 +-
 mypyc/irbuild/match.py             |  355 ++++++
 mypyc/irbuild/prepare.py           |    6 +-
 mypyc/irbuild/statement.py         |    7 +
 mypyc/irbuild/visitor.py           |    3 +-
 mypyc/lib-rt/CPy.h                 |    2 +
 mypyc/lib-rt/dict_ops.c            |    8 +
 mypyc/lib-rt/list_ops.c            |    8 +
 mypyc/options.py                   |    2 +
 mypyc/primitives/dict_ops.py       |   24 +-
 mypyc/primitives/list_ops.py       |   21 +
 mypyc/test-data/irbuild-match.test | 1708 ++++++++++++++++++++++++++++
 mypyc/test-data/run-match.test     |  283 +++++
 mypyc/test/test_irbuild.py         |    4 +
 mypyc/test/test_run.py             |    3 +
 mypyc/test/testutil.py             |    3 +-
 16 files changed, 2430 insertions(+), 9 deletions(-)
 create mode 100644 mypyc/irbuild/match.py
 create mode 100644 mypyc/test-data/irbuild-match.test
 create mode 100644 mypyc/test-data/run-match.test

diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index 4502c201a2e87..34fc1fd766b00 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -629,7 +629,7 @@ def find_attr_initializers(
                 and not isinstance(stmt.rvalue, TempNode)
             ):
                 name = stmt.lvalues[0].name
-                if name in ("__slots__", "__match_args__"):
+                if name == "__slots__":
                     continue
 
                 if name == "__deletable__":
diff --git a/mypyc/irbuild/match.py b/mypyc/irbuild/match.py
new file mode 100644
index 0000000000000..a1e671911ea59
--- /dev/null
+++ b/mypyc/irbuild/match.py
@@ -0,0 +1,355 @@
+from contextlib import contextmanager
+from typing import Generator, List, Optional, Tuple
+
+from mypy.nodes import MatchStmt, NameExpr, TypeInfo
+from mypy.patterns import (
+    AsPattern,
+    ClassPattern,
+    MappingPattern,
+    OrPattern,
+    Pattern,
+    SequencePattern,
+    SingletonPattern,
+    StarredPattern,
+    ValuePattern,
+)
+from mypy.traverser import TraverserVisitor
+from mypy.types import Instance, TupleType, get_proper_type
+from mypyc.ir.ops import BasicBlock, Value
+from mypyc.ir.rtypes import object_rprimitive
+from mypyc.irbuild.builder import IRBuilder
+from mypyc.primitives.dict_ops import (
+    dict_copy,
+    dict_del_item,
+    mapping_has_key,
+    supports_mapping_protocol,
+)
+from mypyc.primitives.generic_ops import generic_ssize_t_len_op
+from mypyc.primitives.list_ops import (
+    sequence_get_item,
+    sequence_get_slice,
+    supports_sequence_protocol,
+)
+from mypyc.primitives.misc_ops import fast_isinstance_op, slow_isinstance_op
+
+# From: https://peps.python.org/pep-0634/#class-patterns
+MATCHABLE_BUILTINS = {
+    "builtins.bool",
+    "builtins.bytearray",
+    "builtins.bytes",
+    "builtins.dict",
+    "builtins.float",
+    "builtins.frozenset",
+    "builtins.int",
+    "builtins.list",
+    "builtins.set",
+    "builtins.str",
+    "builtins.tuple",
+}
+
+
+class MatchVisitor(TraverserVisitor):
+    builder: IRBuilder
+    code_block: BasicBlock
+    next_block: BasicBlock
+    final_block: BasicBlock
+    subject: Value
+    match: MatchStmt
+
+    as_pattern: Optional[AsPattern] = None
+
+    def __init__(self, builder: IRBuilder, match_node: MatchStmt) -> None:
+        self.builder = builder
+
+        self.code_block = BasicBlock()
+        self.next_block = BasicBlock()
+        self.final_block = BasicBlock()
+
+        self.match = match_node
+        self.subject = builder.accept(match_node.subject)
+
+    def build_match_body(self, index: int) -> None:
+        self.builder.activate_block(self.code_block)
+
+        guard = self.match.guards[index]
+
+        if guard:
+            self.code_block = BasicBlock()
+
+            cond = self.builder.accept(guard)
+            self.builder.add_bool_branch(cond, self.code_block, self.next_block)
+
+            self.builder.activate_block(self.code_block)
+
+        self.builder.accept(self.match.bodies[index])
+        self.builder.goto(self.final_block)
+
+    def visit_match_stmt(self, m: MatchStmt) -> None:
+        for i, pattern in enumerate(m.patterns):
+            self.code_block = BasicBlock()
+            self.next_block = BasicBlock()
+
+            pattern.accept(self)
+
+            self.build_match_body(i)
+            self.builder.activate_block(self.next_block)
+
+        self.builder.goto_and_activate(self.final_block)
+
+    def visit_value_pattern(self, pattern: ValuePattern) -> None:
+        value = self.builder.accept(pattern.expr)
+
+        cond = self.builder.binary_op(self.subject, value, "==", pattern.expr.line)
+
+        self.bind_as_pattern(value)
+
+        self.builder.add_bool_branch(cond, self.code_block, self.next_block)
+
+    def visit_or_pattern(self, pattern: OrPattern) -> None:
+        backup_block = self.next_block
+        self.next_block = BasicBlock()
+
+        for p in pattern.patterns:
+            # Hack to ensure the as pattern is bound to each pattern in the
+            # "or" pattern, but not every subpattern
+            backup = self.as_pattern
+            p.accept(self)
+            self.as_pattern = backup
+
+            self.builder.activate_block(self.next_block)
+            self.next_block = BasicBlock()
+
+        self.next_block = backup_block
+        self.builder.goto(self.next_block)
+
+    def visit_class_pattern(self, pattern: ClassPattern) -> None:
+        # TODO: use faster instance check for native classes (while still
+        # making sure to account for inheritence)
+        isinstance_op = (
+            fast_isinstance_op
+            if self.builder.is_builtin_ref_expr(pattern.class_ref)
+            else slow_isinstance_op
+        )
+
+        cond = self.builder.call_c(
+            isinstance_op, [self.subject, self.builder.accept(pattern.class_ref)], pattern.line
+        )
+
+        self.builder.add_bool_branch(cond, self.code_block, self.next_block)
+
+        self.bind_as_pattern(self.subject, new_block=True)
+
+        if pattern.positionals:
+            if pattern.class_ref.fullname in MATCHABLE_BUILTINS:
+                self.builder.activate_block(self.code_block)
+                self.code_block = BasicBlock()
+
+                pattern.positionals[0].accept(self)
+
+                return
+
+            node = pattern.class_ref.node
+            assert isinstance(node, TypeInfo)
+
+            ty = node.names.get("__match_args__")
+            assert ty
+
+            match_args_type = get_proper_type(ty.type)
+            assert isinstance(match_args_type, TupleType)
+
+            match_args: List[str] = []
+
+            for item in match_args_type.items:
+                proper_item = get_proper_type(item)
+                assert isinstance(proper_item, Instance) and proper_item.last_known_value
+
+                match_arg = proper_item.last_known_value.value
+                assert isinstance(match_arg, str)
+
+                match_args.append(match_arg)
+
+            for i, expr in enumerate(pattern.positionals):
+                self.builder.activate_block(self.code_block)
+                self.code_block = BasicBlock()
+
+                # TODO: use faster "get_attr" method instead when calling on native or
+                # builtin objects
+                positional = self.builder.py_get_attr(self.subject, match_args[i], expr.line)
+
+                with self.enter_subpattern(positional):
+                    expr.accept(self)
+
+        for key, value in zip(pattern.keyword_keys, pattern.keyword_values):
+            self.builder.activate_block(self.code_block)
+            self.code_block = BasicBlock()
+
+            # TODO: same as above "get_attr" comment
+            attr = self.builder.py_get_attr(self.subject, key, value.line)
+
+            with self.enter_subpattern(attr):
+                value.accept(self)
+
+    def visit_as_pattern(self, pattern: AsPattern) -> None:
+        if pattern.pattern:
+            old_pattern = self.as_pattern
+            self.as_pattern = pattern
+            pattern.pattern.accept(self)
+            self.as_pattern = old_pattern
+
+        elif pattern.name:
+            target = self.builder.get_assignment_target(pattern.name)
+
+            self.builder.assign(target, self.subject, pattern.line)
+
+        self.builder.goto(self.code_block)
+
+    def visit_singleton_pattern(self, pattern: SingletonPattern) -> None:
+        if pattern.value is None:
+            obj = self.builder.none_object()
+        elif pattern.value is True:
+            obj = self.builder.true()
+        else:
+            obj = self.builder.false()
+
+        cond = self.builder.binary_op(self.subject, obj, "is", pattern.line)
+
+        self.builder.add_bool_branch(cond, self.code_block, self.next_block)
+
+    def visit_mapping_pattern(self, pattern: MappingPattern) -> None:
+        is_dict = self.builder.call_c(supports_mapping_protocol, [self.subject], pattern.line)
+
+        self.builder.add_bool_branch(is_dict, self.code_block, self.next_block)
+
+        keys: List[Value] = []
+
+        for key, value in zip(pattern.keys, pattern.values):
+            self.builder.activate_block(self.code_block)
+            self.code_block = BasicBlock()
+
+            key_value = self.builder.accept(key)
+            keys.append(key_value)
+
+            exists = self.builder.call_c(mapping_has_key, [self.subject, key_value], pattern.line)
+
+            self.builder.add_bool_branch(exists, self.code_block, self.next_block)
+            self.builder.activate_block(self.code_block)
+            self.code_block = BasicBlock()
+
+            item = self.builder.gen_method_call(
+                self.subject, "__getitem__", [key_value], object_rprimitive, pattern.line
+            )
+
+            with self.enter_subpattern(item):
+                value.accept(self)
+
+        if pattern.rest:
+            self.builder.activate_block(self.code_block)
+            self.code_block = BasicBlock()
+
+            rest = self.builder.call_c(dict_copy, [self.subject], pattern.rest.line)
+
+            target = self.builder.get_assignment_target(pattern.rest)
+
+            self.builder.assign(target, rest, pattern.rest.line)
+
+            for i, key_name in enumerate(keys):
+                self.builder.call_c(dict_del_item, [rest, key_name], pattern.keys[i].line)
+
+            self.builder.goto(self.code_block)
+
+    def visit_sequence_pattern(self, seq_pattern: SequencePattern) -> None:
+        star_index, capture, patterns = prep_sequence_pattern(seq_pattern)
+
+        is_list = self.builder.call_c(supports_sequence_protocol, [self.subject], seq_pattern.line)
+
+        self.builder.add_bool_branch(is_list, self.code_block, self.next_block)
+
+        self.builder.activate_block(self.code_block)
+        self.code_block = BasicBlock()
+
+        actual_len = self.builder.call_c(generic_ssize_t_len_op, [self.subject], seq_pattern.line)
+        min_len = len(patterns)
+
+        is_long_enough = self.builder.binary_op(
+            actual_len,
+            self.builder.load_int(min_len),
+            "==" if star_index is None else ">=",
+            seq_pattern.line,
+        )
+
+        self.builder.add_bool_branch(is_long_enough, self.code_block, self.next_block)
+
+        for i, pattern in enumerate(patterns):
+            self.builder.activate_block(self.code_block)
+            self.code_block = BasicBlock()
+
+            if star_index is not None and i >= star_index:
+                current = self.builder.binary_op(
+                    actual_len, self.builder.load_int(min_len - i), "-", pattern.line
+                )
+
+            else:
+                current = self.builder.load_int(i)
+
+            item = self.builder.call_c(sequence_get_item, [self.subject, current], pattern.line)
+
+            with self.enter_subpattern(item):
+                pattern.accept(self)
+
+        if capture and star_index is not None:
+            self.builder.activate_block(self.code_block)
+            self.code_block = BasicBlock()
+
+            capture_end = self.builder.binary_op(
+                actual_len, self.builder.load_int(min_len - star_index), "-", capture.line
+            )
+
+            rest = self.builder.call_c(
+                sequence_get_slice,
+                [self.subject, self.builder.load_int(star_index), capture_end],
+                capture.line,
+            )
+
+            target = self.builder.get_assignment_target(capture)
+            self.builder.assign(target, rest, capture.line)
+
+            self.builder.goto(self.code_block)
+
+    def bind_as_pattern(self, value: Value, new_block: bool = False) -> None:
+        if self.as_pattern and self.as_pattern.pattern and self.as_pattern.name:
+            if new_block:
+                self.builder.activate_block(self.code_block)
+                self.code_block = BasicBlock()
+
+            target = self.builder.get_assignment_target(self.as_pattern.name)
+            self.builder.assign(target, value, self.as_pattern.pattern.line)
+
+            self.as_pattern = None
+
+            if new_block:
+                self.builder.goto(self.code_block)
+
+    @contextmanager
+    def enter_subpattern(self, subject: Value) -> Generator[None, None, None]:
+        old_subject = self.subject
+        self.subject = subject
+        yield
+        self.subject = old_subject
+
+
+def prep_sequence_pattern(
+    seq_pattern: SequencePattern,
+) -> Tuple[Optional[int], Optional[NameExpr], List[Pattern]]:
+    star_index: Optional[int] = None
+    capture: Optional[NameExpr] = None
+    patterns: List[Pattern] = []
+
+    for i, pattern in enumerate(seq_pattern.patterns):
+        if isinstance(pattern, StarredPattern):
+            star_index = i
+            capture = pattern.capture
+
+        else:
+            patterns.append(pattern)
+
+    return star_index, capture, patterns
diff --git a/mypyc/irbuild/prepare.py b/mypyc/irbuild/prepare.py
index 639d1a5ea0d1c..2399647374c07 100644
--- a/mypyc/irbuild/prepare.py
+++ b/mypyc/irbuild/prepare.py
@@ -231,11 +231,7 @@ def prepare_class_def(
 
         if isinstance(node.node, Var):
             assert node.node.type, "Class member %s missing type" % name
-            if not node.node.is_classvar and name not in (
-                "__slots__",
-                "__deletable__",
-                "__match_args__",
-            ):
+            if not node.node.is_classvar and name not in ("__slots__", "__deletable__"):
                 ir.attributes[name] = mapper.type_to_rtype(node.node.type)
         elif isinstance(node.node, (FuncDef, Decorator)):
             prepare_method_def(ir, module_name, cdef, mapper, node.node)
diff --git a/mypyc/irbuild/statement.py b/mypyc/irbuild/statement.py
index a1d36c011aa1a..6e465893607df 100644
--- a/mypyc/irbuild/statement.py
+++ b/mypyc/irbuild/statement.py
@@ -28,6 +28,7 @@
     ImportFrom,
     ListExpr,
     Lvalue,
+    MatchStmt,
     OperatorAssignmentStmt,
     RaiseStmt,
     ReturnStmt,
@@ -99,6 +100,8 @@
     yield_from_except_op,
 )
 
+from .match import MatchVisitor
+
 GenFunc = Callable[[], None]
 ValueGenFunc = Callable[[], Value]
 
@@ -898,3 +901,7 @@ def transform_yield_from_expr(builder: IRBuilder, o: YieldFromExpr) -> Value:
 
 def transform_await_expr(builder: IRBuilder, o: AwaitExpr) -> Value:
     return emit_yield_from_or_await(builder, builder.accept(o.expr), o.line, is_await=True)
+
+
+def transform_match_stmt(builder: IRBuilder, m: MatchStmt) -> None:
+    m.accept(MatchVisitor(builder, m))
diff --git a/mypyc/irbuild/visitor.py b/mypyc/irbuild/visitor.py
index dc126d4104094..d8725ee04dc5c 100644
--- a/mypyc/irbuild/visitor.py
+++ b/mypyc/irbuild/visitor.py
@@ -131,6 +131,7 @@
     transform_import,
     transform_import_all,
     transform_import_from,
+    transform_match_stmt,
     transform_operator_assignment_stmt,
     transform_raise_stmt,
     transform_return_stmt,
@@ -242,7 +243,7 @@ def visit_nonlocal_decl(self, stmt: NonlocalDecl) -> None:
         pass
 
     def visit_match_stmt(self, stmt: MatchStmt) -> None:
-        self.bail("Match statements are not yet supported", stmt.line)
+        transform_match_stmt(self.builder, stmt)
 
     # Expressions
 
diff --git a/mypyc/lib-rt/CPy.h b/mypyc/lib-rt/CPy.h
index cffbbb3e16661..166c851d0155c 100644
--- a/mypyc/lib-rt/CPy.h
+++ b/mypyc/lib-rt/CPy.h
@@ -371,6 +371,7 @@ CPyTagged CPyList_Index(PyObject *list, PyObject *obj);
 PyObject *CPySequence_Multiply(PyObject *seq, CPyTagged t_size);
 PyObject *CPySequence_RMultiply(CPyTagged t_size, PyObject *seq);
 PyObject *CPyList_GetSlice(PyObject *obj, CPyTagged start, CPyTagged end);
+int CPySequence_Check(PyObject *obj);
 
 
 // Dict operations
@@ -402,6 +403,7 @@ PyObject *CPyDict_GetValuesIter(PyObject *dict);
 tuple_T3CIO CPyDict_NextKey(PyObject *dict_or_iter, CPyTagged offset);
 tuple_T3CIO CPyDict_NextValue(PyObject *dict_or_iter, CPyTagged offset);
 tuple_T4CIOO CPyDict_NextItem(PyObject *dict_or_iter, CPyTagged offset);
+int CPyMapping_Check(PyObject *obj);
 
 // Check that dictionary didn't change size during iteration.
 static inline char CPyDict_CheckSize(PyObject *dict, CPyTagged size) {
diff --git a/mypyc/lib-rt/dict_ops.c b/mypyc/lib-rt/dict_ops.c
index b013a8a5f0b93..ba565257fd724 100644
--- a/mypyc/lib-rt/dict_ops.c
+++ b/mypyc/lib-rt/dict_ops.c
@@ -5,6 +5,10 @@
 #include <Python.h>
 #include "CPy.h"
 
+#ifndef Py_TPFLAGS_MAPPING
+#define Py_TPFLAGS_MAPPING (1 << 6)
+#endif
+
 // Dict subclasses like defaultdict override things in interesting
 // ways, so we don't want to just directly use the dict methods. Not
 // sure if it is actually worth doing all this stuff, but it saves
@@ -436,3 +440,7 @@ tuple_T4CIOO CPyDict_NextItem(PyObject *dict_or_iter, CPyTagged offset) {
     Py_INCREF(ret.f3);
     return ret;
 }
+
+int CPyMapping_Check(PyObject *obj) {
+    return Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MAPPING;
+}
diff --git a/mypyc/lib-rt/list_ops.c b/mypyc/lib-rt/list_ops.c
index cb72662e22eee..df87228a0d100 100644
--- a/mypyc/lib-rt/list_ops.c
+++ b/mypyc/lib-rt/list_ops.c
@@ -5,6 +5,10 @@
 #include <Python.h>
 #include "CPy.h"
 
+#ifndef Py_TPFLAGS_SEQUENCE
+#define Py_TPFLAGS_SEQUENCE (1 << 5)
+#endif
+
 PyObject *CPyList_Build(Py_ssize_t len, ...) {
     Py_ssize_t i;
 
@@ -325,3 +329,7 @@ PyObject *CPyList_GetSlice(PyObject *obj, CPyTagged start, CPyTagged end) {
     }
     return CPyObject_GetSlice(obj, start, end);
 }
+
+int CPySequence_Check(PyObject *obj) {
+    return Py_TYPE(obj)->tp_flags & Py_TPFLAGS_SEQUENCE;
+}
diff --git a/mypyc/options.py b/mypyc/options.py
index d554cbed164f7..5f0cf12aeefed 100644
--- a/mypyc/options.py
+++ b/mypyc/options.py
@@ -13,6 +13,7 @@ def __init__(
         target_dir: str | None = None,
         include_runtime_files: bool | None = None,
         capi_version: tuple[int, int] | None = None,
+        python_version: tuple[int, int] | None = None,
     ) -> None:
         self.strip_asserts = strip_asserts
         self.multi_file = multi_file
@@ -28,3 +29,4 @@ def __init__(
         # binaries are backward compatible even if no recent API
         # features are used.
         self.capi_version = capi_version or sys.version_info[:2]
+        self.python_version = python_version
diff --git a/mypyc/primitives/dict_ops.py b/mypyc/primitives/dict_ops.py
index d1dca5a79e635..9f477d0b7b90c 100644
--- a/mypyc/primitives/dict_ops.py
+++ b/mypyc/primitives/dict_ops.py
@@ -63,7 +63,7 @@
 )
 
 # Generic one-argument dict constructor: dict(obj)
-function_op(
+dict_copy = function_op(
     name="builtins.dict",
     arg_types=[object_rprimitive],
     return_type=dict_rprimitive,
@@ -301,3 +301,25 @@
     c_function_name="PyDict_Size",
     error_kind=ERR_NEVER,
 )
+
+# Delete an item from a dict
+dict_del_item = custom_op(
+    arg_types=[object_rprimitive, object_rprimitive],
+    return_type=c_int_rprimitive,
+    c_function_name="PyDict_DelItem",
+    error_kind=ERR_NEG_INT,
+)
+
+supports_mapping_protocol = custom_op(
+    arg_types=[object_rprimitive],
+    return_type=c_int_rprimitive,
+    c_function_name="CPyMapping_Check",
+    error_kind=ERR_NEVER,
+)
+
+mapping_has_key = custom_op(
+    arg_types=[object_rprimitive, object_rprimitive],
+    return_type=c_int_rprimitive,
+    c_function_name="PyMapping_HasKey",
+    error_kind=ERR_NEVER,
+)
diff --git a/mypyc/primitives/list_ops.py b/mypyc/primitives/list_ops.py
index c729e264fc14e..7fe3157f3a382 100644
--- a/mypyc/primitives/list_ops.py
+++ b/mypyc/primitives/list_ops.py
@@ -277,3 +277,24 @@
     c_function_name="CPyList_GetSlice",
     error_kind=ERR_MAGIC,
 )
+
+supports_sequence_protocol = custom_op(
+    arg_types=[object_rprimitive],
+    return_type=c_int_rprimitive,
+    c_function_name="CPySequence_Check",
+    error_kind=ERR_NEVER,
+)
+
+sequence_get_item = custom_op(
+    arg_types=[object_rprimitive, c_pyssize_t_rprimitive],
+    return_type=object_rprimitive,
+    c_function_name="PySequence_GetItem",
+    error_kind=ERR_NEVER,
+)
+
+sequence_get_slice = custom_op(
+    arg_types=[object_rprimitive, c_pyssize_t_rprimitive, c_pyssize_t_rprimitive],
+    return_type=object_rprimitive,
+    c_function_name="PySequence_GetSlice",
+    error_kind=ERR_MAGIC,
+)
diff --git a/mypyc/test-data/irbuild-match.test b/mypyc/test-data/irbuild-match.test
new file mode 100644
index 0000000000000..2afe3d862f517
--- /dev/null
+++ b/mypyc/test-data/irbuild-match.test
@@ -0,0 +1,1708 @@
+[case testMatchValuePattern_python3_10]
+def f():
+    match 123:
+        case 123:
+            print("matched")
+[out]
+def f():
+    r0 :: bit
+    r1 :: str
+    r2 :: object
+    r3 :: str
+    r4 :: object
+    r5 :: object[1]
+    r6 :: object_ptr
+    r7, r8 :: object
+L0:
+    r0 = 246 == 246
+    if r0 goto L1 else goto L2 :: bool
+L1:
+    r1 = 'matched'
+    r2 = builtins :: module
+    r3 = 'print'
+    r4 = CPyObject_GetAttr(r2, r3)
+    r5 = [r1]
+    r6 = load_address r5
+    r7 = _PyObject_Vectorcall(r4, r6, 1, 0)
+    keep_alive r1
+    goto L3
+L2:
+L3:
+    r8 = box(None, 1)
+    return r8
+[case testMatchOrPattern_python3_10]
+def f():
+    match 123:
+        case 123 | 456:
+            print("matched")
+[out]
+def f():
+    r0, r1 :: bit
+    r2 :: str
+    r3 :: object
+    r4 :: str
+    r5 :: object
+    r6 :: object[1]
+    r7 :: object_ptr
+    r8, r9 :: object
+L0:
+    r0 = 246 == 246
+    if r0 goto L3 else goto L1 :: bool
+L1:
+    r1 = 246 == 912
+    if r1 goto L3 else goto L2 :: bool
+L2:
+    goto L4
+L3:
+    r2 = 'matched'
+    r3 = builtins :: module
+    r4 = 'print'
+    r5 = CPyObject_GetAttr(r3, r4)
+    r6 = [r2]
+    r7 = load_address r6
+    r8 = _PyObject_Vectorcall(r5, r7, 1, 0)
+    keep_alive r2
+    goto L5
+L4:
+L5:
+    r9 = box(None, 1)
+    return r9
+[case testMatchOrPatternManyPatterns_python3_10]
+def f():
+    match 1:
+        case 1 | 2 | 3 | 4:
+            print("matched")
+[out]
+def f():
+    r0, r1, r2, r3 :: bit
+    r4 :: str
+    r5 :: object
+    r6 :: str
+    r7 :: object
+    r8 :: object[1]
+    r9 :: object_ptr
+    r10, r11 :: object
+L0:
+    r0 = 2 == 2
+    if r0 goto L5 else goto L1 :: bool
+L1:
+    r1 = 2 == 4
+    if r1 goto L5 else goto L2 :: bool
+L2:
+    r2 = 2 == 6
+    if r2 goto L5 else goto L3 :: bool
+L3:
+    r3 = 2 == 8
+    if r3 goto L5 else goto L4 :: bool
+L4:
+    goto L6
+L5:
+    r4 = 'matched'
+    r5 = builtins :: module
+    r6 = 'print'
+    r7 = CPyObject_GetAttr(r5, r6)
+    r8 = [r4]
+    r9 = load_address r8
+    r10 = _PyObject_Vectorcall(r7, r9, 1, 0)
+    keep_alive r4
+    goto L7
+L6:
+L7:
+    r11 = box(None, 1)
+    return r11
+[case testMatchClassPattern_python3_10]
+def f():
+    match 123:
+        case int():
+            print("matched")
+[out]
+def f():
+    r0, r1 :: object
+    r2 :: bool
+    r3 :: str
+    r4 :: object
+    r5 :: str
+    r6 :: object
+    r7 :: object[1]
+    r8 :: object_ptr
+    r9, r10 :: object
+L0:
+    r0 = load_address PyLong_Type
+    r1 = object 123
+    r2 = CPy_TypeCheck(r1, r0)
+    if r2 goto L1 else goto L2 :: bool
+L1:
+    r3 = 'matched'
+    r4 = builtins :: module
+    r5 = 'print'
+    r6 = CPyObject_GetAttr(r4, r5)
+    r7 = [r3]
+    r8 = load_address r7
+    r9 = _PyObject_Vectorcall(r6, r8, 1, 0)
+    keep_alive r3
+    goto L3
+L2:
+L3:
+    r10 = box(None, 1)
+    return r10
+[case testMatchExaustivePattern_python3_10]
+def f():
+    match 123:
+        case _:
+            print("matched")
+[out]
+def f():
+    r0 :: str
+    r1 :: object
+    r2 :: str
+    r3 :: object
+    r4 :: object[1]
+    r5 :: object_ptr
+    r6, r7 :: object
+L0:
+L1:
+    r0 = 'matched'
+    r1 = builtins :: module
+    r2 = 'print'
+    r3 = CPyObject_GetAttr(r1, r2)
+    r4 = [r0]
+    r5 = load_address r4
+    r6 = _PyObject_Vectorcall(r3, r5, 1, 0)
+    keep_alive r0
+    goto L3
+L2:
+L3:
+    r7 = box(None, 1)
+    return r7
+[case testMatchMultipleBodies_python3_10]
+def f():
+    match 123:
+        case 123:
+            print("matched")
+        case 456:
+            print("no match")
+[out]
+def f():
+    r0 :: bit
+    r1 :: str
+    r2 :: object
+    r3 :: str
+    r4 :: object
+    r5 :: object[1]
+    r6 :: object_ptr
+    r7 :: object
+    r8 :: bit
+    r9 :: str
+    r10 :: object
+    r11 :: str
+    r12 :: object
+    r13 :: object[1]
+    r14 :: object_ptr
+    r15, r16 :: object
+L0:
+    r0 = 246 == 246
+    if r0 goto L1 else goto L2 :: bool
+L1:
+    r1 = 'matched'
+    r2 = builtins :: module
+    r3 = 'print'
+    r4 = CPyObject_GetAttr(r2, r3)
+    r5 = [r1]
+    r6 = load_address r5
+    r7 = _PyObject_Vectorcall(r4, r6, 1, 0)
+    keep_alive r1
+    goto L5
+L2:
+    r8 = 246 == 912
+    if r8 goto L3 else goto L4 :: bool
+L3:
+    r9 = 'no match'
+    r10 = builtins :: module
+    r11 = 'print'
+    r12 = CPyObject_GetAttr(r10, r11)
+    r13 = [r9]
+    r14 = load_address r13
+    r15 = _PyObject_Vectorcall(r12, r14, 1, 0)
+    keep_alive r9
+    goto L5
+L4:
+L5:
+    r16 = box(None, 1)
+    return r16
+[case testMatchMultiBodyAndComplexOr_python3_10]
+def f():
+    match 123:
+        case 1:
+            print("here 1")
+        case 2 | 3:
+            print("here 2 | 3")
+        case 123:
+            print("here 123")
+[out]
+def f():
+    r0 :: bit
+    r1 :: str
+    r2 :: object
+    r3 :: str
+    r4 :: object
+    r5 :: object[1]
+    r6 :: object_ptr
+    r7 :: object
+    r8, r9 :: bit
+    r10 :: str
+    r11 :: object
+    r12 :: str
+    r13 :: object
+    r14 :: object[1]
+    r15 :: object_ptr
+    r16 :: object
+    r17 :: bit
+    r18 :: str
+    r19 :: object
+    r20 :: str
+    r21 :: object
+    r22 :: object[1]
+    r23 :: object_ptr
+    r24, r25 :: object
+L0:
+    r0 = 246 == 2
+    if r0 goto L1 else goto L2 :: bool
+L1:
+    r1 = 'here 1'
+    r2 = builtins :: module
+    r3 = 'print'
+    r4 = CPyObject_GetAttr(r2, r3)
+    r5 = [r1]
+    r6 = load_address r5
+    r7 = _PyObject_Vectorcall(r4, r6, 1, 0)
+    keep_alive r1
+    goto L9
+L2:
+    r8 = 246 == 4
+    if r8 goto L5 else goto L3 :: bool
+L3:
+    r9 = 246 == 6
+    if r9 goto L5 else goto L4 :: bool
+L4:
+    goto L6
+L5:
+    r10 = 'here 2 | 3'
+    r11 = builtins :: module
+    r12 = 'print'
+    r13 = CPyObject_GetAttr(r11, r12)
+    r14 = [r10]
+    r15 = load_address r14
+    r16 = _PyObject_Vectorcall(r13, r15, 1, 0)
+    keep_alive r10
+    goto L9
+L6:
+    r17 = 246 == 246
+    if r17 goto L7 else goto L8 :: bool
+L7:
+    r18 = 'here 123'
+    r19 = builtins :: module
+    r20 = 'print'
+    r21 = CPyObject_GetAttr(r19, r20)
+    r22 = [r18]
+    r23 = load_address r22
+    r24 = _PyObject_Vectorcall(r21, r23, 1, 0)
+    keep_alive r18
+    goto L9
+L8:
+L9:
+    r25 = box(None, 1)
+    return r25
+[case testMatchWithGuard_python3_10]
+def f():
+    match 123:
+        case 123 if True:
+            print("matched")
+[out]
+def f():
+    r0 :: bit
+    r1 :: str
+    r2 :: object
+    r3 :: str
+    r4 :: object
+    r5 :: object[1]
+    r6 :: object_ptr
+    r7, r8 :: object
+L0:
+    r0 = 246 == 246
+    if r0 goto L1 else goto L3 :: bool
+L1:
+    if 1 goto L2 else goto L3 :: bool
+L2:
+    r1 = 'matched'
+    r2 = builtins :: module
+    r3 = 'print'
+    r4 = CPyObject_GetAttr(r2, r3)
+    r5 = [r1]
+    r6 = load_address r5
+    r7 = _PyObject_Vectorcall(r4, r6, 1, 0)
+    keep_alive r1
+    goto L4
+L3:
+L4:
+    r8 = box(None, 1)
+    return r8
+[case testMatchSingleton_python3_10]
+def f():
+    match 123:
+        case True:
+            print("value is True")
+        case False:
+            print("value is False")
+        case None:
+            print("value is None")
+[out]
+def f():
+    r0, r1 :: object
+    r2 :: bit
+    r3 :: str
+    r4 :: object
+    r5 :: str
+    r6 :: object
+    r7 :: object[1]
+    r8 :: object_ptr
+    r9, r10, r11 :: object
+    r12 :: bit
+    r13 :: str
+    r14 :: object
+    r15 :: str
+    r16 :: object
+    r17 :: object[1]
+    r18 :: object_ptr
+    r19, r20, r21 :: object
+    r22 :: bit
+    r23 :: str
+    r24 :: object
+    r25 :: str
+    r26 :: object
+    r27 :: object[1]
+    r28 :: object_ptr
+    r29, r30 :: object
+L0:
+    r0 = object 123
+    r1 = box(bool, 1)
+    r2 = r0 == r1
+    if r2 goto L1 else goto L2 :: bool
+L1:
+    r3 = 'value is True'
+    r4 = builtins :: module
+    r5 = 'print'
+    r6 = CPyObject_GetAttr(r4, r5)
+    r7 = [r3]
+    r8 = load_address r7
+    r9 = _PyObject_Vectorcall(r6, r8, 1, 0)
+    keep_alive r3
+    goto L7
+L2:
+    r10 = object 123
+    r11 = box(bool, 0)
+    r12 = r10 == r11
+    if r12 goto L3 else goto L4 :: bool
+L3:
+    r13 = 'value is False'
+    r14 = builtins :: module
+    r15 = 'print'
+    r16 = CPyObject_GetAttr(r14, r15)
+    r17 = [r13]
+    r18 = load_address r17
+    r19 = _PyObject_Vectorcall(r16, r18, 1, 0)
+    keep_alive r13
+    goto L7
+L4:
+    r20 = load_address _Py_NoneStruct
+    r21 = object 123
+    r22 = r21 == r20
+    if r22 goto L5 else goto L6 :: bool
+L5:
+    r23 = 'value is None'
+    r24 = builtins :: module
+    r25 = 'print'
+    r26 = CPyObject_GetAttr(r24, r25)
+    r27 = [r23]
+    r28 = load_address r27
+    r29 = _PyObject_Vectorcall(r26, r28, 1, 0)
+    keep_alive r23
+    goto L7
+L6:
+L7:
+    r30 = box(None, 1)
+    return r30
+[case testMatchRecursiveOrPattern_python3_10]
+def f():
+    match 1:
+        case 1 | int():
+            print("matched")
+[out]
+def f():
+    r0 :: bit
+    r1, r2 :: object
+    r3 :: bool
+    r4 :: str
+    r5 :: object
+    r6 :: str
+    r7 :: object
+    r8 :: object[1]
+    r9 :: object_ptr
+    r10, r11 :: object
+L0:
+    r0 = 2 == 2
+    if r0 goto L3 else goto L1 :: bool
+L1:
+    r1 = load_address PyLong_Type
+    r2 = object 1
+    r3 = CPy_TypeCheck(r2, r1)
+    if r3 goto L3 else goto L2 :: bool
+L2:
+    goto L4
+L3:
+    r4 = 'matched'
+    r5 = builtins :: module
+    r6 = 'print'
+    r7 = CPyObject_GetAttr(r5, r6)
+    r8 = [r4]
+    r9 = load_address r8
+    r10 = _PyObject_Vectorcall(r7, r9, 1, 0)
+    keep_alive r4
+    goto L5
+L4:
+L5:
+    r11 = box(None, 1)
+    return r11
+[case testMatchAsPattern_python3_10]
+def f():
+    match 123:
+        case 123 as x:
+            print(x)
+[out]
+def f():
+    r0 :: bit
+    r1, x, r2 :: object
+    r3 :: str
+    r4 :: object
+    r5 :: object[1]
+    r6 :: object_ptr
+    r7, r8 :: object
+L0:
+    r0 = 246 == 246
+    r1 = object 123
+    x = r1
+    if r0 goto L1 else goto L2 :: bool
+L1:
+    r2 = builtins :: module
+    r3 = 'print'
+    r4 = CPyObject_GetAttr(r2, r3)
+    r5 = [x]
+    r6 = load_address r5
+    r7 = _PyObject_Vectorcall(r4, r6, 1, 0)
+    keep_alive x
+    goto L3
+L2:
+L3:
+    r8 = box(None, 1)
+    return r8
+[case testMatchAsPatternOnOrPattern_python3_10]
+def f():
+    match 1:
+        case (1 | 2) as x:
+            print(x)
+[out]
+def f():
+    r0 :: bit
+    r1, x :: object
+    r2 :: bit
+    r3, r4 :: object
+    r5 :: str
+    r6 :: object
+    r7 :: object[1]
+    r8 :: object_ptr
+    r9, r10 :: object
+L0:
+    r0 = 2 == 2
+    r1 = object 1
+    x = r1
+    if r0 goto L3 else goto L1 :: bool
+L1:
+    r2 = 2 == 4
+    r3 = object 2
+    x = r3
+    if r2 goto L3 else goto L2 :: bool
+L2:
+    goto L4
+L3:
+    r4 = builtins :: module
+    r5 = 'print'
+    r6 = CPyObject_GetAttr(r4, r5)
+    r7 = [x]
+    r8 = load_address r7
+    r9 = _PyObject_Vectorcall(r6, r8, 1, 0)
+    keep_alive x
+    goto L5
+L4:
+L5:
+    r10 = box(None, 1)
+    return r10
+[case testMatchAsPatternOnClassPattern_python3_10]
+def f():
+    match 123:
+        case int() as i:
+            print(i)
+[out]
+def f():
+    r0, r1 :: object
+    r2 :: bool
+    i :: int
+    r3 :: object
+    r4 :: str
+    r5, r6 :: object
+    r7 :: object[1]
+    r8 :: object_ptr
+    r9, r10 :: object
+L0:
+    r0 = load_address PyLong_Type
+    r1 = object 123
+    r2 = CPy_TypeCheck(r1, r0)
+    if r2 goto L1 else goto L3 :: bool
+L1:
+    i = 246
+L2:
+    r3 = builtins :: module
+    r4 = 'print'
+    r5 = CPyObject_GetAttr(r3, r4)
+    r6 = box(int, i)
+    r7 = [r6]
+    r8 = load_address r7
+    r9 = _PyObject_Vectorcall(r5, r8, 1, 0)
+    keep_alive r6
+    goto L4
+L3:
+L4:
+    r10 = box(None, 1)
+    return r10
+[case testMatchClassPatternWithPositionalArgs_python3_10]
+class Position:
+    __match_args__ = ("x", "y", "z")
+
+    x: int
+    y: int
+    z: int
+
+def f(x):
+    match x:
+        case Position(1, 2, 3):
+            print("matched")
+[out]
+def Position.__mypyc_defaults_setup(__mypyc_self__):
+    __mypyc_self__ :: __main__.Position
+    r0, r1, r2 :: str
+    r3 :: tuple[str, str, str]
+L0:
+    r0 = 'x'
+    r1 = 'y'
+    r2 = 'z'
+    r3 = (r0, r1, r2)
+    __mypyc_self__.__match_args__ = r3
+    return 1
+def f(x):
+    x, r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4 :: str
+    r5, r6, r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11 :: str
+    r12, r13, r14 :: object
+    r15 :: int32
+    r16 :: bit
+    r17 :: bool
+    r18 :: str
+    r19, r20, r21 :: object
+    r22 :: int32
+    r23 :: bit
+    r24 :: bool
+    r25 :: str
+    r26 :: object
+    r27 :: str
+    r28 :: object
+    r29 :: object[1]
+    r30 :: object_ptr
+    r31, r32 :: object
+L0:
+    r0 = __main__.Position :: type
+    r1 = PyObject_IsInstance(x, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L5 :: bool
+L1:
+    r4 = 'x'
+    r5 = CPyObject_GetAttr(x, r4)
+    r6 = object 1
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L2 else goto L5 :: bool
+L2:
+    r11 = 'y'
+    r12 = CPyObject_GetAttr(x, r11)
+    r13 = object 2
+    r14 = PyObject_RichCompare(r12, r13, 2)
+    r15 = PyObject_IsTrue(r14)
+    r16 = r15 >= 0 :: signed
+    r17 = truncate r15: int32 to builtins.bool
+    if r17 goto L3 else goto L5 :: bool
+L3:
+    r18 = 'z'
+    r19 = CPyObject_GetAttr(x, r18)
+    r20 = object 3
+    r21 = PyObject_RichCompare(r19, r20, 2)
+    r22 = PyObject_IsTrue(r21)
+    r23 = r22 >= 0 :: signed
+    r24 = truncate r22: int32 to builtins.bool
+    if r24 goto L4 else goto L5 :: bool
+L4:
+    r25 = 'matched'
+    r26 = builtins :: module
+    r27 = 'print'
+    r28 = CPyObject_GetAttr(r26, r27)
+    r29 = [r25]
+    r30 = load_address r29
+    r31 = _PyObject_Vectorcall(r28, r30, 1, 0)
+    keep_alive r25
+    goto L6
+L5:
+L6:
+    r32 = box(None, 1)
+    return r32
+[case testMatchClassPatternWithKeywordPatterns_python3_10]
+class Position:
+    x: int
+    y: int
+    z: int
+
+def f(x):
+    match x:
+        case Position(z=1, y=2, x=3):
+            print("matched")
+[out]
+def f(x):
+    x, r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4 :: str
+    r5, r6, r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11 :: str
+    r12, r13, r14 :: object
+    r15 :: int32
+    r16 :: bit
+    r17 :: bool
+    r18 :: str
+    r19, r20, r21 :: object
+    r22 :: int32
+    r23 :: bit
+    r24 :: bool
+    r25 :: str
+    r26 :: object
+    r27 :: str
+    r28 :: object
+    r29 :: object[1]
+    r30 :: object_ptr
+    r31, r32 :: object
+L0:
+    r0 = __main__.Position :: type
+    r1 = PyObject_IsInstance(x, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L5 :: bool
+L1:
+    r4 = 'z'
+    r5 = CPyObject_GetAttr(x, r4)
+    r6 = object 1
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L2 else goto L5 :: bool
+L2:
+    r11 = 'y'
+    r12 = CPyObject_GetAttr(x, r11)
+    r13 = object 2
+    r14 = PyObject_RichCompare(r12, r13, 2)
+    r15 = PyObject_IsTrue(r14)
+    r16 = r15 >= 0 :: signed
+    r17 = truncate r15: int32 to builtins.bool
+    if r17 goto L3 else goto L5 :: bool
+L3:
+    r18 = 'x'
+    r19 = CPyObject_GetAttr(x, r18)
+    r20 = object 3
+    r21 = PyObject_RichCompare(r19, r20, 2)
+    r22 = PyObject_IsTrue(r21)
+    r23 = r22 >= 0 :: signed
+    r24 = truncate r22: int32 to builtins.bool
+    if r24 goto L4 else goto L5 :: bool
+L4:
+    r25 = 'matched'
+    r26 = builtins :: module
+    r27 = 'print'
+    r28 = CPyObject_GetAttr(r26, r27)
+    r29 = [r25]
+    r30 = load_address r29
+    r31 = _PyObject_Vectorcall(r28, r30, 1, 0)
+    keep_alive r25
+    goto L6
+L5:
+L6:
+    r32 = box(None, 1)
+    return r32
+[case testMatchClassPatternWithNestedPattern_python3_10]
+class C:
+    num: int
+
+def f(x):
+    match x:
+        case C(num=1 | 2):
+            print("matched")
+[out]
+def f(x):
+    x, r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4 :: str
+    r5, r6, r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11, r12 :: object
+    r13 :: int32
+    r14 :: bit
+    r15 :: bool
+    r16 :: str
+    r17 :: object
+    r18 :: str
+    r19 :: object
+    r20 :: object[1]
+    r21 :: object_ptr
+    r22, r23 :: object
+L0:
+    r0 = __main__.C :: type
+    r1 = PyObject_IsInstance(x, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L5 :: bool
+L1:
+    r4 = 'num'
+    r5 = CPyObject_GetAttr(x, r4)
+    r6 = object 1
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L4 else goto L2 :: bool
+L2:
+    r11 = object 2
+    r12 = PyObject_RichCompare(r5, r11, 2)
+    r13 = PyObject_IsTrue(r12)
+    r14 = r13 >= 0 :: signed
+    r15 = truncate r13: int32 to builtins.bool
+    if r15 goto L4 else goto L3 :: bool
+L3:
+    goto L5
+L4:
+    r16 = 'matched'
+    r17 = builtins :: module
+    r18 = 'print'
+    r19 = CPyObject_GetAttr(r17, r18)
+    r20 = [r16]
+    r21 = load_address r20
+    r22 = _PyObject_Vectorcall(r19, r21, 1, 0)
+    keep_alive r16
+    goto L6
+L5:
+L6:
+    r23 = box(None, 1)
+    return r23
+[case testAsPatternDoesntBleedIntoSubPatterns_python3_10]
+class C:
+    __match_args__ = ("a", "b")
+    a: int
+    b: int
+
+def f(x):
+    match x:
+        case C(1, 2) as y:
+            print("matched")
+[out]
+def C.__mypyc_defaults_setup(__mypyc_self__):
+    __mypyc_self__ :: __main__.C
+    r0, r1 :: str
+    r2 :: tuple[str, str]
+L0:
+    r0 = 'a'
+    r1 = 'b'
+    r2 = (r0, r1)
+    __mypyc_self__.__match_args__ = r2
+    return 1
+def f(x):
+    x, r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4, y :: __main__.C
+    r5 :: str
+    r6, r7, r8 :: object
+    r9 :: int32
+    r10 :: bit
+    r11 :: bool
+    r12 :: str
+    r13, r14, r15 :: object
+    r16 :: int32
+    r17 :: bit
+    r18 :: bool
+    r19 :: str
+    r20 :: object
+    r21 :: str
+    r22 :: object
+    r23 :: object[1]
+    r24 :: object_ptr
+    r25, r26 :: object
+L0:
+    r0 = __main__.C :: type
+    r1 = PyObject_IsInstance(x, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L5 :: bool
+L1:
+    r4 = cast(__main__.C, x)
+    y = r4
+L2:
+    r5 = 'a'
+    r6 = CPyObject_GetAttr(x, r5)
+    r7 = object 1
+    r8 = PyObject_RichCompare(r6, r7, 2)
+    r9 = PyObject_IsTrue(r8)
+    r10 = r9 >= 0 :: signed
+    r11 = truncate r9: int32 to builtins.bool
+    if r11 goto L3 else goto L5 :: bool
+L3:
+    r12 = 'b'
+    r13 = CPyObject_GetAttr(x, r12)
+    r14 = object 2
+    r15 = PyObject_RichCompare(r13, r14, 2)
+    r16 = PyObject_IsTrue(r15)
+    r17 = r16 >= 0 :: signed
+    r18 = truncate r16: int32 to builtins.bool
+    if r18 goto L4 else goto L5 :: bool
+L4:
+    r19 = 'matched'
+    r20 = builtins :: module
+    r21 = 'print'
+    r22 = CPyObject_GetAttr(r20, r21)
+    r23 = [r19]
+    r24 = load_address r23
+    r25 = _PyObject_Vectorcall(r22, r24, 1, 0)
+    keep_alive r19
+    goto L6
+L5:
+L6:
+    r26 = box(None, 1)
+    return r26
+[case testMatchClassPatternPositionalCapture_python3_10]
+class C:
+    __match_args__ = ("x",)
+
+    x: int
+
+def f(x):
+    match x:
+        case C(num):
+            print("matched")
+[out]
+def C.__mypyc_defaults_setup(__mypyc_self__):
+    __mypyc_self__ :: __main__.C
+    r0 :: str
+    r1 :: tuple[str]
+L0:
+    r0 = 'x'
+    r1 = (r0)
+    __mypyc_self__.__match_args__ = r1
+    return 1
+def f(x):
+    x, r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4 :: str
+    r5 :: object
+    r6, num :: int
+    r7 :: str
+    r8 :: object
+    r9 :: str
+    r10 :: object
+    r11 :: object[1]
+    r12 :: object_ptr
+    r13, r14 :: object
+L0:
+    r0 = __main__.C :: type
+    r1 = PyObject_IsInstance(x, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L3 :: bool
+L1:
+    r4 = 'x'
+    r5 = CPyObject_GetAttr(x, r4)
+    r6 = unbox(int, r5)
+    num = r6
+L2:
+    r7 = 'matched'
+    r8 = builtins :: module
+    r9 = 'print'
+    r10 = CPyObject_GetAttr(r8, r9)
+    r11 = [r7]
+    r12 = load_address r11
+    r13 = _PyObject_Vectorcall(r10, r12, 1, 0)
+    keep_alive r7
+    goto L4
+L3:
+L4:
+    r14 = box(None, 1)
+    return r14
+[case testMatchMappingEmpty_python3_10]
+def f(x):
+    match x:
+        case {}:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: str
+    r3 :: object
+    r4 :: str
+    r5 :: object
+    r6 :: object[1]
+    r7 :: object_ptr
+    r8, r9 :: object
+L0:
+    r0 = CPyMapping_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L2 :: bool
+L1:
+    r2 = 'matched'
+    r3 = builtins :: module
+    r4 = 'print'
+    r5 = CPyObject_GetAttr(r3, r4)
+    r6 = [r2]
+    r7 = load_address r6
+    r8 = _PyObject_Vectorcall(r5, r7, 1, 0)
+    keep_alive r2
+    goto L3
+L2:
+L3:
+    r9 = box(None, 1)
+    return r9
+[case testMatchMappingPatternWithKeys_python3_10]
+def f(x):
+    match x:
+        case {"key": "value"}:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: str
+    r3 :: int32
+    r4 :: bit
+    r5 :: object
+    r6 :: str
+    r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11 :: str
+    r12 :: object
+    r13 :: str
+    r14 :: object
+    r15 :: object[1]
+    r16 :: object_ptr
+    r17, r18 :: object
+L0:
+    r0 = CPyMapping_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L4 :: bool
+L1:
+    r2 = 'key'
+    r3 = PyMapping_HasKey(x, r2)
+    r4 = r3 != 0
+    if r4 goto L2 else goto L4 :: bool
+L2:
+    r5 = PyObject_GetItem(x, r2)
+    r6 = 'value'
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L3 else goto L4 :: bool
+L3:
+    r11 = 'matched'
+    r12 = builtins :: module
+    r13 = 'print'
+    r14 = CPyObject_GetAttr(r12, r13)
+    r15 = [r11]
+    r16 = load_address r15
+    r17 = _PyObject_Vectorcall(r14, r16, 1, 0)
+    keep_alive r11
+    goto L5
+L4:
+L5:
+    r18 = box(None, 1)
+    return r18
+[case testMatchMappingPatternWithRest_python3_10]
+def f(x):
+    match x:
+        case {**rest}:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2, rest :: dict
+    r3 :: str
+    r4 :: object
+    r5 :: str
+    r6 :: object
+    r7 :: object[1]
+    r8 :: object_ptr
+    r9, r10 :: object
+L0:
+    r0 = CPyMapping_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L3 :: bool
+L1:
+    r2 = CPyDict_FromAny(x)
+    rest = r2
+L2:
+    r3 = 'matched'
+    r4 = builtins :: module
+    r5 = 'print'
+    r6 = CPyObject_GetAttr(r4, r5)
+    r7 = [r3]
+    r8 = load_address r7
+    r9 = _PyObject_Vectorcall(r6, r8, 1, 0)
+    keep_alive r3
+    goto L4
+L3:
+L4:
+    r10 = box(None, 1)
+    return r10
+[case testMatchMappingPatternWithRestPopKeys_python3_10]
+def f(x):
+    match x:
+        case {"key": "value", **rest}:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: str
+    r3 :: int32
+    r4 :: bit
+    r5 :: object
+    r6 :: str
+    r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11, rest :: dict
+    r12 :: int32
+    r13 :: bit
+    r14 :: str
+    r15 :: object
+    r16 :: str
+    r17 :: object
+    r18 :: object[1]
+    r19 :: object_ptr
+    r20, r21 :: object
+L0:
+    r0 = CPyMapping_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L5 :: bool
+L1:
+    r2 = 'key'
+    r3 = PyMapping_HasKey(x, r2)
+    r4 = r3 != 0
+    if r4 goto L2 else goto L5 :: bool
+L2:
+    r5 = PyObject_GetItem(x, r2)
+    r6 = 'value'
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L3 else goto L5 :: bool
+L3:
+    r11 = CPyDict_FromAny(x)
+    rest = r11
+    r12 = PyDict_DelItem(r11, r2)
+    r13 = r12 >= 0 :: signed
+L4:
+    r14 = 'matched'
+    r15 = builtins :: module
+    r16 = 'print'
+    r17 = CPyObject_GetAttr(r15, r16)
+    r18 = [r14]
+    r19 = load_address r18
+    r20 = _PyObject_Vectorcall(r17, r19, 1, 0)
+    keep_alive r14
+    goto L6
+L5:
+L6:
+    r21 = box(None, 1)
+    return r21
+[case testMatchEmptySequencePattern_python3_10]
+def f(x):
+    match x:
+        case []:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5 :: str
+    r6 :: object
+    r7 :: str
+    r8 :: object
+    r9 :: object[1]
+    r10 :: object_ptr
+    r11, r12 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L3 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 == 0
+    if r4 goto L2 else goto L3 :: bool
+L2:
+    r5 = 'matched'
+    r6 = builtins :: module
+    r7 = 'print'
+    r8 = CPyObject_GetAttr(r6, r7)
+    r9 = [r5]
+    r10 = load_address r9
+    r11 = _PyObject_Vectorcall(r8, r10, 1, 0)
+    keep_alive r5
+    goto L4
+L3:
+L4:
+    r12 = box(None, 1)
+    return r12
+[case testMatchFixedLengthSequencePattern_python3_10]
+def f(x):
+    match x:
+        case [1, 2]:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5, r6, r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11, r12, r13 :: object
+    r14 :: int32
+    r15 :: bit
+    r16 :: bool
+    r17 :: str
+    r18 :: object
+    r19 :: str
+    r20 :: object
+    r21 :: object[1]
+    r22 :: object_ptr
+    r23, r24 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L5 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 == 2
+    if r4 goto L2 else goto L5 :: bool
+L2:
+    r5 = PySequence_GetItem(x, 0)
+    r6 = object 1
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L3 else goto L5 :: bool
+L3:
+    r11 = PySequence_GetItem(x, 1)
+    r12 = object 2
+    r13 = PyObject_RichCompare(r11, r12, 2)
+    r14 = PyObject_IsTrue(r13)
+    r15 = r14 >= 0 :: signed
+    r16 = truncate r14: int32 to builtins.bool
+    if r16 goto L4 else goto L5 :: bool
+L4:
+    r17 = 'matched'
+    r18 = builtins :: module
+    r19 = 'print'
+    r20 = CPyObject_GetAttr(r18, r19)
+    r21 = [r17]
+    r22 = load_address r21
+    r23 = _PyObject_Vectorcall(r20, r22, 1, 0)
+    keep_alive r17
+    goto L6
+L5:
+L6:
+    r24 = box(None, 1)
+    return r24
+[case testMatchSequencePatternWithTrailingUnboundStar_python3_10]
+def f(x):
+    match x:
+        case [1, 2, *_]:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5, r6, r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11, r12, r13 :: object
+    r14 :: int32
+    r15 :: bit
+    r16 :: bool
+    r17 :: str
+    r18 :: object
+    r19 :: str
+    r20 :: object
+    r21 :: object[1]
+    r22 :: object_ptr
+    r23, r24 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L5 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 >= 2 :: signed
+    if r4 goto L2 else goto L5 :: bool
+L2:
+    r5 = PySequence_GetItem(x, 0)
+    r6 = object 1
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L3 else goto L5 :: bool
+L3:
+    r11 = PySequence_GetItem(x, 1)
+    r12 = object 2
+    r13 = PyObject_RichCompare(r11, r12, 2)
+    r14 = PyObject_IsTrue(r13)
+    r15 = r14 >= 0 :: signed
+    r16 = truncate r14: int32 to builtins.bool
+    if r16 goto L4 else goto L5 :: bool
+L4:
+    r17 = 'matched'
+    r18 = builtins :: module
+    r19 = 'print'
+    r20 = CPyObject_GetAttr(r18, r19)
+    r21 = [r17]
+    r22 = load_address r21
+    r23 = _PyObject_Vectorcall(r20, r22, 1, 0)
+    keep_alive r17
+    goto L6
+L5:
+L6:
+    r24 = box(None, 1)
+    return r24
+[case testMatchSequencePatternWithTrailingBoundStar_python3_10]
+def f(x):
+    match x:
+        case [1, 2, *rest]:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5, r6, r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11, r12, r13 :: object
+    r14 :: int32
+    r15 :: bit
+    r16 :: bool
+    r17 :: native_int
+    r18, rest :: object
+    r19 :: str
+    r20 :: object
+    r21 :: str
+    r22 :: object
+    r23 :: object[1]
+    r24 :: object_ptr
+    r25, r26 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L6 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 >= 2 :: signed
+    if r4 goto L2 else goto L6 :: bool
+L2:
+    r5 = PySequence_GetItem(x, 0)
+    r6 = object 1
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L3 else goto L6 :: bool
+L3:
+    r11 = PySequence_GetItem(x, 1)
+    r12 = object 2
+    r13 = PyObject_RichCompare(r11, r12, 2)
+    r14 = PyObject_IsTrue(r13)
+    r15 = r14 >= 0 :: signed
+    r16 = truncate r14: int32 to builtins.bool
+    if r16 goto L4 else goto L6 :: bool
+L4:
+    r17 = r2 - 0
+    r18 = PySequence_GetSlice(x, 2, r17)
+    rest = r18
+L5:
+    r19 = 'matched'
+    r20 = builtins :: module
+    r21 = 'print'
+    r22 = CPyObject_GetAttr(r20, r21)
+    r23 = [r19]
+    r24 = load_address r23
+    r25 = _PyObject_Vectorcall(r22, r24, 1, 0)
+    keep_alive r19
+    goto L7
+L6:
+L7:
+    r26 = box(None, 1)
+    return r26
+[case testMatchSequenceWithStarPatternInTheMiddle_python3_10]
+def f(x):
+    match x:
+        case ["start", *rest, "end"]:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5 :: object
+    r6 :: str
+    r7 :: object
+    r8 :: int32
+    r9 :: bit
+    r10 :: bool
+    r11 :: native_int
+    r12 :: object
+    r13 :: str
+    r14 :: object
+    r15 :: int32
+    r16 :: bit
+    r17 :: bool
+    r18 :: native_int
+    r19, rest :: object
+    r20 :: str
+    r21 :: object
+    r22 :: str
+    r23 :: object
+    r24 :: object[1]
+    r25 :: object_ptr
+    r26, r27 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L6 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 >= 2 :: signed
+    if r4 goto L2 else goto L6 :: bool
+L2:
+    r5 = PySequence_GetItem(x, 0)
+    r6 = 'start'
+    r7 = PyObject_RichCompare(r5, r6, 2)
+    r8 = PyObject_IsTrue(r7)
+    r9 = r8 >= 0 :: signed
+    r10 = truncate r8: int32 to builtins.bool
+    if r10 goto L3 else goto L6 :: bool
+L3:
+    r11 = r2 - 1
+    r12 = PySequence_GetItem(x, r11)
+    r13 = 'end'
+    r14 = PyObject_RichCompare(r12, r13, 2)
+    r15 = PyObject_IsTrue(r14)
+    r16 = r15 >= 0 :: signed
+    r17 = truncate r15: int32 to builtins.bool
+    if r17 goto L4 else goto L6 :: bool
+L4:
+    r18 = r2 - 1
+    r19 = PySequence_GetSlice(x, 1, r18)
+    rest = r19
+L5:
+    r20 = 'matched'
+    r21 = builtins :: module
+    r22 = 'print'
+    r23 = CPyObject_GetAttr(r21, r22)
+    r24 = [r20]
+    r25 = load_address r24
+    r26 = _PyObject_Vectorcall(r23, r25, 1, 0)
+    keep_alive r20
+    goto L7
+L6:
+L7:
+    r27 = box(None, 1)
+    return r27
+[case testMatchSequenceWithStarPatternAtTheStart_python3_10]
+def f(x):
+    match x:
+        case [*rest, 1, 2]:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5 :: native_int
+    r6, r7, r8 :: object
+    r9 :: int32
+    r10 :: bit
+    r11 :: bool
+    r12 :: native_int
+    r13, r14, r15 :: object
+    r16 :: int32
+    r17 :: bit
+    r18 :: bool
+    r19 :: native_int
+    r20, rest :: object
+    r21 :: str
+    r22 :: object
+    r23 :: str
+    r24 :: object
+    r25 :: object[1]
+    r26 :: object_ptr
+    r27, r28 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L6 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 >= 2 :: signed
+    if r4 goto L2 else goto L6 :: bool
+L2:
+    r5 = r2 - 2
+    r6 = PySequence_GetItem(x, r5)
+    r7 = object 1
+    r8 = PyObject_RichCompare(r6, r7, 2)
+    r9 = PyObject_IsTrue(r8)
+    r10 = r9 >= 0 :: signed
+    r11 = truncate r9: int32 to builtins.bool
+    if r11 goto L3 else goto L6 :: bool
+L3:
+    r12 = r2 - 1
+    r13 = PySequence_GetItem(x, r12)
+    r14 = object 2
+    r15 = PyObject_RichCompare(r13, r14, 2)
+    r16 = PyObject_IsTrue(r15)
+    r17 = r16 >= 0 :: signed
+    r18 = truncate r16: int32 to builtins.bool
+    if r18 goto L4 else goto L6 :: bool
+L4:
+    r19 = r2 - 2
+    r20 = PySequence_GetSlice(x, 0, r19)
+    rest = r20
+L5:
+    r21 = 'matched'
+    r22 = builtins :: module
+    r23 = 'print'
+    r24 = CPyObject_GetAttr(r22, r23)
+    r25 = [r21]
+    r26 = load_address r25
+    r27 = _PyObject_Vectorcall(r24, r26, 1, 0)
+    keep_alive r21
+    goto L7
+L6:
+L7:
+    r28 = box(None, 1)
+    return r28
+[case testMatchBuiltinClassPattern_python3_10]
+def f(x):
+    match x:
+        case int(y):
+            print("matched")
+[out]
+def f(x):
+    x, r0 :: object
+    r1 :: bool
+    r2, y :: int
+    r3 :: str
+    r4 :: object
+    r5 :: str
+    r6 :: object
+    r7 :: object[1]
+    r8 :: object_ptr
+    r9, r10 :: object
+L0:
+    r0 = load_address PyLong_Type
+    r1 = CPy_TypeCheck(x, r0)
+    if r1 goto L1 else goto L3 :: bool
+L1:
+    r2 = unbox(int, x)
+    y = r2
+L2:
+    r3 = 'matched'
+    r4 = builtins :: module
+    r5 = 'print'
+    r6 = CPyObject_GetAttr(r4, r5)
+    r7 = [r3]
+    r8 = load_address r7
+    r9 = _PyObject_Vectorcall(r6, r8, 1, 0)
+    keep_alive r3
+    goto L4
+L3:
+L4:
+    r10 = box(None, 1)
+    return r10
+[case testMatchSequenceCaptureAll_python3_10]
+def f(x):
+    match x:
+        case [*rest]:
+            print("matched")
+[out]
+def f(x):
+    x :: object
+    r0 :: int32
+    r1 :: bit
+    r2 :: native_int
+    r3, r4 :: bit
+    r5 :: native_int
+    r6, rest :: object
+    r7 :: str
+    r8 :: object
+    r9 :: str
+    r10 :: object
+    r11 :: object[1]
+    r12 :: object_ptr
+    r13, r14 :: object
+L0:
+    r0 = CPySequence_Check(x)
+    r1 = r0 != 0
+    if r1 goto L1 else goto L4 :: bool
+L1:
+    r2 = PyObject_Size(x)
+    r3 = r2 >= 0 :: signed
+    r4 = r2 >= 0 :: signed
+    if r4 goto L2 else goto L4 :: bool
+L2:
+    r5 = r2 - 0
+    r6 = PySequence_GetSlice(x, 0, r5)
+    rest = r6
+L3:
+    r7 = 'matched'
+    r8 = builtins :: module
+    r9 = 'print'
+    r10 = CPyObject_GetAttr(r8, r9)
+    r11 = [r7]
+    r12 = load_address r11
+    r13 = _PyObject_Vectorcall(r10, r12, 1, 0)
+    keep_alive r7
+    goto L5
+L4:
+L5:
+    r14 = box(None, 1)
+    return r14
+[case testMatchTypeAnnotatedNativeClass_python3_10]
+class A:
+    a: int
+
+def f(x: A | int) -> int:
+    match x:
+        case A(a=a):
+            return a
+        case int():
+            return x
+[out]
+def f(x):
+    x :: union[__main__.A, int]
+    r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4 :: str
+    r5 :: object
+    r6, a :: int
+    r7 :: object
+    r8 :: bool
+    r9 :: int
+L0:
+    r0 = __main__.A :: type
+    r1 = PyObject_IsInstance(x, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L3 :: bool
+L1:
+    r4 = 'a'
+    r5 = CPyObject_GetAttr(x, r4)
+    r6 = unbox(int, r5)
+    a = r6
+L2:
+    return a
+L3:
+    r7 = load_address PyLong_Type
+    r8 = CPy_TypeCheck(x, r7)
+    if r8 goto L4 else goto L5 :: bool
+L4:
+    r9 = unbox(int, x)
+    return r9
+L5:
+L6:
+    unreachable
diff --git a/mypyc/test-data/run-match.test b/mypyc/test-data/run-match.test
new file mode 100644
index 0000000000000..7b7ad9a4342ce
--- /dev/null
+++ b/mypyc/test-data/run-match.test
@@ -0,0 +1,283 @@
+[case testTheBigMatch_python3_10]
+class Person:
+    __match_args__ = ("name", "age")
+
+    name: str
+    age: int
+
+    def __init__(self, name: str, age: int) -> None:
+        self.name = name
+        self.age = age
+
+    def __str__(self) -> str:
+        return f"Person(name={self.name!r}, age={self.age})"
+
+
+def f(x: object) -> None:
+    match x:
+        case 123:
+            print("test 1")
+
+        case 456 | 789:
+            print("test 2")
+
+        case True | False | None:
+            print("test 3")
+
+        case Person("bob" as name, age):
+            print(f"test 4 ({name=}, {age=})")
+
+        case num if num == 5:
+            print("test 5")
+
+        case 6 as num:
+            print(f"test 6 ({num=})")
+
+        case (7 | "7") as value:
+            print(f"test 7 ({value=})")
+
+        case Person("alice", age=123):
+            print("test 8")
+
+        case Person("charlie", age=123 | 456):
+            print("test 9")
+
+        case Person("dave", 123) as dave:
+            print(f"test 10 {dave}")
+
+        case {"test": 11}:
+            print("test 11")
+
+        case {"test": 12, **rest}:
+            print(f"test 12 (rest={rest})")
+
+        case {}:
+            print("test map final")
+
+        case ["test", 13]:
+            print("test 13")
+
+        case ["test", 13, _]:
+            print("test 13b")
+
+        case ["test", 14, *_]:
+            print("test 14")
+
+        # TODO: Fix "rest" being used here coliding with above "rest"
+        case ["test", 15, *rest2]:
+            print(f"test 15 ({rest2})")
+
+        case ["test", *rest3, 16]:
+            print(f"test 16 ({rest3})")
+
+        case [*rest4, "test", 17]:
+            print(f"test 17 ({rest4})")
+
+        case [*rest4, "test", 18, "some", "fluff"]:
+            print(f"test 18 ({rest4})")
+
+        case str("test 19"):
+            print("test 19")
+
+        case str(test_20) if test_20.startswith("test 20"):
+            print(f"test 20 ({test_20[7:]!r})")
+
+        case ("test 21" as value) | ("test 21 as well" as value):
+            print(f"test 21 ({value[7:]!r})")
+
+        case []:
+            print("test sequence final")
+
+        case _:
+            print("test final")
+[file driver.py]
+from native import f, Person
+
+# test 1
+f(123)
+
+# test 2
+f(456)
+f(789)
+
+# test 3
+f(True)
+f(False)
+f(None)
+
+# test 4
+f(Person("bob", 123))
+
+# test 5
+f(5)
+
+# test 6
+f(6)
+
+# test 7
+f(7)
+f("7")
+
+# test 8
+f(Person("alice", 123))
+
+# test 9
+f(Person("charlie", 123))
+f(Person("charlie", 456))
+
+# test 10
+f(Person("dave", 123))
+
+# test 11
+f({"test": 11})
+f({"test": 11, "some": "key"})
+
+# test 12
+f({"test": 12})
+f({"test": 12, "key": "value"})
+f({"test": 12, "key": "value", "abc": "123"})
+
+# test map final
+f({})
+
+# test 13
+f(["test", 13])
+
+# test 13b
+f(["test", 13, "fail"])
+
+# test 14
+f(["test", 14])
+f(["test", 14, "something"])
+
+# test 15
+f(["test", 15])
+f(["test", 15, "something"])
+
+# test 16
+f(["test", 16])
+f(["test", "filler", 16])
+f(["test", "more", "filler", 16])
+
+# test 17
+f(["test", 17])
+f(["stuff", "test", 17])
+f(["more", "stuff", "test", 17])
+
+# test 18
+f(["test", 18, "some", "fluff"])
+f(["stuff", "test", 18, "some", "fluff"])
+f(["more", "stuff", "test", 18, "some", "fluff"])
+
+# test 19
+f("test 19")
+
+# test 20
+f("test 20")
+f("test 20 something else")
+
+# test 21
+f("test 21")
+f("test 21 as well")
+
+# test sequence final
+f([])
+
+# test final
+f("")
+
+[out]
+test 1
+test 2
+test 2
+test 3
+test 3
+test 3
+test 4 (name='bob', age=123)
+test 5
+test 6 (num=6)
+test 7 (value=7)
+test 7 (value='7')
+test 8
+test 9
+test 9
+test 10 Person(name='dave', age=123)
+test 11
+test 11
+test 12 (rest={})
+test 12 (rest={'key': 'value'})
+test 12 (rest={'key': 'value', 'abc': '123'})
+test map final
+test 13
+test 13b
+test 14
+test 14
+test 15 ([])
+test 15 (['something'])
+test 16 ([])
+test 16 (['filler'])
+test 16 (['more', 'filler'])
+test 17 ([])
+test 17 (['stuff'])
+test 17 (['more', 'stuff'])
+test 18 ([])
+test 18 (['stuff'])
+test 18 (['more', 'stuff'])
+test 19
+test 20 ('')
+test 20 (' something else')
+test 21 ('')
+test 21 (' as well')
+test sequence final
+test final
+[case testCustomMappingAndSequenceObjects_python3_10]
+def f(x: object) -> None:
+    match x:
+        case {"key": "value", **rest}:
+            print(rest, type(rest))
+
+        case [1, 2, *rest2]:
+            print(rest2, type(rest2))
+
+[file driver.py]
+from collections.abc import Mapping, Sequence
+
+from native import f
+
+class CustomMapping(Mapping):
+    inner: dict
+
+    def __init__(self, inner: dict) -> None:
+        self.inner = inner
+
+    def __getitem__(self, key):
+        return self.inner[key]
+
+    def __iter__(self):
+        return iter(self.inner)
+
+    def __len__(self) -> int:
+        return len(self.inner)
+
+
+class CustomSequence(Sequence):
+    inner: list
+
+    def __init__(self, inner: list) -> None:
+        self.inner = inner
+
+    def __getitem__(self, index: int) -> None:
+        return self.inner[index]
+
+    def __len__(self) -> int:
+        return len(self.inner)
+
+mapping = CustomMapping({"key": "value", "some": "data"})
+sequence = CustomSequence([1, 2, 3])
+
+f(mapping)
+f(sequence)
+
+[out]
+{'some': 'data'} <class 'dict'>
+[3] <class 'list'>
diff --git a/mypyc/test/test_irbuild.py b/mypyc/test/test_irbuild.py
index 00a8c074da87c..8928f94d62110 100644
--- a/mypyc/test/test_irbuild.py
+++ b/mypyc/test/test_irbuild.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import os.path
+import sys
 
 from mypy.errors import CompileError
 from mypy.test.config import test_temp_dir
@@ -48,6 +49,9 @@
     "irbuild-glue-methods.test",
 ]
 
+if sys.version_info >= (3, 10):
+    files.append("irbuild-match.test")
+
 
 class TestGenOps(MypycDataSuite):
     files = files
diff --git a/mypyc/test/test_run.py b/mypyc/test/test_run.py
index 351caf7c93ed0..fff775ebfab5f 100644
--- a/mypyc/test/test_run.py
+++ b/mypyc/test/test_run.py
@@ -68,6 +68,9 @@
 if sys.version_info >= (3, 8):
     files.append("run-python38.test")
 
+if sys.version_info >= (3, 10):
+    files.append("run-match.test")
+
 setup_format = """\
 from setuptools import setup
 from mypyc.build import mypycify
diff --git a/mypyc/test/testutil.py b/mypyc/test/testutil.py
index 8339889fa9f5f..609ffc27385ea 100644
--- a/mypyc/test/testutil.py
+++ b/mypyc/test/testutil.py
@@ -108,7 +108,7 @@ def build_ir_for_single_file2(
     options.hide_error_codes = True
     options.use_builtins_fixtures = True
     options.strict_optional = True
-    options.python_version = (3, 6)
+    options.python_version = compiler_options.python_version or (3, 6)
     options.export_types = True
     options.preserve_asts = True
     options.allow_empty_bodies = True
@@ -277,6 +277,7 @@ def infer_ir_build_options_from_test_name(name: str) -> CompilerOptions | None:
     m = re.search(r"_python([3-9]+)_([0-9]+)(_|\b)", name)
     if m:
         options.capi_version = (int(m.group(1)), int(m.group(2)))
+        options.python_version = options.capi_version
     elif "_py" in name or "_Python" in name:
         assert False, f"Invalid _py* suffix (should be _pythonX_Y): {name}"
     return options

From b8c03ab6809aab56928f3cd865edb44944a600a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A9ry=20Ogam?= <gery.ogam@gmail.com>
Date: Sat, 3 Dec 2022 00:37:52 +0100
Subject: [PATCH 101/231] Fix incorrect class names in literal_types.rst
 (#14237)

---
 docs/source/literal_types.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/source/literal_types.rst b/docs/source/literal_types.rst
index 7195ccc2b69be..a66d300bd0fd0 100644
--- a/docs/source/literal_types.rst
+++ b/docs/source/literal_types.rst
@@ -495,13 +495,13 @@ the same way Python's runtime does:
     ...     right = 'right'
     Traceback (most recent call last):
       ...
-    TypeError: Other: cannot extend enumeration 'Some'
+    TypeError: AllDirection: cannot extend enumeration 'Direction'
 
   Mypy also catches this error:
 
   .. code-block:: python
 
-    class AllDirection(Direction):  # E: Cannot inherit from final class "Some"
+    class AllDirection(Direction):  # E: Cannot inherit from final class "Direction"
         left = 'left'
         right = 'right'
 

From 734a0b96b79f20b3290ca5fee97c749ccb2e308f Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sun, 4 Dec 2022 14:50:48 +0000
Subject: [PATCH 102/231] Flycheck-mypy is deprecated. Its functionality was
 merged in Flycheck (#14247)

See https://github.com/lbolla/emacs-flycheck-mypy#readme
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 95cacb05d6822..dd09d15ff1526 100644
--- a/README.md
+++ b/README.md
@@ -124,7 +124,7 @@ Mypy can be integrated into popular IDEs:
     `let g:syntastic_python_checkers=['mypy']`
   * Using [ALE](https://github.com/dense-analysis/ale): should be enabled by default when `mypy` is installed,
     or can be explicitly enabled by adding `let b:ale_linters = ['mypy']` in `~/vim/ftplugin/python.vim`
-* Emacs: using [Flycheck](https://github.com/flycheck/) and [Flycheck-mypy](https://github.com/lbolla/emacs-flycheck-mypy)
+* Emacs: using [Flycheck](https://github.com/flycheck/)
 * Sublime Text: [SublimeLinter-contrib-mypy](https://github.com/fredcallaway/SublimeLinter-contrib-mypy)
 * Atom: [linter-mypy](https://atom.io/packages/linter-mypy)
 * PyCharm: [mypy plugin](https://github.com/dropbox/mypy-PyCharm-plugin) (PyCharm integrates

From 7785b6035e919180593f027305171e4a844a947b Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sun, 4 Dec 2022 18:47:57 +0000
Subject: [PATCH 103/231] Stop saying mypy is beta software (#14251)

Ref #13685

cc @Michael0x2a @JukkaL @hauntsaninja

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
---
 README.md             | 9 +--------
 docs/source/index.rst | 6 +++---
 setup.py              | 2 +-
 3 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/README.md b/README.md
index dd09d15ff1526..a8b26f7abd626 100644
--- a/README.md
+++ b/README.md
@@ -160,14 +160,7 @@ To get started with developing mypy, see [CONTRIBUTING.md](CONTRIBUTING.md).
 If you need help getting started, don't hesitate to ask on [gitter](https://gitter.im/python/typing).
 
 
-Development status
-------------------
-
-Mypy is beta software, but it has already been used in production
-for several years at Dropbox and in many other organizations, and
-it has an extensive test suite.
-
-mypyc and compiled version of mypy
+Mypyc and compiled version of mypy
 ----------------------------------
 
 [Mypyc](https://github.com/mypyc/mypyc) uses Python type hints to compile Python
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 1f77e951843d6..27b3a078af6c7 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -39,10 +39,10 @@ understand, debug, and maintain.
 
 .. note::
 
-   Mypy is used in production by many companies and projects, but mypy is
-   officially beta software. There will be occasional changes
+   Although mypy is production ready, there will be occasional changes
    that break backward compatibility. The mypy development team tries to
-   minimize the impact of changes to user code.
+   minimize the impact of changes to user code. In case of a major breaking
+   change, mypy's major version will be bumped.
 
 Contents
 --------
diff --git a/setup.py b/setup.py
index 669e0cc4b6151..a148237f0b95c 100644
--- a/setup.py
+++ b/setup.py
@@ -171,7 +171,7 @@ def run(self):
 
 
 classifiers = [
-    "Development Status :: 4 - Beta",
+    "Development Status :: 5 - Production/Stable",
     "Environment :: Console",
     "Intended Audience :: Developers",
     "License :: OSI Approved :: MIT License",

From 0885d85a7b224cefb56fe63a75bb29ab73a23183 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 5 Dec 2022 03:57:07 +0000
Subject: [PATCH 104/231] Add link to error codes in README (#14249)

Several issues that I have seen recently could be fixed by
enabling/disabling an error code. I think we should attract more
attention to error code customization (especially for new users).
---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index a8b26f7abd626..2ec4be4f0deea 100644
--- a/README.md
+++ b/README.md
@@ -84,6 +84,7 @@ more examples and information.
 In particular, see:
 - [type hints cheat sheet](https://mypy.readthedocs.io/en/stable/cheat_sheet_py3.html)
 - [getting started](https://mypy.readthedocs.io/en/stable/getting_started.html)
+- [list of error codes](https://mypy.readthedocs.io/en/stable/error_code_list.html)
 
 Quick start
 -----------

From 924bc68b07bec2b72ce055f6cd95f6aea11fda7e Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 5 Dec 2022 03:57:23 +0000
Subject: [PATCH 105/231] Advertise mypy daemon in README (#14248)

Now that daemon is more mature and stable I think we can attract some
more attention to it.
---
 README.md | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 2ec4be4f0deea..01d876ead3e4b 100644
--- a/README.md
+++ b/README.md
@@ -110,9 +110,13 @@ programs, even if mypy reports type errors:
     python3 PROGRAM
 
 You can also try mypy in an [online playground](https://mypy-play.net/) (developed by
-Yusuke Miyazaki).
+Yusuke Miyazaki). If you are working with large code bases, you can run mypy in
+[daemon mode], that will give much faster (often sub-second) incremental updates:
+
+    dmypy run -- PROGRAM
 
 [statically typed parts]: https://mypy.readthedocs.io/en/latest/getting_started.html#function-signatures-and-dynamic-vs-static-typing
+[daemon-mode]: https://mypy.readthedocs.io/en/stable/mypy_daemon.html
 
 
 Integrations

From d2ab2e7dd1a4a43b0cb6626a63d722387f53b7bc Mon Sep 17 00:00:00 2001
From: Nikita Sobolev <mail@sobolevn.me>
Date: Tue, 6 Dec 2022 10:52:07 +0300
Subject: [PATCH 106/231] Allow trailing commas in `ini` configuration of
 multiline values (#14240)

Now these two samples are identical:

```ini
[mypy]
enable_error_code =
  truthy-bool,
  redundant-expr,
  unused-awaitable,
  ignore-without-code
```

and

```ini
[mypy]
enable_error_code =
  truthy-bool,
  redundant-expr,
  unused-awaitable,
  ignore-without-code,
```

I've covered some of the changed values, but not all (they are identical
- no need to create so many slow tests).

I've also checked `pyproject.toml`. It does not have this problem: it
uses `[]` to create arrays, so no trailing commas are used there.
---
 mypy/config_parser.py                   | 23 +++++++++++++++-------
 test-data/unit/check-custom-plugin.test |  9 +++++++++
 test-data/unit/cmdline.test             | 26 +++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/mypy/config_parser.py b/mypy/config_parser.py
index 485d2f67f5de6..190782a3bded7 100644
--- a/mypy/config_parser.py
+++ b/mypy/config_parser.py
@@ -137,6 +137,15 @@ def check_follow_imports(choice: str) -> str:
     return choice
 
 
+def split_commas(value: str) -> list[str]:
+    # Uses a bit smarter technique to allow last trailing comma
+    # and to remove last `""` item from the split.
+    items = value.split(",")
+    if items and items[-1] == "":
+        items.pop(-1)
+    return items
+
+
 # For most options, the type of the default value set in options.py is
 # sufficient, and we don't have to do anything here.  This table
 # exists to specify types for values initialized to None or container
@@ -151,13 +160,13 @@ def check_follow_imports(choice: str) -> str:
     "junit_xml": expand_path,
     "follow_imports": check_follow_imports,
     "no_site_packages": bool,
-    "plugins": lambda s: [p.strip() for p in s.split(",")],
-    "always_true": lambda s: [p.strip() for p in s.split(",")],
-    "always_false": lambda s: [p.strip() for p in s.split(",")],
-    "enable_incomplete_feature": lambda s: [p.strip() for p in s.split(",")],
-    "disable_error_code": lambda s: validate_codes([p.strip() for p in s.split(",")]),
-    "enable_error_code": lambda s: validate_codes([p.strip() for p in s.split(",")]),
-    "package_root": lambda s: [p.strip() for p in s.split(",")],
+    "plugins": lambda s: [p.strip() for p in split_commas(s)],
+    "always_true": lambda s: [p.strip() for p in split_commas(s)],
+    "always_false": lambda s: [p.strip() for p in split_commas(s)],
+    "enable_incomplete_feature": lambda s: [p.strip() for p in split_commas(s)],
+    "disable_error_code": lambda s: validate_codes([p.strip() for p in split_commas(s)]),
+    "enable_error_code": lambda s: validate_codes([p.strip() for p in split_commas(s)]),
+    "package_root": lambda s: [p.strip() for p in split_commas(s)],
     "cache_dir": expand_path,
     "python_executable": expand_path,
     "strict": bool,
diff --git a/test-data/unit/check-custom-plugin.test b/test-data/unit/check-custom-plugin.test
index a716109d345e5..d7beea0390e7f 100644
--- a/test-data/unit/check-custom-plugin.test
+++ b/test-data/unit/check-custom-plugin.test
@@ -163,6 +163,15 @@ reveal_type(f())  # N: Revealed type is "builtins.int"
 \[mypy]
 plugins=<ROOT>/test-data/unit/plugins/customentry.py:register
 
+[case testCustomPluginEntryPointFileTrailingComma]
+# flags: --config-file tmp/mypy.ini
+def f() -> str: ...
+reveal_type(f())  # N: Revealed type is "builtins.int"
+[file mypy.ini]
+\[mypy]
+plugins =
+    <ROOT>/test-data/unit/plugins/customentry.py:register,
+
 [case testCustomPluginEntryPoint]
 # flags: --config-file tmp/mypy.ini
 def f() -> str: ...
diff --git a/test-data/unit/cmdline.test b/test-data/unit/cmdline.test
index 92b0af6942bc3..9eba9ea1e9068 100644
--- a/test-data/unit/cmdline.test
+++ b/test-data/unit/cmdline.test
@@ -1570,3 +1570,29 @@ foo.py:1: error: "int" not callable
 1()
 [out]
 foo/m.py:1: error: "int" not callable
+
+[case testCmdlineCfgEnableErrorCodeTrailingComma]
+# cmd: mypy .
+[file mypy.ini]
+\[mypy]
+enable_error_code =
+  truthy-bool,
+  redundant-expr,
+[out]
+
+[case testCmdlineCfgDisableErrorCodeTrailingComma]
+# cmd: mypy .
+[file mypy.ini]
+\[mypy]
+disable_error_code =
+  misc,
+  override,
+[out]
+
+[case testCmdlineCfgAlwaysTrueTrailingComma]
+# cmd: mypy .
+[file mypy.ini]
+\[mypy]
+always_true =
+  MY_VAR,
+[out]

From 7e9aa7433c72e0950229a34e0c086d7829208f06 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tin=20Tvrtkovi=C4=87?= <tinchester@gmail.com>
Date: Tue, 6 Dec 2022 15:42:28 +0100
Subject: [PATCH 107/231] Enable Final instance attributes for attrs (#14232)

A quick patch to enable the following scenario:

```python
@define
class C:
    a: Final[int]  # `a` is a final instance attribute
```

There are some edge cases I haven't covered here that would be complex
to handle and not add much value IMO, so I think this will be useful
like this.
---
 mypy/plugins/attrs.py          | 14 +++++++++++---
 test-data/unit/check-attr.test | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/mypy/plugins/attrs.py b/mypy/plugins/attrs.py
index ce0f45967152c..16e8891e5f575 100644
--- a/mypy/plugins/attrs.py
+++ b/mypy/plugins/attrs.py
@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 from typing import Iterable, List, cast
-from typing_extensions import Final
+from typing_extensions import Final, Literal
 
 import mypy.plugin  # To avoid circular imports.
 from mypy.exprtotype import TypeTranslationError, expr_to_unanalyzed_type
@@ -756,13 +756,14 @@ def _add_init(
     ctx: mypy.plugin.ClassDefContext,
     attributes: list[Attribute],
     adder: MethodAdder,
-    method_name: str,
+    method_name: Literal["__init__", "__attrs_init__"],
 ) -> None:
     """Generate an __init__ method for the attributes and add it to the class."""
-    # Convert attributes to arguments with kw_only arguments at the  end of
+    # Convert attributes to arguments with kw_only arguments at the end of
     # the argument list
     pos_args = []
     kw_only_args = []
+    sym_table = ctx.cls.info.names
     for attribute in attributes:
         if not attribute.init:
             continue
@@ -770,6 +771,13 @@ def _add_init(
             kw_only_args.append(attribute.argument(ctx))
         else:
             pos_args.append(attribute.argument(ctx))
+
+        # If the attribute is Final, present in `__init__` and has
+        # no default, make sure it doesn't error later.
+        if not attribute.has_default and attribute.name in sym_table:
+            sym_node = sym_table[attribute.name].node
+            if isinstance(sym_node, Var) and sym_node.is_final:
+                sym_node.final_set_in_init = True
     args = pos_args + kw_only_args
     if all(
         # We use getattr rather than instance checks because the variable.type
diff --git a/test-data/unit/check-attr.test b/test-data/unit/check-attr.test
index 4d27d5f39d1e7..f555f2ea70111 100644
--- a/test-data/unit/check-attr.test
+++ b/test-data/unit/check-attr.test
@@ -1834,3 +1834,36 @@ class Sub(Base):
 # This matches runtime semantics
 reveal_type(Sub)  # N: Revealed type is "def (*, name: builtins.str, first_name: builtins.str, last_name: builtins.str) -> __main__.Sub"
 [builtins fixtures/property.pyi]
+
+[case testFinalInstanceAttribute]
+from attrs import define
+from typing import Final
+
+@define
+class C:
+    a: Final[int]
+
+reveal_type(C) # N: Revealed type is "def (a: builtins.int) -> __main__.C"
+
+C(1).a = 2 # E: Cannot assign to final attribute "a"
+
+[builtins fixtures/property.pyi]
+
+[case testFinalInstanceAttributeInheritance]
+from attrs import define
+from typing import Final
+
+@define
+class C:
+    a: Final[int]
+
+@define
+class D(C):
+    b: Final[str]
+
+reveal_type(D) # N: Revealed type is "def (a: builtins.int, b: builtins.str) -> __main__.D"
+
+D(1, "").a = 2 # E: Cannot assign to final attribute "a"
+D(1, "").b = "2" # E: Cannot assign to final attribute "b"
+
+[builtins fixtures/property.pyi]
\ No newline at end of file

From dde01d6bfbed3bd0a477d54b15f49e5187b38038 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 6 Dec 2022 15:27:26 +0000
Subject: [PATCH 108/231] [mypyc] Support tuples of native ints (#14252)

A tuple such as `tuple[i64, i64]` can't have a dedicated error value, so
use overlapping error values, similarly to how we support plain native
integers such as `i64`.

For a heterogeneous tuple such as as `tuple[i64, str]` we attempt to
store the error value in the smallest item index where the value type
supports error values (1 in this example).

This affects error returns, undefined attributes, default arguments and
undefined locals.
---
 mypyc/analysis/attrdefined.py |   4 +-
 mypyc/codegen/emit.py         |  55 ++++++++++++-------
 mypyc/codegen/emitclass.py    |   6 +-
 mypyc/codegen/emitfunc.py     |   3 +-
 mypyc/codegen/emitwrapper.py  |   8 +--
 mypyc/ir/func_ir.py           |   4 +-
 mypyc/ir/ops.py               |   5 +-
 mypyc/ir/rtypes.py            |   1 +
 mypyc/irbuild/builder.py      |   3 +-
 mypyc/irbuild/env_class.py    |   4 +-
 mypyc/irbuild/ll_builder.py   |   2 +-
 mypyc/test-data/run-i64.test  | 100 +++++++++++++++++++++++++++++++++-
 mypyc/transform/exceptions.py |  22 ++++++--
 mypyc/transform/uninit.py     |   4 +-
 14 files changed, 173 insertions(+), 48 deletions(-)

diff --git a/mypyc/analysis/attrdefined.py b/mypyc/analysis/attrdefined.py
index dc871a93eba16..1368b7f5315fc 100644
--- a/mypyc/analysis/attrdefined.py
+++ b/mypyc/analysis/attrdefined.py
@@ -91,7 +91,7 @@ def foo(self) -> int:
     SetMem,
     Unreachable,
 )
-from mypyc.ir.rtypes import RInstance, is_fixed_width_rtype
+from mypyc.ir.rtypes import RInstance
 
 # If True, print out all always-defined attributes of native classes (to aid
 # debugging and testing)
@@ -424,5 +424,5 @@ def detect_undefined_bitmap(cl: ClassIR, seen: Set[ClassIR]) -> None:
     if len(cl.base_mro) > 1:
         cl.bitmap_attrs.extend(cl.base_mro[1].bitmap_attrs)
     for n, t in cl.attributes.items():
-        if is_fixed_width_rtype(t) and not cl.is_always_defined(n):
+        if t.error_overlap and not cl.is_always_defined(n):
             cl.bitmap_attrs.append(n)
diff --git a/mypyc/codegen/emit.py b/mypyc/codegen/emit.py
index 15dece700a1e1..368c5dd366ea4 100644
--- a/mypyc/codegen/emit.py
+++ b/mypyc/codegen/emit.py
@@ -364,7 +364,8 @@ def _emit_attr_bitmap_update(
         self, value: str, obj: str, rtype: RType, cl: ClassIR, attr: str, clear: bool
     ) -> None:
         if value:
-            self.emit_line(f"if (unlikely({value} == {self.c_undefined_value(rtype)})) {{")
+            check = self.error_value_check(rtype, value, "==")
+            self.emit_line(f"if (unlikely({check})) {{")
         index = cl.bitmap_attrs.index(attr)
         mask = 1 << (index & (BITMAP_BITS - 1))
         bitmap = self.attr_bitmap_expr(obj, cl, index)
@@ -389,16 +390,10 @@ def emit_undefined_attr_check(
         *,
         unlikely: bool = False,
     ) -> None:
-        if isinstance(rtype, RTuple):
-            check = "{}".format(
-                self.tuple_undefined_check_cond(rtype, attr_expr, self.c_undefined_value, compare)
-            )
-        else:
-            undefined = self.c_undefined_value(rtype)
-            check = f"{attr_expr} {compare} {undefined}"
+        check = self.error_value_check(rtype, attr_expr, compare)
         if unlikely:
             check = f"unlikely({check})"
-        if is_fixed_width_rtype(rtype):
+        if rtype.error_overlap:
             index = cl.bitmap_attrs.index(attr)
             bit = 1 << (index & (BITMAP_BITS - 1))
             attr = self.bitmap_field(index)
@@ -406,25 +401,47 @@ def emit_undefined_attr_check(
             check = f"{check} && !(({obj_expr})->{attr} & {bit})"
         self.emit_line(f"if ({check}) {{")
 
+    def error_value_check(self, rtype: RType, value: str, compare: str) -> str:
+        if isinstance(rtype, RTuple):
+            return self.tuple_undefined_check_cond(
+                rtype, value, self.c_error_value, compare, check_exception=False
+            )
+        else:
+            return f"{value} {compare} {self.c_error_value(rtype)}"
+
     def tuple_undefined_check_cond(
         self,
         rtuple: RTuple,
         tuple_expr_in_c: str,
         c_type_compare_val: Callable[[RType], str],
         compare: str,
+        *,
+        check_exception: bool = True,
     ) -> str:
         if len(rtuple.types) == 0:
             # empty tuple
             return "{}.empty_struct_error_flag {} {}".format(
                 tuple_expr_in_c, compare, c_type_compare_val(int_rprimitive)
             )
-        item_type = rtuple.types[0]
+        if rtuple.error_overlap:
+            i = 0
+            item_type = rtuple.types[0]
+        else:
+            for i, typ in enumerate(rtuple.types):
+                if not typ.error_overlap:
+                    item_type = rtuple.types[i]
+                    break
+            else:
+                assert False, "not expecting tuple with error overlap"
         if isinstance(item_type, RTuple):
             return self.tuple_undefined_check_cond(
-                item_type, tuple_expr_in_c + ".f0", c_type_compare_val, compare
+                item_type, tuple_expr_in_c + f".f{i}", c_type_compare_val, compare
             )
         else:
-            return f"{tuple_expr_in_c}.f0 {compare} {c_type_compare_val(item_type)}"
+            check = f"{tuple_expr_in_c}.f{i} {compare} {c_type_compare_val(item_type)}"
+            if rtuple.error_overlap and check_exception:
+                check += " && PyErr_Occurred()"
+            return check
 
     def tuple_undefined_value(self, rtuple: RTuple) -> str:
         return "tuple_undefined_" + rtuple.unique_id
@@ -986,18 +1003,18 @@ def emit_box(
 
     def emit_error_check(self, value: str, rtype: RType, failure: str) -> None:
         """Emit code for checking a native function return value for uncaught exception."""
-        if is_fixed_width_rtype(rtype):
-            # The error value is also valid as a normal value, so we need to also check
-            # for a raised exception.
-            self.emit_line(f"if ({value} == {self.c_error_value(rtype)} && PyErr_Occurred()) {{")
-        elif not isinstance(rtype, RTuple):
-            self.emit_line(f"if ({value} == {self.c_error_value(rtype)}) {{")
-        else:
+        if isinstance(rtype, RTuple):
             if len(rtype.types) == 0:
                 return  # empty tuples can't fail.
             else:
                 cond = self.tuple_undefined_check_cond(rtype, value, self.c_error_value, "==")
                 self.emit_line(f"if ({cond}) {{")
+        elif rtype.error_overlap:
+            # The error value is also valid as a normal value, so we need to also check
+            # for a raised exception.
+            self.emit_line(f"if ({value} == {self.c_error_value(rtype)} && PyErr_Occurred()) {{")
+        else:
+            self.emit_line(f"if ({value} == {self.c_error_value(rtype)}) {{")
         self.emit_lines(failure, "}")
 
     def emit_gc_visit(self, target: str, rtype: RType) -> None:
diff --git a/mypyc/codegen/emitclass.py b/mypyc/codegen/emitclass.py
index 0fdb6e8a98c3c..1e774bbd01854 100644
--- a/mypyc/codegen/emitclass.py
+++ b/mypyc/codegen/emitclass.py
@@ -20,7 +20,7 @@
 from mypyc.common import BITMAP_BITS, BITMAP_TYPE, NATIVE_PREFIX, PREFIX, REG_PREFIX, use_fastcall
 from mypyc.ir.class_ir import ClassIR, VTableEntries
 from mypyc.ir.func_ir import FUNC_CLASSMETHOD, FUNC_STATICMETHOD, FuncDecl, FuncIR
-from mypyc.ir.rtypes import RTuple, RType, is_fixed_width_rtype, object_rprimitive
+from mypyc.ir.rtypes import RTuple, RType, object_rprimitive
 from mypyc.namegen import NameGenerator
 from mypyc.sametype import is_same_type
 
@@ -960,13 +960,13 @@ def generate_setter(cl: ClassIR, attr: str, rtype: RType, emitter: Emitter) -> N
         emitter.emit_lines("if (!tmp)", "    return -1;")
     emitter.emit_inc_ref("tmp", rtype)
     emitter.emit_line(f"self->{attr_field} = tmp;")
-    if is_fixed_width_rtype(rtype) and not always_defined:
+    if rtype.error_overlap and not always_defined:
         emitter.emit_attr_bitmap_set("tmp", "self", rtype, cl, attr)
 
     if deletable:
         emitter.emit_line("} else")
         emitter.emit_line(f"    self->{attr_field} = {emitter.c_undefined_value(rtype)};")
-        if is_fixed_width_rtype(rtype):
+        if rtype.error_overlap:
             emitter.emit_attr_bitmap_clear("self", rtype, cl, attr)
     emitter.emit_line("return 0;")
     emitter.emit_line("}")
diff --git a/mypyc/codegen/emitfunc.py b/mypyc/codegen/emitfunc.py
index 2c096655f41e8..534c4d1f20eaf 100644
--- a/mypyc/codegen/emitfunc.py
+++ b/mypyc/codegen/emitfunc.py
@@ -60,7 +60,6 @@
     RStruct,
     RTuple,
     RType,
-    is_fixed_width_rtype,
     is_int32_rprimitive,
     is_int64_rprimitive,
     is_int_rprimitive,
@@ -442,7 +441,7 @@ def visit_set_attr(self, op: SetAttr) -> None:
                 self.emitter.emit_dec_ref(attr_expr, attr_rtype)
                 if not always_defined:
                     self.emitter.emit_line("}")
-            elif is_fixed_width_rtype(attr_rtype) and not cl.is_always_defined(op.attr):
+            elif attr_rtype.error_overlap and not cl.is_always_defined(op.attr):
                 # If there is overlap with the error value, update bitmap to mark
                 # attribute as defined.
                 self.emitter.emit_attr_bitmap_set(src, obj, attr_rtype, cl, op.attr)
diff --git a/mypyc/codegen/emitwrapper.py b/mypyc/codegen/emitwrapper.py
index 1abab53bc39d8..1fa1e8548e075 100644
--- a/mypyc/codegen/emitwrapper.py
+++ b/mypyc/codegen/emitwrapper.py
@@ -32,7 +32,6 @@
     RInstance,
     RType,
     is_bool_rprimitive,
-    is_fixed_width_rtype,
     is_int_rprimitive,
     is_object_rprimitive,
     object_rprimitive,
@@ -718,9 +717,10 @@ def generate_arg_check(
     """
     error = error or AssignHandler()
     if typ.is_unboxed:
-        if is_fixed_width_rtype(typ) and optional:
+        if typ.error_overlap and optional:
             # Update bitmap is value is provided.
-            emitter.emit_line(f"{emitter.ctype(typ)} arg_{name} = 0;")
+            init = emitter.c_undefined_value(typ)
+            emitter.emit_line(f"{emitter.ctype(typ)} arg_{name} = {init};")
             emitter.emit_line(f"if (obj_{name} != NULL) {{")
             bitmap = bitmap_name(bitmap_arg_index // BITMAP_BITS)
             emitter.emit_line(f"{bitmap} |= 1 << {bitmap_arg_index & (BITMAP_BITS - 1)};")
@@ -835,7 +835,7 @@ def emit_arg_processing(
                 optional=optional,
                 bitmap_arg_index=bitmap_arg_index,
             )
-            if optional and is_fixed_width_rtype(typ):
+            if optional and typ.error_overlap:
                 bitmap_arg_index += 1
 
     def emit_call(self, not_implemented_handler: str = "") -> None:
diff --git a/mypyc/ir/func_ir.py b/mypyc/ir/func_ir.py
index dc83de24300a5..933230a853a80 100644
--- a/mypyc/ir/func_ir.py
+++ b/mypyc/ir/func_ir.py
@@ -17,7 +17,7 @@
     Register,
     Value,
 )
-from mypyc.ir.rtypes import RType, bitmap_rprimitive, deserialize_type, is_fixed_width_rtype
+from mypyc.ir.rtypes import RType, bitmap_rprimitive, deserialize_type
 from mypyc.namegen import NameGenerator
 
 
@@ -113,7 +113,7 @@ def deserialize(cls, data: JsonDict, ctx: DeserMaps) -> FuncSignature:
 def num_bitmap_args(args: tuple[RuntimeArg, ...]) -> int:
     n = 0
     for arg in args:
-        if is_fixed_width_rtype(arg.type) and arg.kind.is_optional():
+        if arg.type.error_overlap and arg.kind.is_optional():
             n += 1
     return (n + (BITMAP_BITS - 1)) // BITMAP_BITS
 
diff --git a/mypyc/ir/ops.py b/mypyc/ir/ops.py
index 361221f5b7101..1f79ba829d767 100644
--- a/mypyc/ir/ops.py
+++ b/mypyc/ir/ops.py
@@ -28,7 +28,6 @@
     int_rprimitive,
     is_bit_rprimitive,
     is_bool_rprimitive,
-    is_fixed_width_rtype,
     is_int_rprimitive,
     is_none_rprimitive,
     is_pointer_rprimitive,
@@ -632,7 +631,7 @@ def __init__(self, obj: Value, attr: str, line: int, *, borrow: bool = False) ->
         self.class_type = obj.type
         attr_type = obj.type.attr_type(attr)
         self.type = attr_type
-        if is_fixed_width_rtype(attr_type):
+        if attr_type.error_overlap:
             self.error_kind = ERR_MAGIC_OVERLAPPING
         self.is_borrowed = borrow and attr_type.is_refcounted
 
@@ -785,7 +784,7 @@ class TupleGet(RegisterOp):
 
     error_kind = ERR_NEVER
 
-    def __init__(self, src: Value, index: int, line: int) -> None:
+    def __init__(self, src: Value, index: int, line: int = -1) -> None:
         super().__init__(line)
         self.src = src
         self.index = index
diff --git a/mypyc/ir/rtypes.py b/mypyc/ir/rtypes.py
index 6db3f249ca9bf..7fe8a940e4c2a 100644
--- a/mypyc/ir/rtypes.py
+++ b/mypyc/ir/rtypes.py
@@ -572,6 +572,7 @@ def __init__(self, types: list[RType]) -> None:
         # Nominally the max c length is 31 chars, but I'm not honestly worried about this.
         self.struct_name = f"tuple_{self.unique_id}"
         self._ctype = f"{self.struct_name}"
+        self.error_overlap = all(t.error_overlap for t in self.types) and bool(self.types)
 
     def accept(self, visitor: RTypeVisitor[T]) -> T:
         return visitor.visit_rtuple(self)
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
index 443fa6886ea62..6310c25c64fb4 100644
--- a/mypyc/irbuild/builder.py
+++ b/mypyc/irbuild/builder.py
@@ -90,7 +90,6 @@
     c_pyssize_t_rprimitive,
     dict_rprimitive,
     int_rprimitive,
-    is_fixed_width_rtype,
     is_list_rprimitive,
     is_none_rprimitive,
     is_object_rprimitive,
@@ -1308,7 +1307,7 @@ def get_default() -> Value:
 
             assert isinstance(target, AssignmentTargetRegister)
             reg = target.register
-            if not is_fixed_width_rtype(reg.type):
+            if not reg.type.error_overlap:
                 builder.assign_if_null(target.register, get_default, arg.initializer.line)
             else:
                 builder.assign_if_bitmap_unset(
diff --git a/mypyc/irbuild/env_class.py b/mypyc/irbuild/env_class.py
index 416fba6334827..ded8072deb63b 100644
--- a/mypyc/irbuild/env_class.py
+++ b/mypyc/irbuild/env_class.py
@@ -21,7 +21,7 @@ def g() -> int:
 from mypyc.common import BITMAP_BITS, ENV_ATTR_NAME, SELF_NAME, bitmap_name
 from mypyc.ir.class_ir import ClassIR
 from mypyc.ir.ops import Call, GetAttr, SetAttr, Value
-from mypyc.ir.rtypes import RInstance, bitmap_rprimitive, is_fixed_width_rtype, object_rprimitive
+from mypyc.ir.rtypes import RInstance, bitmap_rprimitive, object_rprimitive
 from mypyc.irbuild.builder import IRBuilder, SymbolTarget
 from mypyc.irbuild.context import FuncInfo, GeneratorClass, ImplicitClass
 from mypyc.irbuild.targets import AssignmentTargetAttr
@@ -163,7 +163,7 @@ def num_bitmap_args(builder: IRBuilder, args: list[Argument]) -> int:
     n = 0
     for arg in args:
         t = builder.type_to_rtype(arg.variable.type)
-        if is_fixed_width_rtype(t) and arg.kind.is_optional():
+        if t.error_overlap and arg.kind.is_optional():
             n += 1
     return (n + (BITMAP_BITS - 1)) // BITMAP_BITS
 
diff --git a/mypyc/irbuild/ll_builder.py b/mypyc/irbuild/ll_builder.py
index fe0af5b13a732..88b35a95c08ca 100644
--- a/mypyc/irbuild/ll_builder.py
+++ b/mypyc/irbuild/ll_builder.py
@@ -1034,7 +1034,7 @@ def native_args_to_positional(
             bitmap = 0
             c = 0
             for lst, arg in zip(formal_to_actual, sig_args):
-                if arg.kind.is_optional() and is_fixed_width_rtype(arg.type):
+                if arg.kind.is_optional() and arg.type.error_overlap:
                     if i * BITMAP_BITS <= c < (i + 1) * BITMAP_BITS:
                         if lst:
                             bitmap |= 1 << (c & (BITMAP_BITS - 1))
diff --git a/mypyc/test-data/run-i64.test b/mypyc/test-data/run-i64.test
index ee0a09760ab1a..893b3f808f24c 100644
--- a/mypyc/test-data/run-i64.test
+++ b/mypyc/test-data/run-i64.test
@@ -395,7 +395,7 @@ def test_for_loop() -> None:
     assert sum([x * x for x in range(i64(4 + int()))]) == 1 + 4 + 9
 
 [case testI64ErrorValuesAndUndefined]
-from typing import Any
+from typing import Any, Tuple
 import sys
 
 from mypy_extensions import mypyc_attr
@@ -430,6 +430,33 @@ def test_method_error_value() -> None:
     with assertRaises(ValueError):
         C().maybe_raise(0, True)
 
+def maybe_raise_tuple(n: i64, error: bool) -> Tuple[i64, i64]:
+    if error:
+        raise ValueError()
+    return n, n+ 1
+
+def test_tuple_error_value() -> None:
+    for i in range(-1000, 1000):
+        assert maybe_raise_tuple(i, False) == (i, i + 1)
+    with assertRaises(ValueError):
+        maybe_raise_tuple(0, True)
+    f: Any = maybe_raise_tuple
+    for i in range(-1000, 1000):
+        assert f(i, False) == (i, i + 1)
+    with assertRaises(ValueError):
+        f(0, True)
+
+def maybe_raise_tuple2(n: i64, error: bool) -> Tuple[i64, int]:
+    if error:
+        raise ValueError()
+    return n, n+ 1
+
+def test_tuple_error_value_2() -> None:
+    for i in range(-1000, 1000):
+        assert maybe_raise_tuple2(i, False) == (i, i + 1)
+    with assertRaises(ValueError):
+        maybe_raise_tuple(0, True)
+
 def test_unbox_int() -> None:
     for i in list(range(-1000, 1000)) + [-(1 << 63), (1 << 63) - 1]:
         o: Any = i
@@ -733,8 +760,34 @@ def test_del() -> None:
     with assertRaises(AttributeError):
         o.x
 
+class UndefinedTuple:
+    def __init__(self, x: i64, y: i64) -> None:
+        if x != 0:
+            self.t = (x, y)
+
+def test_undefined_native_int_tuple() -> None:
+    o = UndefinedTuple(MAGIC, MAGIC)
+    assert o.t[0] == MAGIC
+    assert o.t[1] == MAGIC
+    o = UndefinedTuple(0, 0)
+    with assertRaises(AttributeError):
+        o.t
+    o = UndefinedTuple(-13, 45)
+    assert o.t == (-13, 45)
+
+def test_undefined_native_int_tuple_via_any() -> None:
+    cls: Any = UndefinedTuple
+    o: Any = cls(MAGIC, MAGIC)
+    assert o.t[0] == MAGIC
+    assert o.t[1] == MAGIC
+    o = cls(0, 0)
+    with assertRaises(AttributeError):
+        o.t
+    o = UndefinedTuple(-13, 45)
+    assert o.t == (-13, 45)
+
 [case testI64DefaultArgValues]
-from typing import Any, Iterator
+from typing import Any, Iterator, Tuple
 from typing_extensions import Final
 
 MAGIC: Final = -113
@@ -893,6 +946,31 @@ def test_kw_only_default_args() -> None:
     assert kw_only2(a=2, c=4) == 12
     assert kw_only2(c=4, a=2) == 12
 
+def tuples(t: Tuple[i64, i64] = (MAGIC, MAGIC)) -> i64:
+    return t[0] + t[1]
+
+def test_tuple_arg_defaults() -> None:
+    assert tuples() == 2 * MAGIC
+    assert tuples((1, 2)) == 3
+    assert tuples((MAGIC, MAGIC)) == 2 * MAGIC
+    tuples2: Any = tuples
+    assert tuples2() == 2 * MAGIC
+    assert tuples2((1, 2)) == 3
+    assert tuples2((MAGIC, MAGIC)) == 2 * MAGIC
+
+class TupleInit:
+    def __init__(self, t: Tuple[i64, i64] = (MAGIC, MAGIC)) -> None:
+        self.t = t[0] + t[1]
+
+def test_tuple_init_arg_defaults() -> None:
+    assert TupleInit().t == 2 * MAGIC
+    assert TupleInit((1, 2)).t == 3
+    assert TupleInit((MAGIC, MAGIC)).t == 2 * MAGIC
+    o: Any = TupleInit
+    assert o().t == 2 * MAGIC
+    assert o((1, 2)).t == 3
+    assert o((MAGIC, MAGIC)).t == 2 * MAGIC
+
 def many_args(
     a1: i64 = 0,
     a2: i64 = 1,
@@ -1060,6 +1138,24 @@ def test_assign_error_value_conditionally() -> None:
     assert y == MAGIC
     assert z == MAGIC
 
+def tuple_case(x: i64, y: i64) -> None:
+    if not int():
+        t = (x, y)
+    assert t == (x, y)
+    if int():
+        t2 = (x, y)
+    try:
+        print(t2)
+    except NameError as e:
+        assert str(e) == 'local variable "t2" referenced before assignment'
+    else:
+        assert False
+
+def test_conditionally_undefined_tuple() -> None:
+    tuple_case(2, 3)
+    tuple_case(-2, -3)
+    tuple_case(MAGIC, MAGIC)
+
 def test_many_locals() -> None:
     x = int()
     if x:
diff --git a/mypyc/transform/exceptions.py b/mypyc/transform/exceptions.py
index cc638142c397d..2851955ff38fa 100644
--- a/mypyc/transform/exceptions.py
+++ b/mypyc/transform/exceptions.py
@@ -26,12 +26,14 @@
     GetAttr,
     Integer,
     LoadErrorValue,
+    Op,
     RegisterOp,
     Return,
     SetAttr,
+    TupleGet,
     Value,
 )
-from mypyc.ir.rtypes import bool_rprimitive
+from mypyc.ir.rtypes import RTuple, bool_rprimitive
 from mypyc.primitives.exc_ops import err_occurred_op
 from mypyc.primitives.registry import CFunctionDescription
 
@@ -100,9 +102,7 @@ def split_blocks_at_errors(
                     # semantics, using a temporary bool with value false
                     target = Integer(0, bool_rprimitive)
                 elif op.error_kind == ERR_MAGIC_OVERLAPPING:
-                    errvalue = Integer(int(target.type.c_undefined), rtype=op.type)
-                    comp = ComparisonOp(target, errvalue, ComparisonOp.EQ)
-                    cur_block.ops.append(comp)
+                    comp = insert_overlapping_error_value_check(cur_block.ops, target)
                     new_block2 = BasicBlock()
                     new_blocks.append(new_block2)
                     branch = Branch(
@@ -163,3 +163,17 @@ def adjust_error_kinds(block: BasicBlock) -> None:
         if isinstance(op, SetAttr):
             if op.class_type.class_ir.is_always_defined(op.attr):
                 op.error_kind = ERR_NEVER
+
+
+def insert_overlapping_error_value_check(ops: list[Op], target: Value) -> ComparisonOp:
+    """Append to ops to check for an overlapping error value."""
+    typ = target.type
+    if isinstance(typ, RTuple):
+        item = TupleGet(target, 0)
+        ops.append(item)
+        return insert_overlapping_error_value_check(ops, item)
+    else:
+        errvalue = Integer(int(typ.c_undefined), rtype=typ)
+        op = ComparisonOp(target, errvalue, ComparisonOp.EQ)
+        ops.append(op)
+        return op
diff --git a/mypyc/transform/uninit.py b/mypyc/transform/uninit.py
index 041dd2545dff9..6bf71ac4a8bcd 100644
--- a/mypyc/transform/uninit.py
+++ b/mypyc/transform/uninit.py
@@ -20,7 +20,7 @@
     Unreachable,
     Value,
 )
-from mypyc.ir.rtypes import bitmap_rprimitive, is_fixed_width_rtype
+from mypyc.ir.rtypes import bitmap_rprimitive
 
 
 def insert_uninit_checks(ir: FuncIR) -> None:
@@ -77,7 +77,7 @@ def split_blocks_at_uninits(
                         init_registers.append(src)
                         init_registers_set.add(src)
 
-                    if not is_fixed_width_rtype(src.type):
+                    if not src.type.error_overlap:
                         cur_block.ops.append(
                             Branch(
                                 src,

From 7da2abf9a5a05fffc3d07caef31681c50bc9d6e7 Mon Sep 17 00:00:00 2001
From: jhance <jhance@users.noreply.github.com>
Date: Tue, 6 Dec 2022 10:08:06 -0800
Subject: [PATCH 109/231] Replace TypeList in constraints with TupleType
 (#14257)

Now that the fallback is available, we can construct TupleTypes instead
of TypeLists which will simplify constraint solving as it won't need to
know to match TupleTypes with TypeLists.
---
 mypy/constraints.py          | 22 ++++++++++++++++------
 mypy/expandtype.py           |  7 +++----
 mypy/test/testconstraints.py | 16 ++++++++++++----
 3 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index 6efb9997d36f1..3a6553a307fdc 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -29,7 +29,6 @@
     Type,
     TypeAliasType,
     TypedDictType,
-    TypeList,
     TypeOfAny,
     TypeQuery,
     TypeType,
@@ -135,7 +134,13 @@ def infer_constraints_for_callable(
 
             unpacked_type = get_proper_type(unpack_type.type)
             if isinstance(unpacked_type, TypeVarTupleType):
-                constraints.append(Constraint(unpacked_type, SUPERTYPE_OF, TypeList(actual_types)))
+                constraints.append(
+                    Constraint(
+                        unpacked_type,
+                        SUPERTYPE_OF,
+                        TupleType(actual_types, unpacked_type.tuple_fallback),
+                    )
+                )
             elif isinstance(unpacked_type, TupleType):
                 # Prefixes get converted to positional args, so technically the only case we
                 # should have here is like Tuple[Unpack[Ts], Y1, Y2, Y3]. If this turns out
@@ -147,12 +152,13 @@ def infer_constraints_for_callable(
                 suffix_len = len(unpacked_type.items) - 1
                 constraints.append(
                     Constraint(
-                        inner_unpacked_type, SUPERTYPE_OF, TypeList(actual_types[:-suffix_len])
+                        inner_unpacked_type,
+                        SUPERTYPE_OF,
+                        TupleType(actual_types[:-suffix_len], inner_unpacked_type.tuple_fallback),
                     )
                 )
             else:
                 assert False, "mypy bug: unhandled constraint inference case"
-
         else:
             for actual in actuals:
                 actual_arg_type = arg_types[actual]
@@ -640,7 +646,9 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                         if isinstance(instance_unpack, TypeVarTupleType):
                             res.append(
                                 Constraint(
-                                    instance_unpack, SUBTYPE_OF, TypeList(list(mapped_middle))
+                                    instance_unpack,
+                                    SUBTYPE_OF,
+                                    TupleType(list(mapped_middle), instance_unpack.tuple_fallback),
                                 )
                             )
                         elif (
@@ -742,7 +750,9 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                         if isinstance(template_unpack, TypeVarTupleType):
                             res.append(
                                 Constraint(
-                                    template_unpack, SUPERTYPE_OF, TypeList(list(mapped_middle))
+                                    template_unpack,
+                                    SUPERTYPE_OF,
+                                    TupleType(list(mapped_middle), template_unpack.tuple_fallback),
                                 )
                             )
                         elif (
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 96d556121fd4f..1458fb74ce946 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -22,7 +22,6 @@
     Type,
     TypeAliasType,
     TypedDictType,
-    TypeList,
     TypeType,
     TypeVarId,
     TypeVarLikeType,
@@ -95,7 +94,9 @@ def expand_type_by_instance(typ: Type, instance: Instance) -> Type:
                 instance.type.type_var_tuple_prefix,
                 instance.type.type_var_tuple_suffix,
             )
-            variables = {tvars_middle[0].id: TypeList(list(args_middle))}
+            tvar = tvars_middle[0]
+            assert isinstance(tvar, TypeVarTupleType)
+            variables = {tvar.id: TupleType(list(args_middle), tvar.tuple_fallback)}
             instance_args = args_prefix + args_suffix
             tvars = tvars_prefix + tvars_suffix
         else:
@@ -447,8 +448,6 @@ def expand_unpack_with_variables(
         repl = get_proper_type(variables.get(t.type.id, t))
         if isinstance(repl, TupleType):
             return repl.items
-        if isinstance(repl, TypeList):
-            return repl.items
         elif isinstance(repl, Instance) and repl.type.fullname == "builtins.tuple":
             return repl
         elif isinstance(repl, AnyType):
diff --git a/mypy/test/testconstraints.py b/mypy/test/testconstraints.py
index 6b8f596dd6050..fc6960e0d8a0a 100644
--- a/mypy/test/testconstraints.py
+++ b/mypy/test/testconstraints.py
@@ -5,7 +5,7 @@
 from mypy.constraints import SUBTYPE_OF, SUPERTYPE_OF, Constraint, infer_constraints
 from mypy.test.helpers import Suite
 from mypy.test.typefixture import TypeFixture
-from mypy.types import Instance, TupleType, TypeList, UnpackType
+from mypy.types import Instance, TupleType, UnpackType
 
 
 class ConstraintsSuite(Suite):
@@ -27,13 +27,19 @@ def test_basic_type_var_tuple_subtype(self) -> None:
         fx = self.fx
         assert infer_constraints(
             Instance(fx.gvi, [UnpackType(fx.ts)]), Instance(fx.gvi, [fx.a, fx.b]), SUBTYPE_OF
-        ) == [Constraint(type_var=fx.ts, op=SUBTYPE_OF, target=TypeList([fx.a, fx.b]))]
+        ) == [
+            Constraint(type_var=fx.ts, op=SUBTYPE_OF, target=TupleType([fx.a, fx.b], fx.std_tuple))
+        ]
 
     def test_basic_type_var_tuple(self) -> None:
         fx = self.fx
         assert infer_constraints(
             Instance(fx.gvi, [UnpackType(fx.ts)]), Instance(fx.gvi, [fx.a, fx.b]), SUPERTYPE_OF
-        ) == [Constraint(type_var=fx.ts, op=SUPERTYPE_OF, target=TypeList([fx.a, fx.b]))]
+        ) == [
+            Constraint(
+                type_var=fx.ts, op=SUPERTYPE_OF, target=TupleType([fx.a, fx.b], fx.std_tuple)
+            )
+        ]
 
     def test_type_var_tuple_with_prefix_and_suffix(self) -> None:
         fx = self.fx
@@ -45,7 +51,9 @@ def test_type_var_tuple_with_prefix_and_suffix(self) -> None:
             )
         ) == {
             Constraint(type_var=fx.t, op=SUPERTYPE_OF, target=fx.a),
-            Constraint(type_var=fx.ts, op=SUPERTYPE_OF, target=TypeList([fx.b, fx.c])),
+            Constraint(
+                type_var=fx.ts, op=SUPERTYPE_OF, target=TupleType([fx.b, fx.c], fx.std_tuple)
+            ),
             Constraint(type_var=fx.s, op=SUPERTYPE_OF, target=fx.d),
         }
 

From 695ea3017fee084c9d2ec17d9b28f8af905e3b63 Mon Sep 17 00:00:00 2001
From: KotlinIsland <65446343+KotlinIsland@users.noreply.github.com>
Date: Thu, 8 Dec 2022 09:16:30 +1000
Subject: [PATCH 110/231] =?UTF-8?q?(=F0=9F=8E=81)=20canwecolor=F0=9F=9A=80?=
 =?UTF-8?q?=20(#14051)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Last time i checked it wasn't the 1960's. So I think the CI could be
colorized.

Configured pytest, tox, mypy(#7771) and pip¹ (I already already
colorized black and isort when I initially added them)


1: Pip doesn't work yet https://github.com/pypa/pip/issues/10909, so
this is just a placedholder for when it (hopefully) soon will.

Co-authored-by: KotlinIsland <kotlinisland@users.noreply.github.com>
---
 .github/workflows/test.yml | 10 ++++++++++
 tox.ini                    |  4 ++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 3fdb83ff15b45..9cc2d82ad9113 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -102,6 +102,16 @@ jobs:
     name: ${{ matrix.name }}
     env:
       TOX_SKIP_MISSING_INTERPRETERS: False
+      # Rich (pip)
+      FORCE_COLOR: 1
+      # Tox
+      PY_COLORS: 1
+      # Mypy (see https://github.com/python/mypy/issues/7771)
+      TERM: xterm-color
+      MYPY_FORCE_COLOR: 1
+      MYPY_FORCE_TERMINAL_WIDTH: 200
+      # Pytest
+      PYTEST_ADDOPTS: --color=yes
     steps:
     - uses: actions/checkout@v3
     - uses: actions/setup-python@v4
diff --git a/tox.ini b/tox.ini
index 92810bed99814..a155ec7263869 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,7 +2,6 @@
 minversion = 3.8.0
 skip_missing_interpreters = {env:TOX_SKIP_MISSING_INTERPRETERS:True}
 envlist =
-    py36,
     py37,
     py38,
     py39,
@@ -14,7 +13,7 @@ isolated_build = true
 
 [testenv]
 description = run the test driver with {basepython}
-passenv = PYTEST_XDIST_WORKER_COUNT PROGRAMDATA PROGRAMFILES(X86)
+passenv = PYTEST_XDIST_WORKER_COUNT PROGRAMDATA PROGRAMFILES(X86) PYTEST_ADDOPTS
 deps = -rtest-requirements.txt
 commands = python -m pytest {posargs}
 
@@ -27,6 +26,7 @@ commands =
 
 [testenv:type]
 description = type check ourselves
+passenv = TERM MYPY_FORCE_COLOR MYPY_FORCE_TERMINAL_WIDTH
 commands =
     python -m mypy --config-file mypy_self_check.ini -p mypy -p mypyc
     python -m mypy --config-file mypy_self_check.ini misc --exclude misc/fix_annotate.py --exclude misc/async_matrix.py --exclude misc/sync-typeshed.py

From 7849b8f15dccf69173b4ff172524c4d82a70bc2d Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Sat, 10 Dec 2022 16:37:15 +0100
Subject: [PATCH 111/231] Rename `partially-defined` error codes (#14267)

Rename `partially-defined` to `possibly-undefined` and `use-before-def`
to `used-before-def`.

Ref #14226
---
 mypy/build.py                                 |  14 +-
 mypy/errorcodes.py                            |   8 +-
 mypy/messages.py                              |   4 +-
 mypy/partially_defined.py                     |  20 +--
 mypy/server/update.py                         |   2 +-
 ...ned.test => check-possibly-undefined.test} | 126 +++++++++---------
 test-data/unit/check-python310.test           |   8 +-
 test-data/unit/check-python38.test            |   4 +-
 8 files changed, 93 insertions(+), 93 deletions(-)
 rename test-data/unit/{check-partially-defined.test => check-possibly-undefined.test} (77%)

diff --git a/mypy/build.py b/mypy/build.py
index b85b49483739d..7da3e71ce25e2 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -50,7 +50,7 @@
 from mypy.indirection import TypeIndirectionVisitor
 from mypy.messages import MessageBuilder
 from mypy.nodes import Import, ImportAll, ImportBase, ImportFrom, MypyFile, SymbolTable, TypeInfo
-from mypy.partially_defined import PartiallyDefinedVariableVisitor
+from mypy.partially_defined import PossiblyUndefinedVariableVisitor
 from mypy.semanal import SemanticAnalyzer
 from mypy.semanal_pass1 import SemanticAnalyzerPreAnalysis
 from mypy.util import (
@@ -2347,18 +2347,18 @@ def type_check_second_pass(self) -> bool:
         self.time_spent_us += time_spent_us(t0)
         return result
 
-    def detect_partially_defined_vars(self, type_map: dict[Expression, Type]) -> None:
+    def detect_possibly_undefined_vars(self, type_map: dict[Expression, Type]) -> None:
         assert self.tree is not None, "Internal error: method must be called on parsed file only"
         if self.tree.is_stub:
             # We skip stub files because they aren't actually executed.
             return
         manager = self.manager
         if manager.errors.is_error_code_enabled(
-            codes.PARTIALLY_DEFINED
-        ) or manager.errors.is_error_code_enabled(codes.USE_BEFORE_DEF):
+            codes.POSSIBLY_UNDEFINED
+        ) or manager.errors.is_error_code_enabled(codes.USED_BEFORE_DEF):
             manager.errors.set_file(self.xpath, self.tree.fullname, options=manager.options)
             self.tree.accept(
-                PartiallyDefinedVariableVisitor(
+                PossiblyUndefinedVariableVisitor(
                     MessageBuilder(manager.errors, manager.modules), type_map, manager.options
                 )
             )
@@ -3412,7 +3412,7 @@ def process_stale_scc(graph: Graph, scc: list[str], manager: BuildManager) -> No
         graph[id].type_check_first_pass()
         if not graph[id].type_checker().deferred_nodes:
             unfinished_modules.discard(id)
-            graph[id].detect_partially_defined_vars(graph[id].type_map())
+            graph[id].detect_possibly_undefined_vars(graph[id].type_map())
             graph[id].finish_passes()
 
     while unfinished_modules:
@@ -3421,7 +3421,7 @@ def process_stale_scc(graph: Graph, scc: list[str], manager: BuildManager) -> No
                 continue
             if not graph[id].type_check_second_pass():
                 unfinished_modules.discard(id)
-                graph[id].detect_partially_defined_vars(graph[id].type_map())
+                graph[id].detect_possibly_undefined_vars(graph[id].type_map())
                 graph[id].finish_passes()
     for id in stale:
         graph[id].generate_unused_ignore_notes()
diff --git a/mypy/errorcodes.py b/mypy/errorcodes.py
index 1c15407a955bc..6b266cc7b4299 100644
--- a/mypy/errorcodes.py
+++ b/mypy/errorcodes.py
@@ -140,8 +140,8 @@ def __str__(self) -> str:
 ANNOTATION_UNCHECKED = ErrorCode(
     "annotation-unchecked", "Notify about type annotations in unchecked functions", "General"
 )
-PARTIALLY_DEFINED: Final[ErrorCode] = ErrorCode(
-    "partially-defined",
+POSSIBLY_UNDEFINED: Final[ErrorCode] = ErrorCode(
+    "possibly-undefined",
     "Warn about variables that are defined only in some execution paths",
     "General",
     default_enabled=False,
@@ -192,8 +192,8 @@ def __str__(self) -> str:
     "General",
     default_enabled=False,
 )
-USE_BEFORE_DEF: Final[ErrorCode] = ErrorCode(
-    "use-before-def",
+USED_BEFORE_DEF: Final[ErrorCode] = ErrorCode(
+    "used-before-def",
     "Warn about variables that are used before they are defined",
     "General",
     default_enabled=False,
diff --git a/mypy/messages.py b/mypy/messages.py
index 85fa305125343..85811561e1761 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -1229,10 +1229,10 @@ def undefined_in_superclass(self, member: str, context: Context) -> None:
         self.fail(f'"{member}" undefined in superclass', context)
 
     def variable_may_be_undefined(self, name: str, context: Context) -> None:
-        self.fail(f'Name "{name}" may be undefined', context, code=codes.PARTIALLY_DEFINED)
+        self.fail(f'Name "{name}" may be undefined', context, code=codes.POSSIBLY_UNDEFINED)
 
     def var_used_before_def(self, name: str, context: Context) -> None:
-        self.fail(f'Name "{name}" is used before definition', context, code=codes.USE_BEFORE_DEF)
+        self.fail(f'Name "{name}" is used before definition', context, code=codes.USED_BEFORE_DEF)
 
     def first_argument_for_super_must_be_type(self, actual: Type, context: Context) -> None:
         actual = get_proper_type(actual)
diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 3ec8db3665cd7..5f5253515b618 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -104,7 +104,7 @@ def skip_branch(self) -> None:
         assert len(self.branches) > 0
         self.branches[-1].skipped = True
 
-    def is_partially_defined(self, name: str) -> bool:
+    def is_possibly_undefined(self, name: str) -> bool:
         assert len(self.branches) > 0
         return name in self.branches[-1].may_be_defined
 
@@ -213,10 +213,10 @@ def pop_undefined_ref(self, name: str) -> set[NameExpr]:
         assert len(self.scopes) > 0
         return self._scope().pop_undefined_ref(name)
 
-    def is_partially_defined(self, name: str) -> bool:
+    def is_possibly_undefined(self, name: str) -> bool:
         assert len(self._scope().branch_stmts) > 0
         # A variable is undefined if it's in a set of `may_be_defined` but not in `must_be_defined`.
-        return self._scope().branch_stmts[-1].is_partially_defined(name)
+        return self._scope().branch_stmts[-1].is_possibly_undefined(name)
 
     def is_defined_in_different_branch(self, name: str) -> bool:
         """This will return true if a variable is defined in a branch that's not the current branch."""
@@ -243,7 +243,7 @@ def __init__(self) -> None:
         self.has_break = False
 
 
-class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
+class PossiblyUndefinedVariableVisitor(ExtendedTraverserVisitor):
     """Detects the following cases:
     - A variable that's defined only part of the time.
     - If a variable is used before definition
@@ -253,7 +253,7 @@ class PartiallyDefinedVariableVisitor(ExtendedTraverserVisitor):
         x = 1
     print(x)  # Error: "x" may be undefined.
 
-    Example of a use before definition:
+    Example of a used before definition:
     x = y
     y: int = 2
 
@@ -273,15 +273,15 @@ def __init__(
             self.tracker.record_definition(name)
 
     def var_used_before_def(self, name: str, context: Context) -> None:
-        if self.msg.errors.is_error_code_enabled(errorcodes.USE_BEFORE_DEF):
+        if self.msg.errors.is_error_code_enabled(errorcodes.USED_BEFORE_DEF):
             self.msg.var_used_before_def(name, context)
 
     def variable_may_be_undefined(self, name: str, context: Context) -> None:
-        if self.msg.errors.is_error_code_enabled(errorcodes.PARTIALLY_DEFINED):
+        if self.msg.errors.is_error_code_enabled(errorcodes.POSSIBLY_UNDEFINED):
             self.msg.variable_may_be_undefined(name, context)
 
     def process_definition(self, name: str) -> None:
-        # Was this name previously used? If yes, it's a use-before-definition error.
+        # Was this name previously used? If yes, it's a used-before-definition error.
         refs = self.tracker.pop_undefined_ref(name)
         for ref in refs:
             self.var_used_before_def(name, ref)
@@ -471,7 +471,7 @@ def visit_starred_pattern(self, o: StarredPattern) -> None:
     def visit_name_expr(self, o: NameExpr) -> None:
         if refers_to_builtin(o):
             return
-        if self.tracker.is_partially_defined(o.name):
+        if self.tracker.is_possibly_undefined(o.name):
             # A variable is only defined in some branches.
             self.variable_may_be_undefined(o.name, o)
             # We don't want to report the error on the same variable multiple times.
@@ -488,7 +488,7 @@ def visit_name_expr(self, o: NameExpr) -> None:
             # 2. The variable is defined later in the code.
             # Case (1) will be caught by semantic analyzer. Case (2) is a forward ref that should
             # be caught by this visitor. Save the ref for later, so that if we see a definition,
-            # we know it's a use-before-definition scenario.
+            # we know it's a used-before-definition scenario.
             self.tracker.record_undefined_ref(o)
         super().visit_name_expr(o)
 
diff --git a/mypy/server/update.py b/mypy/server/update.py
index a1f57b5a67467..e9750dec1e2a8 100644
--- a/mypy/server/update.py
+++ b/mypy/server/update.py
@@ -662,7 +662,7 @@ def restore(ids: list[str]) -> None:
     state.type_checker().reset()
     state.type_check_first_pass()
     state.type_check_second_pass()
-    state.detect_partially_defined_vars(state.type_map())
+    state.detect_possibly_undefined_vars(state.type_map())
     t2 = time.time()
     state.finish_passes()
     t3 = time.time()
diff --git a/test-data/unit/check-partially-defined.test b/test-data/unit/check-possibly-undefined.test
similarity index 77%
rename from test-data/unit/check-partially-defined.test
rename to test-data/unit/check-possibly-undefined.test
index 623e897e865d4..d99943572a384 100644
--- a/test-data/unit/check-partially-defined.test
+++ b/test-data/unit/check-possibly-undefined.test
@@ -1,5 +1,5 @@
 [case testDefinedInOneBranch]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     a = 1
 else:
@@ -8,7 +8,7 @@ z = a + 1  # E: Name "a" may be undefined
 z = a + 1  # We only report the error on first occurrence.
 
 [case testElif]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     a = 1
 elif int():
@@ -19,14 +19,14 @@ else:
 z = a + 1  # E: Name "a" may be undefined
 
 [case testUsedInIf]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     y = 1
 if int():
     x = y  # E: Name "y" may be undefined
 
 [case testDefinedInAllBranches]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     a = 1
 elif int():
@@ -36,13 +36,13 @@ else:
 z = a + 1
 
 [case testOmittedElse]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     a = 1
 z = a + 1  # E: Name "a" may be undefined
 
 [case testUpdatedInIf]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 # Variable a is already defined. Just updating it in an "if" is acceptable.
 a = 1
 if int():
@@ -50,7 +50,7 @@ if int():
 z = a + 1
 
 [case testNestedIf]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     if int():
         a = 1
@@ -65,7 +65,7 @@ else:
 z = a + b  # E: Name "a" may be undefined
 
 [case testVeryNestedIf]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     if int():
         if int():
@@ -81,7 +81,7 @@ else:
 z = a + b  # E: Name "a" may be undefined
 
 [case testTupleUnpack]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 
 if int():
     (x, y) = (1, 2)
@@ -91,7 +91,7 @@ a = y + x  # E: Name "x" may be undefined
 a = y + z  # E: Name "z" may be undefined
 
 [case testIndexExpr]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 
 if int():
     *x, y = (1, 2)
@@ -101,7 +101,7 @@ a = x  # No error.
 b = y  # E: Name "y" may be undefined
 
 [case testRedefined]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 y = 3
 if int():
     if int():
@@ -115,7 +115,7 @@ else:
 x = y + 2
 
 [case testFunction]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f0() -> None:
     if int():
         def some_func() -> None:
@@ -134,21 +134,21 @@ def f1() -> None:
     some_func()  # No error.
 
 [case testLambda]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f0(b: bool) -> None:
     if b:
         fn = lambda: 2
     y = fn   # E: Name "fn" may be undefined
 
-[case testUseBeforeDefClass]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+[case testUsedBeforeDefClass]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def f(x: A):  # No error here.
     pass
 y = A()  # E: Name "A" is used before definition
 class A: pass
 
 [case testClassScope]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 class C:
     x = 0
     def f0(self) -> None: pass
@@ -163,26 +163,26 @@ y = x  # E: Name "x" is used before definition
 x = 1
 
 [case testClassInsideFunction]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def f() -> None:
     class C: pass
 
 c = C()  # E: Name "C" is used before definition
 class C: pass
 
-[case testUseBeforeDefFunc]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+[case testUsedBeforeDefFunc]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 foo() # E: Name "foo" is used before definition
 def foo(): pass
 [case testGenerator]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 if int():
     a = 3
 s = [a + 1 for a in [1, 2, 3]]
 x = a  # E: Name "a" may be undefined
 
 [case testScope]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def foo() -> None:
     if int():
         y = 2
@@ -192,7 +192,7 @@ if int():
 x = y  # E: Name "y" may be undefined
 
 [case testVarDefinedInOuterScopeUpdated]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def f0() -> None:
     global x
     y = x
@@ -201,7 +201,7 @@ def f0() -> None:
 x = 2
 
 [case testNonlocalVar]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def f0() -> None:
     x = 2
 
@@ -212,7 +212,7 @@ def f0() -> None:
 
 
 [case testGlobalDeclarationAfterUsage]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def f0() -> None:
     y = x  # E: Name "x" is used before definition
     global x
@@ -220,7 +220,7 @@ def f0() -> None:
 
 x = 2
 [case testVarDefinedInOuterScope]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def f0() -> None:
   global x
   y = x  # We do not detect such errors right now.
@@ -228,21 +228,21 @@ def f0() -> None:
 f0()
 x = 1
 [case testDefinedInOuterScopeNoError]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 def foo() -> None:
     bar()
 
 def bar() -> None:
     foo()
 [case testFuncParams]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def foo(a: int) -> None:
     if int():
         a = 2
     x = a
 
 [case testWhile]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 while int():
     a = 1
 
@@ -289,7 +289,7 @@ y = f  # E: Name "f" may be undefined
 y = g
 
 [case testForLoop]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 for x in [1, 2, 3]:
     if x:
         x = 1
@@ -300,7 +300,7 @@ else:
 a = z + y  # E: Name "y" may be undefined
 
 [case testReturn]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f1() -> int:
     if int():
         x = 1
@@ -351,8 +351,8 @@ def f6() -> int:
         return x
     return x  # E: Name "x" may be undefined
 
-[case testDefinedDifferentBranchUseBeforeDef]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+[case testDefinedDifferentBranchUsedBeforeDef]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 
 def f0() -> None:
     if int():
@@ -382,8 +382,8 @@ def f2() -> None:
             x = 2
         w = x  # No error.
 
-[case testDefinedDifferentBranchPartiallyDefined]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+[case testDefinedDifferentBranchPossiblyUndefined]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 
 def f0() -> None:
     first_iter = True
@@ -424,7 +424,7 @@ def f3() -> None:
         y = x  # E: Name "x" may be undefined
 
 [case testAssert]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f1() -> int:
     if int():
         x = 1
@@ -442,7 +442,7 @@ def f2() -> int:
     return x  # E: Name "x" may be undefined
 
 [case testRaise]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f1() -> int:
     if int():
         x = 1
@@ -461,7 +461,7 @@ def f2() -> int:
 [builtins fixtures/exception.pyi]
 
 [case testContinue]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f1() -> int:
     while int():
         if int():
@@ -495,7 +495,7 @@ def f3() -> None:
         y = x
 
 [case testBreak]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 def f1() -> None:
     while int():
         if int():
@@ -526,7 +526,7 @@ def f3() -> None:
     z = x  # E: Name "x" may be undefined
 
 [case testNoReturn]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 
 from typing import NoReturn
 def fail() -> NoReturn:
@@ -545,7 +545,7 @@ def f() -> None:
     z = x
 
 [case testDictComprehension]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 
 def f() -> None:
     for _ in [1, 2]:
@@ -562,7 +562,7 @@ def f() -> None:
 [builtins fixtures/dict.pyi]
 
 [case testWithStmt]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 from contextlib import contextmanager
 
 @contextmanager
@@ -582,7 +582,7 @@ def f() -> None:
 [builtins fixtures/tuple.pyi]
 
 [case testUnreachable]
-# flags: --enable-error-code partially-defined
+# flags: --enable-error-code possibly-undefined
 import typing
 
 if typing.TYPE_CHECKING:
@@ -600,8 +600,8 @@ else:
 a = z
 [typing fixtures/typing-medium.pyi]
 
-[case testUseBeforeDef]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDef]
+# flags: --enable-error-code used-before-def
 
 def f0() -> None:
     x = y  # E: Name "y" is used before definition
@@ -611,7 +611,7 @@ def f2() -> None:
     if int():
         pass
     else:
-        # No use-before-def error.
+        # No used-before-def error.
         y = z  # E: Name "z" is not defined
 
     def inner2() -> None:
@@ -632,8 +632,8 @@ def f4() -> None:
         x = z  # E: Name "z" is used before definition
     z: int = 2
 
-[case testUseBeforeDefImportsBasic]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefImportsBasic]
+# flags: --enable-error-code used-before-def
 import foo  # type: ignore
 import x.y  # type: ignore
 
@@ -653,8 +653,8 @@ def f3() -> None:
     a = x.y  # No error.
     x: int = 1
 
-[case testUseBeforeDefImportBasicRename]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefImportBasicRename]
+# flags: --enable-error-code used-before-def
 import x.y as z  # type: ignore
 from typing import Any
 
@@ -674,16 +674,16 @@ def f3() -> None:
     a = y  # E: Name "y" is used before definition
     y: int = 1
 
-[case testUseBeforeDefImportFrom]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefImportFrom]
+# flags: --enable-error-code used-before-def
 from foo import x  # type: ignore
 
 def f0() -> None:
     a = x  # No error.
     x: int = 1
 
-[case testUseBeforeDefImportFromRename]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefImportFromRename]
+# flags: --enable-error-code used-before-def
 from foo import x as y  # type: ignore
 
 def f0() -> None:
@@ -694,8 +694,8 @@ def f1() -> None:
     a = x  # E: Name "x" is used before definition
     x: int = 1
 
-[case testUseBeforeDefFunctionDeclarations]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefFunctionDeclarations]
+# flags: --enable-error-code used-before-def
 
 def f0() -> None:
     def inner() -> None:
@@ -704,30 +704,30 @@ def f0() -> None:
     inner()  # No error.
     inner = lambda: None
 
-[case testUseBeforeDefBuiltins]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefBuiltins]
+# flags: --enable-error-code used-before-def
 
 def f0() -> None:
     s = type(123)
     type = "abc"
     a = type
 
-[case testUseBeforeDefImplicitModuleAttrs]
-# flags: --enable-error-code use-before-def
+[case testUsedBeforeDefImplicitModuleAttrs]
+# flags: --enable-error-code used-before-def
 a = __name__  # No error.
 __name__ = "abc"
 
 [case testUntypedDef]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 
 def f():
     if int():
         x = 0
-    z = y  # No use-before-def error because def is untyped.
-    y = x  # No partially-defined error because def is untyped.
+    z = y  # No used-before-def error because def is untyped.
+    y = x  # No possibly-undefined error because def is untyped.
 
 [case testUntypedDefCheckUntypedDefs]
-# flags: --enable-error-code partially-defined --enable-error-code use-before-def --check-untyped-defs
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def --check-untyped-defs
 
 def f():
     if int():
diff --git a/test-data/unit/check-python310.test b/test-data/unit/check-python310.test
index 1967e7f4810b1..12fd2b43c80a9 100644
--- a/test-data/unit/check-python310.test
+++ b/test-data/unit/check-python310.test
@@ -1726,8 +1726,8 @@ def my_func(pairs: Iterable[tuple[S, S]]) -> None:
                                    # N: Revealed type is "Tuple[builtins.str, builtins.str]"
 [builtins fixtures/tuple.pyi]
 
-[case testPartiallyDefinedMatch]
-# flags: --enable-error-code partially-defined
+[case testPossiblyUndefinedMatch]
+# flags: --enable-error-code possibly-undefined
 def f0(x: int | str) -> int:
     match x:
         case int():
@@ -1789,8 +1789,8 @@ def f6(a: object) -> None:
             pass
 [builtins fixtures/tuple.pyi]
 
-[case testPartiallyDefinedMatchUnreachable]
-# flags: --enable-error-code partially-defined
+[case testPossiblyUndefinedMatchUnreachable]
+# flags: --enable-error-code possibly-undefined
 import typing
 
 def f0(x: int) -> int:
diff --git a/test-data/unit/check-python38.test b/test-data/unit/check-python38.test
index 30bdadf900c3a..c8fb1eb5aac87 100644
--- a/test-data/unit/check-python38.test
+++ b/test-data/unit/check-python38.test
@@ -707,8 +707,8 @@ def foo(name: str, /, **kwargs: Unpack[Person]) -> None:  # Allowed
     ...
 [builtins fixtures/dict.pyi]
 
-[case testPartiallyDefinedWithAssignmentExpr]
-# flags: --python-version 3.8 --enable-error-code partially-defined
+[case testPossiblyUndefinedWithAssignmentExpr]
+# flags: --python-version 3.8 --enable-error-code possibly-undefined
 def f1() -> None:
     d = {0: 1}
     if int():

From b0003aff931c12298fb462aa4cece18610ee4d05 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sun, 11 Dec 2022 19:30:13 -0800
Subject: [PATCH 112/231] stubtest: catch BaseException on module imports
 (#14284)

This came up in https://github.com/python/typeshed/pull/9347
---
 mypy/stubtest.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 5e39b996076b5..0f8df607858fa 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -205,7 +205,9 @@ def test_module(module_name: str) -> Iterator[Error]:
 
     try:
         runtime = silent_import_module(module_name)
-    except Exception as e:
+    except KeyboardInterrupt:
+        raise
+    except BaseException as e:
         yield Error([module_name], f"failed to import, {type(e).__name__}: {e}", stub, MISSING)
         return
 
@@ -1500,7 +1502,9 @@ def build_stubs(modules: list[str], options: Options, find_submodules: bool = Fa
                     for m in pkgutil.walk_packages(runtime.__path__, runtime.__name__ + ".")
                     if m.name not in all_modules
                 )
-            except Exception:
+            except KeyboardInterrupt:
+                raise
+            except BaseException:
                 pass
 
     if sources:

From 42dc1c431ed252de41f96d65367623ebac9e1bb8 Mon Sep 17 00:00:00 2001
From: Hugo van Kemenade <hugovk@users.noreply.github.com>
Date: Mon, 12 Dec 2022 11:06:02 +0200
Subject: [PATCH 113/231] Replace unsafe PY_*_VERSION comparisons to fix for
 Python 4.0 (#14280)

`#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 7`

For example, this is true for Python 3.7-3.11 but also true for Python
4.7-4.11. Instead, `PY_VERSION_HEX` should be used.

https://docs.python.org/3.11/c-api/apiabiversion.html

```c
/* Version as a single 4-byte hex number, e.g. 0x010502B2 == 1.5.2b2.
   Use this for numeric comparisons, e.g. #if PY_VERSION_HEX >= ... */
```

https://github.com/python/cpython/blob/2e279e85fece187b6058718ac7e82d1692461e26/Include/patchlevel.h#L29-L30

Remove compatibility code that only applied to EOL and unsupported
Python versions (<= 3.6)
---
 mypy/stubtest.py             |  3 ---
 mypyc/common.py              | 12 ++----------
 mypyc/lib-rt/CPy.h           |  9 ++-------
 mypyc/lib-rt/getargsfast.c   |  5 -----
 mypyc/lib-rt/pythonsupport.h | 29 +++--------------------------
 5 files changed, 7 insertions(+), 51 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 0f8df607858fa..a7a72235fed19 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -1533,9 +1533,6 @@ def get_typeshed_stdlib_modules(
     stdlib_py_versions = mypy.modulefinder.load_stdlib_py_versions(custom_typeshed_dir)
     if version_info is None:
         version_info = sys.version_info[0:2]
-    # Typeshed's minimum supported Python 3 is Python 3.7
-    if sys.version_info < (3, 7):
-        version_info = (3, 7)
 
     def exists_in_version(module: str) -> bool:
         assert version_info is not None
diff --git a/mypyc/common.py b/mypyc/common.py
index 6b0bbcee5fc9c..7412ebef47528 100644
--- a/mypyc/common.py
+++ b/mypyc/common.py
@@ -44,13 +44,6 @@
 
 PLATFORM_SIZE = 4 if IS_32_BIT_PLATFORM else 8
 
-# Python 3.5 on macOS uses a hybrid 32/64-bit build that requires some workarounds.
-# The same generated C will be compiled in both 32 and 64 bit modes when building mypy
-# wheels (for an unknown reason).
-#
-# Note that we use "in ['darwin']" because of https://github.com/mypyc/mypyc/issues/761.
-IS_MIXED_32_64_BIT_BUILD: Final = sys.platform in ["darwin"] and sys.version_info < (3, 6)
-
 # Maximum value for a short tagged integer.
 MAX_SHORT_INT: Final = 2 ** (8 * int(SIZEOF_SIZE_T) - 2) - 1
 
@@ -59,9 +52,8 @@
 
 # Maximum value for a short tagged integer represented as a C integer literal.
 #
-# Note: Assume that the compiled code uses the same bit width as mypyc, except for
-#       Python 3.5 on macOS.
-MAX_LITERAL_SHORT_INT: Final = MAX_SHORT_INT if not IS_MIXED_32_64_BIT_BUILD else 2**30 - 1
+# Note: Assume that the compiled code uses the same bit width as mypyc
+MAX_LITERAL_SHORT_INT: Final = MAX_SHORT_INT
 MIN_LITERAL_SHORT_INT: Final = -MAX_LITERAL_SHORT_INT - 1
 
 # Decription of the C type used to track the definedness of attributes and
diff --git a/mypyc/lib-rt/CPy.h b/mypyc/lib-rt/CPy.h
index 166c851d0155c..7ee914a037dc4 100644
--- a/mypyc/lib-rt/CPy.h
+++ b/mypyc/lib-rt/CPy.h
@@ -499,13 +499,8 @@ static inline bool CPy_KeepPropagating(void) {
 }
 // We want to avoid the public PyErr_GetExcInfo API for these because
 // it requires a bunch of spurious refcount traffic on the parts of
-// the triple we don't care about. Unfortunately the layout of the
-// data structure changed in 3.7 so we need to handle that.
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 7
+// the triple we don't care about.
 #define CPy_ExcState() PyThreadState_GET()->exc_info
-#else
-#define CPy_ExcState() PyThreadState_GET()
-#endif
 
 void CPy_Raise(PyObject *exc);
 void CPy_Reraise(void);
@@ -527,7 +522,7 @@ void CPy_AttributeError(const char *filename, const char *funcname, const char *
 
 // Misc operations
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 8
+#if PY_VERSION_HEX >= 0x03080000
 #define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_BEGIN(op, dealloc)
 #define CPy_TRASHCAN_END(op) Py_TRASHCAN_END
 #else
diff --git a/mypyc/lib-rt/getargsfast.c b/mypyc/lib-rt/getargsfast.c
index afb161e643c76..387deed4399b3 100644
--- a/mypyc/lib-rt/getargsfast.c
+++ b/mypyc/lib-rt/getargsfast.c
@@ -18,9 +18,6 @@
 #include <Python.h>
 #include "CPy.h"
 
-/* None of this is supported on Python 3.6 or earlier */
-#if PY_VERSION_HEX >= 0x03070000
-
 #define PARSER_INITED(parser) ((parser)->kwtuple != NULL)
 
 /* Forward */
@@ -570,5 +567,3 @@ skipitem_fast(const char **p_format, va_list *p_va)
 
     *p_format = format;
 }
-
-#endif
diff --git a/mypyc/lib-rt/pythonsupport.h b/mypyc/lib-rt/pythonsupport.h
index cd66c4cb4df8d..8a1159a988538 100644
--- a/mypyc/lib-rt/pythonsupport.h
+++ b/mypyc/lib-rt/pythonsupport.h
@@ -22,7 +22,6 @@ extern "C" {
 
 /////////////////////////////////////////
 // Adapted from bltinmodule.c in Python 3.7.0
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 7
 _Py_IDENTIFIER(__mro_entries__);
 static PyObject*
 update_bases(PyObject *bases)
@@ -96,16 +95,8 @@ update_bases(PyObject *bases)
     Py_XDECREF(new_bases);
     return NULL;
 }
-#else
-static PyObject*
-update_bases(PyObject *bases)
-{
-    return bases;
-}
-#endif
 
 // From Python 3.7's typeobject.c
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 6
 _Py_IDENTIFIER(__init_subclass__);
 static int
 init_subclass(PyTypeObject *type, PyObject *kwds)
@@ -134,14 +125,6 @@ init_subclass(PyTypeObject *type, PyObject *kwds)
     return 0;
 }
 
-#else
-static int
-init_subclass(PyTypeObject *type, PyObject *kwds)
-{
-    return 0;
-}
-#endif
-
 // Adapted from longobject.c in Python 3.7.0
 
 /* This function adapted from PyLong_AsLongLongAndOverflow, but with
@@ -306,7 +289,7 @@ list_count(PyListObject *self, PyObject *value)
     return CPyTagged_ShortFromSsize_t(count);
 }
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION < 8
+#if PY_VERSION_HEX < 0x03080000
 static PyObject *
 _PyDict_GetItemStringWithError(PyObject *v, const char *key)
 {
@@ -321,13 +304,7 @@ _PyDict_GetItemStringWithError(PyObject *v, const char *key)
 }
 #endif
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION < 6
-/* _PyUnicode_EqualToASCIIString got added in 3.5.3 (argh!) so we can't actually know
- * whether it will be present at runtime, so we just assume we don't have it in 3.5. */
-#define CPyUnicode_EqualToASCIIString(x, y) (PyUnicode_CompareWithASCIIString((x), (y)) == 0)
-#elif PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 6
 #define CPyUnicode_EqualToASCIIString(x, y) _PyUnicode_EqualToASCIIString(x, y)
-#endif
 
 // Adapted from genobject.c in Python 3.7.2
 // Copied because it wasn't in 3.5.2 and it is undocumented anyways.
@@ -390,7 +367,7 @@ _CPyDictView_New(PyObject *dict, PyTypeObject *type)
 }
 #endif
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >=10
+#if PY_VERSION_HEX >= 0x030A0000  // 3.10
 static int
 _CPyObject_HasAttrId(PyObject *v, _Py_Identifier *name) {
     PyObject *tmp = NULL;
@@ -404,7 +381,7 @@ _CPyObject_HasAttrId(PyObject *v, _Py_Identifier *name) {
 #define _CPyObject_HasAttrId _PyObject_HasAttrId
 #endif
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION < 9
+#if PY_VERSION_HEX < 0x03090000
 // OneArgs and NoArgs functions got added in 3.9
 #define _PyObject_CallMethodIdNoArgs(self, name) \
     _PyObject_CallMethodIdObjArgs((self), (name), NULL)

From 7eef68af8b91e4509ddf73eb37c22a1a2197039d Mon Sep 17 00:00:00 2001
From: Harrison McCarty <mccarth@purdue.edu>
Date: Tue, 13 Dec 2022 14:16:52 -0800
Subject: [PATCH 114/231] Added error for class attribute access with slot
 (#14125)

Fixed #13103

Adds a check to class attribute access to ensure it isn't a defined
slot.
---
 mypy/checkmember.py             |  4 ++++
 mypy/message_registry.py        |  1 +
 test-data/unit/check-slots.test | 10 ++++++++++
 3 files changed, 15 insertions(+)

diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index 554b49d3eda21..e3c7c95a64b9c 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -912,6 +912,10 @@ def analyze_class_attribute_access(
         if isinstance(node.node, TypeInfo):
             mx.msg.fail(message_registry.CANNOT_ASSIGN_TO_TYPE, mx.context)
 
+    # Refuse class attribute access if slot defined
+    if info.slots and name in info.slots:
+        mx.msg.fail(message_registry.CLASS_VAR_CONFLICTS_SLOTS.format(name), mx.context)
+
     # If a final attribute was declared on `self` in `__init__`, then it
     # can't be accessed on the class object.
     if node.implicit and isinstance(node.node, Var) and node.node.is_final:
diff --git a/mypy/message_registry.py b/mypy/message_registry.py
index a067763d8d664..7827a2818be9d 100644
--- a/mypy/message_registry.py
+++ b/mypy/message_registry.py
@@ -137,6 +137,7 @@ def with_additional_msg(self, info: str) -> ErrorMessage:
 MODULE_LEVEL_GETATTRIBUTE: Final = ErrorMessage(
     "__getattribute__ is not valid at the module level"
 )
+CLASS_VAR_CONFLICTS_SLOTS: Final = '"{}" in __slots__ conflicts with class variable access'
 NAME_NOT_IN_SLOTS: Final = ErrorMessage(
     'Trying to assign name "{}" that is not in "__slots__" of type "{}"'
 )
diff --git a/test-data/unit/check-slots.test b/test-data/unit/check-slots.test
index 96e4eba3c9669..8beb0d8bf3f74 100644
--- a/test-data/unit/check-slots.test
+++ b/test-data/unit/check-slots.test
@@ -517,3 +517,13 @@ class A:
         self.b = 2
         self.missing = 3
 [builtins fixtures/tuple.pyi]
+
+[case testSlotsWithClassVar]
+from typing import ClassVar
+class X:
+    __slots__ = ('a',)
+    a: int
+x = X()
+X.a  # E: "a" in __slots__ conflicts with class variable access
+x.a
+[builtins fixtures/tuple.pyi]

From d62be28cc85efd759d808b983e1cf55242c2d71a Mon Sep 17 00:00:00 2001
From: KotlinIsland <65446343+KotlinIsland@users.noreply.github.com>
Date: Wed, 14 Dec 2022 19:42:33 +1000
Subject: [PATCH 115/231] Run against 3.12-dev in CI (#14050)

---
 .github/workflows/test.yml | 18 ++++++++++++++++++
 mypyc/test/test_run.py     |  3 +++
 test-requirements.txt      |  2 +-
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9cc2d82ad9113..a02378cc01ab0 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -137,3 +137,21 @@ jobs:
       run: tox -e ${{ matrix.toxenv }} --notest
     - name: Test
       run: tox -e ${{ matrix.toxenv }} --skip-pkg-install -- ${{ matrix.tox_extra_args }}
+
+  python-nightly:
+    runs-on: ubuntu-latest
+    name: Test suite with Python nightly
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.12-dev'
+      - name: Install tox
+        run: pip install --upgrade 'setuptools!=50' tox==3.24.5
+      - name: Setup tox environment
+        run: tox -e py --notest
+      - name: Test
+        run: tox -e py --skip-pkg-install -- "-n 2"
+        continue-on-error: true
+      - name: Mark as a success
+        run: exit 0
diff --git a/mypyc/test/test_run.py b/mypyc/test/test_run.py
index fff775ebfab5f..c867c9d37dac7 100644
--- a/mypyc/test/test_run.py
+++ b/mypyc/test/test_run.py
@@ -312,6 +312,9 @@ def run_case_step(self, testcase: DataDrivenTestCase, incremental_step: int) ->
             stderr=subprocess.STDOUT,
             env=env,
         )
+        if sys.version_info >= (3, 12):
+            # TODO: testDecorators1 hangs on 3.12, remove this once fixed
+            proc.wait(timeout=30)
         output = proc.communicate()[0].decode("utf8")
         outlines = output.splitlines()
 
diff --git a/test-requirements.txt b/test-requirements.txt
index 6f0c1b065ad45..8ae94237f5ea6 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -7,7 +7,7 @@ flake8==5.0.4           # must match version in .pre-commit-config.yaml
 flake8-bugbear==22.9.23 # must match version in .pre-commit-config.yaml
 flake8-noqa==1.2.9      # must match version in .pre-commit-config.yaml
 isort[colors]==5.10.1   # must match version in .pre-commit-config.yaml
-lxml>=4.9.1; python_version<'3.11' or sys_platform!='win32'
+lxml>=4.9.1; (python_version<'3.11' or sys_platform!='win32') and python_version<'3.12'
 psutil>=4.0
 # pytest 6.2.3 does not support Python 3.10
 pytest>=6.2.4

From 369525071a548c03ddea1c428207c8801e73192f Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 14 Dec 2022 17:35:56 -0800
Subject: [PATCH 116/231] Sync typeshed (#14295)

Source commit:

https://github.com/python/typeshed/commit/9bddd3a3f1abfaf6335c2139a77ff1ff69eb4b54
---
 mypy/typeshed/stdlib/_ast.pyi                 |  6 ++--
 mypy/typeshed/stdlib/asyncio/runners.pyi      |  9 +++++-
 mypy/typeshed/stdlib/email/message.pyi        |  7 +++--
 mypy/typeshed/stdlib/http/client.pyi          |  8 +++++-
 .../stdlib/multiprocessing/context.pyi        |  4 +--
 mypy/typeshed/stdlib/multiprocessing/util.pyi |  4 +--
 mypy/typeshed/stdlib/types.pyi                |  2 +-
 mypy/typeshed/stdlib/typing.pyi               |  7 +++--
 mypy/typeshed/stdlib/unittest/case.pyi        |  2 +-
 mypy/typeshed/stdlib/zipfile.pyi              | 28 +++++++++++--------
 10 files changed, 51 insertions(+), 26 deletions(-)

diff --git a/mypy/typeshed/stdlib/_ast.pyi b/mypy/typeshed/stdlib/_ast.pyi
index f723b7eff8bb9..7bc47266d713e 100644
--- a/mypy/typeshed/stdlib/_ast.pyi
+++ b/mypy/typeshed/stdlib/_ast.pyi
@@ -104,14 +104,14 @@ class Assign(stmt):
 class AugAssign(stmt):
     if sys.version_info >= (3, 10):
         __match_args__ = ("target", "op", "value")
-    target: expr
+    target: Name | Attribute | Subscript
     op: operator
     value: expr
 
 class AnnAssign(stmt):
     if sys.version_info >= (3, 10):
         __match_args__ = ("target", "annotation", "value", "simple")
-    target: expr
+    target: Name | Attribute | Subscript
     annotation: expr
     value: expr | None
     simple: int
@@ -355,7 +355,7 @@ if sys.version_info >= (3, 8):
     class NamedExpr(expr):
         if sys.version_info >= (3, 10):
             __match_args__ = ("target", "value")
-        target: expr
+        target: Name
         value: expr
 
 class Attribute(expr):
diff --git a/mypy/typeshed/stdlib/asyncio/runners.pyi b/mypy/typeshed/stdlib/asyncio/runners.pyi
index 49d236bbee9e0..74ed83ed8dc4a 100644
--- a/mypy/typeshed/stdlib/asyncio/runners.pyi
+++ b/mypy/typeshed/stdlib/asyncio/runners.pyi
@@ -3,6 +3,7 @@ from _typeshed import Self
 from collections.abc import Callable, Coroutine
 from contextvars import Context
 from typing import Any, TypeVar
+from typing_extensions import final
 
 from .events import AbstractEventLoop
 
@@ -13,6 +14,7 @@ else:
 _T = TypeVar("_T")
 
 if sys.version_info >= (3, 11):
+    @final
     class Runner:
         def __init__(self, *, debug: bool | None = ..., loop_factory: Callable[[], AbstractEventLoop] | None = ...) -> None: ...
         def __enter__(self: Self) -> Self: ...
@@ -21,7 +23,12 @@ if sys.version_info >= (3, 11):
         def get_loop(self) -> AbstractEventLoop: ...
         def run(self, coro: Coroutine[Any, Any, _T], *, context: Context | None = ...) -> _T: ...
 
-if sys.version_info >= (3, 8):
+if sys.version_info >= (3, 12):
+    def run(
+        main: Coroutine[Any, Any, _T], *, debug: bool | None = ..., loop_factory: Callable[[], AbstractEventLoop] | None = ...
+    ) -> _T: ...
+
+elif sys.version_info >= (3, 8):
     def run(main: Coroutine[Any, Any, _T], *, debug: bool | None = ...) -> _T: ...
 
 else:
diff --git a/mypy/typeshed/stdlib/email/message.pyi b/mypy/typeshed/stdlib/email/message.pyi
index 3c59aeeb2d014..c6b77cdde0544 100644
--- a/mypy/typeshed/stdlib/email/message.pyi
+++ b/mypy/typeshed/stdlib/email/message.pyi
@@ -5,7 +5,7 @@ from email.charset import Charset
 from email.contentmanager import ContentManager
 from email.errors import MessageDefect
 from email.policy import Policy
-from typing import Any, TypeVar
+from typing import Any, TypeVar, overload
 from typing_extensions import TypeAlias
 
 __all__ = ["Message", "EmailMessage"]
@@ -54,7 +54,10 @@ class Message:
     def get_filename(self, failobj: _T = ...) -> _T | str: ...
     def get_boundary(self, failobj: _T = ...) -> _T | str: ...
     def set_boundary(self, boundary: str) -> None: ...
-    def get_content_charset(self, failobj: _T = ...) -> _T | str: ...
+    @overload
+    def get_content_charset(self) -> str | None: ...
+    @overload
+    def get_content_charset(self, failobj: _T) -> str | _T: ...
     def get_charsets(self, failobj: _T = ...) -> _T | list[str]: ...
     def walk(self: Self) -> Generator[Self, None, None]: ...
     def get_content_disposition(self) -> str | None: ...
diff --git a/mypy/typeshed/stdlib/http/client.pyi b/mypy/typeshed/stdlib/http/client.pyi
index ad794ed9b073b..53cefc0a33d1c 100644
--- a/mypy/typeshed/stdlib/http/client.pyi
+++ b/mypy/typeshed/stdlib/http/client.pyi
@@ -154,7 +154,13 @@ class HTTPConnection:
         blocksize: int = ...,
     ) -> None: ...
     def request(
-        self, method: str, url: str, body: _DataType | None = ..., headers: Mapping[str, str] = ..., *, encode_chunked: bool = ...
+        self,
+        method: str,
+        url: str,
+        body: _DataType | str | None = ...,
+        headers: Mapping[str, str] = ...,
+        *,
+        encode_chunked: bool = ...,
     ) -> None: ...
     def getresponse(self) -> HTTPResponse: ...
     def set_debuglevel(self, level: int) -> None: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/context.pyi b/mypy/typeshed/stdlib/multiprocessing/context.pyi
index f6380e2cfcbf0..6622dca19ade3 100644
--- a/mypy/typeshed/stdlib/multiprocessing/context.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/context.pyi
@@ -2,7 +2,7 @@ import ctypes
 import sys
 from collections.abc import Callable, Iterable, Sequence
 from ctypes import _CData
-from logging import Logger
+from logging import Logger, _Level as _LoggingLevel
 from multiprocessing import popen_fork, popen_forkserver, popen_spawn_posix, popen_spawn_win32, queues, synchronize
 from multiprocessing.managers import SyncManager
 from multiprocessing.pool import Pool as _Pool
@@ -107,7 +107,7 @@ class BaseContext:
     ) -> Any: ...
     def freeze_support(self) -> None: ...
     def get_logger(self) -> Logger: ...
-    def log_to_stderr(self, level: str | None = ...) -> Logger: ...
+    def log_to_stderr(self, level: _LoggingLevel | None = ...) -> Logger: ...
     def allow_connection_pickling(self) -> None: ...
     def set_executable(self, executable: str) -> None: ...
     def set_forkserver_preload(self, module_names: list[str]) -> None: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/util.pyi b/mypy/typeshed/stdlib/multiprocessing/util.pyi
index 4b93b7a6a4722..263781da94322 100644
--- a/mypy/typeshed/stdlib/multiprocessing/util.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/util.pyi
@@ -1,7 +1,7 @@
 import threading
 from _typeshed import Incomplete, ReadableBuffer, SupportsTrunc
 from collections.abc import Callable, Iterable, Mapping, MutableMapping, Sequence
-from logging import Logger
+from logging import Logger, _Level as _LoggingLevel
 from typing import Any, SupportsInt
 from typing_extensions import SupportsIndex
 
@@ -37,7 +37,7 @@ def debug(msg: object, *args: object) -> None: ...
 def info(msg: object, *args: object) -> None: ...
 def sub_warning(msg: object, *args: object) -> None: ...
 def get_logger() -> Logger: ...
-def log_to_stderr(level: int | None = ...) -> Logger: ...
+def log_to_stderr(level: _LoggingLevel | None = ...) -> Logger: ...
 def is_abstract_socket_namespace(address: str | bytes | None) -> bool: ...
 
 abstract_sockets_supported: bool
diff --git a/mypy/typeshed/stdlib/types.pyi b/mypy/typeshed/stdlib/types.pyi
index 4047cf84593d3..a40b6280f47c1 100644
--- a/mypy/typeshed/stdlib/types.pyi
+++ b/mypy/typeshed/stdlib/types.pyi
@@ -569,7 +569,7 @@ _P = ParamSpec("_P")
 # it's not really an Awaitable, but can be used in an await expression. Real type: Generator & Awaitable
 # The type: ignore is due to overlapping overloads, not the use of ParamSpec
 @overload
-def coroutine(func: Callable[_P, Generator[_R, Any, Any]]) -> Callable[_P, Awaitable[_R]]: ...  # type: ignore[misc]
+def coroutine(func: Callable[_P, Generator[Any, Any, _R]]) -> Callable[_P, Awaitable[_R]]: ...  # type: ignore[misc]
 @overload
 def coroutine(func: _Fn) -> _Fn: ...
 
diff --git a/mypy/typeshed/stdlib/typing.pyi b/mypy/typeshed/stdlib/typing.pyi
index cc27ae7dbda2a..71018003b6d9b 100644
--- a/mypy/typeshed/stdlib/typing.pyi
+++ b/mypy/typeshed/stdlib/typing.pyi
@@ -325,7 +325,7 @@ class SupportsRound(Protocol[_T_co]):
     def __round__(self, __ndigits: int) -> _T_co: ...
 
 @runtime_checkable
-class Sized(Protocol):
+class Sized(Protocol, metaclass=ABCMeta):
     @abstractmethod
     def __len__(self) -> int: ...
 
@@ -452,7 +452,10 @@ class Container(Protocol[_T_co]):
     def __contains__(self, __x: object) -> bool: ...
 
 @runtime_checkable
-class Collection(Sized, Iterable[_T_co], Container[_T_co], Protocol[_T_co]): ...
+class Collection(Iterable[_T_co], Container[_T_co], Protocol[_T_co]):
+    # Implement Sized (but don't have it as a base class).
+    @abstractmethod
+    def __len__(self) -> int: ...
 
 class Sequence(Collection[_T_co], Reversible[_T_co], Generic[_T_co]):
     @overload
diff --git a/mypy/typeshed/stdlib/unittest/case.pyi b/mypy/typeshed/stdlib/unittest/case.pyi
index c75539a97368c..42633ed13bb86 100644
--- a/mypy/typeshed/stdlib/unittest/case.pyi
+++ b/mypy/typeshed/stdlib/unittest/case.pyi
@@ -104,7 +104,7 @@ class TestCase:
     def tearDownClass(cls) -> None: ...
     def run(self, result: unittest.result.TestResult | None = ...) -> unittest.result.TestResult | None: ...
     def __call__(self, result: unittest.result.TestResult | None = ...) -> unittest.result.TestResult | None: ...
-    def skipTest(self, reason: Any) -> None: ...
+    def skipTest(self, reason: Any) -> NoReturn: ...
     def subTest(self, msg: Any = ..., **params: Any) -> AbstractContextManager[None]: ...
     def debug(self) -> None: ...
     if sys.version_info < (3, 11):
diff --git a/mypy/typeshed/stdlib/zipfile.pyi b/mypy/typeshed/stdlib/zipfile.pyi
index e964cd6eda871..60134c915da70 100644
--- a/mypy/typeshed/stdlib/zipfile.pyi
+++ b/mypy/typeshed/stdlib/zipfile.pyi
@@ -29,6 +29,7 @@ _DateTuple: TypeAlias = tuple[int, int, int, int, int, int]
 _ReadWriteMode: TypeAlias = Literal["r", "w"]
 _ReadWriteBinaryMode: TypeAlias = Literal["r", "w", "rb", "wb"]
 _ZipFileMode: TypeAlias = Literal["r", "w", "x", "a"]
+_CompressionMode: TypeAlias = Literal[0, 8, 12, 14]
 
 class BadZipFile(Exception): ...
 
@@ -100,7 +101,7 @@ class ZipFile:
     fp: IO[bytes] | None
     NameToInfo: dict[str, ZipInfo]
     start_dir: int  # undocumented
-    compression: int  # undocumented
+    compression: _CompressionMode  # undocumented
     compresslevel: int | None  # undocumented
     mode: _ZipFileMode  # undocumented
     pwd: bytes | None  # undocumented
@@ -110,7 +111,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: Literal["r"] = ...,
-            compression: int = ...,
+            compression: _CompressionMode = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
             *,
@@ -122,7 +123,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: _ZipFileMode = ...,
-            compression: int = ...,
+            compression: _CompressionMode = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
             *,
@@ -134,7 +135,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: _ZipFileMode = ...,
-            compression: int = ...,
+            compression: _CompressionMode = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
             *,
@@ -145,7 +146,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: _ZipFileMode = ...,
-            compression: int = ...,
+            compression: _CompressionMode = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
         ) -> None: ...
@@ -184,14 +185,19 @@ class ZipFile:
 
 class PyZipFile(ZipFile):
     def __init__(
-        self, file: str | IO[bytes], mode: _ZipFileMode = ..., compression: int = ..., allowZip64: bool = ..., optimize: int = ...
+        self,
+        file: str | IO[bytes],
+        mode: _ZipFileMode = ...,
+        compression: _CompressionMode = ...,
+        allowZip64: bool = ...,
+        optimize: int = ...,
     ) -> None: ...
     def writepy(self, pathname: str, basename: str = ..., filterfunc: Callable[[str], bool] | None = ...) -> None: ...
 
 class ZipInfo:
     filename: str
     date_time: _DateTuple
-    compress_type: int
+    compress_type: _CompressionMode
     comment: bytes
     extra: bytes
     create_system: int
@@ -269,10 +275,10 @@ if sys.version_info >= (3, 8):
 
 def is_zipfile(filename: StrOrBytesPath | _SupportsReadSeekTell) -> bool: ...
 
-ZIP_STORED: int
-ZIP_DEFLATED: int
+ZIP_STORED: Literal[0]
+ZIP_DEFLATED: Literal[8]
 ZIP64_LIMIT: int
 ZIP_FILECOUNT_LIMIT: int
 ZIP_MAX_COMMENT: int
-ZIP_BZIP2: int
-ZIP_LZMA: int
+ZIP_BZIP2: Literal[12]
+ZIP_LZMA: Literal[14]

From df6e828198205e91e88b2f202e72441c531d5227 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 15 Dec 2022 10:18:08 +0000
Subject: [PATCH 117/231] Constant fold initializers of final variables
 (#14283)

Now mypy can figure out the values of final variables even if the
initializer has some operations on constant values:
```
A: Final = 2  # This has always worked
A: Final = -(1 << 2)  # This is now supported
B: Final = 'x' + 'y'  # This also now works
```
Currently we support integer arithmetic and bitwise operations, and
string concatenation.

This can be useful with literal types, but my main goal was to improve
constant folding in mypyc. In particular, this helps constant folding
with native ints in cases like these:
```
FLAG1: Final = 1 << 4
FLAG2: Final = 1 << 5

def f() -> i64:
    return FLAG1 | FLAG2  # Can now be constant folded
```

We still have another constant folding pass in mypyc, since it does some
things more aggressively (e.g. it constant folds some member expression
references).

Work on mypyc/mypyc#772.

Also helps with mypyc/mypyc#862.
---
 mypy/constant_fold.py                      | 116 ++++++++++
 mypy/semanal.py                            |  73 +++---
 mypy/types.py                              |   5 +-
 mypyc/irbuild/constant_fold.py             |  59 +----
 mypyc/test-data/irbuild-basic.test         |   2 +-
 mypyc/test-data/irbuild-constant-fold.test |  14 +-
 mypyc/test-data/irbuild-i64.test           |  41 ++++
 mypyc/test-data/irbuild-int.test           |  48 ++++
 mypyc/test-data/run-classes.test           |  11 +
 test-data/unit/check-expressions.test      |   2 +-
 test-data/unit/check-inference.test        |   2 +-
 test-data/unit/check-modules.test          |  16 +-
 test-data/unit/errorstream.test            |   4 +-
 test-data/unit/semanal-basic.test          |  50 +++--
 test-data/unit/semanal-classes.test        |  15 +-
 test-data/unit/semanal-expressions.test    |  55 +++--
 test-data/unit/semanal-modules.test        |  60 +++--
 test-data/unit/semanal-python310.test      |  50 +++--
 test-data/unit/semanal-statements.test     | 248 +++++++++++++++++++--
 test-data/unit/semanal-symtable.test       |  12 +-
 20 files changed, 646 insertions(+), 237 deletions(-)
 create mode 100644 mypy/constant_fold.py

diff --git a/mypy/constant_fold.py b/mypy/constant_fold.py
new file mode 100644
index 0000000000000..a22c1b9ba9e58
--- /dev/null
+++ b/mypy/constant_fold.py
@@ -0,0 +1,116 @@
+"""Constant folding of expressions.
+
+For example, 3 + 5 can be constant folded into 8.
+"""
+
+from __future__ import annotations
+
+from typing import Union
+from typing_extensions import Final
+
+from mypy.nodes import Expression, FloatExpr, IntExpr, NameExpr, OpExpr, StrExpr, UnaryExpr, Var
+
+# All possible result types of constant folding
+ConstantValue = Union[int, bool, float, str]
+CONST_TYPES: Final = (int, bool, float, str)
+
+
+def constant_fold_expr(expr: Expression, cur_mod_id: str) -> ConstantValue | None:
+    """Return the constant value of an expression for supported operations.
+
+    Among other things, support int arithmetic and string
+    concatenation. For example, the expression 3 + 5 has the constant
+    value 8.
+
+    Also bind simple references to final constants defined in the
+    current module (cur_mod_id). Binding to references is best effort
+    -- we don't bind references to other modules. Mypyc trusts these
+    to be correct in compiled modules, so that it can replace a
+    constant expression (or a reference to one) with the statically
+    computed value. We don't want to infer constant values based on
+    stubs, in particular, as these might not match the implementation
+    (due to version skew, for example).
+
+    Return None if unsuccessful.
+    """
+    if isinstance(expr, IntExpr):
+        return expr.value
+    if isinstance(expr, StrExpr):
+        return expr.value
+    if isinstance(expr, FloatExpr):
+        return expr.value
+    elif isinstance(expr, NameExpr):
+        if expr.name == "True":
+            return True
+        elif expr.name == "False":
+            return False
+        node = expr.node
+        if (
+            isinstance(node, Var)
+            and node.is_final
+            and node.fullname.rsplit(".", 1)[0] == cur_mod_id
+        ):
+            value = node.final_value
+            if isinstance(value, (CONST_TYPES)):
+                return value
+    elif isinstance(expr, OpExpr):
+        left = constant_fold_expr(expr.left, cur_mod_id)
+        right = constant_fold_expr(expr.right, cur_mod_id)
+        if isinstance(left, int) and isinstance(right, int):
+            return constant_fold_binary_int_op(expr.op, left, right)
+        elif isinstance(left, str) and isinstance(right, str):
+            return constant_fold_binary_str_op(expr.op, left, right)
+    elif isinstance(expr, UnaryExpr):
+        value = constant_fold_expr(expr.expr, cur_mod_id)
+        if isinstance(value, int):
+            return constant_fold_unary_int_op(expr.op, value)
+    return None
+
+
+def constant_fold_binary_int_op(op: str, left: int, right: int) -> int | None:
+    if op == "+":
+        return left + right
+    if op == "-":
+        return left - right
+    elif op == "*":
+        return left * right
+    elif op == "//":
+        if right != 0:
+            return left // right
+    elif op == "%":
+        if right != 0:
+            return left % right
+    elif op == "&":
+        return left & right
+    elif op == "|":
+        return left | right
+    elif op == "^":
+        return left ^ right
+    elif op == "<<":
+        if right >= 0:
+            return left << right
+    elif op == ">>":
+        if right >= 0:
+            return left >> right
+    elif op == "**":
+        if right >= 0:
+            ret = left**right
+            assert isinstance(ret, int)
+            return ret
+    return None
+
+
+def constant_fold_unary_int_op(op: str, value: int) -> int | None:
+    if op == "-":
+        return -value
+    elif op == "~":
+        return ~value
+    elif op == "+":
+        return value
+    return None
+
+
+def constant_fold_binary_str_op(op: str, left: str, right: str) -> str | None:
+    if op == "+":
+        return left + right
+    return None
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 266dc891b6979..fee66ae9b2ccf 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -55,6 +55,7 @@
 from typing_extensions import Final, TypeAlias as _TypeAlias
 
 from mypy import errorcodes as codes, message_registry
+from mypy.constant_fold import constant_fold_expr
 from mypy.errorcodes import ErrorCode
 from mypy.errors import Errors, report_internal_error
 from mypy.exprtotype import TypeTranslationError, expr_to_unanalyzed_type
@@ -91,7 +92,6 @@
     AwaitExpr,
     Block,
     BreakStmt,
-    BytesExpr,
     CallExpr,
     CastExpr,
     ClassDef,
@@ -108,7 +108,6 @@
     Expression,
     ExpressionStmt,
     FakeExpression,
-    FloatExpr,
     ForStmt,
     FuncBase,
     FuncDef,
@@ -121,7 +120,6 @@
     ImportBase,
     ImportFrom,
     IndexExpr,
-    IntExpr,
     LambdaExpr,
     ListComprehension,
     ListExpr,
@@ -250,7 +248,6 @@
     FunctionLike,
     Instance,
     LiteralType,
-    LiteralValue,
     NoneType,
     Overloaded,
     Parameters,
@@ -3138,7 +3135,8 @@ def store_final_status(self, s: AssignmentStmt) -> None:
                 node = s.lvalues[0].node
                 if isinstance(node, Var):
                     node.is_final = True
-                    node.final_value = self.unbox_literal(s.rvalue)
+                    if s.type:
+                        node.final_value = constant_fold_expr(s.rvalue, self.cur_mod_id)
                     if self.is_class_scope() and (
                         isinstance(s.rvalue, TempNode) and s.rvalue.no_rhs
                     ):
@@ -3198,13 +3196,6 @@ def flatten_lvalues(self, lvalues: list[Expression]) -> list[Expression]:
                 res.append(lv)
         return res
 
-    def unbox_literal(self, e: Expression) -> int | float | bool | str | None:
-        if isinstance(e, (IntExpr, FloatExpr, StrExpr)):
-            return e.value
-        elif isinstance(e, NameExpr) and e.name in ("True", "False"):
-            return True if e.name == "True" else False
-        return None
-
     def process_type_annotation(self, s: AssignmentStmt) -> None:
         """Analyze type annotation or infer simple literal type."""
         if s.type:
@@ -3259,39 +3250,33 @@ def is_annotated_protocol_member(self, s: AssignmentStmt) -> bool:
 
     def analyze_simple_literal_type(self, rvalue: Expression, is_final: bool) -> Type | None:
         """Return builtins.int if rvalue is an int literal, etc.
-        If this is a 'Final' context, we return "Literal[...]" instead."""
-        if self.options.semantic_analysis_only or self.function_stack:
-            # Skip this if we're only doing the semantic analysis pass.
-            # This is mostly to avoid breaking unit tests.
-            # Also skip inside a function; this is to avoid confusing
+
+        If this is a 'Final' context, we return "Literal[...]" instead.
+        """
+        if self.function_stack:
+            # Skip inside a function; this is to avoid confusing
             # the code that handles dead code due to isinstance()
             # inside type variables with value restrictions (like
             # AnyStr).
             return None
-        if isinstance(rvalue, FloatExpr):
-            return self.named_type_or_none("builtins.float")
-
-        value: LiteralValue | None = None
-        type_name: str | None = None
-        if isinstance(rvalue, IntExpr):
-            value, type_name = rvalue.value, "builtins.int"
-        if isinstance(rvalue, StrExpr):
-            value, type_name = rvalue.value, "builtins.str"
-        if isinstance(rvalue, BytesExpr):
-            value, type_name = rvalue.value, "builtins.bytes"
-
-        if type_name is not None:
-            assert value is not None
-            typ = self.named_type_or_none(type_name)
-            if typ and is_final:
-                return typ.copy_modified(
-                    last_known_value=LiteralType(
-                        value=value, fallback=typ, line=typ.line, column=typ.column
-                    )
-                )
-            return typ
 
-        return None
+        value = constant_fold_expr(rvalue, self.cur_mod_id)
+        if value is None:
+            return None
+
+        if isinstance(value, bool):
+            type_name = "builtins.bool"
+        elif isinstance(value, int):
+            type_name = "builtins.int"
+        elif isinstance(value, str):
+            type_name = "builtins.str"
+        elif isinstance(value, float):
+            type_name = "builtins.float"
+
+        typ = self.named_type_or_none(type_name)
+        if typ and is_final:
+            return typ.copy_modified(last_known_value=LiteralType(value=value, fallback=typ))
+        return typ
 
     def analyze_alias(
         self, name: str, rvalue: Expression, allow_placeholder: bool = False
@@ -3827,6 +3812,14 @@ def store_declared_types(self, lvalue: Lvalue, typ: Type) -> None:
                 var = lvalue.node
                 var.type = typ
                 var.is_ready = True
+                typ = get_proper_type(typ)
+                if (
+                    var.is_final
+                    and isinstance(typ, Instance)
+                    and typ.last_known_value
+                    and (not self.type or not self.type.is_enum)
+                ):
+                    var.final_value = typ.last_known_value.value
             # If node is not a variable, we'll catch it elsewhere.
         elif isinstance(lvalue, TupleExpr):
             typ = get_proper_type(typ)
diff --git a/mypy/types.py b/mypy/types.py
index b5a4f90d5ec3a..0ba0985436ed4 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -67,7 +67,10 @@
 # Note: Although "Literal[None]" is a valid type, we internally always convert
 # such a type directly into "None". So, "None" is not a valid parameter of
 # LiteralType and is omitted from this list.
-LiteralValue: _TypeAlias = Union[int, str, bool]
+#
+# Note: Float values are only used internally. They are not accepted within
+# Literal[...].
+LiteralValue: _TypeAlias = Union[int, str, bool, float]
 
 
 # If we only import type_visitor in the middle of the file, mypy
diff --git a/mypyc/irbuild/constant_fold.py b/mypyc/irbuild/constant_fold.py
index 8d0a7fea5d90e..4e9eb53b9222f 100644
--- a/mypyc/irbuild/constant_fold.py
+++ b/mypyc/irbuild/constant_fold.py
@@ -1,6 +1,11 @@
 """Constant folding of IR values.
 
 For example, 3 + 5 can be constant folded into 8.
+
+This is mostly like mypy.constant_fold, but we can bind some additional
+NameExpr and MemberExpr references here, since we have more knowledge
+about which definitions can be trusted -- we constant fold only references
+to other compiled modules in the same compilation unit.
 """
 
 from __future__ import annotations
@@ -8,6 +13,11 @@
 from typing import Union
 from typing_extensions import Final
 
+from mypy.constant_fold import (
+    constant_fold_binary_int_op,
+    constant_fold_binary_str_op,
+    constant_fold_unary_int_op,
+)
 from mypy.nodes import Expression, IntExpr, MemberExpr, NameExpr, OpExpr, StrExpr, UnaryExpr, Var
 from mypyc.irbuild.builder import IRBuilder
 
@@ -51,52 +61,3 @@ def constant_fold_expr(builder: IRBuilder, expr: Expression) -> ConstantValue |
         if isinstance(value, int):
             return constant_fold_unary_int_op(expr.op, value)
     return None
-
-
-def constant_fold_binary_int_op(op: str, left: int, right: int) -> int | None:
-    if op == "+":
-        return left + right
-    if op == "-":
-        return left - right
-    elif op == "*":
-        return left * right
-    elif op == "//":
-        if right != 0:
-            return left // right
-    elif op == "%":
-        if right != 0:
-            return left % right
-    elif op == "&":
-        return left & right
-    elif op == "|":
-        return left | right
-    elif op == "^":
-        return left ^ right
-    elif op == "<<":
-        if right >= 0:
-            return left << right
-    elif op == ">>":
-        if right >= 0:
-            return left >> right
-    elif op == "**":
-        if right >= 0:
-            ret = left**right
-            assert isinstance(ret, int)
-            return ret
-    return None
-
-
-def constant_fold_unary_int_op(op: str, value: int) -> int | None:
-    if op == "-":
-        return -value
-    elif op == "~":
-        return ~value
-    elif op == "+":
-        return value
-    return None
-
-
-def constant_fold_binary_str_op(op: str, left: str, right: str) -> str | None:
-    if op == "+":
-        return left + right
-    return None
diff --git a/mypyc/test-data/irbuild-basic.test b/mypyc/test-data/irbuild-basic.test
index 4f5c9487bb1d7..16b085ad4927e 100644
--- a/mypyc/test-data/irbuild-basic.test
+++ b/mypyc/test-data/irbuild-basic.test
@@ -3273,7 +3273,7 @@ L2:
 [case testFinalStaticInt]
 from typing import Final
 
-x: Final = 1 + 1
+x: Final = 1 + int()
 
 def f() -> int:
     return x - 1
diff --git a/mypyc/test-data/irbuild-constant-fold.test b/mypyc/test-data/irbuild-constant-fold.test
index dd75c01443f17..7d9127887aa6b 100644
--- a/mypyc/test-data/irbuild-constant-fold.test
+++ b/mypyc/test-data/irbuild-constant-fold.test
@@ -205,23 +205,13 @@ Y: Final = 2 + 4
 
 def f() -> None:
     a = X + 1
-    # TODO: Constant fold this as well
     a = Y + 1
 [out]
 def f():
-    a, r0 :: int
-    r1 :: bool
-    r2 :: int
+    a :: int
 L0:
     a = 12
-    r0 = __main__.Y :: static
-    if is_error(r0) goto L1 else goto L2
-L1:
-    r1 = raise NameError('value for final name "Y" was not set')
-    unreachable
-L2:
-    r2 = CPyTagged_Add(r0, 2)
-    a = r2
+    a = 14
     return 1
 
 [case testIntConstantFoldingClassFinal]
diff --git a/mypyc/test-data/irbuild-i64.test b/mypyc/test-data/irbuild-i64.test
index ecedab2cd45df..9c942ea752193 100644
--- a/mypyc/test-data/irbuild-i64.test
+++ b/mypyc/test-data/irbuild-i64.test
@@ -1663,3 +1663,44 @@ L1:
     x = 12
 L2:
     return 1
+
+[case testI64FinalConstants]
+from typing_extensions import Final
+from mypy_extensions import i64
+
+A: Final = -1
+B: Final = -(1 + 3*2)
+C: Final = 0
+D: Final = A - B
+E: Final[i64] = 1 + 3
+
+def f1() -> i64:
+    return A
+
+def f2() -> i64:
+    return A + B
+
+def f3() -> i64:
+    return C
+
+def f4() -> i64:
+    return D
+
+def f5() -> i64:
+    return E
+[out]
+def f1():
+L0:
+    return -1
+def f2():
+L0:
+    return -8
+def f3():
+L0:
+    return 0
+def f4():
+L0:
+    return 6
+def f5():
+L0:
+    return 4
diff --git a/mypyc/test-data/irbuild-int.test b/mypyc/test-data/irbuild-int.test
index 8bf43cfa4923d..e193c16ef979d 100644
--- a/mypyc/test-data/irbuild-int.test
+++ b/mypyc/test-data/irbuild-int.test
@@ -155,3 +155,51 @@ def divby8(x):
 L0:
     r0 = CPyTagged_Rshift(x, 6)
     return r0
+
+[case testFinalConstantFolding]
+from typing_extensions import Final
+
+X: Final = -1
+Y: Final = -(1 + 3*2)
+Z: Final = Y + 1
+
+class C:
+    A: Final = 1
+    B: Final = -1
+
+def f1() -> int:
+    return X
+
+def f2() -> int:
+    return X + Y
+
+def f3() -> int:
+    return Z
+
+def f4() -> int:
+    return C.A
+
+def f5() -> int:
+    return C.B
+[out]
+def C.__mypyc_defaults_setup(__mypyc_self__):
+    __mypyc_self__ :: __main__.C
+L0:
+    __mypyc_self__.A = 2
+    __mypyc_self__.B = -2
+    return 1
+def f1():
+L0:
+    return -2
+def f2():
+L0:
+    return -16
+def f3():
+L0:
+    return -12
+def f4():
+L0:
+    return 2
+def f5():
+L0:
+    return -2
diff --git a/mypyc/test-data/run-classes.test b/mypyc/test-data/run-classes.test
index 177bae0cc8956..2af519dc7aa87 100644
--- a/mypyc/test-data/run-classes.test
+++ b/mypyc/test-data/run-classes.test
@@ -2256,3 +2256,14 @@ class Derived(Base):
     pass
 
 assert Derived()() == 1
+
+[case testClassWithFinalAttribute]
+from typing_extensions import Final
+
+class C:
+    A: Final = -1
+    a: Final = [A]
+
+def test_final_attribute() -> None:
+    assert C.A == -1
+    assert C.a == [-1]
diff --git a/test-data/unit/check-expressions.test b/test-data/unit/check-expressions.test
index f7aa43d43f3e8..6b42141b2b155 100644
--- a/test-data/unit/check-expressions.test
+++ b/test-data/unit/check-expressions.test
@@ -1724,7 +1724,7 @@ reveal_type = 1
 [case testRevealForward]
 def f() -> None:
     reveal_type(x)
-x = 1 + 1
+x = 1 + int()
 [out]
 main:2: note: Revealed type is "builtins.int"
 
diff --git a/test-data/unit/check-inference.test b/test-data/unit/check-inference.test
index 6767f1c7995c6..45a833e5210c5 100644
--- a/test-data/unit/check-inference.test
+++ b/test-data/unit/check-inference.test
@@ -1979,7 +1979,7 @@ class A:
 [case testMultipassAndTopLevelVariable]
 y = x # E: Cannot determine type of "x"
 y()
-x = 1+0
+x = 1+int()
 [out]
 
 [case testMultipassAndDecoratedMethod]
diff --git a/test-data/unit/check-modules.test b/test-data/unit/check-modules.test
index b3267f66653d8..26bd0f92ed9ee 100644
--- a/test-data/unit/check-modules.test
+++ b/test-data/unit/check-modules.test
@@ -1348,13 +1348,13 @@ import a
 import b
 def f() -> int:
     return b.x
-y = 0 + 0
+y = 0 + int()
 [file b.py]
 import a
 def g() -> int:
     reveal_type(a.y)
     return a.y
-x = 1 + 1
+x = 1 + int()
 [out]
 tmp/b.py:3: note: Revealed type is "builtins.int"
 
@@ -1365,12 +1365,12 @@ import b
 def f() -> int:
     reveal_type(b.x)
     return b.x
-y = 0 + 0
+y = 0 + int()
 [file b.py]
 import a
 def g() -> int:
     return a.y
-x = 1 + 1
+x = 1 + int()
 [out]
 tmp/a.py:3: note: Revealed type is "builtins.int"
 
@@ -1385,7 +1385,7 @@ class C:
         self.x2 = b.b
 [file b.py]
 import a
-b = 1 + 1
+b = 1 + int()
 [out]
 tmp/a.py:4: error: Cannot determine type of "x2"
 
@@ -1398,7 +1398,7 @@ def f() -> None:
     a + ''
 [file b.py]
 import a
-x = 1 + 1
+x = 1 + int()
 [out]
 tmp/a.py:4: error: Unsupported operand types for + ("int" and "str")
 
@@ -1411,7 +1411,7 @@ def f() -> None:
     a + ''
 [file b.py]
 import a
-x = 1 + 1
+x = 1 + int()
 [out]
 tmp/a.py:4: error: Unsupported operand types for + ("int" and "str")
 
@@ -1424,7 +1424,7 @@ def g() -> None:
 @b.deco
 def f(a: str) -> int: pass
 reveal_type(f)
-x = 1 + 1
+x = 1 + int()
 [file b.py]
 from typing import Callable, TypeVar
 import a
diff --git a/test-data/unit/errorstream.test b/test-data/unit/errorstream.test
index 8a73748d27ff8..46af433f8916e 100644
--- a/test-data/unit/errorstream.test
+++ b/test-data/unit/errorstream.test
@@ -36,14 +36,14 @@ import b
 def f() -> int:
     reveal_type(b.x)
     return b.x
-y = 0 + 0
+y = 0 + int()
 [file b.py]
 import a
 def g() -> int:
     reveal_type(a.y)
     return a.y
 1 / ''
-x = 1 + 1
+x = 1 + int()
 
 [out]
 ==== Errors flushed ====
diff --git a/test-data/unit/semanal-basic.test b/test-data/unit/semanal-basic.test
index 4b60ab99f8698..870c686807c30 100644
--- a/test-data/unit/semanal-basic.test
+++ b/test-data/unit/semanal-basic.test
@@ -8,8 +8,9 @@ x
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   ExpressionStmt:2(
     NameExpr(x [__main__.x])))
 
@@ -25,8 +26,9 @@ MypyFile:1(
       NameExpr(y* [__main__.y]))
     IntExpr(2))
   AssignmentStmt:2(
-    NameExpr(z* [__main__.z])
-    IntExpr(3))
+    NameExpr(z [__main__.z])
+    IntExpr(3)
+    builtins.int)
   ExpressionStmt:3(
     TupleExpr:3(
       NameExpr(x [__main__.x])
@@ -61,8 +63,9 @@ MypyFile:1(
       NameExpr(f [__main__.f])
       Args()))
   AssignmentStmt:3(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   FuncDef:4(
     f
     Block:4(
@@ -117,8 +120,9 @@ MypyFile:1(
           NameExpr(g [__main__.g])
           Args()))))
   AssignmentStmt:4(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   FuncDef:5(
     g
     Block:5(
@@ -134,8 +138,9 @@ def f(y):
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   AssignmentStmt:2(
     NameExpr(x [__main__.x])
     IntExpr(2))
@@ -163,8 +168,9 @@ x
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   FuncDef:2(
     f
     Block:2(
@@ -498,17 +504,21 @@ MypyFile:1(
       ExpressionStmt:3(
         Ellipsis)))
   AssignmentStmt:4(
-    NameExpr(x* [__main__.x] = 1)
-    IntExpr(1))
+    NameExpr(x [__main__.x] = 1)
+    IntExpr(1)
+    Literal[1]?)
   AssignmentStmt:5(
-    NameExpr(y* [__main__.y] = 1.0)
-    FloatExpr(1.0))
+    NameExpr(y [__main__.y] = 1.0)
+    FloatExpr(1.0)
+    Literal[1.0]?)
   AssignmentStmt:6(
-    NameExpr(s* [__main__.s] = hi)
-    StrExpr(hi))
+    NameExpr(s [__main__.s] = hi)
+    StrExpr(hi)
+    Literal['hi']?)
   AssignmentStmt:7(
-    NameExpr(t* [__main__.t] = True)
-    NameExpr(True [builtins.True]))
+    NameExpr(t [__main__.t] = True)
+    NameExpr(True [builtins.True])
+    Literal[True]?)
   AssignmentStmt:8(
     NameExpr(n* [__main__.n] = None)
     CallExpr:8(
diff --git a/test-data/unit/semanal-classes.test b/test-data/unit/semanal-classes.test
index 082a3fe690502..86f8b8656fb61 100644
--- a/test-data/unit/semanal-classes.test
+++ b/test-data/unit/semanal-classes.test
@@ -248,8 +248,9 @@ MypyFile:1(
   ClassDef:1(
     A
     AssignmentStmt:2(
-      NameExpr(x* [m])
-      IntExpr(1))
+      NameExpr(x [m])
+      IntExpr(1)
+      builtins.int)
     AssignmentStmt:3(
       NameExpr(y* [m])
       NameExpr(x [__main__.A.x]))))
@@ -287,8 +288,9 @@ MypyFile:1(
         NameExpr(A [__main__.A]))
       Then(
         AssignmentStmt:3(
-          NameExpr(x* [m])
-          IntExpr(1)))
+          NameExpr(x [m])
+          IntExpr(1)
+          builtins.int))
       Else(
         AssignmentStmt:5(
           NameExpr(x [__main__.A.x])
@@ -541,8 +543,9 @@ MypyFile:1(
   ClassDef:2(
     A
     AssignmentStmt:3(
-      NameExpr(X* [m])
-      IntExpr(1))
+      NameExpr(X [m])
+      IntExpr(1)
+      builtins.int)
     FuncDef:4(
       f
       Args(
diff --git a/test-data/unit/semanal-expressions.test b/test-data/unit/semanal-expressions.test
index 98bf32708f1b8..fa07e533a842a 100644
--- a/test-data/unit/semanal-expressions.test
+++ b/test-data/unit/semanal-expressions.test
@@ -15,8 +15,9 @@ x.y
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   ExpressionStmt:2(
     MemberExpr:2(
       NameExpr(x [__main__.x])
@@ -80,8 +81,9 @@ not x
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   ExpressionStmt:2(
     UnaryExpr:2(
       -
@@ -187,8 +189,9 @@ a = 0
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:2(
     ListComprehension:2(
       GeneratorExpr:2(
@@ -223,8 +226,9 @@ b = [x for x in a if x]
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   AssignmentStmt:2(
     NameExpr(b* [__main__.b])
     ListComprehension:2(
@@ -240,8 +244,9 @@ a = 0
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:2(
     SetComprehension:2(
       GeneratorExpr:2(
@@ -258,8 +263,9 @@ b = {x for x in a if x}
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   AssignmentStmt:2(
     NameExpr(b* [__main__.b])
     SetComprehension:2(
@@ -275,8 +281,9 @@ a = 0
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:2(
     DictionaryComprehension:2(
       NameExpr(x [l])
@@ -293,8 +300,9 @@ b = {x: x + 1 for x in a if x}
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   AssignmentStmt:2(
     NameExpr(b* [__main__.b])
     DictionaryComprehension:2(
@@ -313,8 +321,9 @@ a = 0
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:2(
     GeneratorExpr:2(
       NameExpr(x [l])
@@ -327,8 +336,9 @@ a = 0
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(a* [__main__.a])
-    IntExpr(0))
+    NameExpr(a [__main__.a])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:2(
     GeneratorExpr:2(
       NameExpr(x [l])
@@ -345,8 +355,9 @@ lambda: x
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(0))
+    NameExpr(x [__main__.x])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:2(
     LambdaExpr:2(
       Block:2(
diff --git a/test-data/unit/semanal-modules.test b/test-data/unit/semanal-modules.test
index 16b9a9b182502..8ffd7d2488dca 100644
--- a/test-data/unit/semanal-modules.test
+++ b/test-data/unit/semanal-modules.test
@@ -16,8 +16,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/x.py
   AssignmentStmt:1(
-    NameExpr(y* [x.y])
-    IntExpr(1)))
+    NameExpr(y [x.y])
+    IntExpr(1)
+    builtins.int))
 
 [case testImportedNameInType]
 import m
@@ -51,8 +52,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/m.py
   AssignmentStmt:1(
-    NameExpr(y* [m.y])
-    IntExpr(1)))
+    NameExpr(y [m.y])
+    IntExpr(1)
+    builtins.int))
 
 [case testImportFromType]
 from m import c
@@ -342,8 +344,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/m/n.py
   AssignmentStmt:1(
-    NameExpr(x* [m.n.x])
-    IntExpr(1)))
+    NameExpr(x [m.n.x])
+    IntExpr(1)
+    builtins.int))
 
 [case testImportFromSubmodule]
 from m._n import x
@@ -448,8 +451,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/m/n/k.py
   AssignmentStmt:1(
-    NameExpr(x* [m.n.k.x])
-    IntExpr(1)))
+    NameExpr(x [m.n.k.x])
+    IntExpr(1)
+    builtins.int))
 
 [case testImportInSubmodule]
 import m._n
@@ -609,8 +613,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/x.py
   AssignmentStmt:1(
-    NameExpr(y* [x.y])
-    IntExpr(1)))
+    NameExpr(y [x.y])
+    IntExpr(1)
+    builtins.int))
 
 [case testRelativeImport0]
 import m.x
@@ -637,8 +642,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/m/z.py
   AssignmentStmt:1(
-    NameExpr(y* [m.z.y])
-    IntExpr(1)))
+    NameExpr(y [m.z.y])
+    IntExpr(1)
+    builtins.int))
 
 [case testRelativeImport1]
 import m.t.b as b
@@ -673,13 +679,15 @@ MypyFile:1(
 MypyFile:1(
   tmp/m/x.py
   AssignmentStmt:1(
-    NameExpr(y* [m.x.y])
-    IntExpr(1)))
+    NameExpr(y [m.x.y])
+    IntExpr(1)
+    builtins.int))
 MypyFile:1(
   tmp/m/z.py
   AssignmentStmt:1(
-    NameExpr(y* [m.z.y])
-    IntExpr(3)))
+    NameExpr(y [m.z.y])
+    IntExpr(3)
+    builtins.int))
 
 [case testRelativeImport2]
 import m.t.b as b
@@ -712,13 +720,15 @@ MypyFile:1(
 MypyFile:1(
   tmp/m/x.py
   AssignmentStmt:1(
-    NameExpr(y* [m.x.y])
-    IntExpr(1)))
+    NameExpr(y [m.x.y])
+    IntExpr(1)
+    builtins.int))
 MypyFile:1(
   tmp/m/z.py
   AssignmentStmt:1(
-    NameExpr(y* [m.z.y])
-    IntExpr(3)))
+    NameExpr(y [m.z.y])
+    IntExpr(3)
+    builtins.int))
 
 [case testRelativeImport3]
 import m.t
@@ -762,8 +772,9 @@ MypyFile:1(
 MypyFile:1(
   tmp/m/z.py
   AssignmentStmt:1(
-    NameExpr(zy* [m.z.zy])
-    IntExpr(3)))
+    NameExpr(zy [m.z.zy])
+    IntExpr(3)
+    builtins.int))
 
 [case testRelativeImportFromSameModule]
 import m.x
@@ -914,5 +925,6 @@ MypyFile:1(
 MypyFile:1(
   tmp/x.py
   AssignmentStmt:1(
-    NameExpr(a* [x.a])
-    IntExpr(1)))
+    NameExpr(a [x.a])
+    IntExpr(1)
+    builtins.int))
diff --git a/test-data/unit/semanal-python310.test b/test-data/unit/semanal-python310.test
index a009636575dcd..9418ac2912b2f 100644
--- a/test-data/unit/semanal-python310.test
+++ b/test-data/unit/semanal-python310.test
@@ -8,8 +8,9 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -28,8 +29,9 @@ a
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -49,8 +51,9 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -78,8 +81,9 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -99,8 +103,9 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -121,11 +126,13 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   AssignmentStmt:2(
-    NameExpr(a* [__main__.a])
-    IntExpr(1))
+    NameExpr(a [__main__.a])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:3(
     NameExpr(x [__main__.x])
     Pattern(
@@ -144,8 +151,9 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -164,8 +172,9 @@ match x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:2(
     NameExpr(x [__main__.x])
     Pattern(
@@ -191,8 +200,9 @@ b = 1
 MypyFile:1(
   Import:1(_a)
   AssignmentStmt:3(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   MatchStmt:4(
     NameExpr(x [__main__.x])
     Pattern(
diff --git a/test-data/unit/semanal-statements.test b/test-data/unit/semanal-statements.test
index fdc5ca2bbbdd9..27ff101c04d01 100644
--- a/test-data/unit/semanal-statements.test
+++ b/test-data/unit/semanal-statements.test
@@ -272,8 +272,9 @@ else:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   IfStmt:2(
     If(
       NameExpr(x [__main__.x]))
@@ -326,8 +327,9 @@ MypyFile:1(
       NameExpr(y* [__main__.y]))
     IntExpr(1))
   AssignmentStmt:2(
-    NameExpr(xx* [__main__.xx])
-    IntExpr(1))
+    NameExpr(xx [__main__.xx])
+    IntExpr(1)
+    builtins.int)
   AssignmentStmt:3(
     MemberExpr:3(
       NameExpr(x [__main__.x])
@@ -408,8 +410,9 @@ MypyFile:1(
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   AssignmentStmt:2(
     TupleExpr:2(
       NameExpr(y* [__main__.y]))
@@ -436,8 +439,9 @@ y, x = 1
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   AssignmentStmt:2(
     TupleExpr:2(
       NameExpr(y* [__main__.y])
@@ -450,8 +454,9 @@ y, (x, z) = 1
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   AssignmentStmt:2(
     TupleExpr:2(
       NameExpr(y* [__main__.y])
@@ -468,8 +473,9 @@ if x:
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   IfStmt:2(
     If(
       NameExpr(x [__main__.x]))
@@ -510,8 +516,9 @@ del x
 [out]
 MypyFile:1(
   AssignmentStmt:1(
-    NameExpr(x* [__main__.x])
-    IntExpr(1))
+    NameExpr(x [__main__.x])
+    IntExpr(1)
+    builtins.int)
   DelStmt:2(
     NameExpr(x [__main__.x])))
 
@@ -961,16 +968,18 @@ MypyFile:1(
     Block:2(
       PassStmt:2()))
   AssignmentStmt:3(
-    NameExpr(x'* [__main__.x'])
-    IntExpr(0))
+    NameExpr(x' [__main__.x'])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:4(
     CallExpr:4(
       NameExpr(f [__main__.f])
       Args(
         NameExpr(x' [__main__.x']))))
   AssignmentStmt:5(
-    NameExpr(x* [__main__.x])
-    StrExpr())
+    NameExpr(x [__main__.x])
+    StrExpr()
+    builtins.str)
   ExpressionStmt:6(
     CallExpr:6(
       NameExpr(f [__main__.f])
@@ -993,8 +1002,9 @@ MypyFile:1(
     Block:2(
       PassStmt:2()))
   AssignmentStmt:3(
-    NameExpr(x* [__main__.x])
-    IntExpr(0))
+    NameExpr(x [__main__.x])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:4(
     CallExpr:4(
       NameExpr(f [__main__.f])
@@ -1046,15 +1056,17 @@ x = ''
 [out]
 MypyFile:1(
   AssignmentStmt:2(
-    NameExpr(x* [__main__.x])
-    IntExpr(0))
+    NameExpr(x [__main__.x])
+    IntExpr(0)
+    builtins.int)
   ExpressionStmt:3(
     NameExpr(x [__main__.x]))
   ClassDef:4(
     A
     AssignmentStmt:5(
-      NameExpr(x* [m])
-      IntExpr(1)))
+      NameExpr(x [m])
+      IntExpr(1)
+      builtins.int))
   AssignmentStmt:6(
     NameExpr(x [__main__.x])
     StrExpr()))
@@ -1114,3 +1126,191 @@ MypyFile:1(
       AssignmentStmt:5(
         NameExpr(y [__main__.y])
         IntExpr(1)))))
+
+[case testConstantFold1]
+from typing_extensions import Final
+add: Final = 15 + 47
+add_mul: Final = (2 + 3) * 5
+sub: Final = 7 - 11
+bit_and: Final = 6 & 10
+bit_or: Final = 6 | 10
+bit_xor: Final = 6 ^ 10
+lshift: Final = 5 << 2
+rshift: Final = 13 >> 2
+lshift0: Final = 5 << 0
+rshift0: Final = 13 >> 0
+[out]
+MypyFile:1(
+  ImportFrom:1(typing_extensions, [Final])
+  AssignmentStmt:2(
+    NameExpr(add [__main__.add] = 62)
+    OpExpr:2(
+      +
+      IntExpr(15)
+      IntExpr(47))
+    Literal[62]?)
+  AssignmentStmt:3(
+    NameExpr(add_mul [__main__.add_mul] = 25)
+    OpExpr:3(
+      *
+      OpExpr:3(
+        +
+        IntExpr(2)
+        IntExpr(3))
+      IntExpr(5))
+    Literal[25]?)
+  AssignmentStmt:4(
+    NameExpr(sub [__main__.sub] = -4)
+    OpExpr:4(
+      -
+      IntExpr(7)
+      IntExpr(11))
+    Literal[-4]?)
+  AssignmentStmt:5(
+    NameExpr(bit_and [__main__.bit_and] = 2)
+    OpExpr:5(
+      &
+      IntExpr(6)
+      IntExpr(10))
+    Literal[2]?)
+  AssignmentStmt:6(
+    NameExpr(bit_or [__main__.bit_or] = 14)
+    OpExpr:6(
+      |
+      IntExpr(6)
+      IntExpr(10))
+    Literal[14]?)
+  AssignmentStmt:7(
+    NameExpr(bit_xor [__main__.bit_xor] = 12)
+    OpExpr:7(
+      ^
+      IntExpr(6)
+      IntExpr(10))
+    Literal[12]?)
+  AssignmentStmt:8(
+    NameExpr(lshift [__main__.lshift] = 20)
+    OpExpr:8(
+      <<
+      IntExpr(5)
+      IntExpr(2))
+    Literal[20]?)
+  AssignmentStmt:9(
+    NameExpr(rshift [__main__.rshift] = 3)
+    OpExpr:9(
+      >>
+      IntExpr(13)
+      IntExpr(2))
+    Literal[3]?)
+  AssignmentStmt:10(
+    NameExpr(lshift0 [__main__.lshift0] = 5)
+    OpExpr:10(
+      <<
+      IntExpr(5)
+      IntExpr(0))
+    Literal[5]?)
+  AssignmentStmt:11(
+    NameExpr(rshift0 [__main__.rshift0] = 13)
+    OpExpr:11(
+      >>
+      IntExpr(13)
+      IntExpr(0))
+    Literal[13]?))
+
+[case testConstantFold2]
+from typing_extensions import Final
+neg1: Final = -5
+neg2: Final = --1
+neg3: Final = -0
+pos: Final = +5
+inverted1: Final = ~0
+inverted2: Final = ~5
+inverted3: Final = ~3
+p0: Final = 3**0
+p1: Final = 3**5
+p2: Final = (-5)**3
+p3: Final = 0**0
+s: Final = 'x' + 'y'
+[out]
+MypyFile:1(
+  ImportFrom:1(typing_extensions, [Final])
+  AssignmentStmt:2(
+    NameExpr(neg1 [__main__.neg1] = -5)
+    UnaryExpr:2(
+      -
+      IntExpr(5))
+    Literal[-5]?)
+  AssignmentStmt:3(
+    NameExpr(neg2 [__main__.neg2] = 1)
+    UnaryExpr:3(
+      -
+      UnaryExpr:3(
+        -
+        IntExpr(1)))
+    Literal[1]?)
+  AssignmentStmt:4(
+    NameExpr(neg3 [__main__.neg3] = 0)
+    UnaryExpr:4(
+      -
+      IntExpr(0))
+    Literal[0]?)
+  AssignmentStmt:5(
+    NameExpr(pos [__main__.pos] = 5)
+    UnaryExpr:5(
+      +
+      IntExpr(5))
+    Literal[5]?)
+  AssignmentStmt:6(
+    NameExpr(inverted1 [__main__.inverted1] = -1)
+    UnaryExpr:6(
+      ~
+      IntExpr(0))
+    Literal[-1]?)
+  AssignmentStmt:7(
+    NameExpr(inverted2 [__main__.inverted2] = -6)
+    UnaryExpr:7(
+      ~
+      IntExpr(5))
+    Literal[-6]?)
+  AssignmentStmt:8(
+    NameExpr(inverted3 [__main__.inverted3] = -4)
+    UnaryExpr:8(
+      ~
+      IntExpr(3))
+    Literal[-4]?)
+  AssignmentStmt:9(
+    NameExpr(p0 [__main__.p0] = 1)
+    OpExpr:9(
+      **
+      IntExpr(3)
+      IntExpr(0))
+    Literal[1]?)
+  AssignmentStmt:10(
+    NameExpr(p1 [__main__.p1] = 243)
+    OpExpr:10(
+      **
+      IntExpr(3)
+      IntExpr(5))
+    Literal[243]?)
+  AssignmentStmt:11(
+    NameExpr(p2 [__main__.p2] = -125)
+    OpExpr:11(
+      **
+      UnaryExpr:11(
+        -
+        IntExpr(5))
+      IntExpr(3))
+    Literal[-125]?)
+  AssignmentStmt:12(
+    NameExpr(p3 [__main__.p3] = 1)
+    OpExpr:12(
+      **
+      IntExpr(0)
+      IntExpr(0))
+    Literal[1]?)
+  AssignmentStmt:13(
+    NameExpr(s [__main__.s] = xy)
+    OpExpr:13(
+      +
+      StrExpr(x)
+      StrExpr(y))
+    Literal['xy']?))
diff --git a/test-data/unit/semanal-symtable.test b/test-data/unit/semanal-symtable.test
index bdf4f52ae5fc6..c886080557b06 100644
--- a/test-data/unit/semanal-symtable.test
+++ b/test-data/unit/semanal-symtable.test
@@ -9,7 +9,7 @@ x = 1
 [out]
 __main__:
   SymbolTable(
-    x : Gdef/Var (__main__.x))
+    x : Gdef/Var (__main__.x) : builtins.int)
 
 [case testFuncDef]
 def f(): pass
@@ -35,7 +35,7 @@ __main__:
     m : Gdef/MypyFile (m))
 m:
   SymbolTable(
-    x : Gdef/Var (m.x))
+    x : Gdef/Var (m.x) : builtins.int)
 
 [case testImportFromModule]
 from m import x
@@ -49,7 +49,7 @@ __main__:
 m:
   SymbolTable(
     x : Gdef/TypeInfo (m.x)
-    y : Gdef/Var (m.y))
+    y : Gdef/Var (m.y) : builtins.int)
 
 [case testImportAs]
 from m import x as xx
@@ -63,7 +63,7 @@ __main__:
 m:
   SymbolTable(
     x : Gdef/TypeInfo (m.x)
-    y : Gdef/Var (m.y))
+    y : Gdef/Var (m.y) : builtins.int)
 
 [case testFailingImports]
 from sys import non_existing1  # type: ignore
@@ -80,7 +80,7 @@ __main__:
     non_existing4 : Gdef/Var (__main__.non_existing4) : Any)
 sys:
   SymbolTable(
-    platform : Gdef/Var (sys.platform)
+    platform : Gdef/Var (sys.platform) : builtins.str
     version_info : Gdef/Var (sys.version_info))
 
 [case testDecorator]
@@ -95,6 +95,6 @@ def g() -> None:
 [out]
 __main__:
   SymbolTable(
-    Callable : Gdef/Var (typing.Callable)
+    Callable : Gdef/Var (typing.Callable) : builtins.int
     dec : Gdef/FuncDef (__main__.dec) : def (f: def ()) -> def ()
     g : Gdef/Decorator (__main__.g) : def ())

From 96ac8b3e71c743b02ea4e3c84da0248659e40f82 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Fri, 16 Dec 2022 15:43:58 -0800
Subject: [PATCH 118/231] [partially defined] implement support for try
 statements (#14114)

This adds support for try/except/finally/else check.

The implementation ended up pretty complicated because it had to handle
jumps different for finally. It took me a few iterations to get to this
solution and that's the cleanest one I could come up with.

Closes #13928.
---
 mypy/partially_defined.py                    | 113 +++++++++++-
 test-data/unit/check-possibly-undefined.test | 184 +++++++++++++++++++
 2 files changed, 295 insertions(+), 2 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 5f5253515b618..9b3e105f64ef3 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -31,6 +31,7 @@
     RefExpr,
     ReturnStmt,
     StarExpr,
+    TryStmt,
     TupleExpr,
     WhileStmt,
     WithStmt,
@@ -66,6 +67,13 @@ def __init__(
         self.must_be_defined = set(must_be_defined)
         self.skipped = skipped
 
+    def copy(self) -> BranchState:
+        return BranchState(
+            must_be_defined=set(self.must_be_defined),
+            may_be_defined=set(self.may_be_defined),
+            skipped=self.skipped,
+        )
+
 
 class BranchStatement:
     def __init__(self, initial_state: BranchState) -> None:
@@ -77,6 +85,11 @@ def __init__(self, initial_state: BranchState) -> None:
             )
         ]
 
+    def copy(self) -> BranchStatement:
+        result = BranchStatement(self.initial_state)
+        result.branches = [b.copy() for b in self.branches]
+        return result
+
     def next_branch(self) -> None:
         self.branches.append(
             BranchState(
@@ -90,6 +103,11 @@ def record_definition(self, name: str) -> None:
         self.branches[-1].must_be_defined.add(name)
         self.branches[-1].may_be_defined.discard(name)
 
+    def delete_var(self, name: str) -> None:
+        assert len(self.branches) > 0
+        self.branches[-1].must_be_defined.discard(name)
+        self.branches[-1].may_be_defined.discard(name)
+
     def record_nested_branch(self, state: BranchState) -> None:
         assert len(self.branches) > 0
         current_branch = self.branches[-1]
@@ -151,6 +169,11 @@ def __init__(self, stmts: list[BranchStatement]) -> None:
         self.branch_stmts: list[BranchStatement] = stmts
         self.undefined_refs: dict[str, set[NameExpr]] = {}
 
+    def copy(self) -> Scope:
+        result = Scope([s.copy() for s in self.branch_stmts])
+        result.undefined_refs = self.undefined_refs.copy()
+        return result
+
     def record_undefined_ref(self, o: NameExpr) -> None:
         if o.name not in self.undefined_refs:
             self.undefined_refs[o.name] = set()
@@ -166,6 +189,15 @@ class DefinedVariableTracker:
     def __init__(self) -> None:
         # There's always at least one scope. Within each scope, there's at least one "global" BranchingStatement.
         self.scopes: list[Scope] = [Scope([BranchStatement(BranchState())])]
+        # disable_branch_skip is used to disable skipping a branch due to a return/raise/etc. This is useful
+        # in things like try/except/finally statements.
+        self.disable_branch_skip = False
+
+    def copy(self) -> DefinedVariableTracker:
+        result = DefinedVariableTracker()
+        result.scopes = [s.copy() for s in self.scopes]
+        result.disable_branch_skip = self.disable_branch_skip
+        return result
 
     def _scope(self) -> Scope:
         assert len(self.scopes) > 0
@@ -195,7 +227,7 @@ def end_branch_statement(self) -> None:
 
     def skip_branch(self) -> None:
         # Only skip branch if we're outside of "root" branch statement.
-        if len(self._scope().branch_stmts) > 1:
+        if len(self._scope().branch_stmts) > 1 and not self.disable_branch_skip:
             self._scope().branch_stmts[-1].skip_branch()
 
     def record_definition(self, name: str) -> None:
@@ -203,6 +235,11 @@ def record_definition(self, name: str) -> None:
         assert len(self.scopes[-1].branch_stmts) > 0
         self._scope().branch_stmts[-1].record_definition(name)
 
+    def delete_var(self, name: str) -> None:
+        assert len(self.scopes) > 0
+        assert len(self.scopes[-1].branch_stmts) > 0
+        self._scope().branch_stmts[-1].delete_var(name)
+
     def record_undefined_ref(self, o: NameExpr) -> None:
         """Records an undefined reference. These can later be retrieved via `pop_undefined_ref`."""
         assert len(self.scopes) > 0
@@ -268,6 +305,7 @@ def __init__(
         self.type_map = type_map
         self.options = options
         self.loops: list[Loop] = []
+        self.try_depth = 0
         self.tracker = DefinedVariableTracker()
         for name in implicit_module_attrs:
             self.tracker.record_definition(name)
@@ -432,6 +470,75 @@ def visit_expression_stmt(self, o: ExpressionStmt) -> None:
             self.tracker.skip_branch()
         super().visit_expression_stmt(o)
 
+    def visit_try_stmt(self, o: TryStmt) -> None:
+        """
+        Note that finding undefined vars in `finally` requires different handling from
+        the rest of the code. In particular, we want to disallow skipping branches due to jump
+        statements in except/else clauses for finally but not for other cases. Imagine a case like:
+        def f() -> int:
+            try:
+                x = 1
+            except:
+                # This jump statement needs to be handled differently depending on whether or
+                # not we're trying to process `finally` or not.
+                return 0
+            finally:
+                # `x` may be undefined here.
+                pass
+            # `x` is always defined here.
+            return x
+        """
+        self.try_depth += 1
+        if o.finally_body is not None:
+            # In order to find undefined vars in `finally`, we need to
+            # process try/except with branch skipping disabled. However, for the rest of the code
+            # after finally, we need to process try/except with branch skipping enabled.
+            # Therefore, we need to process try/finally twice.
+            # Because processing is not idempotent, we should make a copy of the tracker.
+            old_tracker = self.tracker.copy()
+            self.tracker.disable_branch_skip = True
+            self.process_try_stmt(o)
+            self.tracker = old_tracker
+        self.process_try_stmt(o)
+        self.try_depth -= 1
+
+    def process_try_stmt(self, o: TryStmt) -> None:
+        """
+        Processes try statement decomposing it into the following:
+        if ...:
+            body
+            else_body
+        elif ...:
+            except 1
+        elif ...:
+            except 2
+        else:
+            except n
+        finally
+        """
+        self.tracker.start_branch_statement()
+        o.body.accept(self)
+        if o.else_body is not None:
+            o.else_body.accept(self)
+        if len(o.handlers) > 0:
+            assert len(o.handlers) == len(o.vars) == len(o.types)
+            for i in range(len(o.handlers)):
+                self.tracker.next_branch()
+                exc_type = o.types[i]
+                if exc_type is not None:
+                    exc_type.accept(self)
+                var = o.vars[i]
+                if var is not None:
+                    self.process_definition(var.name)
+                    var.accept(self)
+                o.handlers[i].accept(self)
+                if var is not None:
+                    self.tracker.delete_var(var.name)
+        self.tracker.end_branch_statement()
+
+        if o.finally_body is not None:
+            o.finally_body.accept(self)
+
     def visit_while_stmt(self, o: WhileStmt) -> None:
         o.expr.accept(self)
         self.tracker.start_branch_statement()
@@ -478,7 +585,9 @@ def visit_name_expr(self, o: NameExpr) -> None:
             self.tracker.record_definition(o.name)
         elif self.tracker.is_defined_in_different_branch(o.name):
             # A variable is defined in one branch but used in a different branch.
-            if self.loops:
+            if self.loops or self.try_depth > 0:
+                # If we're in a loop or in a try, we can't be sure that this variable
+                # is undefined. Report it as "may be undefined".
                 self.variable_may_be_undefined(o.name, o)
             else:
                 self.var_used_before_def(o.name, o)
diff --git a/test-data/unit/check-possibly-undefined.test b/test-data/unit/check-possibly-undefined.test
index d99943572a384..ee7020252de83 100644
--- a/test-data/unit/check-possibly-undefined.test
+++ b/test-data/unit/check-possibly-undefined.test
@@ -525,6 +525,190 @@ def f3() -> None:
         y = x
     z = x  # E: Name "x" may be undefined
 
+[case testTryBasic]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
+def f1() -> int:
+    try:
+        x = 1
+    except:
+        pass
+    return x  # E: Name "x" may be undefined
+
+def f2() -> int:
+    try:
+        pass
+    except:
+        x = 1
+    return x  # E: Name "x" may be undefined
+
+def f3() -> int:
+    try:
+        x = 1
+    except:
+        y = x  # E: Name "x" may be undefined
+    return x  # E: Name "x" may be undefined
+
+def f4() -> int:
+    try:
+        x = 1
+    except:
+        return 0
+    return x
+
+def f5() -> int:
+    try:
+        x = 1
+    except:
+        raise
+    return x
+
+def f6() -> None:
+    try:
+        pass
+    except BaseException as exc:
+        x = exc  # No error.
+        exc = BaseException()
+    # This case is covered by the other check, not by possibly undefined check.
+    y = exc # E: Trying to read deleted variable "exc"
+
+def f7() -> int:
+    try:
+        if int():
+            x = 1
+        assert False
+    except:
+        pass
+    return x  # E: Name "x" may be undefined
+[builtins fixtures/exception.pyi]
+
+[case testTryMultiExcept]
+# flags: --enable-error-code possibly-undefined
+def f1() -> int:
+    try:
+        x = 1
+    except BaseException:
+        x = 2
+    except:
+        x = 3
+    return x
+
+def f2() -> int:
+    try:
+        x = 1
+    except BaseException:
+        pass
+    except:
+        x = 3
+    return x  # E: Name "x" may be undefined
+[builtins fixtures/exception.pyi]
+
+[case testTryFinally]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
+def f1() -> int:
+    try:
+        x = 1
+    finally:
+        x = 2
+    return x
+
+def f2() -> int:
+    try:
+        pass
+    except:
+        pass
+    finally:
+        x = 2
+    return x
+
+def f3() -> int:
+    try:
+        x = 1
+    except:
+        pass
+    finally:
+        y = x  # E: Name "x" may be undefined
+    return x
+
+def f4() -> int:
+    try:
+        x = 0
+    except BaseException:
+        raise
+    finally:
+        y = x  # E: Name "x" may be undefined
+    return y
+
+def f5() -> int:
+    try:
+        if int():
+            x = 1
+        else:
+            return 0
+    finally:
+        pass
+    return x  # No error.
+
+def f6() -> int:
+    try:
+        if int():
+            x = 1
+        else:
+            return 0
+    finally:
+        a = x  # E: Name "x" may be undefined
+    return a
+[builtins fixtures/exception.pyi]
+
+[case testTryElse]
+# flags: --enable-error-code possibly-undefined
+def f1() -> int:
+    try:
+        return 0
+    except BaseException:
+        x = 1
+    else:
+        x = 2
+    finally:
+        y = x
+    return y
+
+def f2() -> int:
+    try:
+        pass
+    except:
+        x = 1
+    else:
+        x = 2
+    return x
+
+def f3() -> int:
+    try:
+        pass
+    except:
+        x = 1
+    else:
+        pass
+    return x  # E: Name "x" may be undefined
+
+def f4() -> int:
+    try:
+        x = 1
+    except:
+        x = 2
+    else:
+        pass
+    return x
+
+def f5() -> int:
+    try:
+        pass
+    except:
+        x = 1
+    else:
+        return 1
+    return x
+[builtins fixtures/exception.pyi]
+
 [case testNoReturn]
 # flags: --enable-error-code possibly-undefined
 

From b1388e0b479868623f9bcb18491f8b041c68e512 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Mon, 19 Dec 2022 06:48:30 -0800
Subject: [PATCH 119/231] [used-before-def] fix false positive inside loop
 (#14307)

A similar case was addressed in #14176 but I missed the part where it
doesn't need to be defined in a different branch. This makes the fix
more complete.
---
 mypy/partially_defined.py                    | 5 ++++-
 test-data/unit/check-possibly-undefined.test | 7 ++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 9b3e105f64ef3..fd322bbf0ad6a 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -322,7 +322,10 @@ def process_definition(self, name: str) -> None:
         # Was this name previously used? If yes, it's a used-before-definition error.
         refs = self.tracker.pop_undefined_ref(name)
         for ref in refs:
-            self.var_used_before_def(name, ref)
+            if self.loops:
+                self.variable_may_be_undefined(name, ref)
+            else:
+                self.var_used_before_def(name, ref)
         self.tracker.record_definition(name)
 
     def visit_global_decl(self, o: GlobalDecl) -> None:
diff --git a/test-data/unit/check-possibly-undefined.test b/test-data/unit/check-possibly-undefined.test
index ee7020252de83..c632225c540b5 100644
--- a/test-data/unit/check-possibly-undefined.test
+++ b/test-data/unit/check-possibly-undefined.test
@@ -382,7 +382,7 @@ def f2() -> None:
             x = 2
         w = x  # No error.
 
-[case testDefinedDifferentBranchPossiblyUndefined]
+[case testPossiblyUndefinedLoop]
 # flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 
 def f0() -> None:
@@ -423,6 +423,11 @@ def f3() -> None:
     else:
         y = x  # E: Name "x" may be undefined
 
+def f4() -> None:
+    while int():
+        y = x  # E: Name "x" may be undefined
+        x: int = 1
+
 [case testAssert]
 # flags: --enable-error-code possibly-undefined
 def f1() -> int:

From d391f108c195533a5800afe73f5b3257babc83a3 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Mon, 19 Dec 2022 06:49:33 -0800
Subject: [PATCH 120/231] [undefined vars] skip visiting unreachable else
 clauses (#14308)

In particular, ran into an issue with an `if TYPE_CHECKING` case, so I
added a test for that.
---
 mypy/partially_defined.py                    |  5 +--
 test-data/unit/check-possibly-undefined.test | 34 ++++++++++++--------
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index fd322bbf0ad6a..644a472486151 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -366,9 +366,10 @@ def visit_if_stmt(self, o: IfStmt) -> None:
             b.accept(self)
             self.tracker.next_branch()
         if o.else_body:
-            if o.else_body.is_unreachable:
+            if not o.else_body.is_unreachable:
+                o.else_body.accept(self)
+            else:
                 self.tracker.skip_branch()
-            o.else_body.accept(self)
         self.tracker.end_branch_statement()
 
     def visit_match_stmt(self, o: MatchStmt) -> None:
diff --git a/test-data/unit/check-possibly-undefined.test b/test-data/unit/check-possibly-undefined.test
index c632225c540b5..aa535a1ce081e 100644
--- a/test-data/unit/check-possibly-undefined.test
+++ b/test-data/unit/check-possibly-undefined.test
@@ -771,22 +771,30 @@ def f() -> None:
 [builtins fixtures/tuple.pyi]
 
 [case testUnreachable]
-# flags: --enable-error-code possibly-undefined
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
 import typing
 
-if typing.TYPE_CHECKING:
-    x = 1
-elif int():
-    y = 1
-else:
-    y = 2
-a = x
+def f0() -> None:
+    if typing.TYPE_CHECKING:
+        x = 1
+    elif int():
+        y = 1
+    else:
+        y = 2
+    a = x
 
-if not typing.TYPE_CHECKING:
-    pass
-else:
-    z = 1
-a = z
+def f1() -> None:
+    if not typing.TYPE_CHECKING:
+        pass
+    else:
+        z = 1
+    a = z
+
+def f2() -> None:
+    if typing.TYPE_CHECKING:
+        x = 1
+    else:
+        y = x
 [typing fixtures/typing-medium.pyi]
 
 [case testUsedBeforeDef]

From 97d9ed59a0e33c86efd37fa90a4cbdb53c9b62a0 Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Mon, 19 Dec 2022 17:06:21 +0100
Subject: [PATCH 121/231] Add basic support for `typing_extensions.TypeVar`
 (#14313)

This PR only adds the existing `TypeVar` support for the
`typing_extensions` variant.
I.e. it does not include support for `default` or `infer_variance`.

Fixes #14312
---
 mypy/semanal.py                               |  2 +-
 test-data/unit/check-generics.test            | 33 +++++++++++++++++++
 test-data/unit/lib-stub/typing_extensions.pyi |  7 ++--
 3 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index fee66ae9b2ccf..9160097028305 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -3847,7 +3847,7 @@ def process_typevar_declaration(self, s: AssignmentStmt) -> bool:
         Return True if this looks like a type variable declaration (but maybe
         with errors), otherwise return False.
         """
-        call = self.get_typevarlike_declaration(s, ("typing.TypeVar",))
+        call = self.get_typevarlike_declaration(s, ("typing.TypeVar", "typing_extensions.TypeVar"))
         if not call:
             return False
 
diff --git a/test-data/unit/check-generics.test b/test-data/unit/check-generics.test
index dd7e31528a4fe..27441ce908fe8 100644
--- a/test-data/unit/check-generics.test
+++ b/test-data/unit/check-generics.test
@@ -2663,3 +2663,36 @@ def foo(x: A) -> A:
                 # N: (Hint: Use "B" in function signature to bind "B" inside a function)
         return y.x
     return bar()[0]
+
+
+-- TypeVar imported from typing_extensions
+-- ---------------------------------------
+
+[case testTypeVarTypingExtensionsSimpleGeneric]
+from typing import Generic
+from typing_extensions import TypeVar
+
+T = TypeVar("T")
+
+class A(Generic[T]):
+    def __init__(self, value: T) -> None:
+        self.value = value
+
+a: A = A(8)
+b: A[str] = A("")
+
+reveal_type(A(1.23))  # N: Revealed type is "__main__.A[builtins.float]"
+
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVarTypingExtensionsSimpleBound]
+from typing_extensions import TypeVar
+
+T= TypeVar("T")
+
+def func(var: T) -> T:
+    return var
+
+reveal_type(func(1))  # N: Revealed type is "builtins.int"
+
+[builtins fixtures/tuple.pyi]
diff --git a/test-data/unit/lib-stub/typing_extensions.pyi b/test-data/unit/lib-stub/typing_extensions.pyi
index e92f7e9135027..cbf692fc71111 100644
--- a/test-data/unit/lib-stub/typing_extensions.pyi
+++ b/test-data/unit/lib-stub/typing_extensions.pyi
@@ -1,10 +1,11 @@
-from typing import TypeVar, Any, Mapping, Iterator, NoReturn as NoReturn, Dict, Type
+import typing
+from typing import Any, Mapping, Iterator, NoReturn as NoReturn, Dict, Type
 from typing import TYPE_CHECKING as TYPE_CHECKING
 from typing import NewType as NewType, overload as overload
 
 import sys
 
-_T = TypeVar('_T')
+_T = typing.TypeVar('_T')
 
 class _SpecialForm:
     def __getitem__(self, typeargs: Any) -> Any:
@@ -25,6 +26,8 @@ Literal: _SpecialForm = ...
 
 Annotated: _SpecialForm = ...
 
+TypeVar: _SpecialForm
+
 ParamSpec: _SpecialForm
 Concatenate: _SpecialForm
 

From d5dc1fb4cc6ff969f125f5fb8bc51c2a29659bc1 Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Mon, 19 Dec 2022 23:27:50 +0100
Subject: [PATCH 122/231] Add `--debug-serialize` option (#14155)

Currently, `mypy_primer` sets `--cache-dir=/dev/null` which disables
cache generation. This can result in errors being missed which would
normally come up during `tree.serialize()`. Removing
`--cache-dir=/dev/null` isn't practical.

This PR adds a new debug / test option `--debug-serialize` which runs
`tree.serialize()` even if cache generation is disabled to help detect
serialize errors earlier.

**Refs**
* #14137
*
https://github.com/hauntsaninja/mypy_primer/pull/54#pullrequestreview-1187145602

cc: @hauntsaninja
---
 mypy/build.py   | 6 ++++++
 mypy/main.py    | 3 +++
 mypy/options.py | 3 +++
 3 files changed, 12 insertions(+)

diff --git a/mypy/build.py b/mypy/build.py
index 7da3e71ce25e2..d2bcd572969e8 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2479,6 +2479,12 @@ def write_cache(self) -> None:
             or self.options.cache_dir == os.devnull
             or self.options.fine_grained_incremental
         ):
+            if self.options.debug_serialize:
+                try:
+                    self.tree.serialize()
+                except Exception:
+                    print(f"Error serializing {self.id}", file=self.manager.stdout)
+                    raise  # Propagate to display traceback
             return
         is_errors = self.transitive_error
         if is_errors:
diff --git a/mypy/main.py b/mypy/main.py
index 8f60d13074a08..47dea2ae9797a 100644
--- a/mypy/main.py
+++ b/mypy/main.py
@@ -1126,6 +1126,9 @@ def add_invertible_flag(
     parser.add_argument(
         "--cache-map", nargs="+", dest="special-opts:cache_map", help=argparse.SUPPRESS
     )
+    # --debug-serialize will run tree.serialize() even if cache generation is disabled.
+    # Useful for mypy_primer to detect serialize errors earlier.
+    parser.add_argument("--debug-serialize", action="store_true", help=argparse.SUPPRESS)
     # This one is deprecated, but we will keep it for few releases.
     parser.add_argument(
         "--enable-incomplete-features", action="store_true", help=argparse.SUPPRESS
diff --git a/mypy/options.py b/mypy/options.py
index ffb6b201e70be..92c96a92c531f 100644
--- a/mypy/options.py
+++ b/mypy/options.py
@@ -249,6 +249,9 @@ def __init__(self) -> None:
         # Read cache files in fine-grained incremental mode (cache must include dependencies)
         self.use_fine_grained_cache = False
 
+        # Run tree.serialize() even if cache generation is disabled
+        self.debug_serialize = False
+
         # Tune certain behaviors when being used as a front-end to mypyc. Set per-module
         # in modules being compiled. Not in the config file or command line.
         self.mypyc = False

From 2e3144c6a27cbe15d22c5240100b96b98cba6dbd Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Tue, 20 Dec 2022 00:25:00 +0100
Subject: [PATCH 123/231] Enable `--debug-serialize` for mypy_primer (#14318)

Enable the `--debug-serialize` option to help catch issues during
serialization which would normally be skipped by mypy_primer.

Followup to #14155
---
 .github/workflows/mypy_primer.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/mypy_primer.yml b/.github/workflows/mypy_primer.yml
index d26372aa66359..9eef1c1c7466f 100644
--- a/.github/workflows/mypy_primer.yml
+++ b/.github/workflows/mypy_primer.yml
@@ -62,6 +62,7 @@ jobs:
             --new $GITHUB_SHA --old base_commit \
             --num-shards 5 --shard-index ${{ matrix.shard-index }} \
             --debug \
+            --additional-flags="--debug-serialize" \
             --output concise \
             | tee diff_${{ matrix.shard-index }}.txt
           ) || [ $? -eq 1 ]

From fcd705d3149906d1fa892c4ae9e5458275007b24 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Tue, 20 Dec 2022 07:09:05 +0000
Subject: [PATCH 124/231] Update `stubinfo.py` for recent typeshed changes
 (#14265)

Removals from `stubinfo.py`:
- `atomicwrites` is archived and deprecated at runtime; stubs were
removed from typeshed in https://github.com/python/typeshed/pull/8925
- `attrs` has had inline types for a very long time now
- `chardet` recently cut a release with inline types; typeshed's stubs
were marked obsolete in https://github.com/python/typeshed/pull/9318
- `cryptography` has had inline types for a very long time now; the only
reason why it's still in typeshed is because other typeshed packages
need `types-cryptography` as a dependency, and our testing
infrastructure therefore can't currently cope with it being removed from
typeshed.
- `emoji` recently cut a release bundling stubs with the runtime
package; typeshed's stubs were marked obsolete in
https://github.com/python/typeshed/pull/9051
- `termcolor` recently cut a release with inline types; typeshed's stubs
were marked obsolete in https://github.com/python/typeshed/pull/8746
- `prettytable` recently cut a release with inline types; typeshed's
stubs were marked obsolete in
https://github.com/python/typeshed/pull/9023

Additions:
- Stubs for `Xlib` were added in
https://github.com/python/typeshed/pull/9279
- Stubs for `consolemenu` were added in
https://github.com/python/typeshed/pull/8820
- Stubs for `dockerfile_parse` were added in
https://github.com/python/typeshed/pull/9305
- Stubs for `flask_migrate` were added in
https://github.com/python/typeshed/pull/8967
- Stubs for `paho.mqtt` were added in
https://github.com/python/typeshed/pull/8853
- Stubs for `pycocotools` were added in
https://github.com/python/typeshed/pull/9086
- Stubs for many `pywin32` modules were added in
https://github.com/python/typeshed/pull/8825, and multiple follow-up PRs
- Stubs for `pyscreeze` were added in
https://github.com/python/typeshed/pull/8823
---
 mypy/stubinfo.py | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/mypy/stubinfo.py b/mypy/stubinfo.py
index b8dea5d0046b4..15bd96d9f4b4c 100644
--- a/mypy/stubinfo.py
+++ b/mypy/stubinfo.py
@@ -20,14 +20,11 @@ def stub_package_name(prefix: str) -> str:
 # Package name can have one or two components ('a' or 'a.b').
 legacy_bundled_packages = {
     "aiofiles": "types-aiofiles",
-    "atomicwrites": "types-atomicwrites",
-    "attr": "types-attrs",
     "backports": "types-backports",
     "backports_abc": "types-backports_abc",
     "bleach": "types-bleach",
     "boto": "types-boto",
     "cachetools": "types-cachetools",
-    "chardet": "types-chardet",
     "click_spinner": "types-click-spinner",
     "contextvars": "types-contextvars",
     "croniter": "types-croniter",
@@ -38,7 +35,6 @@ def stub_package_name(prefix: str) -> str:
     "decorator": "types-decorator",
     "deprecated": "types-Deprecated",
     "docutils": "types-docutils",
-    "emoji": "types-emoji",
     "first": "types-first",
     "geoip2": "types-geoip2",
     "gflags": "types-python-gflags",
@@ -64,7 +60,6 @@ def stub_package_name(prefix: str) -> str:
     "six": "types-six",
     "slugify": "types-python-slugify",
     "tabulate": "types-tabulate",
-    "termcolor": "types-termcolor",
     "toml": "types-toml",
     "typed_ast": "types-typed-ast",
     "tzlocal": "types-tzlocal",
@@ -83,10 +78,14 @@ def stub_package_name(prefix: str) -> str:
 # Note that these packages are omitted for now:
 #   sqlalchemy: It's unclear which stub package to suggest. There's also
 #               a mypy plugin available.
+#   pika:       typeshed's stubs are on PyPI as types-pika-ts.
+#               types-pika already exists on PyPI, and is more complete in many ways,
+#               but is a non-typeshed stubs package.
 non_bundled_packages = {
     "MySQLdb": "types-mysqlclient",
     "PIL": "types-Pillow",
     "PyInstaller": "types-pyinstaller",
+    "Xlib": "types-python-xlib",
     "annoy": "types-annoy",
     "appdirs": "types-appdirs",
     "aws_xray_sdk": "types-aws-xray-sdk",
@@ -100,9 +99,11 @@ def stub_package_name(prefix: str) -> str:
     "chevron": "types-chevron",
     "colorama": "types-colorama",
     "commonmark": "types-commonmark",
-    "cryptography": "types-cryptography",
+    "consolemenu": "types-console-menu",
+    "crontab": "types-python-crontab",
     "d3dshot": "types-D3DShot",
     "dj_database_url": "types-dj-database-url",
+    "dockerfile_parse": "types-dockerfile-parse",
     "docopt": "types-docopt",
     "editdistance": "types-editdistance",
     "entrypoints": "types-entrypoints",
@@ -115,6 +116,7 @@ def stub_package_name(prefix: str) -> str:
     "flake8_simplify": "types-flake8-simplify",
     "flake8_typing_imports": "types-flake8-typing-imports",
     "flask_cors": "types-Flask-Cors",
+    "flask_migrate": "types-Flask-Migrate",
     "flask_sqlalchemy": "types-Flask-SQLAlchemy",
     "fpdf": "types-fpdf2",
     "gdb": "types-gdb",
@@ -134,22 +136,28 @@ def stub_package_name(prefix: str) -> str:
     "oauthlib": "types-oauthlib",
     "openpyxl": "types-openpyxl",
     "opentracing": "types-opentracing",
+    "paho.mqtt": "types-paho-mqtt",
     "parsimonious": "types-parsimonious",
     "passlib": "types-passlib",
     "passpy": "types-passpy",
+    "peewee": "types-peewee",
     "pep8ext_naming": "types-pep8-naming",
     "playsound": "types-playsound",
-    "prettytable": "types-prettytable",
     "psutil": "types-psutil",
     "psycopg2": "types-psycopg2",
     "pyaudio": "types-pyaudio",
     "pyautogui": "types-PyAutoGUI",
+    "pycocotools": "types-pycocotools",
     "pyflakes": "types-pyflakes",
     "pygments": "types-Pygments",
     "pyi_splash": "types-pyinstaller",
     "pynput": "types-pynput",
+    "pythoncom": "types-pywin32",
+    "pythonwin": "types-pywin32",
+    "pyscreeze": "types-PyScreeze",
     "pysftp": "types-pysftp",
     "pytest_lazyfixture": "types-pytest-lazy-fixture",
+    "pywintypes": "types-pywin32",
     "regex": "types-regex",
     "send2trash": "types-Send2Trash",
     "slumber": "types-slumber",
@@ -163,6 +171,12 @@ def stub_package_name(prefix: str) -> str:
     "urllib3": "types-urllib3",
     "vobject": "types-vobject",
     "whatthepatch": "types-whatthepatch",
+    "win32": "types-pywin32",
+    "win32api": "types-pywin32",
+    "win32con": "types-pywin32",
+    "win32com": "types-pywin32",
+    "win32comext": "types-pywin32",
+    "win32gui": "types-pywin32",
     "xmltodict": "types-xmltodict",
     "xxhash": "types-xxhash",
     "zxcvbn": "types-zxcvbn",

From c4144640a98fb7ddc1eaacc26f659042d1a27e75 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 20 Dec 2022 09:52:43 +0000
Subject: [PATCH 125/231] Optimize implementation of TypedDict types for **kwds
 (#14316)

The implementation copied lots of callable types even when not using
the new feature, which was expensive. Now we only generate a copy if a
callable actually uses TypedDict types for **kwds.

This made self check 7-8% faster (when compiled with -O0).

The original implementation was in
https://github.com/python/mypy/pull/13471.
---
 mypy/types.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index 0ba0985436ed4..ab2caa96e5359 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -1757,7 +1757,7 @@ def copy_modified(
         from_concatenate: Bogus[bool] = _dummy,
         unpack_kwargs: Bogus[bool] = _dummy,
     ) -> CT:
-        return type(self)(
+        modified = CallableType(
             arg_types=arg_types if arg_types is not _dummy else self.arg_types,
             arg_kinds=arg_kinds if arg_kinds is not _dummy else self.arg_kinds,
             arg_names=arg_names if arg_names is not _dummy else self.arg_names,
@@ -1782,6 +1782,9 @@ def copy_modified(
             ),
             unpack_kwargs=unpack_kwargs if unpack_kwargs is not _dummy else self.unpack_kwargs,
         )
+        # Optimization: Only NewTypes are supported as subtypes since
+        # the class is effectively final, so we can use a cast safely.
+        return cast(CT, modified)
 
     def var_arg(self) -> FormalArgument | None:
         """The formal argument for *args."""
@@ -1976,7 +1979,7 @@ def expand_param_spec(
 
     def with_unpacked_kwargs(self) -> NormalizedCallableType:
         if not self.unpack_kwargs:
-            return NormalizedCallableType(self.copy_modified())
+            return cast(NormalizedCallableType, self)
         last_type = get_proper_type(self.arg_types[-1])
         assert isinstance(last_type, TypedDictType)
         extra_kinds = [
@@ -2126,7 +2129,9 @@ def get_name(self) -> str | None:
         return self._items[0].name
 
     def with_unpacked_kwargs(self) -> Overloaded:
-        return Overloaded([i.with_unpacked_kwargs() for i in self.items])
+        if any(i.unpack_kwargs for i in self.items):
+            return Overloaded([i.with_unpacked_kwargs() for i in self.items])
+        return self
 
     def accept(self, visitor: TypeVisitor[T]) -> T:
         return visitor.visit_overloaded(self)

From c588852451ec63f9a26fefe5eb82976aa03d611c Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 20 Dec 2022 15:35:38 +0000
Subject: [PATCH 126/231] Speed up freshening type variables (#14323)

Only perform type variable freshening if it's needed, i.e. there is a
nested generic callable, since it's fairly expensive. Make the check for
generic callables fast by creating a specialized type query visitor base
class for queries with bool results. The visitor tries hard to avoid
memory allocation in typical cases, since allocation is slow.

This addresses at least some of the performance regression in #14095.
This improved self-check performance by about 3% when compiled with
mypyc (-O2).

The new visitor class can potentially help with other type queries as
well. I'll explore it in follow-up PRs.
---
 mypy/expandtype.py   |  26 +++++++-
 mypy/type_visitor.py | 156 +++++++++++++++++++++++++++++++++++++++++++
 mypy/types.py        |   5 +-
 3 files changed, 183 insertions(+), 4 deletions(-)

diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 1458fb74ce946..ca562ede264f3 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -1,11 +1,14 @@
 from __future__ import annotations
 
 from typing import Iterable, Mapping, Sequence, TypeVar, cast, overload
+from typing_extensions import Final
 
 from mypy.nodes import ARG_POS, ARG_STAR, Var
 from mypy.type_visitor import TypeTranslator
 from mypy.types import (
+    ANY_STRATEGY,
     AnyType,
+    BoolTypeQuery,
     CallableType,
     DeletedType,
     ErasedType,
@@ -138,13 +141,30 @@ def freshen_function_type_vars(callee: F) -> F:
         return cast(F, fresh_overload)
 
 
+class HasGenericCallable(BoolTypeQuery):
+    def __init__(self) -> None:
+        super().__init__(ANY_STRATEGY)
+
+    def visit_callable_type(self, t: CallableType) -> bool:
+        return t.is_generic() or super().visit_callable_type(t)
+
+
+# Share a singleton since this is performance sensitive
+has_generic_callable: Final = HasGenericCallable()
+
+
 T = TypeVar("T", bound=Type)
 
 
 def freshen_all_functions_type_vars(t: T) -> T:
-    result = t.accept(FreshenCallableVisitor())
-    assert isinstance(result, type(t))
-    return result
+    result: Type
+    has_generic_callable.reset()
+    if not t.accept(has_generic_callable):
+        return t  # Fast path to avoid expensive freshening
+    else:
+        result = t.accept(FreshenCallableVisitor())
+        assert isinstance(result, type(t))
+        return result
 
 
 class FreshenCallableVisitor(TypeTranslator):
diff --git a/mypy/type_visitor.py b/mypy/type_visitor.py
index 0f5ac05e68ac3..823e74e7e2830 100644
--- a/mypy/type_visitor.py
+++ b/mypy/type_visitor.py
@@ -15,6 +15,7 @@
 
 from abc import abstractmethod
 from typing import Any, Callable, Generic, Iterable, Sequence, TypeVar, cast
+from typing_extensions import Final
 
 from mypy_extensions import mypyc_attr, trait
 
@@ -417,3 +418,158 @@ def visit_type_alias_type(self, t: TypeAliasType) -> T:
     def query_types(self, types: Iterable[Type]) -> T:
         """Perform a query for a list of types using the strategy to combine the results."""
         return self.strategy([t.accept(self) for t in types])
+
+
+# Return True if at least one type component returns True
+ANY_STRATEGY: Final = 0
+# Return True if no type component returns False
+ALL_STRATEGY: Final = 1
+
+
+class BoolTypeQuery(SyntheticTypeVisitor[bool]):
+    """Visitor for performing recursive queries of types with a bool result.
+
+    Use TypeQuery if you need non-bool results.
+
+    'strategy' is used to combine results for a series of types. It must
+    be ANY_STRATEGY or ALL_STRATEGY.
+
+    Note: This visitor keeps an internal state (tracks type aliases to avoid
+    recursion), so it should *never* be re-used for querying different types
+    unless you call reset() first.
+    """
+
+    def __init__(self, strategy: int) -> None:
+        self.strategy = strategy
+        if strategy == ANY_STRATEGY:
+            self.default = False
+        else:
+            assert strategy == ALL_STRATEGY
+            self.default = True
+        # Keep track of the type aliases already visited. This is needed to avoid
+        # infinite recursion on types like A = Union[int, List[A]]. An empty set is
+        # represented as None as a micro-optimization.
+        self.seen_aliases: set[TypeAliasType] | None = None
+        # By default, we eagerly expand type aliases, and query also types in the
+        # alias target. In most cases this is a desired behavior, but we may want
+        # to skip targets in some cases (e.g. when collecting type variables).
+        self.skip_alias_target = False
+
+    def reset(self) -> None:
+        """Clear mutable state (but preserve strategy).
+
+        This *must* be called if you want to reuse the visitor.
+        """
+        self.seen_aliases = None
+
+    def visit_unbound_type(self, t: UnboundType) -> bool:
+        return self.query_types(t.args)
+
+    def visit_type_list(self, t: TypeList) -> bool:
+        return self.query_types(t.items)
+
+    def visit_callable_argument(self, t: CallableArgument) -> bool:
+        return t.typ.accept(self)
+
+    def visit_any(self, t: AnyType) -> bool:
+        return self.default
+
+    def visit_uninhabited_type(self, t: UninhabitedType) -> bool:
+        return self.default
+
+    def visit_none_type(self, t: NoneType) -> bool:
+        return self.default
+
+    def visit_erased_type(self, t: ErasedType) -> bool:
+        return self.default
+
+    def visit_deleted_type(self, t: DeletedType) -> bool:
+        return self.default
+
+    def visit_type_var(self, t: TypeVarType) -> bool:
+        return self.query_types([t.upper_bound] + t.values)
+
+    def visit_param_spec(self, t: ParamSpecType) -> bool:
+        return self.default
+
+    def visit_type_var_tuple(self, t: TypeVarTupleType) -> bool:
+        return self.default
+
+    def visit_unpack_type(self, t: UnpackType) -> bool:
+        return self.query_types([t.type])
+
+    def visit_parameters(self, t: Parameters) -> bool:
+        return self.query_types(t.arg_types)
+
+    def visit_partial_type(self, t: PartialType) -> bool:
+        return self.default
+
+    def visit_instance(self, t: Instance) -> bool:
+        return self.query_types(t.args)
+
+    def visit_callable_type(self, t: CallableType) -> bool:
+        # FIX generics
+        # Avoid allocating any objects here as an optimization.
+        args = self.query_types(t.arg_types)
+        ret = t.ret_type.accept(self)
+        if self.strategy == ANY_STRATEGY:
+            return args or ret
+        else:
+            return args and ret
+
+    def visit_tuple_type(self, t: TupleType) -> bool:
+        return self.query_types(t.items)
+
+    def visit_typeddict_type(self, t: TypedDictType) -> bool:
+        return self.query_types(list(t.items.values()))
+
+    def visit_raw_expression_type(self, t: RawExpressionType) -> bool:
+        return self.default
+
+    def visit_literal_type(self, t: LiteralType) -> bool:
+        return self.default
+
+    def visit_star_type(self, t: StarType) -> bool:
+        return t.type.accept(self)
+
+    def visit_union_type(self, t: UnionType) -> bool:
+        return self.query_types(t.items)
+
+    def visit_overloaded(self, t: Overloaded) -> bool:
+        return self.query_types(t.items)  # type: ignore[arg-type]
+
+    def visit_type_type(self, t: TypeType) -> bool:
+        return t.item.accept(self)
+
+    def visit_ellipsis_type(self, t: EllipsisType) -> bool:
+        return self.default
+
+    def visit_placeholder_type(self, t: PlaceholderType) -> bool:
+        return self.query_types(t.args)
+
+    def visit_type_alias_type(self, t: TypeAliasType) -> bool:
+        # Skip type aliases already visited types to avoid infinite recursion.
+        # TODO: Ideally we should fire subvisitors here (or use caching) if we care
+        #       about duplicates.
+        if self.seen_aliases is None:
+            self.seen_aliases = set()
+        elif t in self.seen_aliases:
+            return self.default
+        self.seen_aliases.add(t)
+        if self.skip_alias_target:
+            return self.query_types(t.args)
+        return get_proper_type(t).accept(self)
+
+    def query_types(self, types: list[Type] | tuple[Type, ...]) -> bool:
+        """Perform a query for a sequence of types using the strategy to combine the results."""
+        # Special-case for lists and tuples to allow mypyc to produce better code.
+        if isinstance(types, list):
+            if self.strategy == ANY_STRATEGY:
+                return any(t.accept(self) for t in types)
+            else:
+                return all(t.accept(self) for t in types)
+        else:
+            if self.strategy == ANY_STRATEGY:
+                return any(t.accept(self) for t in types)
+            else:
+                return all(t.accept(self) for t in types)
diff --git a/mypy/types.py b/mypy/types.py
index ab2caa96e5359..5c1fe2a0e960b 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -2879,7 +2879,10 @@ def get_proper_types(it: Iterable[Type | None]) -> list[ProperType] | list[Prope
 # to make it easier to gradually get modules working with mypyc.
 # Import them here, after the types are defined.
 # This is intended as a re-export also.
-from mypy.type_visitor import (  # noqa: F811
+from mypy.type_visitor import (  # noqa: F811,F401
+    ALL_STRATEGY as ALL_STRATEGY,
+    ANY_STRATEGY as ANY_STRATEGY,
+    BoolTypeQuery as BoolTypeQuery,
     SyntheticTypeVisitor as SyntheticTypeVisitor,
     TypeQuery as TypeQuery,
     TypeTranslator as TypeTranslator,

From d35e571ef303ec63f4c8c3437669c858d85329eb Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 20 Dec 2022 15:45:18 +0000
Subject: [PATCH 127/231] Optimize type parameter checks in subtype checking
 (#14324)

Avoid the use of a nested function, which are a bit slow when compiled
with mypyc. Also avoid a callable value and instead call a function
directly, which allows using faster native calls.

Based on a quick experiment, this speeds up self check by about 3%.

This addresses some of the slowdown introduced in #13303.
---
 mypy/subtypes.py | 60 ++++++++++++++++++++++--------------------------
 1 file changed, 28 insertions(+), 32 deletions(-)

diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index e4667c45fbc5f..bdeeed6c6d675 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -330,34 +330,28 @@ def check_item(left: Type, right: Type, subtype_context: SubtypeContext) -> bool
 
 
 def check_type_parameter(
-    lefta: Type, righta: Type, variance: int, proper_subtype: bool, subtype_context: SubtypeContext
+    left: Type, right: Type, variance: int, proper_subtype: bool, subtype_context: SubtypeContext
 ) -> bool:
-    def check(left: Type, right: Type) -> bool:
-        return (
-            is_proper_subtype(left, right, subtype_context=subtype_context)
-            if proper_subtype
-            else is_subtype(left, right, subtype_context=subtype_context)
-        )
-
     if variance == COVARIANT:
-        return check(lefta, righta)
+        if proper_subtype:
+            return is_proper_subtype(left, right, subtype_context=subtype_context)
+        else:
+            return is_subtype(left, right, subtype_context=subtype_context)
     elif variance == CONTRAVARIANT:
-        return check(righta, lefta)
+        if proper_subtype:
+            return is_proper_subtype(right, left, subtype_context=subtype_context)
+        else:
+            return is_subtype(right, left, subtype_context=subtype_context)
     else:
         if proper_subtype:
             # We pass ignore_promotions=False because it is a default for subtype checks.
             # The actual value will be taken from the subtype_context, and it is whatever
             # the original caller passed.
             return is_same_type(
-                lefta, righta, ignore_promotions=False, subtype_context=subtype_context
+                left, right, ignore_promotions=False, subtype_context=subtype_context
             )
-        return is_equivalent(lefta, righta, subtype_context=subtype_context)
-
-
-def ignore_type_parameter(
-    lefta: Type, righta: Type, variance: int, proper_subtype: bool, subtype_context: SubtypeContext
-) -> bool:
-    return True
+        else:
+            return is_equivalent(left, right, subtype_context=subtype_context)
 
 
 class SubtypeVisitor(TypeVisitor[bool]):
@@ -366,9 +360,6 @@ def __init__(self, right: Type, subtype_context: SubtypeContext, proper_subtype:
         self.orig_right = right
         self.proper_subtype = proper_subtype
         self.subtype_context = subtype_context
-        self.check_type_parameter = (
-            ignore_type_parameter if subtype_context.ignore_type_params else check_type_parameter
-        )
         self.options = subtype_context.options
         self._subtype_kind = SubtypeVisitor.build_subtype_kind(subtype_context, proper_subtype)
 
@@ -572,17 +563,22 @@ def check_mixed(
                     )
                 else:
                     type_params = zip(t.args, right.args, right.type.defn.type_vars)
-                for lefta, righta, tvar in type_params:
-                    if isinstance(tvar, TypeVarType):
-                        if not self.check_type_parameter(
-                            lefta, righta, tvar.variance, self.proper_subtype, self.subtype_context
-                        ):
-                            nominal = False
-                    else:
-                        if not self.check_type_parameter(
-                            lefta, righta, COVARIANT, self.proper_subtype, self.subtype_context
-                        ):
-                            nominal = False
+                if not self.subtype_context.ignore_type_params:
+                    for lefta, righta, tvar in type_params:
+                        if isinstance(tvar, TypeVarType):
+                            if not check_type_parameter(
+                                lefta,
+                                righta,
+                                tvar.variance,
+                                self.proper_subtype,
+                                self.subtype_context,
+                            ):
+                                nominal = False
+                        else:
+                            if not check_type_parameter(
+                                lefta, righta, COVARIANT, self.proper_subtype, self.subtype_context
+                            ):
+                                nominal = False
                 if nominal:
                     TypeState.record_subtype_cache_entry(self._subtype_kind, left, right)
                 return nominal

From b5fc748a1ccb65a9d4dc0eef897c71ee8b15ddc9 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 20 Dec 2022 15:45:42 +0000
Subject: [PATCH 128/231] Optimize subtype checking by avoiding a nested
 function (#14325)

Mypyc isn't good at compiling nested functions, and this one was in one
of the hottest code paths in all of mypy. The nested function wasn't
even used that often, but mypyc would still construct a closure object
every time.

This adds some code duplication, but it's well worth it. Amazingly, this
speeds up self-check by about 10%, if my measurements are to be trusted!

This addresses some of the slowdown introduced in #13303. #14324
addresses another related slowdown.
---
 mypy/subtypes.py | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index bdeeed6c6d675..b8d59977f986e 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -289,18 +289,20 @@ def _is_subtype(
         # ErasedType as we do for non-proper subtyping.
         return True
 
-    def check_item(left: Type, right: Type, subtype_context: SubtypeContext) -> bool:
-        if proper_subtype:
-            return is_proper_subtype(left, right, subtype_context=subtype_context)
-        return is_subtype(left, right, subtype_context=subtype_context)
-
     if isinstance(right, UnionType) and not isinstance(left, UnionType):
         # Normally, when 'left' is not itself a union, the only way
         # 'left' can be a subtype of the union 'right' is if it is a
         # subtype of one of the items making up the union.
-        is_subtype_of_item = any(
-            check_item(orig_left, item, subtype_context) for item in right.items
-        )
+        if proper_subtype:
+            is_subtype_of_item = any(
+                is_proper_subtype(orig_left, item, subtype_context=subtype_context)
+                for item in right.items
+            )
+        else:
+            is_subtype_of_item = any(
+                is_subtype(orig_left, item, subtype_context=subtype_context)
+                for item in right.items
+            )
         # Recombine rhs literal types, to make an enum type a subtype
         # of a union of all enum items as literal types. Only do it if
         # the previous check didn't succeed, since recombining can be
@@ -312,9 +314,16 @@ def check_item(left: Type, right: Type, subtype_context: SubtypeContext) -> bool
             and (left.type.is_enum or left.type.fullname == "builtins.bool")
         ):
             right = UnionType(mypy.typeops.try_contracting_literals_in_union(right.items))
-            is_subtype_of_item = any(
-                check_item(orig_left, item, subtype_context) for item in right.items
-            )
+            if proper_subtype:
+                is_subtype_of_item = any(
+                    is_proper_subtype(orig_left, item, subtype_context=subtype_context)
+                    for item in right.items
+                )
+            else:
+                is_subtype_of_item = any(
+                    is_subtype(orig_left, item, subtype_context=subtype_context)
+                    for item in right.items
+                )
         # However, if 'left' is a type variable T, T might also have
         # an upper bound which is itself a union. This case will be
         # handled below by the SubtypeVisitor. We have to check both

From 7ed4f5ef3cff221505a54851a23fd80fa0a412c6 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 20 Dec 2022 17:12:57 +0000
Subject: [PATCH 129/231] Speed up recursive type check (#14326)

Use a faster type query visitor and reuse visitor across calls.

This should speed up type checking slightly. My measurements show a
~0.5% improvement, but it may be below the noise floor.
---
 mypy/types.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index 5c1fe2a0e960b..bff83ba52df6a 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3321,17 +3321,22 @@ def has_type_vars(typ: Type) -> bool:
     return typ.accept(HasTypeVars())
 
 
-class HasRecursiveType(TypeQuery[bool]):
+class HasRecursiveType(BoolTypeQuery):
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(ANY_STRATEGY)
 
     def visit_type_alias_type(self, t: TypeAliasType) -> bool:
         return t.is_recursive or self.query_types(t.args)
 
 
+# Use singleton since this is hot (note: call reset() before using)
+_has_recursive_type: Final = HasRecursiveType()
+
+
 def has_recursive_types(typ: Type) -> bool:
     """Check if a type contains any recursive aliases (recursively)."""
-    return typ.accept(HasRecursiveType())
+    _has_recursive_type.reset()
+    return typ.accept(_has_recursive_type)
 
 
 def flatten_nested_unions(

From 41574e0cc521987376dc8c149095b3483aff80ff Mon Sep 17 00:00:00 2001
From: Ilya Konstantinov <ilya.konstantinov@gmail.com>
Date: Tue, 20 Dec 2022 16:04:04 -0500
Subject: [PATCH 130/231] Allow 'in' to narrow TypedDict unions (#13838)

`in` could narrow unions of TypeDicts, e.g.
```python
class A(TypedDict)
   foo: int

@final
class B(TypedDict):
   bar: int

union: Union[A, B] = ...
value: int
if 'foo' in union:
  # Cannot be a B as it is final and has no "foo" field, so must be an A
  value = union['foo']
else:
  # Cannot be an A as those went to the if branch
  value = union['bar']
```
---
 mypy/checker.py                              |  91 +++++++--
 mypy/types.py                                |   4 +
 test-data/unit/check-typeddict.test          | 185 +++++++++++++++++++
 test-data/unit/fixtures/typing-typeddict.pyi |   1 +
 4 files changed, 262 insertions(+), 19 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 1c8956ae6722a..d56d3e2716f1c 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -5097,6 +5097,45 @@ def conditional_callable_type_map(
 
         return None, {}
 
+    def conditional_types_for_iterable(
+        self, item_type: Type, iterable_type: Type
+    ) -> tuple[Type | None, Type | None]:
+        """
+        Narrows the type of `iterable_type` based on the type of `item_type`.
+        For now, we only support narrowing unions of TypedDicts based on left operand being literal string(s).
+        """
+        if_types: list[Type] = []
+        else_types: list[Type] = []
+
+        iterable_type = get_proper_type(iterable_type)
+        if isinstance(iterable_type, UnionType):
+            possible_iterable_types = get_proper_types(iterable_type.relevant_items())
+        else:
+            possible_iterable_types = [iterable_type]
+
+        item_str_literals = try_getting_str_literals_from_type(item_type)
+
+        for possible_iterable_type in possible_iterable_types:
+            if item_str_literals and isinstance(possible_iterable_type, TypedDictType):
+                for key in item_str_literals:
+                    if key in possible_iterable_type.required_keys:
+                        if_types.append(possible_iterable_type)
+                    elif (
+                        key in possible_iterable_type.items or not possible_iterable_type.is_final
+                    ):
+                        if_types.append(possible_iterable_type)
+                        else_types.append(possible_iterable_type)
+                    else:
+                        else_types.append(possible_iterable_type)
+            else:
+                if_types.append(possible_iterable_type)
+                else_types.append(possible_iterable_type)
+
+        return (
+            UnionType.make_union(if_types) if if_types else None,
+            UnionType.make_union(else_types) if else_types else None,
+        )
+
     def _is_truthy_type(self, t: ProperType) -> bool:
         return (
             (
@@ -5412,28 +5451,42 @@ def has_no_custom_eq_checks(t: Type) -> bool:
                 elif operator in {"in", "not in"}:
                     assert len(expr_indices) == 2
                     left_index, right_index = expr_indices
-                    if left_index not in narrowable_operand_index_to_hash:
-                        continue
-
                     item_type = operand_types[left_index]
-                    collection_type = operand_types[right_index]
+                    iterable_type = operand_types[right_index]
 
-                    # We only try and narrow away 'None' for now
-                    if not is_optional(item_type):
-                        continue
+                    if_map, else_map = {}, {}
+
+                    if left_index in narrowable_operand_index_to_hash:
+                        # We only try and narrow away 'None' for now
+                        if is_optional(item_type):
+                            collection_item_type = get_proper_type(
+                                builtin_item_type(iterable_type)
+                            )
+                            if (
+                                collection_item_type is not None
+                                and not is_optional(collection_item_type)
+                                and not (
+                                    isinstance(collection_item_type, Instance)
+                                    and collection_item_type.type.fullname == "builtins.object"
+                                )
+                                and is_overlapping_erased_types(item_type, collection_item_type)
+                            ):
+                                if_map[operands[left_index]] = remove_optional(item_type)
+
+                    if right_index in narrowable_operand_index_to_hash:
+                        if_type, else_type = self.conditional_types_for_iterable(
+                            item_type, iterable_type
+                        )
+                        expr = operands[right_index]
+                        if if_type is None:
+                            if_map = None
+                        else:
+                            if_map[expr] = if_type
+                        if else_type is None:
+                            else_map = None
+                        else:
+                            else_map[expr] = else_type
 
-                    collection_item_type = get_proper_type(builtin_item_type(collection_type))
-                    if collection_item_type is None or is_optional(collection_item_type):
-                        continue
-                    if (
-                        isinstance(collection_item_type, Instance)
-                        and collection_item_type.type.fullname == "builtins.object"
-                    ):
-                        continue
-                    if is_overlapping_erased_types(item_type, collection_item_type):
-                        if_map, else_map = {operands[left_index]: remove_optional(item_type)}, {}
-                    else:
-                        continue
                 else:
                     if_map = {}
                     else_map = {}
diff --git a/mypy/types.py b/mypy/types.py
index bff83ba52df6a..383e5621060e1 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -2334,6 +2334,10 @@ def deserialize(cls, data: JsonDict) -> TypedDictType:
             Instance.deserialize(data["fallback"]),
         )
 
+    @property
+    def is_final(self) -> bool:
+        return self.fallback.type.is_final
+
     def is_anonymous(self) -> bool:
         return self.fallback.type.fullname in TPDICT_FB_NAMES
 
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index fbef6157087c0..d277fa441b1e7 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -2025,6 +2025,191 @@ v = {bad2: 2}  # E: Extra key "bad" for TypedDict "Value"
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
 
+[case testOperatorContainsNarrowsTypedDicts_unionWithList]
+from __future__ import annotations
+from typing import assert_type, TypedDict, Union
+from typing_extensions import final
+
+@final
+class D(TypedDict):
+    foo: int
+
+
+d_or_list: D | list[str]
+
+if 'foo' in d_or_list:
+    assert_type(d_or_list, Union[D, list[str]])
+elif 'bar' in d_or_list:
+    assert_type(d_or_list, list[str])
+else:
+    assert_type(d_or_list, list[str])
+
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testOperatorContainsNarrowsTypedDicts_total]
+from __future__ import annotations
+from typing import assert_type, Literal, TypedDict, TypeVar, Union
+from typing_extensions import final
+
+@final
+class D1(TypedDict):
+    foo: int
+
+
+@final
+class D2(TypedDict):
+    bar: int
+
+
+d: D1 | D2
+
+if 'foo' in d:
+    assert_type(d, D1)
+else:
+    assert_type(d, D2)
+
+foo_or_bar: Literal['foo', 'bar']
+if foo_or_bar in d:
+    assert_type(d, Union[D1, D2])
+else:
+    assert_type(d, Union[D1, D2])
+
+foo_or_invalid: Literal['foo', 'invalid']
+if foo_or_invalid in d:
+    assert_type(d, D1)
+    # won't narrow 'foo_or_invalid'
+    assert_type(foo_or_invalid, Literal['foo', 'invalid'])
+else:
+    assert_type(d, Union[D1, D2])
+    # won't narrow 'foo_or_invalid'
+    assert_type(foo_or_invalid, Literal['foo', 'invalid'])
+
+TD = TypeVar('TD', D1, D2)
+
+def f(arg: TD) -> None:
+    value: int
+    if 'foo' in arg:
+        assert_type(arg['foo'], int)
+    else:
+        assert_type(arg['bar'], int)
+
+
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testOperatorContainsNarrowsTypedDicts_final]
+# flags: --warn-unreachable
+from __future__ import annotations
+from typing import assert_type, TypedDict, Union
+from typing_extensions import final
+
+@final
+class DFinal(TypedDict):
+    foo: int
+
+
+class DNotFinal(TypedDict):
+    bar: int
+
+
+d_not_final: DNotFinal
+
+if 'bar' in d_not_final:
+    assert_type(d_not_final, DNotFinal)
+else:
+    spam = 'ham'  # E: Statement is unreachable
+
+if 'spam' in d_not_final:
+    assert_type(d_not_final, DNotFinal)
+else:
+    assert_type(d_not_final, DNotFinal)
+
+d_final: DFinal
+
+if 'spam' in d_final:
+    spam = 'ham'  # E: Statement is unreachable
+else:
+    assert_type(d_final, DFinal)
+
+d_union: DFinal | DNotFinal
+
+if 'foo' in d_union:
+    assert_type(d_union, Union[DFinal, DNotFinal])
+else:
+    assert_type(d_union, DNotFinal)
+
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testOperatorContainsNarrowsTypedDicts_partialThroughTotalFalse]
+from __future__ import annotations
+from typing import assert_type, Literal, TypedDict, Union
+from typing_extensions import final
+
+@final
+class DTotal(TypedDict):
+    required_key: int
+
+
+@final
+class DNotTotal(TypedDict, total=False):
+    optional_key: int
+
+
+d: DTotal | DNotTotal
+
+if 'required_key' in d:
+    assert_type(d, DTotal)
+else:
+    assert_type(d, DNotTotal)
+
+if 'optional_key' in d:
+    assert_type(d, DNotTotal)
+else:
+    assert_type(d, Union[DTotal, DNotTotal])
+
+key: Literal['optional_key', 'required_key']
+if key in d:
+    assert_type(d, Union[DTotal, DNotTotal])
+else:
+    assert_type(d, Union[DTotal, DNotTotal])
+
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testOperatorContainsNarrowsTypedDicts_partialThroughNotRequired]
+from __future__ import annotations
+from typing import assert_type, Required, NotRequired, TypedDict, Union
+from typing_extensions import final
+
+@final
+class D1(TypedDict):
+    required_key: Required[int]
+    optional_key: NotRequired[int]
+
+
+@final
+class D2(TypedDict):
+    abc: int
+    xyz: int
+
+
+d: D1 | D2
+
+if 'required_key' in d:
+    assert_type(d, D1)
+else:
+    assert_type(d, D2)
+
+if 'optional_key' in d:
+    assert_type(d, D1)
+else:
+    assert_type(d, Union[D1, D2])
+
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
 [case testCannotSubclassFinalTypedDict]
 from typing import TypedDict
 from typing_extensions import final
diff --git a/test-data/unit/fixtures/typing-typeddict.pyi b/test-data/unit/fixtures/typing-typeddict.pyi
index e398dff3fc6b8..92ae402b9ea58 100644
--- a/test-data/unit/fixtures/typing-typeddict.pyi
+++ b/test-data/unit/fixtures/typing-typeddict.pyi
@@ -9,6 +9,7 @@
 from abc import ABCMeta
 
 cast = 0
+assert_type = 0
 overload = 0
 Any = 0
 Union = 0

From f7ed65b0ff3b1bb82ff5e305129bfc251dfeec1d Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 20 Dec 2022 23:15:29 +0000
Subject: [PATCH 131/231] Revert "[mypyc] Use tabs instead of spaces in emitted
 C code (#14016)" (#14152)

This reverts commit dbcbb3f5c3ef791c98088da0bd1dfa6cbf51f301.

The indentation in generated code is now inconsistent if using 4-space
tabs. We should either use tabs or spaces consistently everywhere, since
we can't expect everybody to have the same tab width.

The broken indentation can be seen by compiling a hello world program
and opening it in an editor configured to use 4-space tabs.

Since there is a lot of code in mypyc that assumes a 4-space
indentation, fixing it all is probably only feasible by normalizing the
indentation during the emit phase. However, the normalization step might
actually slow down compilation slightly, whereas the intent of the
original change to improve efficiency, so this change may ultimately be
impractical. In the future we should make it possible to normalize tabs
without any significant cost, but I'm not sure if that's possible right
now.
---
 mypyc/codegen/emit.py          | 6 +++---
 mypyc/test/test_emit.py        | 2 +-
 mypyc/test/test_emitfunc.py    | 6 +++---
 mypyc/test/test_emitwrapper.py | 3 +--
 4 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/mypyc/codegen/emit.py b/mypyc/codegen/emit.py
index 368c5dd366ea4..6e0c89dd0ecf3 100644
--- a/mypyc/codegen/emit.py
+++ b/mypyc/codegen/emit.py
@@ -176,10 +176,10 @@ def __init__(
     # Low-level operations
 
     def indent(self) -> None:
-        self._indent += 1
+        self._indent += 4
 
     def dedent(self) -> None:
-        self._indent -= 1
+        self._indent -= 4
         assert self._indent >= 0
 
     def label(self, label: BasicBlock) -> str:
@@ -194,7 +194,7 @@ def attr(self, name: str) -> str:
     def emit_line(self, line: str = "") -> None:
         if line.startswith("}"):
             self.dedent()
-        self.fragments.append(self._indent * "\t" + line + "\n")
+        self.fragments.append(self._indent * " " + line + "\n")
         if line.endswith("{"):
             self.indent()
 
diff --git a/mypyc/test/test_emit.py b/mypyc/test/test_emit.py
index 1b624a7a6cdb7..7351cd7fb13ee 100644
--- a/mypyc/test/test_emit.py
+++ b/mypyc/test/test_emit.py
@@ -28,4 +28,4 @@ def test_emit_line(self) -> None:
         emitter.emit_line("a {")
         emitter.emit_line("f();")
         emitter.emit_line("}")
-        assert emitter.fragments == ["line;\n", "a {\n", "\tf();\n", "}\n"]
+        assert emitter.fragments == ["line;\n", "a {\n", "    f();\n", "}\n"]
diff --git a/mypyc/test/test_emitfunc.py b/mypyc/test/test_emitfunc.py
index 3b44f7e444c8e..d7dcf3be532b5 100644
--- a/mypyc/test/test_emitfunc.py
+++ b/mypyc/test/test_emitfunc.py
@@ -833,7 +833,7 @@ def assert_emit(
 
         op.accept(visitor)
         frags = declarations.fragments + emitter.fragments
-        actual_lines = [line.strip(" \t") for line in frags]
+        actual_lines = [line.strip(" ") for line in frags]
         assert all(line.endswith("\n") for line in actual_lines)
         actual_lines = [line.rstrip("\n") for line in actual_lines]
         if not expected.strip():
@@ -900,7 +900,7 @@ def test_simple(self) -> None:
                 "    return cpy_r_arg;\n",
                 "}\n",
             ],
-            [line.replace("\t", 4 * " ") for line in result],
+            result,
             msg="Generated code invalid",
         )
 
@@ -927,6 +927,6 @@ def test_register(self) -> None:
                 "    CPy_Unreachable();\n",
                 "}\n",
             ],
-            [line.replace("\t", 4 * " ") for line in result],
+            result,
             msg="Generated code invalid",
         )
diff --git a/mypyc/test/test_emitwrapper.py b/mypyc/test/test_emitwrapper.py
index ec5adb4c6622c..c4465656444c5 100644
--- a/mypyc/test/test_emitwrapper.py
+++ b/mypyc/test/test_emitwrapper.py
@@ -56,6 +56,5 @@ def test_check_int(self) -> None:
         )
 
     def assert_lines(self, expected: list[str], actual: list[str]) -> None:
-        actual = [line.rstrip("\n").replace(4 * " ", "\t") for line in actual]
-        expected = [line.replace(4 * " ", "\t") for line in expected]
+        actual = [line.rstrip("\n") for line in actual]
         assert_string_arrays_equal(expected, actual, "Invalid output")

From cb1d1a0baba37f35268cb605b7345726f257f960 Mon Sep 17 00:00:00 2001
From: Lefteris Karapetsas <lefteris@refu.co>
Date: Wed, 21 Dec 2022 00:16:51 +0100
Subject: [PATCH 132/231] Fix RST markup in type_narrowing.rst (#14253)

Switch :py:func:type to py:class:type in type_narrowing.rst. The former does not render properly in the docs

This is a tiny follow up from
https://github.com/python/mypy/pull/14246#issuecomment-1336467793
---
 docs/source/type_narrowing.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/source/type_narrowing.rst b/docs/source/type_narrowing.rst
index 806835ed33a50..72a8166791401 100644
--- a/docs/source/type_narrowing.rst
+++ b/docs/source/type_narrowing.rst
@@ -16,7 +16,7 @@ The simplest way to narrow a type is to use one of the supported expressions:
 
 - :py:func:`isinstance` like in ``isinstance(obj, float)`` will narrow ``obj`` to have ``float`` type
 - :py:func:`issubclass` like in ``issubclass(cls, MyClass)`` will narrow ``cls`` to be ``Type[MyClass]``
-- :py:func:`type` like in ``type(obj) is int`` will narrow ``obj`` to have ``int`` type
+- :py:class:`type` like in ``type(obj) is int`` will narrow ``obj`` to have ``int`` type
 - :py:func:`callable` like in ``callable(obj)`` will narrow object to callable type
 
 Type narrowing is contextual. For example, based on the condition, mypy will narrow an expression only within an ``if`` branch:

From 2d5108b343ad11f5e2087e9e8ed55202cbd3237c Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 21 Dec 2022 10:27:09 +0000
Subject: [PATCH 133/231] Change various type queries into faster bool type
 queries (#14330)

I measured a 1% performance improvement in self check.
---
 mypy/checker.py        |  7 ++++---
 mypy/checkexpr.py      | 20 ++++++++++----------
 mypy/semanal_shared.py |  6 +++---
 mypy/typeanal.py       | 10 ++++++----
 mypy/types.py          |  4 ++--
 5 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index d56d3e2716f1c..119ce6ae63383 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -177,8 +177,10 @@
     tuple_fallback,
 )
 from mypy.types import (
+    ANY_STRATEGY,
     OVERLOAD_NAMES,
     AnyType,
+    BoolTypeQuery,
     CallableType,
     DeletedType,
     ErasedType,
@@ -196,7 +198,6 @@
     TypedDictType,
     TypeGuardedType,
     TypeOfAny,
-    TypeQuery,
     TypeTranslator,
     TypeType,
     TypeVarId,
@@ -7134,7 +7135,7 @@ def is_valid_inferred_type(typ: Type, is_lvalue_final: bool = False) -> bool:
     return not typ.accept(InvalidInferredTypes())
 
 
-class InvalidInferredTypes(TypeQuery[bool]):
+class InvalidInferredTypes(BoolTypeQuery):
     """Find type components that are not valid for an inferred type.
 
     These include <Erased> type, and any <nothing> types resulting from failed
@@ -7142,7 +7143,7 @@ class InvalidInferredTypes(TypeQuery[bool]):
     """
 
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(ANY_STRATEGY)
 
     def visit_uninhabited_type(self, t: UninhabitedType) -> bool:
         return t.ambiguous
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index b97c78cba2fcd..65be472ccec7f 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -5106,9 +5106,9 @@ def has_any_type(t: Type, ignore_in_type_obj: bool = False) -> bool:
     return t.accept(HasAnyType(ignore_in_type_obj))
 
 
-class HasAnyType(types.TypeQuery[bool]):
+class HasAnyType(types.BoolTypeQuery):
     def __init__(self, ignore_in_type_obj: bool) -> None:
-        super().__init__(any)
+        super().__init__(types.ANY_STRATEGY)
         self.ignore_in_type_obj = ignore_in_type_obj
 
     def visit_any(self, t: AnyType) -> bool:
@@ -5185,7 +5185,7 @@ def replace_callable_return_type(c: CallableType, new_ret_type: Type) -> Callabl
     return c.copy_modified(ret_type=new_ret_type)
 
 
-class ArgInferSecondPassQuery(types.TypeQuery[bool]):
+class ArgInferSecondPassQuery(types.BoolTypeQuery):
     """Query whether an argument type should be inferred in the second pass.
 
     The result is True if the type has a type variable in a callable return
@@ -5194,17 +5194,17 @@ class ArgInferSecondPassQuery(types.TypeQuery[bool]):
     """
 
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(types.ANY_STRATEGY)
 
     def visit_callable_type(self, t: CallableType) -> bool:
         return self.query_types(t.arg_types) or t.accept(HasTypeVarQuery())
 
 
-class HasTypeVarQuery(types.TypeQuery[bool]):
+class HasTypeVarQuery(types.BoolTypeQuery):
     """Visitor for querying whether a type has a type variable component."""
 
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(types.ANY_STRATEGY)
 
     def visit_type_var(self, t: TypeVarType) -> bool:
         return True
@@ -5214,11 +5214,11 @@ def has_erased_component(t: Type | None) -> bool:
     return t is not None and t.accept(HasErasedComponentsQuery())
 
 
-class HasErasedComponentsQuery(types.TypeQuery[bool]):
+class HasErasedComponentsQuery(types.BoolTypeQuery):
     """Visitor for querying whether a type has an erased component."""
 
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(types.ANY_STRATEGY)
 
     def visit_erased_type(self, t: ErasedType) -> bool:
         return True
@@ -5228,11 +5228,11 @@ def has_uninhabited_component(t: Type | None) -> bool:
     return t is not None and t.accept(HasUninhabitedComponentsQuery())
 
 
-class HasUninhabitedComponentsQuery(types.TypeQuery[bool]):
+class HasUninhabitedComponentsQuery(types.BoolTypeQuery):
     """Visitor for querying whether a type has an UninhabitedType component."""
 
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(types.ANY_STRATEGY)
 
     def visit_uninhabited_type(self, t: UninhabitedType) -> bool:
         return True
diff --git a/mypy/semanal_shared.py b/mypy/semanal_shared.py
index ee9218f02b3e7..e5be4aa55cd31 100644
--- a/mypy/semanal_shared.py
+++ b/mypy/semanal_shared.py
@@ -21,7 +21,7 @@
     TypeInfo,
 )
 from mypy.tvar_scope import TypeVarLikeScope
-from mypy.type_visitor import TypeQuery
+from mypy.type_visitor import ANY_STRATEGY, BoolTypeQuery
 from mypy.types import (
     TPDICT_FB_NAMES,
     FunctionLike,
@@ -319,9 +319,9 @@ def paramspec_kwargs(
     )
 
 
-class HasPlaceholders(TypeQuery[bool]):
+class HasPlaceholders(BoolTypeQuery):
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(ANY_STRATEGY)
 
     def visit_placeholder_type(self, t: PlaceholderType) -> bool:
         return True
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 468b10fc98474..e4f56924d2d7d 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -42,11 +42,13 @@
 from mypy.tvar_scope import TypeVarLikeScope
 from mypy.types import (
     ANNOTATED_TYPE_NAMES,
+    ANY_STRATEGY,
     FINAL_TYPE_NAMES,
     LITERAL_TYPE_NAMES,
     NEVER_NAMES,
     TYPE_ALIAS_NAMES,
     AnyType,
+    BoolTypeQuery,
     CallableArgument,
     CallableType,
     DeletedType,
@@ -1944,9 +1946,9 @@ def has_any_from_unimported_type(t: Type) -> bool:
     return t.accept(HasAnyFromUnimportedType())
 
 
-class HasAnyFromUnimportedType(TypeQuery[bool]):
+class HasAnyFromUnimportedType(BoolTypeQuery):
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(ANY_STRATEGY)
 
     def visit_any(self, t: AnyType) -> bool:
         return t.type_of_any == TypeOfAny.from_unimported_type
@@ -2033,10 +2035,10 @@ def find_self_type(typ: Type, lookup: Callable[[str], SymbolTableNode | None]) -
     return typ.accept(HasSelfType(lookup))
 
 
-class HasSelfType(TypeQuery[bool]):
+class HasSelfType(BoolTypeQuery):
     def __init__(self, lookup: Callable[[str], SymbolTableNode | None]) -> None:
         self.lookup = lookup
-        super().__init__(any)
+        super().__init__(ANY_STRATEGY)
 
     def visit_unbound_type(self, t: UnboundType) -> bool:
         sym = self.lookup(t.name)
diff --git a/mypy/types.py b/mypy/types.py
index 383e5621060e1..86a700d524699 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3305,9 +3305,9 @@ def replace_alias_tvars(
     return new_tp
 
 
-class HasTypeVars(TypeQuery[bool]):
+class HasTypeVars(BoolTypeQuery):
     def __init__(self) -> None:
-        super().__init__(any)
+        super().__init__(ANY_STRATEGY)
         self.skip_alias_target = True
 
     def visit_type_var(self, t: TypeVarType) -> bool:

From 4e32da85bdae5b379711c6a1443a58e37d003037 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 21 Dec 2022 11:37:06 +0000
Subject: [PATCH 134/231] Refactor TypeState into a singleton class (#14327)

This helps mypyc, since accessing mutable attributes of singleton
instances is faster than accessing class variables. The implementation
is also arguably a bit cleaner.

This seems performance-neutral or a very minor optimization, but if we
continue to add attributes to TypeState, this can help.
---
 mypy/build.py           |   8 +--
 mypy/checkexpr.py       |   8 +--
 mypy/constraints.py     |   8 +--
 mypy/mro.py             |   4 +-
 mypy/server/astmerge.py |   4 +-
 mypy/server/aststrip.py |   4 +-
 mypy/server/deps.py     |   6 +-
 mypy/server/update.py   |   6 +-
 mypy/solve.py           |   4 +-
 mypy/subtypes.py        |  20 +++---
 mypy/test/testdeps.py   |   4 +-
 mypy/typestate.py       | 141 ++++++++++++++++++++--------------------
 12 files changed, 108 insertions(+), 109 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index d2bcd572969e8..2e0fa455554af 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -100,7 +100,7 @@
     stub_package_name,
 )
 from mypy.types import Type
-from mypy.typestate import TypeState, reset_global_state
+from mypy.typestate import reset_global_state, type_state
 from mypy.version import __version__
 
 # Switch to True to produce debug output related to fine-grained incremental
@@ -276,7 +276,7 @@ def _build(
     try:
         graph = dispatch(sources, manager, stdout)
         if not options.fine_grained_incremental:
-            TypeState.reset_all_subtype_caches()
+            type_state.reset_all_subtype_caches()
         if options.timing_stats is not None:
             dump_timing_stats(options.timing_stats, graph)
         if options.line_checking_stats is not None:
@@ -2459,7 +2459,7 @@ def update_fine_grained_deps(self, deps: dict[str, set[str]]) -> None:
             from mypy.server.deps import merge_dependencies  # Lazy import to speed up startup
 
             merge_dependencies(self.compute_fine_grained_deps(), deps)
-            TypeState.update_protocol_deps(deps)
+            type_state.update_protocol_deps(deps)
 
     def valid_references(self) -> set[str]:
         assert self.ancestors is not None
@@ -2926,7 +2926,7 @@ def dispatch(sources: list[BuildSource], manager: BuildManager, stdout: TextIO)
             # then we need to collect fine grained protocol dependencies.
             # Since these are a global property of the program, they are calculated after we
             # processed the whole graph.
-            TypeState.add_all_protocol_deps(manager.fg_deps)
+            type_state.add_all_protocol_deps(manager.fg_deps)
             if not manager.options.fine_grained_incremental:
                 rdeps = generate_deps_for_cache(manager, graph)
                 write_deps_cache(rdeps, manager, graph)
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 65be472ccec7f..d839ad4925fde 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -162,7 +162,7 @@
     is_self_type_like,
     remove_optional,
 )
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 from mypy.typevars import fill_typevars
 from mypy.util import split_module_names
 from mypy.visitor import ExpressionVisitor
@@ -1591,13 +1591,13 @@ def allow_unions(self, type_context: Type) -> Iterator[None]:
         # of joins. This is a bit arbitrary, but in practice it works for most
         # cases. A cleaner alternative would be to switch to single bin type
         # inference, but this is a lot of work.
-        old = TypeState.infer_unions
+        old = type_state.infer_unions
         if has_recursive_types(type_context):
-            TypeState.infer_unions = True
+            type_state.infer_unions = True
         try:
             yield
         finally:
-            TypeState.infer_unions = old
+            type_state.infer_unions = old
 
     def infer_arg_types_in_context(
         self,
diff --git a/mypy/constraints.py b/mypy/constraints.py
index 3a6553a307fdc..fe3c1a19ff181 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -48,7 +48,7 @@
     is_named_instance,
     is_union_with_any,
 )
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 from mypy.typevartuples import (
     extract_unpack,
     find_unpack_in_list,
@@ -198,7 +198,7 @@ def infer_constraints(template: Type, actual: Type, direction: int) -> list[Cons
     if any(
         get_proper_type(template) == get_proper_type(t)
         and get_proper_type(actual) == get_proper_type(a)
-        for (t, a) in reversed(TypeState.inferring)
+        for (t, a) in reversed(type_state.inferring)
     ):
         return []
     if has_recursive_types(template) or isinstance(get_proper_type(template), Instance):
@@ -207,9 +207,9 @@ def infer_constraints(template: Type, actual: Type, direction: int) -> list[Cons
         if not has_type_vars(template):
             # Return early on an empty branch.
             return []
-        TypeState.inferring.append((template, actual))
+        type_state.inferring.append((template, actual))
         res = _infer_constraints(template, actual, direction)
-        TypeState.inferring.pop()
+        type_state.inferring.pop()
         return res
     return _infer_constraints(template, actual, direction)
 
diff --git a/mypy/mro.py b/mypy/mro.py
index 912cf3e2e341a..cc9f88a9d0455 100644
--- a/mypy/mro.py
+++ b/mypy/mro.py
@@ -4,7 +4,7 @@
 
 from mypy.nodes import TypeInfo
 from mypy.types import Instance
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 
 
 def calculate_mro(info: TypeInfo, obj_type: Callable[[], Instance] | None = None) -> None:
@@ -17,7 +17,7 @@ def calculate_mro(info: TypeInfo, obj_type: Callable[[], Instance] | None = None
     info.mro = mro
     # The property of falling back to Any is inherited.
     info.fallback_to_any = any(baseinfo.fallback_to_any for baseinfo in info.mro)
-    TypeState.reset_all_subtype_caches_for(info)
+    type_state.reset_all_subtype_caches_for(info)
 
 
 class MroError(Exception):
diff --git a/mypy/server/astmerge.py b/mypy/server/astmerge.py
index 04422036b67b0..6ce737c425209 100644
--- a/mypy/server/astmerge.py
+++ b/mypy/server/astmerge.py
@@ -110,7 +110,7 @@
     UnionType,
     UnpackType,
 )
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 from mypy.util import get_prefix, replace_object_state
 
 
@@ -360,7 +360,7 @@ def fixup_and_reset_typeinfo(self, node: TypeInfo) -> TypeInfo:
             # The subclass relationships may change, so reset all caches relevant to the
             # old MRO.
             new = cast(TypeInfo, self.replacements[node])
-            TypeState.reset_all_subtype_caches_for(new)
+            type_state.reset_all_subtype_caches_for(new)
         return self.fixup(node)
 
     def fixup_type(self, typ: Type | None) -> None:
diff --git a/mypy/server/aststrip.py b/mypy/server/aststrip.py
index 83d90f31e8c43..b0666f8e1ff4d 100644
--- a/mypy/server/aststrip.py
+++ b/mypy/server/aststrip.py
@@ -66,7 +66,7 @@
 )
 from mypy.traverser import TraverserVisitor
 from mypy.types import CallableType
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 
 SavedAttributes: _TypeAlias = Dict[Tuple[ClassDef, str], SymbolTableNode]
 
@@ -143,7 +143,7 @@ def visit_class_def(self, node: ClassDef) -> None:
             super().visit_class_def(node)
         node.defs.body.extend(node.removed_statements)
         node.removed_statements = []
-        TypeState.reset_subtype_caches_for(node.info)
+        type_state.reset_subtype_caches_for(node.info)
         # Kill the TypeInfo, since there is none before semantic analysis.
         node.info = CLASSDEF_NO_INFO
         node.analyzed = None
diff --git a/mypy/server/deps.py b/mypy/server/deps.py
index 45d7947641da0..eb40737061bf0 100644
--- a/mypy/server/deps.py
+++ b/mypy/server/deps.py
@@ -172,7 +172,7 @@ class 'mod.Cls'. This can also refer to an attribute inherited from a
     UnpackType,
     get_proper_type,
 )
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 from mypy.util import correct_relative_import
 
 
@@ -344,7 +344,7 @@ def process_type_info(self, info: TypeInfo) -> None:
                 self.add_dependency(
                     make_wildcard_trigger(base_info.fullname), target=make_trigger(target)
                 )
-                # More protocol dependencies are collected in TypeState._snapshot_protocol_deps
+                # More protocol dependencies are collected in type_state._snapshot_protocol_deps
                 # after a full run or update is finished.
 
         self.add_type_alias_deps(self.scope.current_target())
@@ -1123,7 +1123,7 @@ def dump_all_dependencies(
         deps = get_dependencies(node, type_map, python_version, options)
         for trigger, targets in deps.items():
             all_deps.setdefault(trigger, set()).update(targets)
-    TypeState.add_all_protocol_deps(all_deps)
+    type_state.add_all_protocol_deps(all_deps)
 
     for trigger, targets in sorted(all_deps.items(), key=lambda x: x[0]):
         print(trigger)
diff --git a/mypy/server/update.py b/mypy/server/update.py
index e9750dec1e2a8..9bea1998c0e5a 100644
--- a/mypy/server/update.py
+++ b/mypy/server/update.py
@@ -157,7 +157,7 @@
 from mypy.server.deps import get_dependencies_of_target, merge_dependencies
 from mypy.server.target import trigger_to_target
 from mypy.server.trigger import WILDCARD_TAG, make_trigger
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 from mypy.util import module_prefix, split_target
 
 MAX_ITER: Final = 1000
@@ -869,7 +869,7 @@ def propagate_changes_using_dependencies(
         # We need to do this to avoid false negatives if the protocol itself is
         # unchanged, but was marked stale because its sub- (or super-) type changed.
         for info in stale_protos:
-            TypeState.reset_subtype_caches_for(info)
+            type_state.reset_subtype_caches_for(info)
         # Then fully reprocess all targets.
         # TODO: Preserve order (set is not optimal)
         for id, nodes in sorted(todo.items(), key=lambda x: x[0]):
@@ -1081,7 +1081,7 @@ def update_deps(
         for trigger, targets in new_deps.items():
             deps.setdefault(trigger, set()).update(targets)
     # Merge also the newly added protocol deps (if any).
-    TypeState.update_protocol_deps(deps)
+    type_state.update_protocol_deps(deps)
 
 
 def lookup_target(
diff --git a/mypy/solve.py b/mypy/solve.py
index c9c7db1ae26c7..b8304d29c1ce9 100644
--- a/mypy/solve.py
+++ b/mypy/solve.py
@@ -18,7 +18,7 @@
     UnionType,
     get_proper_type,
 )
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 
 
 def solve_constraints(
@@ -54,7 +54,7 @@ def solve_constraints(
                 if bottom is None:
                     bottom = c.target
                 else:
-                    if TypeState.infer_unions:
+                    if type_state.infer_unions:
                         # This deviates from the general mypy semantics because
                         # recursive types are union-heavy in 95% of cases.
                         bottom = UnionType.make_union([bottom, c.target])
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index b8d59977f986e..994c4081addd8 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -60,7 +60,7 @@
     get_proper_type,
     is_named_instance,
 )
-from mypy.typestate import SubtypeKind, TypeState
+from mypy.typestate import SubtypeKind, type_state
 from mypy.typevars import fill_typevars_with_any
 from mypy.typevartuples import extract_unpack, fully_split_with_mapped_and_template
 
@@ -154,7 +154,7 @@ def is_subtype(
                 options,
             }
         ), "Don't pass both context and individual flags"
-    if TypeState.is_assumed_subtype(left, right):
+    if type_state.is_assumed_subtype(left, right):
         return True
     if mypy.typeops.is_recursive_pair(left, right):
         # This case requires special care because it may cause infinite recursion.
@@ -174,7 +174,7 @@ def is_subtype(
         #     B = Union[int, Tuple[B, ...]]
         # When checking if A <: B we push pair (A, B) onto 'assuming' stack, then when after few
         # steps we come back to initial call is_subtype(A, B) and immediately return True.
-        with pop_on_exit(TypeState.get_assumptions(is_proper=False), left, right):
+        with pop_on_exit(type_state.get_assumptions(is_proper=False), left, right):
             return _is_subtype(left, right, subtype_context, proper_subtype=False)
     return _is_subtype(left, right, subtype_context, proper_subtype=False)
 
@@ -215,11 +215,11 @@ def is_proper_subtype(
                 ignore_uninhabited,
             }
         ), "Don't pass both context and individual flags"
-    if TypeState.is_assumed_proper_subtype(left, right):
+    if type_state.is_assumed_proper_subtype(left, right):
         return True
     if mypy.typeops.is_recursive_pair(left, right):
         # Same as for non-proper subtype, see detailed comment there for explanation.
-        with pop_on_exit(TypeState.get_assumptions(is_proper=True), left, right):
+        with pop_on_exit(type_state.get_assumptions(is_proper=True), left, right):
             return _is_subtype(left, right, subtype_context, proper_subtype=True)
     return _is_subtype(left, right, subtype_context, proper_subtype=True)
 
@@ -445,14 +445,14 @@ def visit_instance(self, left: Instance) -> bool:
         if isinstance(right, TupleType) and mypy.typeops.tuple_fallback(right).type.is_enum:
             return self._is_subtype(left, mypy.typeops.tuple_fallback(right))
         if isinstance(right, Instance):
-            if TypeState.is_cached_subtype_check(self._subtype_kind, left, right):
+            if type_state.is_cached_subtype_check(self._subtype_kind, left, right):
                 return True
             if not self.subtype_context.ignore_promotions:
                 for base in left.type.mro:
                     if base._promote and any(
                         self._is_subtype(p, self.right) for p in base._promote
                     ):
-                        TypeState.record_subtype_cache_entry(self._subtype_kind, left, right)
+                        type_state.record_subtype_cache_entry(self._subtype_kind, left, right)
                         return True
                 # Special case: Low-level integer types are compatible with 'int'. We can't
                 # use promotions, since 'int' is already promoted to low-level integer types,
@@ -589,7 +589,7 @@ def check_mixed(
                             ):
                                 nominal = False
                 if nominal:
-                    TypeState.record_subtype_cache_entry(self._subtype_kind, left, right)
+                    type_state.record_subtype_cache_entry(self._subtype_kind, left, right)
                 return nominal
             if right.type.is_protocol and is_protocol_implementation(
                 left, right, proper_subtype=self.proper_subtype
@@ -978,7 +978,7 @@ def f(self) -> A: ...
     if skip is None:
         skip = []
     # We need to record this check to generate protocol fine-grained dependencies.
-    TypeState.record_protocol_subtype_check(left.type, right.type)
+    type_state.record_protocol_subtype_check(left.type, right.type)
     # nominal subtyping currently ignores '__init__' and '__new__' signatures
     members_not_to_check = {"__init__", "__new__"}
     members_not_to_check.update(skip)
@@ -1078,7 +1078,7 @@ def named_type(fullname: str) -> Instance:
         subtype_context=SubtypeContext(ignore_pos_arg_names=ignore_names),
         proper_subtype=proper_subtype,
     )
-    TypeState.record_subtype_cache_entry(subtype_kind, left, right)
+    type_state.record_subtype_cache_entry(subtype_kind, left, right)
     return True
 
 
diff --git a/mypy/test/testdeps.py b/mypy/test/testdeps.py
index ae1c613f7563e..3343762cfaafd 100644
--- a/mypy/test/testdeps.py
+++ b/mypy/test/testdeps.py
@@ -15,7 +15,7 @@
 from mypy.test.data import DataDrivenTestCase, DataSuite
 from mypy.test.helpers import assert_string_arrays_equal, find_test_files, parse_options
 from mypy.types import Type
-from mypy.typestate import TypeState
+from mypy.typestate import type_state
 
 # Only dependencies in these modules are dumped
 dumped_modules = ["__main__", "pkg", "pkg.mod"]
@@ -54,7 +54,7 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
                     for source in new_deps:
                         deps[source].update(new_deps[source])
 
-            TypeState.add_all_protocol_deps(deps)
+            type_state.add_all_protocol_deps(deps)
 
             for source, targets in sorted(deps.items()):
                 if source.startswith(("<enum", "<typing", "<mypy")):
diff --git a/mypy/typestate.py b/mypy/typestate.py
index 7398f0d7f5242..9cbad17aa7bdf 100644
--- a/mypy/typestate.py
+++ b/mypy/typestate.py
@@ -5,7 +5,7 @@
 
 from __future__ import annotations
 
-from typing import ClassVar, Dict, Set, Tuple
+from typing import Dict, Set, Tuple
 from typing_extensions import Final, TypeAlias as _TypeAlias
 
 from mypy.nodes import TypeInfo
@@ -40,7 +40,7 @@ class TypeState:
     # was done in strict optional mode and of the specific *kind* of subtyping relationship,
     # which we represent as an arbitrary hashable tuple.
     # We need the caches, since subtype checks for structural types are very slow.
-    _subtype_caches: Final[SubtypeCache] = {}
+    _subtype_caches: Final[SubtypeCache]
 
     # This contains protocol dependencies generated after running a full build,
     # or after an update. These dependencies are special because:
@@ -53,7 +53,7 @@ class TypeState:
     # A blocking error will be generated in this case, since we can't proceed safely.
     # For the description of kinds of protocol dependencies and corresponding examples,
     # see _snapshot_protocol_deps.
-    proto_deps: ClassVar[dict[str, set[str]] | None] = {}
+    proto_deps: dict[str, set[str]] | None
 
     # Protocols (full names) a given class attempted to implement.
     # Used to calculate fine grained protocol dependencies and optimize protocol
@@ -61,13 +61,13 @@ class TypeState:
     # of type a.A to a function expecting something compatible with protocol p.P,
     # we'd have 'a.A' -> {'p.P', ...} in the map. This map is flushed after every incremental
     # update.
-    _attempted_protocols: Final[dict[str, set[str]]] = {}
+    _attempted_protocols: Final[dict[str, set[str]]]
     # We also snapshot protocol members of the above protocols. For example, if we pass
     # a value of type a.A to a function expecting something compatible with Iterable, we'd have
     # 'a.A' -> {'__iter__', ...} in the map. This map is also flushed after every incremental
     # update. This map is needed to only generate dependencies like <a.A.__iter__> -> <a.A>
     # instead of a wildcard to avoid unnecessarily invalidating classes.
-    _checked_against_members: Final[dict[str, set[str]]] = {}
+    _checked_against_members: Final[dict[str, set[str]]]
     # TypeInfos that appeared as a left type (subtype) in a subtype check since latest
     # dependency snapshot update. This is an optimisation for fine grained mode; during a full
     # run we only take a dependency snapshot at the very end, so this set will contain all
@@ -75,74 +75,78 @@ class TypeState:
     # dependencies generated from (typically) few TypeInfos that were subtype-checked
     # (i.e. appeared as r.h.s. in an assignment or an argument in a function call in
     # a re-checked target) during the update.
-    _rechecked_types: Final[set[TypeInfo]] = set()
+    _rechecked_types: Final[set[TypeInfo]]
 
     # The two attributes below are assumption stacks for subtyping relationships between
     # recursive type aliases. Normally, one would pass type assumptions as an additional
     # arguments to is_subtype(), but this would mean updating dozens of related functions
     # threading this through all callsites (see also comment for TypeInfo.assuming).
-    _assuming: Final[list[tuple[Type, Type]]] = []
-    _assuming_proper: Final[list[tuple[Type, Type]]] = []
+    _assuming: Final[list[tuple[Type, Type]]]
+    _assuming_proper: Final[list[tuple[Type, Type]]]
     # Ditto for inference of generic constraints against recursive type aliases.
-    inferring: Final[list[tuple[Type, Type]]] = []
+    inferring: Final[list[tuple[Type, Type]]]
     # Whether to use joins or unions when solving constraints, see checkexpr.py for details.
-    infer_unions: ClassVar = False
+    infer_unions: bool
 
     # N.B: We do all of the accesses to these properties through
     # TypeState, instead of making these classmethods and accessing
     # via the cls parameter, since mypyc can optimize accesses to
     # Final attributes of a directly referenced type.
 
-    @staticmethod
-    def is_assumed_subtype(left: Type, right: Type) -> bool:
-        for (l, r) in reversed(TypeState._assuming):
+    def __init__(self) -> None:
+        self._subtype_caches = {}
+        self.proto_deps = {}
+        self._attempted_protocols = {}
+        self._checked_against_members = {}
+        self._rechecked_types = set()
+        self._assuming = []
+        self._assuming_proper = []
+        self.inferring = []
+        self.infer_unions = False
+
+    def is_assumed_subtype(self, left: Type, right: Type) -> bool:
+        for (l, r) in reversed(self._assuming):
             if get_proper_type(l) == get_proper_type(left) and get_proper_type(
                 r
             ) == get_proper_type(right):
                 return True
         return False
 
-    @staticmethod
-    def is_assumed_proper_subtype(left: Type, right: Type) -> bool:
-        for (l, r) in reversed(TypeState._assuming_proper):
+    def is_assumed_proper_subtype(self, left: Type, right: Type) -> bool:
+        for (l, r) in reversed(self._assuming_proper):
             if get_proper_type(l) == get_proper_type(left) and get_proper_type(
                 r
             ) == get_proper_type(right):
                 return True
         return False
 
-    @staticmethod
-    def get_assumptions(is_proper: bool) -> list[tuple[Type, Type]]:
+    def get_assumptions(self, is_proper: bool) -> list[tuple[Type, Type]]:
         if is_proper:
-            return TypeState._assuming_proper
-        return TypeState._assuming
+            return self._assuming_proper
+        return self._assuming
 
-    @staticmethod
-    def reset_all_subtype_caches() -> None:
+    def reset_all_subtype_caches(self) -> None:
         """Completely reset all known subtype caches."""
-        TypeState._subtype_caches.clear()
+        self._subtype_caches.clear()
 
-    @staticmethod
-    def reset_subtype_caches_for(info: TypeInfo) -> None:
+    def reset_subtype_caches_for(self, info: TypeInfo) -> None:
         """Reset subtype caches (if any) for a given supertype TypeInfo."""
-        if info in TypeState._subtype_caches:
-            TypeState._subtype_caches[info].clear()
+        if info in self._subtype_caches:
+            self._subtype_caches[info].clear()
 
-    @staticmethod
-    def reset_all_subtype_caches_for(info: TypeInfo) -> None:
+    def reset_all_subtype_caches_for(self, info: TypeInfo) -> None:
         """Reset subtype caches (if any) for a given supertype TypeInfo and its MRO."""
         for item in info.mro:
-            TypeState.reset_subtype_caches_for(item)
+            self.reset_subtype_caches_for(item)
 
-    @staticmethod
-    def is_cached_subtype_check(kind: SubtypeKind, left: Instance, right: Instance) -> bool:
+    def is_cached_subtype_check(self, kind: SubtypeKind, left: Instance, right: Instance) -> bool:
         if left.last_known_value is not None or right.last_known_value is not None:
             # If there is a literal last known value, give up. There
             # will be an unbounded number of potential types to cache,
             # making caching less effective.
             return False
         info = right.type
-        cache = TypeState._subtype_caches.get(info)
+        cache = self._subtype_caches.get(info)
         if cache is None:
             return False
         subcache = cache.get(kind)
@@ -150,36 +154,32 @@ def is_cached_subtype_check(kind: SubtypeKind, left: Instance, right: Instance)
             return False
         return (left, right) in subcache
 
-    @staticmethod
-    def record_subtype_cache_entry(kind: SubtypeKind, left: Instance, right: Instance) -> None:
+    def record_subtype_cache_entry(
+        self, kind: SubtypeKind, left: Instance, right: Instance
+    ) -> None:
         if left.last_known_value is not None or right.last_known_value is not None:
             # These are unlikely to match, due to the large space of
             # possible values.  Avoid uselessly increasing cache sizes.
             return
-        cache = TypeState._subtype_caches.setdefault(right.type, dict())
+        cache = self._subtype_caches.setdefault(right.type, dict())
         cache.setdefault(kind, set()).add((left, right))
 
-    @staticmethod
-    def reset_protocol_deps() -> None:
+    def reset_protocol_deps(self) -> None:
         """Reset dependencies after a full run or before a daemon shutdown."""
-        TypeState.proto_deps = {}
-        TypeState._attempted_protocols.clear()
-        TypeState._checked_against_members.clear()
-        TypeState._rechecked_types.clear()
+        self.proto_deps = {}
+        self._attempted_protocols.clear()
+        self._checked_against_members.clear()
+        self._rechecked_types.clear()
 
-    @staticmethod
-    def record_protocol_subtype_check(left_type: TypeInfo, right_type: TypeInfo) -> None:
+    def record_protocol_subtype_check(self, left_type: TypeInfo, right_type: TypeInfo) -> None:
         assert right_type.is_protocol
-        TypeState._rechecked_types.add(left_type)
-        TypeState._attempted_protocols.setdefault(left_type.fullname, set()).add(
-            right_type.fullname
-        )
-        TypeState._checked_against_members.setdefault(left_type.fullname, set()).update(
+        self._rechecked_types.add(left_type)
+        self._attempted_protocols.setdefault(left_type.fullname, set()).add(right_type.fullname)
+        self._checked_against_members.setdefault(left_type.fullname, set()).update(
             right_type.protocol_members
         )
 
-    @staticmethod
-    def _snapshot_protocol_deps() -> dict[str, set[str]]:
+    def _snapshot_protocol_deps(self) -> dict[str, set[str]]:
         """Collect protocol attribute dependencies found so far from registered subtype checks.
 
         There are three kinds of protocol dependencies. For example, after a subtype check:
@@ -209,8 +209,8 @@ def __iter__(self) -> Iterator[int]:
         'subtypes.is_protocol_implementation').
         """
         deps: dict[str, set[str]] = {}
-        for info in TypeState._rechecked_types:
-            for attr in TypeState._checked_against_members[info.fullname]:
+        for info in self._rechecked_types:
+            for attr in self._checked_against_members[info.fullname]:
                 # The need for full MRO here is subtle, during an update, base classes of
                 # a concrete class may not be reprocessed, so not all <B.x> -> <C.x> deps
                 # are added.
@@ -220,7 +220,7 @@ def __iter__(self) -> Iterator[int]:
                         # TODO: avoid everything from typeshed
                         continue
                     deps.setdefault(trigger, set()).add(make_trigger(info.fullname))
-            for proto in TypeState._attempted_protocols[info.fullname]:
+            for proto in self._attempted_protocols[info.fullname]:
                 trigger = make_trigger(info.fullname)
                 if "typing" in trigger or "builtins" in trigger:
                     continue
@@ -233,46 +233,45 @@ def __iter__(self) -> Iterator[int]:
                 deps.setdefault(trigger, set()).add(proto)
         return deps
 
-    @staticmethod
-    def update_protocol_deps(second_map: dict[str, set[str]] | None = None) -> None:
+    def update_protocol_deps(self, second_map: dict[str, set[str]] | None = None) -> None:
         """Update global protocol dependency map.
 
         We update the global map incrementally, using a snapshot only from recently
         type checked types. If second_map is given, update it as well. This is currently used
         by FineGrainedBuildManager that maintains normal (non-protocol) dependencies.
         """
-        assert (
-            TypeState.proto_deps is not None
-        ), "This should not be called after failed cache load"
-        new_deps = TypeState._snapshot_protocol_deps()
+        assert self.proto_deps is not None, "This should not be called after failed cache load"
+        new_deps = self._snapshot_protocol_deps()
         for trigger, targets in new_deps.items():
-            TypeState.proto_deps.setdefault(trigger, set()).update(targets)
+            self.proto_deps.setdefault(trigger, set()).update(targets)
         if second_map is not None:
             for trigger, targets in new_deps.items():
                 second_map.setdefault(trigger, set()).update(targets)
-        TypeState._rechecked_types.clear()
-        TypeState._attempted_protocols.clear()
-        TypeState._checked_against_members.clear()
+        self._rechecked_types.clear()
+        self._attempted_protocols.clear()
+        self._checked_against_members.clear()
 
-    @staticmethod
-    def add_all_protocol_deps(deps: dict[str, set[str]]) -> None:
+    def add_all_protocol_deps(self, deps: dict[str, set[str]]) -> None:
         """Add all known protocol dependencies to deps.
 
         This is used by tests and debug output, and also when collecting
         all collected or loaded dependencies as part of build.
         """
-        TypeState.update_protocol_deps()  # just in case
-        if TypeState.proto_deps is not None:
-            for trigger, targets in TypeState.proto_deps.items():
+        self.update_protocol_deps()  # just in case
+        if self.proto_deps is not None:
+            for trigger, targets in self.proto_deps.items():
                 deps.setdefault(trigger, set()).update(targets)
 
 
+type_state: Final = TypeState()
+
+
 def reset_global_state() -> None:
     """Reset most existing global state.
 
     Currently most of it is in this module. Few exceptions are strict optional status and
     and functools.lru_cache.
     """
-    TypeState.reset_all_subtype_caches()
-    TypeState.reset_protocol_deps()
+    type_state.reset_all_subtype_caches()
+    type_state.reset_protocol_deps()
     TypeVarId.next_raw_id = 1

From 87335997808207a138125a2f52fb8f4dc5a69fa3 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 21 Dec 2022 12:56:20 +0000
Subject: [PATCH 135/231] Avoid the use of a context manager in hot code path
 (#14331)

Mypyc can't optimize context managers yet, so it's best to avoid them in
hot code paths.

This sacrifices some code quality for a considerable perf gain. This
improved self-check performance by 4%.
---
 mypy/checkexpr.py | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index d839ad4925fde..c990e9b59f985 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -1583,21 +1583,21 @@ def infer_arg_types_in_empty_context(self, args: list[Expression]) -> list[Type]
                 res.append(arg_type)
         return res
 
-    @contextmanager
-    def allow_unions(self, type_context: Type) -> Iterator[None]:
-        # This is a hack to better support inference for recursive types.
-        # When the outer context for a function call is known to be recursive,
-        # we solve type constraints inferred from arguments using unions instead
-        # of joins. This is a bit arbitrary, but in practice it works for most
-        # cases. A cleaner alternative would be to switch to single bin type
-        # inference, but this is a lot of work.
+    def infer_more_unions_for_recursive_type(self, type_context: Type) -> bool:
+        """Adjust type inference of unions if type context has a recursive type.
+
+        Return the old state. The caller must assign it to type_state.infer_unions
+        afterwards.
+
+        This is a hack to better support inference for recursive types.
+
+        Note: This is performance-sensitive and must not be a context manager
+        until mypyc supports them better.
+        """
         old = type_state.infer_unions
         if has_recursive_types(type_context):
             type_state.infer_unions = True
-        try:
-            yield
-        finally:
-            type_state.infer_unions = old
+        return old
 
     def infer_arg_types_in_context(
         self,
@@ -1618,8 +1618,16 @@ def infer_arg_types_in_context(
         for i, actuals in enumerate(formal_to_actual):
             for ai in actuals:
                 if not arg_kinds[ai].is_star():
-                    with self.allow_unions(callee.arg_types[i]):
-                        res[ai] = self.accept(args[ai], callee.arg_types[i])
+                    arg_type = callee.arg_types[i]
+                    # When the outer context for a function call is known to be recursive,
+                    # we solve type constraints inferred from arguments using unions instead
+                    # of joins. This is a bit arbitrary, but in practice it works for most
+                    # cases. A cleaner alternative would be to switch to single bin type
+                    # inference, but this is a lot of work.
+                    old = self.infer_more_unions_for_recursive_type(arg_type)
+                    res[ai] = self.accept(args[ai], arg_type)
+                    # We need to manually restore union inference state, ugh.
+                    type_state.infer_unions = old
 
         # Fill in the rest of the argument types.
         for i, t in enumerate(res):

From 1a7823ecaad94d8da11b626de90c37972c00c43e Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 21 Dec 2022 14:13:16 +0000
Subject: [PATCH 136/231] Tool to compare performance of any number of mypy
 commits/branches (#14332)

The script compiles some mypy commits in parallel and then measures how
long each version takes to self-check a specific mypy commit. It
measures the performance 15 times for each commit and takes the average.

Based on some experiments, the noise floor on my Linux desktop is about
0.5% to 1.0%. Any difference above 1.0% is likely significant, I
believe. For differences between 0.5% and 1.0% it makes sense to repeat
the measurement a few times.

The interesting part of the output looks something like this:
```
...
=== Results ===

145d8a41b17ab1ba8707589be9cb5d56bbebd0ea 8.207s (0.0%)
145d8a41b17ab1ba8707589be9cb5d56bbebd0ea~1 8.105s (-1.2%)
```

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
---
 misc/perf_compare.py | 146 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 misc/perf_compare.py

diff --git a/misc/perf_compare.py b/misc/perf_compare.py
new file mode 100644
index 0000000000000..be05bb6ddc32a
--- /dev/null
+++ b/misc/perf_compare.py
@@ -0,0 +1,146 @@
+"""Compare performance of mypyc-compiled mypy between one or more commits/branches.
+
+Simple usage:
+
+  python misc/perf_compare.py my-branch master ...
+
+What this does:
+
+ * Create a temp clone of the mypy repo for each target commit to measure
+ * Checkout a target commit in each of the clones
+ * Compile mypyc in each of the clones *in parallel*
+ * Create another temp clone of the mypy repo as the code to check
+ * Self check with each of the compiled mypys N times
+ * Report the average runtimes and relative performance
+ * Remove the temp clones
+"""
+
+from __future__ import annotations
+
+import argparse
+import glob
+import os
+import random
+import shutil
+import statistics
+import subprocess
+import sys
+import threading
+import time
+
+
+def heading(s: str) -> None:
+    print()
+    print(f"=== {s} ===")
+    print()
+
+
+def build_mypy(target_dir: str) -> None:
+    env = os.environ.copy()
+    env["CC"] = "clang"
+    env["MYPYC_OPT_LEVEL"] = "2"
+    cmd = [sys.executable, "setup.py", "--use-mypyc", "build_ext", "--inplace"]
+    subprocess.run(cmd, env=env, check=True, cwd=target_dir)
+
+
+def clone(target_dir: str, commit: str | None) -> None:
+    heading(f"Cloning mypy to {target_dir}")
+    repo_dir = os.getcwd()
+    if os.path.isdir(target_dir):
+        print(f"{target_dir} exists: deleting")
+        shutil.rmtree(target_dir)
+    subprocess.run(["git", "clone", repo_dir, target_dir], check=True)
+    if commit:
+        subprocess.run(["git", "checkout", commit], check=True, cwd=target_dir)
+
+
+def run_benchmark(compiled_dir: str, check_dir: str) -> float:
+    cache_dir = os.path.join(compiled_dir, ".mypy_cache")
+    if os.path.isdir(cache_dir):
+        shutil.rmtree(cache_dir)
+    env = os.environ.copy()
+    env["PYTHONPATH"] = os.path.abspath(compiled_dir)
+    abschk = os.path.abspath(check_dir)
+    cmd = [
+        sys.executable,
+        "-m",
+        "mypy",
+        "--config-file",
+        os.path.join(abschk, "mypy_self_check.ini"),
+    ]
+    cmd += glob.glob(os.path.join(abschk, "mypy/*.py"))
+    cmd += glob.glob(os.path.join(abschk, "mypy/*/*.py"))
+    t0 = time.time()
+    # Ignore errors, since some commits being measured may generate additional errors.
+    subprocess.run(cmd, cwd=compiled_dir, env=env)
+    return time.time() - t0
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("commit", nargs="+")
+    args = parser.parse_args()
+    commits = args.commit
+    num_runs = 16
+
+    if not (os.path.isdir(".git") and os.path.isdir("mypyc")):
+        sys.exit("error: Run this the mypy repo root")
+
+    build_threads = []
+    target_dirs = []
+    for i, commit in enumerate(commits):
+        target_dir = f"mypy.{i}.tmpdir"
+        target_dirs.append(target_dir)
+        clone(target_dir, commit)
+        t = threading.Thread(target=lambda: build_mypy(target_dir))
+        t.start()
+        build_threads.append(t)
+
+    self_check_dir = "mypy.self.tmpdir"
+    clone(self_check_dir, commits[0])
+
+    heading("Compiling mypy")
+    print("(This will take a while...)")
+
+    for t in build_threads:
+        t.join()
+
+    print(f"Finished compiling mypy ({len(commits)} builds)")
+
+    heading("Performing measurements")
+
+    results: dict[str, list[float]] = {}
+    for n in range(num_runs):
+        if n == 0:
+            print("Warmup...")
+        else:
+            print(f"Run {n}/{num_runs - 1}...")
+        items = list(enumerate(commits))
+        random.shuffle(items)
+        for i, commit in items:
+            tt = run_benchmark(target_dirs[i], self_check_dir)
+            # Don't record the first warm-up run
+            if n > 0:
+                print(f"{commit}: t={tt:.3f}s")
+                results.setdefault(commit, []).append(tt)
+
+    print()
+    heading("Results")
+    first = -1.0
+    for commit in commits:
+        tt = statistics.mean(results[commit])
+        if first < 0:
+            delta = "0.0%"
+            first = tt
+        else:
+            d = (tt / first) - 1
+            delta = f"{d:+.1%}"
+        print(f"{commit:<25} {tt:.3f}s ({delta})")
+
+    shutil.rmtree(self_check_dir)
+    for target_dir in target_dirs:
+        shutil.rmtree(target_dir)
+
+
+if __name__ == "__main__":
+    main()

From 25146105416863c4237380354b7f15102448b324 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Wed, 21 Dec 2022 14:55:34 +0000
Subject: [PATCH 137/231] Fix docs build (#14334)

The docs build is currently failing on `master`: see e.g.
https://github.com/python/mypy/actions/runs/3748461486/jobs/6365827914.

It looks like it was broken by the release of `attrs` 22.2.0 earlier
today. Specifically, it looks like
https://github.com/python-attrs/attrs/commit/1bb28648248e1bed63c1c6b077e7fe4b8260efc8
broke mypy's docs build.

I think this fixes things.
---
 docs/source/additional_features.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/source/additional_features.rst b/docs/source/additional_features.rst
index 19e0d4dcce015..ef5bf9e8936df 100644
--- a/docs/source/additional_features.rst
+++ b/docs/source/additional_features.rst
@@ -177,7 +177,7 @@ Caveats/Known Issues
   will complain about not understanding the argument and the type annotation in
   :py:meth:`__init__ <object.__init__>` will be replaced by ``Any``.
 
-* :ref:`Validator decorators <attrs:examples_validators>`
+* :ref:`Validator decorators <attrs:examples-validators>`
   and `default decorators <http://www.attrs.org/en/stable/examples.html#defaults>`_
   are not type-checked against the attribute they are setting/validating.
 

From 31b041344eab4b84971924cdcb45ba06dffe6d6c Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Thu, 22 Dec 2022 23:27:49 +0000
Subject: [PATCH 138/231] stubtest: Improve heuristics for determining whether
 global-namespace names are imported (#14270)

Stubtest currently has both false-positives and false-negatives when it
comes to verifying constants in the global namespace of a module.

This PR fixes the false positive by using `inspect.getsourcelines()` to
dynamically retrieve the module source code. It then uses `symtable` to
analyse that source code to gather a list of names which are known to be
imported.

The PR fixes the false negative by only using the `__module__` heuristic
on objects which are callable. The vast majority of callable objects
will be types or functions. For these objects, the `__module__`
attribute will give a good indication of whether the object originates
from another module or not; for other objects, it's less useful.
---
 mypy/stubtest.py          | 50 ++++++++++++++++++++++++++++++++++-----
 mypy/test/teststubtest.py |  3 +++
 2 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index a7a72235fed19..5946324d46190 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -15,6 +15,7 @@
 import os
 import pkgutil
 import re
+import symtable
 import sys
 import traceback
 import types
@@ -283,6 +284,36 @@ def _verify_exported_names(
     )
 
 
+def _get_imported_symbol_names(runtime: types.ModuleType) -> frozenset[str] | None:
+    """Retrieve the names in the global namespace which are known to be imported.
+
+    1). Use inspect to retrieve the source code of the module
+    2). Use symtable to parse the source and retrieve names that are known to be imported
+        from other modules.
+
+    If either of the above steps fails, return `None`.
+
+    Note that if a set of names is returned,
+    it won't include names imported via `from foo import *` imports.
+    """
+    try:
+        source = inspect.getsource(runtime)
+    except (OSError, TypeError, SyntaxError):
+        return None
+
+    if not source.strip():
+        # The source code for the module was an empty file,
+        # no point in parsing it with symtable
+        return frozenset()
+
+    try:
+        module_symtable = symtable.symtable(source, runtime.__name__, "exec")
+    except SyntaxError:
+        return None
+
+    return frozenset(sym.get_name() for sym in module_symtable.get_symbols() if sym.is_imported())
+
+
 @verify.register(nodes.MypyFile)
 def verify_mypyfile(
     stub: nodes.MypyFile, runtime: MaybeMissing[types.ModuleType], object_path: list[str]
@@ -312,15 +343,22 @@ def verify_mypyfile(
         if not o.module_hidden and (not is_probably_private(m) or hasattr(runtime, m))
     }
 
+    imported_symbols = _get_imported_symbol_names(runtime)
+
     def _belongs_to_runtime(r: types.ModuleType, attr: str) -> bool:
         obj = getattr(r, attr)
-        try:
-            obj_mod = getattr(obj, "__module__", None)
-        except Exception:
+        if isinstance(obj, types.ModuleType):
             return False
-        if obj_mod is not None:
-            return bool(obj_mod == r.__name__)
-        return not isinstance(obj, types.ModuleType)
+        if callable(obj):
+            try:
+                obj_mod = getattr(obj, "__module__", None)
+            except Exception:
+                return False
+            if obj_mod is not None:
+                return bool(obj_mod == r.__name__)
+        if imported_symbols is not None:
+            return attr not in imported_symbols
+        return True
 
     runtime_public_contents = (
         runtime_all_as_set
diff --git a/mypy/test/teststubtest.py b/mypy/test/teststubtest.py
index 812333e3feb49..5e59d8efec63a 100644
--- a/mypy/test/teststubtest.py
+++ b/mypy/test/teststubtest.py
@@ -1082,6 +1082,9 @@ def test_missing_no_runtime_all(self) -> Iterator[Case]:
         yield Case(stub="", runtime="import sys", error=None)
         yield Case(stub="", runtime="def g(): ...", error="g")
         yield Case(stub="", runtime="CONSTANT = 0", error="CONSTANT")
+        yield Case(stub="", runtime="import re; constant = re.compile('foo')", error="constant")
+        yield Case(stub="", runtime="from json.scanner import NUMBER_RE", error=None)
+        yield Case(stub="", runtime="from string import ascii_letters", error=None)
 
     @collect_cases
     def test_non_public_1(self) -> Iterator[Case]:

From c246a527008c28cf4970b28b85f7ccb5ce6ba285 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sun, 25 Dec 2022 14:38:25 -0600
Subject: [PATCH 139/231] Improve searchability for module level type ignore
 errors (#14342)

---
 docs/source/common_issues.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/source/common_issues.rst b/docs/source/common_issues.rst
index 42962581702f2..465035307d5de 100644
--- a/docs/source/common_issues.rst
+++ b/docs/source/common_issues.rst
@@ -188,6 +188,8 @@ Ignoring a whole file
 
 A ``# type: ignore`` comment at the top of a module (before any statements,
 including imports or docstrings) has the effect of ignoring the entire contents of the module.
+This behaviour can be surprising and result in
+"Module ... has no attribute ... [attr-defined]" errors.
 
 To only ignore errors, use a top-level ``# mypy: ignore-errors`` comment instead.
 To only ignore errors with a specific error code, use a top-level

From 01a1bf6bf4615e548b195b657756f9c57f8631a4 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 26 Dec 2022 10:29:08 +0000
Subject: [PATCH 140/231] Speed up the implementation of hasattr() checks
 (#14333)

This makes the implementation of hasattr() checks faster (introduced in
#13544).

In particular, since the `extra_attrs` attribute used for hasattr()
checks is usually None, I micro-optimized the codepaths to avoid
expensive operations whenever there are no hasattr() checks.

Also avoid expensive operations on simple unions and order `isinstance`
checks so that common types are checked first.

I measured a 2% performance uplift in self-check.
---
 mypy/meet.py    |  2 +-
 mypy/typeops.py | 42 ++++++++++++++++++++++++++++--------------
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/mypy/meet.py b/mypy/meet.py
index 5c187eeb37d46..8760b8c6d4fe5 100644
--- a/mypy/meet.py
+++ b/mypy/meet.py
@@ -76,7 +76,7 @@ def meet_types(s: Type, t: Type) -> ProperType:
         # Code in checker.py should merge any extra_items where possible, so we
         # should have only compatible extra_items here. We check this before
         # the below subtype check, so that extra_attrs will not get erased.
-        if is_same_type(s, t) and (s.extra_attrs or t.extra_attrs):
+        if (s.extra_attrs or t.extra_attrs) and is_same_type(s, t):
             if s.extra_attrs and t.extra_attrs:
                 if len(s.extra_attrs.attrs) > len(t.extra_attrs.attrs):
                     # Return the one that has more precise information.
diff --git a/mypy/typeops.py b/mypy/typeops.py
index 9f224e02c0887..baf5b8552eff8 100644
--- a/mypy/typeops.py
+++ b/mypy/typeops.py
@@ -33,6 +33,7 @@
     ENUM_REMOVED_PROPS,
     AnyType,
     CallableType,
+    ExtraAttrs,
     FormalArgument,
     FunctionLike,
     Instance,
@@ -466,16 +467,27 @@ def make_simplified_union(
 
     result = get_proper_type(UnionType.make_union(simplified_set, line, column))
 
-    # Step 4: At last, we erase any (inconsistent) extra attributes on instances.
-    extra_attrs_set = set()
-    for item in items:
-        instance = try_getting_instance_fallback(item)
-        if instance and instance.extra_attrs:
-            extra_attrs_set.add(instance.extra_attrs)
-
-    fallback = try_getting_instance_fallback(result)
-    if len(extra_attrs_set) > 1 and fallback:
-        fallback.extra_attrs = None
+    nitems = len(items)
+    if nitems > 1 and (
+        nitems > 2 or not (type(items[0]) is NoneType or type(items[1]) is NoneType)
+    ):
+        # Step 4: At last, we erase any (inconsistent) extra attributes on instances.
+
+        # Initialize with None instead of an empty set as a micro-optimization. The set
+        # is needed very rarely, so we try to avoid constructing it.
+        extra_attrs_set: set[ExtraAttrs] | None = None
+        for item in items:
+            instance = try_getting_instance_fallback(item)
+            if instance and instance.extra_attrs:
+                if extra_attrs_set is None:
+                    extra_attrs_set = {instance.extra_attrs}
+                else:
+                    extra_attrs_set.add(instance.extra_attrs)
+
+        if extra_attrs_set is not None and len(extra_attrs_set) > 1:
+            fallback = try_getting_instance_fallback(result)
+            if fallback:
+                fallback.extra_attrs = None
 
     return result
 
@@ -1006,13 +1018,15 @@ def try_getting_instance_fallback(typ: Type) -> Instance | None:
     typ = get_proper_type(typ)
     if isinstance(typ, Instance):
         return typ
-    elif isinstance(typ, TupleType):
-        return typ.partial_fallback
-    elif isinstance(typ, TypedDictType):
+    elif isinstance(typ, LiteralType):
         return typ.fallback
+    elif isinstance(typ, NoneType):
+        return None  # Fast path for None, which is common
     elif isinstance(typ, FunctionLike):
         return typ.fallback
-    elif isinstance(typ, LiteralType):
+    elif isinstance(typ, TupleType):
+        return typ.partial_fallback
+    elif isinstance(typ, TypedDictType):
         return typ.fallback
     elif isinstance(typ, TypeVarType):
         return try_getting_instance_fallback(typ.upper_bound)

From 5349f9a6e3ea53a7def2e895cfb3bc3938880052 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 26 Dec 2022 10:29:51 +0000
Subject: [PATCH 141/231] Avoid slow error message logic if errors not shown to
 user (#14336)

This helps with await-related errors introduced in #12958, in
particular, which are expensive to generate. If errors are ignored (e.g.
in third-party libraries) or we don't care about the error message, use
simpler error message logic. We also often filter out error messages
temporarily, so any effort in constructing a nice error message is
wasted.

We could skip even more logic, but this should cover many of the
important code paths.

This speeds up self check by about 2%.
---
 mypy/checker.py     |   4 ++
 mypy/checkexpr.py   |   3 +-
 mypy/checkmember.py |   5 +-
 mypy/errors.py      |  18 ++++++
 mypy/messages.py    | 133 ++++++++++++++++++++++++++------------------
 5 files changed, 106 insertions(+), 57 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 119ce6ae63383..7c5fcba1bb09f 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -5936,6 +5936,10 @@ def check_subtype(
         if isinstance(msg, str):
             msg = ErrorMessage(msg, code=code)
 
+        if self.msg.prefer_simple_messages():
+            self.fail(msg, context)  # Fast path -- skip all fancy logic
+            return False
+
         orig_subtype = subtype
         subtype = get_proper_type(subtype)
         orig_supertype = supertype
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index c990e9b59f985..5993639be4062 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -2157,7 +2157,8 @@ def check_arg(
             self.msg.incompatible_argument_note(
                 original_caller_type, callee_type, context, code=code
             )
-            self.chk.check_possible_missing_await(caller_type, callee_type, context)
+            if not self.msg.prefer_simple_messages():
+                self.chk.check_possible_missing_await(caller_type, callee_type, context)
 
     def check_overload_call(
         self,
diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index e3c7c95a64b9c..918ce7520454e 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -272,8 +272,9 @@ def report_missing_attribute(
     override_info: TypeInfo | None = None,
 ) -> Type:
     res_type = mx.msg.has_no_attr(original_type, typ, name, mx.context, mx.module_symbol_table)
-    if may_be_awaitable_attribute(name, typ, mx, override_info):
-        mx.msg.possible_missing_await(mx.context)
+    if not mx.msg.prefer_simple_messages():
+        if may_be_awaitable_attribute(name, typ, mx, override_info):
+            mx.msg.possible_missing_await(mx.context)
     return res_type
 
 
diff --git a/mypy/errors.py b/mypy/errors.py
index bfc44a858010e..d1e13ad701fca 100644
--- a/mypy/errors.py
+++ b/mypy/errors.py
@@ -737,6 +737,24 @@ def is_errors_for_file(self, file: str) -> bool:
         """Are there any errors for the given file?"""
         return file in self.error_info_map
 
+    def prefer_simple_messages(self) -> bool:
+        """Should we generate simple/fast error messages?
+
+        Return True if errors are not shown to user, i.e. errors are ignored
+        or they are collected for internal use only.
+
+        If True, we should prefer to generate a simple message quickly.
+        All normal errors should still be reported.
+        """
+        if self.file in self.ignored_files:
+            # Errors ignored, so no point generating fancy messages
+            return True
+        for _watcher in self._watchers:
+            if _watcher._filter is True and _watcher._filtered is None:
+                # Errors are filtered
+                return True
+        return False
+
     def raise_error(self, use_stdout: bool = True) -> NoReturn:
         """Raise a CompileError with the generated messages.
 
diff --git a/mypy/messages.py b/mypy/messages.py
index 85811561e1761..b8c04fe2b8e98 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -191,6 +191,14 @@ def disable_type_names(self) -> Iterator[None]:
     def are_type_names_disabled(self) -> bool:
         return len(self._disable_type_names) > 0 and self._disable_type_names[-1]
 
+    def prefer_simple_messages(self) -> bool:
+        """Should we generate simple/fast error messages?
+
+        If errors aren't shown to the user, we don't want to waste cyles producing
+        complex error messages.
+        """
+        return self.errors.prefer_simple_messages()
+
     def report(
         self,
         msg: str,
@@ -685,64 +693,69 @@ def incompatible_argument(
                 actual_type_str, expected_type_str
             )
         else:
-            try:
-                expected_type = callee.arg_types[m - 1]
-            except IndexError:  # Varargs callees
-                expected_type = callee.arg_types[-1]
-            arg_type_str, expected_type_str = format_type_distinctly(
-                arg_type, expected_type, bare=True
-            )
-            if arg_kind == ARG_STAR:
-                arg_type_str = "*" + arg_type_str
-            elif arg_kind == ARG_STAR2:
-                arg_type_str = "**" + arg_type_str
-
-            # For function calls with keyword arguments, display the argument name rather than the
-            # number.
-            arg_label = str(n)
-            if isinstance(outer_context, CallExpr) and len(outer_context.arg_names) >= n:
-                arg_name = outer_context.arg_names[n - 1]
-                if arg_name is not None:
-                    arg_label = f'"{arg_name}"'
-            if (
-                arg_kind == ARG_STAR2
-                and isinstance(arg_type, TypedDictType)
-                and m <= len(callee.arg_names)
-                and callee.arg_names[m - 1] is not None
-                and callee.arg_kinds[m - 1] != ARG_STAR2
-            ):
-                arg_name = callee.arg_names[m - 1]
-                assert arg_name is not None
-                arg_type_str, expected_type_str = format_type_distinctly(
-                    arg_type.items[arg_name], expected_type, bare=True
-                )
-                arg_label = f'"{arg_name}"'
-            if isinstance(outer_context, IndexExpr) and isinstance(outer_context.index, StrExpr):
-                msg = 'Value of "{}" has incompatible type {}; expected {}'.format(
-                    outer_context.index.value,
-                    quote_type_string(arg_type_str),
-                    quote_type_string(expected_type_str),
-                )
+            if self.prefer_simple_messages():
+                msg = "Argument has incompatible type"
             else:
-                msg = "Argument {} {}has incompatible type {}; expected {}".format(
-                    arg_label,
-                    target,
-                    quote_type_string(arg_type_str),
-                    quote_type_string(expected_type_str),
+                try:
+                    expected_type = callee.arg_types[m - 1]
+                except IndexError:  # Varargs callees
+                    expected_type = callee.arg_types[-1]
+                arg_type_str, expected_type_str = format_type_distinctly(
+                    arg_type, expected_type, bare=True
                 )
+                if arg_kind == ARG_STAR:
+                    arg_type_str = "*" + arg_type_str
+                elif arg_kind == ARG_STAR2:
+                    arg_type_str = "**" + arg_type_str
+
+                # For function calls with keyword arguments, display the argument name rather
+                # than the number.
+                arg_label = str(n)
+                if isinstance(outer_context, CallExpr) and len(outer_context.arg_names) >= n:
+                    arg_name = outer_context.arg_names[n - 1]
+                    if arg_name is not None:
+                        arg_label = f'"{arg_name}"'
+                if (
+                    arg_kind == ARG_STAR2
+                    and isinstance(arg_type, TypedDictType)
+                    and m <= len(callee.arg_names)
+                    and callee.arg_names[m - 1] is not None
+                    and callee.arg_kinds[m - 1] != ARG_STAR2
+                ):
+                    arg_name = callee.arg_names[m - 1]
+                    assert arg_name is not None
+                    arg_type_str, expected_type_str = format_type_distinctly(
+                        arg_type.items[arg_name], expected_type, bare=True
+                    )
+                    arg_label = f'"{arg_name}"'
+                if isinstance(outer_context, IndexExpr) and isinstance(
+                    outer_context.index, StrExpr
+                ):
+                    msg = 'Value of "{}" has incompatible type {}; expected {}'.format(
+                        outer_context.index.value,
+                        quote_type_string(arg_type_str),
+                        quote_type_string(expected_type_str),
+                    )
+                else:
+                    msg = "Argument {} {}has incompatible type {}; expected {}".format(
+                        arg_label,
+                        target,
+                        quote_type_string(arg_type_str),
+                        quote_type_string(expected_type_str),
+                    )
+                expected_type = get_proper_type(expected_type)
+                if isinstance(expected_type, UnionType):
+                    expected_types = list(expected_type.items)
+                else:
+                    expected_types = [expected_type]
+                for type in get_proper_types(expected_types):
+                    if isinstance(arg_type, Instance) and isinstance(type, Instance):
+                        notes = append_invariance_notes(notes, arg_type, type)
             object_type = get_proper_type(object_type)
             if isinstance(object_type, TypedDictType):
                 code = codes.TYPEDDICT_ITEM
             else:
                 code = codes.ARG_TYPE
-            expected_type = get_proper_type(expected_type)
-            if isinstance(expected_type, UnionType):
-                expected_types = list(expected_type.items)
-            else:
-                expected_types = [expected_type]
-            for type in get_proper_types(expected_types):
-                if isinstance(arg_type, Instance) and isinstance(type, Instance):
-                    notes = append_invariance_notes(notes, arg_type, type)
         self.fail(msg, context, code=code)
         if notes:
             for note_msg in notes:
@@ -756,6 +769,8 @@ def incompatible_argument_note(
         context: Context,
         code: ErrorCode | None,
     ) -> None:
+        if self.prefer_simple_messages():
+            return
         if isinstance(
             original_caller_type, (Instance, TupleType, TypedDictType, TypeType, CallableType)
         ):
@@ -832,7 +847,9 @@ def invalid_index_type(
     def too_few_arguments(
         self, callee: CallableType, context: Context, argument_names: Sequence[str | None] | None
     ) -> None:
-        if argument_names is not None:
+        if self.prefer_simple_messages():
+            msg = "Too few arguments"
+        elif argument_names is not None:
             num_positional_args = sum(k is None for k in argument_names)
             arguments_left = callee.arg_names[num_positional_args : callee.min_args]
             diff = [k for k in arguments_left if k not in argument_names]
@@ -856,7 +873,10 @@ def missing_named_argument(self, callee: CallableType, context: Context, name: s
         self.fail(msg, context, code=codes.CALL_ARG)
 
     def too_many_arguments(self, callee: CallableType, context: Context) -> None:
-        msg = "Too many arguments" + for_function(callee)
+        if self.prefer_simple_messages():
+            msg = "Too many arguments"
+        else:
+            msg = "Too many arguments" + for_function(callee)
         self.fail(msg, context, code=codes.CALL_ARG)
         self.maybe_note_about_special_args(callee, context)
 
@@ -874,11 +894,16 @@ def too_many_arguments_from_typed_dict(
         self.fail(msg, context)
 
     def too_many_positional_arguments(self, callee: CallableType, context: Context) -> None:
-        msg = "Too many positional arguments" + for_function(callee)
+        if self.prefer_simple_messages():
+            msg = "Too many positional arguments"
+        else:
+            msg = "Too many positional arguments" + for_function(callee)
         self.fail(msg, context)
         self.maybe_note_about_special_args(callee, context)
 
     def maybe_note_about_special_args(self, callee: CallableType, context: Context) -> None:
+        if self.prefer_simple_messages():
+            return
         # https://github.com/python/mypy/issues/11309
         first_arg = callee.def_extras.get("first_arg")
         if first_arg and first_arg not in {"self", "cls", "mcs"}:

From 632304f90923ba38483d94de3cf58d486966f4f0 Mon Sep 17 00:00:00 2001
From: Avasam <samuel.06@hotmail.com>
Date: Tue, 27 Dec 2022 23:24:21 -0500
Subject: [PATCH 142/231] mypy_primer_comment: Resolve node.js 12 actions
 deprecation warning (#14352)

Resolves the following warning:

![image](https://user-images.githubusercontent.com/1350584/209748053-dc33f93c-5c34-4cd2-863f-6e54207d9b4f.png)

By using https://github.com/kanga333/comment-hider/releases/tag/v0.4.0
---
 .github/workflows/mypy_primer_comment.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/mypy_primer_comment.yml b/.github/workflows/mypy_primer_comment.yml
index b20eaf471c9a3..12ce91c129109 100644
--- a/.github/workflows/mypy_primer_comment.yml
+++ b/.github/workflows/mypy_primer_comment.yml
@@ -90,8 +90,8 @@ jobs:
             return prNumber
 
       - name: Hide old comments
-        # v0.3.0
-        uses: kanga333/comment-hider@bbdf5b562fbec24e6f60572d8f712017428b92e0
+        # v0.4.0
+        uses: kanga333/comment-hider@c12bb20b48aeb8fc098e35967de8d4f8018fffdf
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           leave_visible: 1

From 61a21baf7e37069b829f19bd74416c01f1b84404 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 28 Dec 2022 13:23:42 +0000
Subject: [PATCH 143/231] Micro-optimization: avoid Bogus[int] types that cause
 needless boxing (#14354)

I want to get rid of all the bogus types eventually.
---
 mypy/types.py | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index 86a700d524699..480af0fa852bf 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -153,6 +153,9 @@
 # A placeholder used for Bogus[...] parameters
 _dummy: Final[Any] = object()
 
+# A placeholder for int parameters
+_dummy_int: Final = -999999
+
 
 class TypeOfAny:
     """
@@ -540,8 +543,8 @@ def copy_modified(
         values: Bogus[list[Type]] = _dummy,
         upper_bound: Bogus[Type] = _dummy,
         id: Bogus[TypeVarId | int] = _dummy,
-        line: Bogus[int] = _dummy,
-        column: Bogus[int] = _dummy,
+        line: int = _dummy_int,
+        column: int = _dummy_int,
     ) -> TypeVarType:
         return TypeVarType(
             self.name,
@@ -550,8 +553,8 @@ def copy_modified(
             self.values if values is _dummy else values,
             self.upper_bound if upper_bound is _dummy else upper_bound,
             self.variance,
-            self.line if line is _dummy else line,
-            self.column if column is _dummy else column,
+            self.line if line == _dummy_int else line,
+            self.column if column == _dummy_int else column,
         )
 
     def accept(self, visitor: TypeVisitor[T]) -> T:
@@ -658,14 +661,14 @@ def copy_modified(
         self,
         *,
         id: Bogus[TypeVarId | int] = _dummy,
-        flavor: Bogus[int] = _dummy,
+        flavor: int = _dummy_int,
         prefix: Bogus[Parameters] = _dummy,
     ) -> ParamSpecType:
         return ParamSpecType(
             self.name,
             self.fullname,
             id if id is not _dummy else self.id,
-            flavor if flavor is not _dummy else self.flavor,
+            flavor if flavor != _dummy_int else self.flavor,
             self.upper_bound,
             line=self.line,
             column=self.column,
@@ -1024,10 +1027,10 @@ def accept(self, visitor: TypeVisitor[T]) -> T:
     def copy_modified(
         self,
         # Mark with Bogus because _dummy is just an object (with type Any)
-        type_of_any: Bogus[int] = _dummy,
+        type_of_any: int = _dummy_int,
         original_any: Bogus[AnyType | None] = _dummy,
     ) -> AnyType:
-        if type_of_any is _dummy:
+        if type_of_any == _dummy_int:
             type_of_any = self.type_of_any
         if original_any is _dummy:
             original_any = self.source_any
@@ -1745,8 +1748,8 @@ def copy_modified(
         name: Bogus[str | None] = _dummy,
         definition: Bogus[SymbolNode] = _dummy,
         variables: Bogus[Sequence[TypeVarLikeType]] = _dummy,
-        line: Bogus[int] = _dummy,
-        column: Bogus[int] = _dummy,
+        line: int = _dummy_int,
+        column: int = _dummy_int,
         is_ellipsis_args: Bogus[bool] = _dummy,
         implicit: Bogus[bool] = _dummy,
         special_sig: Bogus[str | None] = _dummy,
@@ -1766,8 +1769,8 @@ def copy_modified(
             name=name if name is not _dummy else self.name,
             definition=definition if definition is not _dummy else self.definition,
             variables=variables if variables is not _dummy else self.variables,
-            line=line if line is not _dummy else self.line,
-            column=column if column is not _dummy else self.column,
+            line=line if line != _dummy_int else self.line,
+            column=column if column != _dummy_int else self.column,
             is_ellipsis_args=(
                 is_ellipsis_args if is_ellipsis_args is not _dummy else self.is_ellipsis_args
             ),

From 1f8621c483baf4641c317ad755f814bcb9e41296 Mon Sep 17 00:00:00 2001
From: Hugues <hugues.bruant@affirm.com>
Date: Wed, 28 Dec 2022 05:58:38 -0800
Subject: [PATCH 144/231] subtypes: fast path for Union/Union subtype check
 (#14277)

Enums are exploded into Union of Literal when narrowed.

Conditional branches on enum values can result in multiple distinct
narrowing of the same enum which are later subject to subtype checks
(most notably via `is_same_type`, when exiting frame context in the binder).
Such checks would have quadratic complexity: `O(N*M)` where `N` and `M`
are the number of entries in each narrowed enum variable, and led to drastic
slowdown if any of the enums involved has a large number of values.

Implement a linear-time fast path where literals are quickly filtered, with
a fallback to the slow path for more complex values.

In our codebase there is one method with a chain of a dozen `if`
statements operating on instances of an enum with a hundreds of values.
Prior to the regression it was typechecked in less than 1s. After the regression
it takes over 13min to typecheck. This patch fully fixes the regression for us.

Fixes #13821.
---
 mypy/subtypes.py | 30 ++++++++++++++++++++++++++++++
 mypy/types.py    |  9 +++++++++
 2 files changed, 39 insertions(+)

diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 994c4081addd8..61ba7af5147f4 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -57,6 +57,7 @@
     UninhabitedType,
     UnionType,
     UnpackType,
+    _flattened,
     get_proper_type,
     is_named_instance,
 )
@@ -891,6 +892,35 @@ def visit_union_type(self, left: UnionType) -> bool:
                 if not self._is_subtype(item, self.orig_right):
                     return False
             return True
+
+        elif isinstance(self.right, UnionType):
+            # prune literals early to avoid nasty quadratic behavior which would otherwise arise when checking
+            # subtype relationships between slightly different narrowings of an Enum
+            # we achieve O(N+M) instead of O(N*M)
+
+            fast_check: set[ProperType] = set()
+
+            for item in _flattened(self.right.relevant_items()):
+                p_item = get_proper_type(item)
+                if isinstance(p_item, LiteralType):
+                    fast_check.add(p_item)
+                elif isinstance(p_item, Instance):
+                    if p_item.last_known_value is None:
+                        fast_check.add(p_item)
+                    else:
+                        fast_check.add(p_item.last_known_value)
+
+            for item in left.relevant_items():
+                p_item = get_proper_type(item)
+                if p_item in fast_check:
+                    continue
+                lit_type = mypy.typeops.simple_literal_type(p_item)
+                if lit_type in fast_check:
+                    continue
+                if not self._is_subtype(item, self.orig_right):
+                    return False
+            return True
+
         return all(self._is_subtype(item, self.orig_right) for item in left.items)
 
     def visit_partial_type(self, left: PartialType) -> bool:
diff --git a/mypy/types.py b/mypy/types.py
index 480af0fa852bf..83c5b88032a30 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3346,6 +3346,15 @@ def has_recursive_types(typ: Type) -> bool:
     return typ.accept(_has_recursive_type)
 
 
+def _flattened(types: Iterable[Type]) -> Iterable[Type]:
+    for t in types:
+        tp = get_proper_type(t)
+        if isinstance(tp, UnionType):
+            yield from _flattened(tp.items)
+        else:
+            yield t
+
+
 def flatten_nested_unions(
     types: Iterable[Type], handle_type_alias_type: bool = True
 ) -> list[Type]:

From 109c8ce84685136d1cd89c86d4b3458272a6144f Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Wed, 28 Dec 2022 06:01:14 -0800
Subject: [PATCH 145/231] [undefined vars] fix per-module error code override
 bug (#14351)

This one would occur because we set the errors module with global
options, instead of per-module override ones.
It only mattered for checks that happened after the partially undefined
checks, which (I believe) is only the unused `type: ignore` checks.

This was discovered when updating tests for #14166.

I've also cleaned up the function signature a little.
---
 mypy/build.py                   | 10 +++++-----
 mypy/server/update.py           |  2 +-
 test-data/unit/check-flags.test |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index 2e0fa455554af..1747c4518c632 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2347,19 +2347,19 @@ def type_check_second_pass(self) -> bool:
         self.time_spent_us += time_spent_us(t0)
         return result
 
-    def detect_possibly_undefined_vars(self, type_map: dict[Expression, Type]) -> None:
+    def detect_possibly_undefined_vars(self) -> None:
         assert self.tree is not None, "Internal error: method must be called on parsed file only"
         if self.tree.is_stub:
             # We skip stub files because they aren't actually executed.
             return
         manager = self.manager
+        manager.errors.set_file(self.xpath, self.tree.fullname, options=self.options)
         if manager.errors.is_error_code_enabled(
             codes.POSSIBLY_UNDEFINED
         ) or manager.errors.is_error_code_enabled(codes.USED_BEFORE_DEF):
-            manager.errors.set_file(self.xpath, self.tree.fullname, options=manager.options)
             self.tree.accept(
                 PossiblyUndefinedVariableVisitor(
-                    MessageBuilder(manager.errors, manager.modules), type_map, manager.options
+                    MessageBuilder(manager.errors, manager.modules), self.type_map(), self.options
                 )
             )
 
@@ -3418,7 +3418,7 @@ def process_stale_scc(graph: Graph, scc: list[str], manager: BuildManager) -> No
         graph[id].type_check_first_pass()
         if not graph[id].type_checker().deferred_nodes:
             unfinished_modules.discard(id)
-            graph[id].detect_possibly_undefined_vars(graph[id].type_map())
+            graph[id].detect_possibly_undefined_vars()
             graph[id].finish_passes()
 
     while unfinished_modules:
@@ -3427,7 +3427,7 @@ def process_stale_scc(graph: Graph, scc: list[str], manager: BuildManager) -> No
                 continue
             if not graph[id].type_check_second_pass():
                 unfinished_modules.discard(id)
-                graph[id].detect_possibly_undefined_vars(graph[id].type_map())
+                graph[id].detect_possibly_undefined_vars()
                 graph[id].finish_passes()
     for id in stale:
         graph[id].generate_unused_ignore_notes()
diff --git a/mypy/server/update.py b/mypy/server/update.py
index 9bea1998c0e5a..83cce22873a12 100644
--- a/mypy/server/update.py
+++ b/mypy/server/update.py
@@ -662,7 +662,7 @@ def restore(ids: list[str]) -> None:
     state.type_checker().reset()
     state.type_check_first_pass()
     state.type_check_second_pass()
-    state.detect_possibly_undefined_vars(state.type_map())
+    state.detect_possibly_undefined_vars()
     t2 = time.time()
     state.finish_passes()
     t3 = time.time()
diff --git a/test-data/unit/check-flags.test b/test-data/unit/check-flags.test
index 33723b7fee768..a76463e3106bf 100644
--- a/test-data/unit/check-flags.test
+++ b/test-data/unit/check-flags.test
@@ -2110,7 +2110,7 @@ if foo: ...  # E: Function "Callable[[], int]" could always be true in boolean c
 42 + "no"  # type: ignore
 [file mypy.ini]
 \[mypy]
-enable_error_code = ignore-without-code, truthy-bool
+enable_error_code = ignore-without-code, truthy-bool, used-before-def
 
 \[mypy-tests.*]
 disable_error_code = ignore-without-code

From 20e9733e32ddff6ecbaddb7be61ae36b6c4978d0 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Wed, 28 Dec 2022 06:16:31 -0800
Subject: [PATCH 146/231] [undefined vars] do not double report errors in class
 defs (#14350)

These errors are already reported by the (new) semantic analyzer.

I've discovered this while updating unit tests for new semanal in
#14166.

Tests are included.
---
 mypy/partially_defined.py                    | 49 +++++++++++++-------
 test-data/unit/check-possibly-undefined.test | 27 +++++++++++
 2 files changed, 60 insertions(+), 16 deletions(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 644a472486151..c63c62c3e3937 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from enum import Enum
+
 from mypy import checker, errorcodes
 from mypy.messages import MessageBuilder
 from mypy.nodes import (
@@ -164,13 +166,21 @@ def done(self) -> BranchState:
         )
 
 
+class ScopeType(Enum):
+    Global = 1
+    Class = 2
+    Func = 3
+    Generator = 3
+
+
 class Scope:
-    def __init__(self, stmts: list[BranchStatement]) -> None:
+    def __init__(self, stmts: list[BranchStatement], scope_type: ScopeType) -> None:
         self.branch_stmts: list[BranchStatement] = stmts
+        self.scope_type = scope_type
         self.undefined_refs: dict[str, set[NameExpr]] = {}
 
     def copy(self) -> Scope:
-        result = Scope([s.copy() for s in self.branch_stmts])
+        result = Scope([s.copy() for s in self.branch_stmts], self.scope_type)
         result.undefined_refs = self.undefined_refs.copy()
         return result
 
@@ -188,7 +198,7 @@ class DefinedVariableTracker:
 
     def __init__(self) -> None:
         # There's always at least one scope. Within each scope, there's at least one "global" BranchingStatement.
-        self.scopes: list[Scope] = [Scope([BranchStatement(BranchState())])]
+        self.scopes: list[Scope] = [Scope([BranchStatement(BranchState())], ScopeType.Global)]
         # disable_branch_skip is used to disable skipping a branch due to a return/raise/etc. This is useful
         # in things like try/except/finally statements.
         self.disable_branch_skip = False
@@ -203,13 +213,18 @@ def _scope(self) -> Scope:
         assert len(self.scopes) > 0
         return self.scopes[-1]
 
-    def enter_scope(self) -> None:
+    def enter_scope(self, scope_type: ScopeType) -> None:
         assert len(self._scope().branch_stmts) > 0
-        self.scopes.append(Scope([BranchStatement(self._scope().branch_stmts[-1].branches[-1])]))
+        self.scopes.append(
+            Scope([BranchStatement(self._scope().branch_stmts[-1].branches[-1])], scope_type)
+        )
 
     def exit_scope(self) -> None:
         self.scopes.pop()
 
+    def in_scope(self, scope_type: ScopeType) -> bool:
+        return self._scope().scope_type == scope_type
+
     def start_branch_statement(self) -> None:
         assert len(self._scope().branch_stmts) > 0
         self._scope().branch_stmts.append(
@@ -320,12 +335,14 @@ def variable_may_be_undefined(self, name: str, context: Context) -> None:
 
     def process_definition(self, name: str) -> None:
         # Was this name previously used? If yes, it's a used-before-definition error.
-        refs = self.tracker.pop_undefined_ref(name)
-        for ref in refs:
-            if self.loops:
-                self.variable_may_be_undefined(name, ref)
-            else:
-                self.var_used_before_def(name, ref)
+        if not self.tracker.in_scope(ScopeType.Class):
+            # Errors in class scopes are caught by the semantic analyzer.
+            refs = self.tracker.pop_undefined_ref(name)
+            for ref in refs:
+                if self.loops:
+                    self.variable_may_be_undefined(name, ref)
+                else:
+                    self.var_used_before_def(name, ref)
         self.tracker.record_definition(name)
 
     def visit_global_decl(self, o: GlobalDecl) -> None:
@@ -392,7 +409,7 @@ def visit_match_stmt(self, o: MatchStmt) -> None:
 
     def visit_func_def(self, o: FuncDef) -> None:
         self.process_definition(o.name)
-        self.tracker.enter_scope()
+        self.tracker.enter_scope(ScopeType.Func)
         super().visit_func_def(o)
         self.tracker.exit_scope()
 
@@ -405,14 +422,14 @@ def visit_func(self, o: FuncItem) -> None:
         super().visit_func(o)
 
     def visit_generator_expr(self, o: GeneratorExpr) -> None:
-        self.tracker.enter_scope()
+        self.tracker.enter_scope(ScopeType.Generator)
         for idx in o.indices:
             self.process_lvalue(idx)
         super().visit_generator_expr(o)
         self.tracker.exit_scope()
 
     def visit_dictionary_comprehension(self, o: DictionaryComprehension) -> None:
-        self.tracker.enter_scope()
+        self.tracker.enter_scope(ScopeType.Generator)
         for idx in o.indices:
             self.process_lvalue(idx)
         super().visit_dictionary_comprehension(o)
@@ -446,7 +463,7 @@ def visit_return_stmt(self, o: ReturnStmt) -> None:
         self.tracker.skip_branch()
 
     def visit_lambda_expr(self, o: LambdaExpr) -> None:
-        self.tracker.enter_scope()
+        self.tracker.enter_scope(ScopeType.Func)
         super().visit_lambda_expr(o)
         self.tracker.exit_scope()
 
@@ -613,7 +630,7 @@ def visit_with_stmt(self, o: WithStmt) -> None:
 
     def visit_class_def(self, o: ClassDef) -> None:
         self.process_definition(o.name)
-        self.tracker.enter_scope()
+        self.tracker.enter_scope(ScopeType.Class)
         super().visit_class_def(o)
         self.tracker.exit_scope()
 
diff --git a/test-data/unit/check-possibly-undefined.test b/test-data/unit/check-possibly-undefined.test
index aa535a1ce081e..802635c30b35a 100644
--- a/test-data/unit/check-possibly-undefined.test
+++ b/test-data/unit/check-possibly-undefined.test
@@ -931,3 +931,30 @@ def f():
         x = 0
     z = y  # E: Name "y" is used before definition
     y: int = x  # E: Name "x" may be undefined
+
+[case testClassBody]
+# flags: --enable-error-code possibly-undefined --enable-error-code used-before-def
+
+class A:
+    # The following should not only trigger an error from semantic analyzer, but not the used-before-def check.
+    y = x + 1  # E: Name "x" is not defined
+    x = 0
+    # Same as above but in a loop, which should trigger a possibly-undefined error.
+    for _ in [1, 2, 3]:
+        b = a + 1  # E: Name "a" is not defined
+        a = 0
+
+
+class B:
+    if int():
+        x = 0
+    else:
+        # This type of check is not caught by the semantic analyzer. If we ever update it to catch such issues,
+        # we should make sure that errors are not double-reported.
+        y = x  # E: Name "x" is used before definition
+    for _ in [1, 2, 3]:
+        if int():
+            a = 0
+        else:
+            # Same as above but in a loop.
+            b = a  # E: Name "a" may be undefined

From 45bed9c994b1082a050e26958c1847b53ad82357 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 28 Dec 2022 14:23:35 +0000
Subject: [PATCH 147/231] Optimization: Remove expensive context manager in
 type analyzer (#14357)

This makes mypy a bit faster and the implementation seems a little
cleaner as well.

(Various small optimizations, including this, together netted a 6%
performance improvement in self check.)
---
 mypy/typeanal.py | 68 +++++++++++++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 29 deletions(-)

diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index e4f56924d2d7d..28f293613d501 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -268,10 +268,13 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                         self.api.record_incomplete_ref()
                     # Always allow ParamSpec for placeholders, if they are actually not valid,
                     # they will be reported later, after we resolve placeholders.
-                    with self.set_allow_param_spec_literals(True):
-                        return PlaceholderType(
-                            node.fullname, self.anal_array(t.args, allow_param_spec=True), t.line
-                        )
+                    return PlaceholderType(
+                        node.fullname,
+                        self.anal_array(
+                            t.args, allow_param_spec=True, allow_param_spec_literals=True
+                        ),
+                        t.line,
+                    )
                 else:
                     if self.api.final_iteration:
                         self.cannot_resolve_type(t)
@@ -382,10 +385,13 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
                 return special
             if isinstance(node, TypeAlias):
                 self.aliases_used.add(fullname)
-                with self.set_allow_param_spec_literals(node.has_param_spec_type):
-                    an_args = self.anal_array(t.args, allow_param_spec=True)
-                    if node.has_param_spec_type and len(node.alias_tvars) == 1:
-                        an_args = self.pack_paramspec_args(an_args)
+                an_args = self.anal_array(
+                    t.args,
+                    allow_param_spec=True,
+                    allow_param_spec_literals=node.has_param_spec_type,
+                )
+                if node.has_param_spec_type and len(node.alias_tvars) == 1:
+                    an_args = self.pack_paramspec_args(an_args)
 
                 disallow_any = self.options.disallow_any_generics and not self.is_typeshed_stub
                 res = expand_type_alias(
@@ -660,17 +666,22 @@ def analyze_type_with_type_info(
             fallback = Instance(info, [AnyType(TypeOfAny.special_form)], ctx.line)
             return TupleType(self.anal_array(args), fallback, ctx.line)
 
-        # This is a heuristic: it will be checked later anyways but the error
-        # message may be worse.
-        with self.set_allow_param_spec_literals(info.has_param_spec_type):
-            # Analyze arguments and (usually) construct Instance type. The
-            # number of type arguments and their values are
-            # checked only later, since we do not always know the
-            # valid count at this point. Thus we may construct an
-            # Instance with an invalid number of type arguments.
-            instance = Instance(
-                info, self.anal_array(args, allow_param_spec=True), ctx.line, ctx.column
-            )
+        # Analyze arguments and (usually) construct Instance type. The
+        # number of type arguments and their values are
+        # checked only later, since we do not always know the
+        # valid count at this point. Thus we may construct an
+        # Instance with an invalid number of type arguments.
+        #
+        # We allow ParamSpec literals based on a heuristic: it will be
+        # checked later anyways but the error message may be worse.
+        instance = Instance(
+            info,
+            self.anal_array(
+                args, allow_param_spec=True, allow_param_spec_literals=info.has_param_spec_type
+            ),
+            ctx.line,
+            ctx.column,
+        )
         if len(info.type_vars) == 1 and info.has_param_spec_type:
             instance.args = tuple(self.pack_paramspec_args(instance.args))
 
@@ -1466,11 +1477,19 @@ def is_defined_type_var(self, tvar: str, context: Context) -> bool:
         return self.tvar_scope.get_binding(tvar_node) is not None
 
     def anal_array(
-        self, a: Iterable[Type], nested: bool = True, *, allow_param_spec: bool = False
+        self,
+        a: Iterable[Type],
+        nested: bool = True,
+        *,
+        allow_param_spec: bool = False,
+        allow_param_spec_literals: bool = False,
     ) -> list[Type]:
+        old_allow_param_spec_literals = self.allow_param_spec_literals
+        self.allow_param_spec_literals = allow_param_spec_literals
         res: list[Type] = []
         for t in a:
             res.append(self.anal_type(t, nested, allow_param_spec=allow_param_spec))
+        self.allow_param_spec_literals = old_allow_param_spec_literals
         return self.check_unpacks_in_list(res)
 
     def anal_type(self, t: Type, nested: bool = True, *, allow_param_spec: bool = False) -> Type:
@@ -1558,15 +1577,6 @@ def tuple_type(self, items: list[Type]) -> TupleType:
         any_type = AnyType(TypeOfAny.special_form)
         return TupleType(items, fallback=self.named_type("builtins.tuple", [any_type]))
 
-    @contextmanager
-    def set_allow_param_spec_literals(self, to: bool) -> Iterator[None]:
-        old = self.allow_param_spec_literals
-        try:
-            self.allow_param_spec_literals = to
-            yield
-        finally:
-            self.allow_param_spec_literals = old
-
 
 TypeVarLikeList = List[Tuple[str, TypeVarLikeExpr]]
 

From ec4404ae331170f6d033f442906a547dec319e02 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 28 Dec 2022 14:24:07 +0000
Subject: [PATCH 148/231] Optimization: Enable always defined attributes in
 Type subclasses (#14356)

Use lazy initialization to avoid method calls in `__init__`. This allows
mypyc to infer more always defined attributes.

(Various small optimizations, including this, together netted a 6%
performance improvement in self check.)
---
 mypy/types.py | 35 ++++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index 83c5b88032a30..b48280466c3e3 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -201,7 +201,7 @@ def deserialize_type(data: JsonDict | str) -> Type:
 class Type(mypy.nodes.Context):
     """Abstract base class for all types."""
 
-    __slots__ = ("can_be_true", "can_be_false")
+    __slots__ = ("_can_be_true", "_can_be_false")
     # 'can_be_true' and 'can_be_false' mean whether the value of the
     # expression can be true or false in a boolean context. They are useful
     # when inferring the type of logic expressions like `x and y`.
@@ -214,8 +214,29 @@ class Type(mypy.nodes.Context):
 
     def __init__(self, line: int = -1, column: int = -1) -> None:
         super().__init__(line, column)
-        self.can_be_true = self.can_be_true_default()
-        self.can_be_false = self.can_be_false_default()
+        # Value of these can be -1 (use the default, lazy init), 0 (false) or 1 (true)
+        self._can_be_true = -1
+        self._can_be_false = -1
+
+    @property
+    def can_be_true(self) -> bool:
+        if self._can_be_true == -1:  # Lazy init helps mypyc
+            self._can_be_true = self.can_be_true_default()
+        return bool(self._can_be_true)
+
+    @can_be_true.setter
+    def can_be_true(self, v: bool) -> None:
+        self._can_be_true = v
+
+    @property
+    def can_be_false(self) -> bool:
+        if self._can_be_false == -1:  # Lazy init helps mypyc
+            self._can_be_false = self.can_be_false_default()
+        return bool(self._can_be_false)
+
+    @can_be_false.setter
+    def can_be_false(self, v: bool) -> None:
+        self._can_be_false = v
 
     def can_be_true_default(self) -> bool:
         return True
@@ -264,10 +285,10 @@ def __init__(
         line: int = -1,
         column: int = -1,
     ) -> None:
+        super().__init__(line, column)
         self.alias = alias
         self.args = args
         self.type_ref: str | None = None
-        super().__init__(line, column)
 
     def _expand_once(self) -> Type:
         """Expand to the target type exactly once.
@@ -1424,7 +1445,7 @@ class FunctionLike(ProperType):
 
     def __init__(self, line: int = -1, column: int = -1) -> None:
         super().__init__(line, column)
-        self.can_be_false = False
+        self._can_be_false = False
 
     @abstractmethod
     def is_type_obj(self) -> bool:
@@ -2183,10 +2204,10 @@ def __init__(
         column: int = -1,
         implicit: bool = False,
     ) -> None:
+        super().__init__(line, column)
         self.partial_fallback = fallback
         self.items = items
         self.implicit = implicit
-        super().__init__(line, column)
 
     def can_be_true_default(self) -> bool:
         if self.can_be_any_bool():
@@ -2495,8 +2516,8 @@ class LiteralType(ProperType):
     def __init__(
         self, value: LiteralValue, fallback: Instance, line: int = -1, column: int = -1
     ) -> None:
-        self.value = value
         super().__init__(line, column)
+        self.value = value
         self.fallback = fallback
         self._hash = -1  # Cached hash value
 

From c29a414695be922bdcbdf6d1df9881ce7f28ccbf Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 28 Dec 2022 15:30:07 +0000
Subject: [PATCH 149/231] Require setuptools>=65.5.1 (#14355)

Address dependabot alert about security vulnerability
(https://nvd.nist.gov/vuln/detail/CVE-2022-40897).
---
 test-requirements.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-requirements.txt b/test-requirements.txt
index 8ae94237f5ea6..76255044e2dd5 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -15,5 +15,5 @@ pytest-xdist>=1.34.0
 pytest-forked>=1.3.0,<2.0.0
 pytest-cov>=2.10.0
 py>=1.5.2
-setuptools!=50
+setuptools>=65.5.1
 six

From 8e7e22001646034586523a239056f657980451eb Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 28 Dec 2022 15:38:15 +0000
Subject: [PATCH 150/231] Optimization: Avoid a few uses of contextmanagers in
 semantic analyzer (#14360)

This helps mypyc.

(Various small optimizations, including this, together netted a 6%
performance improvement in self check.)
---
 mypy/semanal.py | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 9160097028305..eceb96ca63eea 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -50,7 +50,7 @@
 
 from __future__ import annotations
 
-from contextlib import contextmanager, nullcontext
+from contextlib import contextmanager
 from typing import Any, Callable, Collection, Iterable, Iterator, List, TypeVar, cast
 from typing_extensions import Final, TypeAlias as _TypeAlias
 
@@ -2645,11 +2645,15 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
         # But we can't use a full visit because it may emit extra incomplete refs (namely
         # when analysing any type applications there) thus preventing the further analysis.
         # To break the tie, we first analyse rvalue partially, if it can be a type alias.
-        with self.basic_type_applications_set(s):
-            with self.allow_unbound_tvars_set() if self.can_possibly_be_index_alias(
-                s
-            ) else nullcontext():
+        if self.can_possibly_be_index_alias(s):
+            old_basic_type_applications = self.basic_type_applications
+            self.basic_type_applications = True
+            with self.allow_unbound_tvars_set():
                 s.rvalue.accept(self)
+            self.basic_type_applications = old_basic_type_applications
+        else:
+            s.rvalue.accept(self)
+
         if self.found_incomplete_ref(tag) or self.should_wait_rhs(s.rvalue):
             # Initializer couldn't be fully analyzed. Defer the current node and give up.
             # Make sure that if we skip the definition of some local names, they can't be
@@ -2819,17 +2823,6 @@ def can_possibly_be_index_alias(self, s: AssignmentStmt) -> bool:
         # Something that looks like Foo = Bar[Baz, ...]
         return True
 
-    @contextmanager
-    def basic_type_applications_set(self, s: AssignmentStmt) -> Iterator[None]:
-        old = self.basic_type_applications
-        # As an optimization, only use the double visit logic if this
-        # can possibly be a recursive type alias.
-        self.basic_type_applications = self.can_possibly_be_index_alias(s)
-        try:
-            yield
-        finally:
-            self.basic_type_applications = old
-
     def is_type_ref(self, rv: Expression, bare: bool = False) -> bool:
         """Does this expression refer to a type?
 

From 86dad8ada970a7e37433b74c27019db29f607abc Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 28 Dec 2022 15:41:47 +0000
Subject: [PATCH 151/231] [mypyc] Simplify union types (#14363)

We can sometimes simplify a mypyc RType union, even if the mypy union
couldn't be simplified. A typical example is `list[x] | list[y]` which
can be simplified to just `list`. Previously this would generate a
redundant union `union[list, list]`.
---
 mypyc/irbuild/mapper.py               | 13 +++++++++-
 mypyc/test-data/irbuild-lists.test    | 37 +++++++++++++++++++++++++++
 mypyc/test-data/irbuild-optional.test | 14 ++++------
 3 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/mypyc/irbuild/mapper.py b/mypyc/irbuild/mapper.py
index 4364b2b6c5115..a108766644ce5 100644
--- a/mypyc/irbuild/mapper.py
+++ b/mypyc/irbuild/mapper.py
@@ -116,7 +116,18 @@ def type_to_rtype(self, typ: Type | None) -> RType:
         elif isinstance(typ, NoneTyp):
             return none_rprimitive
         elif isinstance(typ, UnionType):
-            return RUnion([self.type_to_rtype(item) for item in typ.items])
+            # Remove redundant items using set + list to preserve item order
+            seen = set()
+            items = []
+            for item in typ.items:
+                rtype = self.type_to_rtype(item)
+                if rtype not in seen:
+                    items.append(rtype)
+                    seen.add(rtype)
+            if len(items) > 1:
+                return RUnion(items)
+            else:
+                return items[0]
         elif isinstance(typ, AnyType):
             return object_rprimitive
         elif isinstance(typ, TypeType):
diff --git a/mypyc/test-data/irbuild-lists.test b/mypyc/test-data/irbuild-lists.test
index 47f7ada709e36..b82217465fefa 100644
--- a/mypyc/test-data/irbuild-lists.test
+++ b/mypyc/test-data/irbuild-lists.test
@@ -428,3 +428,40 @@ L4:
 L5:
     res = r8
     return 1
+
+[case testSimplifyListUnion]
+from typing import List, Union
+
+def f(a: Union[List[str], List[bytes], int]) -> int:
+    if isinstance(a, list):
+        return len(a)
+    return a
+[out]
+def f(a):
+    a :: union[list, int]
+    r0 :: object
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+    r4 :: list
+    r5 :: ptr
+    r6 :: native_int
+    r7 :: short_int
+    r8 :: int
+L0:
+    r0 = load_address PyList_Type
+    r1 = PyObject_IsInstance(a, r0)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    if r3 goto L1 else goto L2 :: bool
+L1:
+    r4 = borrow cast(list, a)
+    r5 = get_element_ptr r4 ob_size :: PyVarObject
+    r6 = load_mem r5 :: native_int*
+    keep_alive r4
+    r7 = r6 << 1
+    keep_alive a
+    return r7
+L2:
+    r8 = unbox(int, a)
+    return r8
diff --git a/mypyc/test-data/irbuild-optional.test b/mypyc/test-data/irbuild-optional.test
index 4b1d3d1ffec2b..e98cf1b19e2e9 100644
--- a/mypyc/test-data/irbuild-optional.test
+++ b/mypyc/test-data/irbuild-optional.test
@@ -527,14 +527,10 @@ class B:
 
 [out]
 def f(o):
-    o :: union[object, object]
-    r0 :: object
-    r1 :: str
-    r2, r3 :: object
+    o :: object
+    r0 :: str
+    r1 :: object
 L0:
-    r0 = o
-    r1 = 'x'
-    r2 = CPyObject_GetAttr(r0, r1)
-    r3 = r2
-L1:
+    r0 = 'x'
+    r1 = CPyObject_GetAttr(o, r0)
     return 1

From 9dc624bec2e76810548651d72fcfe4619bdb4a78 Mon Sep 17 00:00:00 2001
From: Joshua Bronson <jabronson@gmail.com>
Date: Wed, 28 Dec 2022 19:05:29 -0500
Subject: [PATCH 152/231] [mypyc] Improve error message for multiple
 inheritance. (#14344)

Ref: mypyc/mypyc#962
---
 mypyc/irbuild/classdef.py        | 2 +-
 mypyc/test-data/commandline.test | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index 34fc1fd766b00..b1f2ed1a1a65f 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -84,7 +84,7 @@ def transform_class_def(builder: IRBuilder, cdef: ClassDef) -> None:
     # classes aren't necessarily populated yet at
     # prepare_class_def time.
     if any(ir.base_mro[i].base != ir.base_mro[i + 1] for i in range(len(ir.base_mro) - 1)):
-        builder.error("Non-trait MRO must be linear", cdef.line)
+        builder.error("Multiple inheritance is not supported (except for traits)", cdef.line)
 
     if ir.allow_interpreted_subclasses:
         for parent in ir.mro:
diff --git a/mypyc/test-data/commandline.test b/mypyc/test-data/commandline.test
index 6612df9e18861..bc2713a20f7dd 100644
--- a/mypyc/test-data/commandline.test
+++ b/mypyc/test-data/commandline.test
@@ -164,7 +164,7 @@ class Trait2(Concrete2):
 class NonExt(Concrete1):  # E: Non-extension classes may not inherit from extension classes
     pass
 
-class Nope(Trait1, Concrete2):  # E: Non-trait bases must appear first in parent list  # E: Non-trait MRO must be linear
+class Nope(Trait1, Concrete2):  # E: Non-trait bases must appear first in parent list  # E: Multiple inheritance is not supported (except for traits)
     pass
 
 @decorator

From 5e817cd808b5d1ecd6f2d93c20b6e6fd1de94514 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Thu, 29 Dec 2022 01:17:11 +0000
Subject: [PATCH 153/231] Stubtest: clean up the `_belongs_to_runtime` function
 (#14361)

There's a small semantic change in this PR (instead of returning `False`
if trying to access the `__module__` attribute raises an exception, we
now just move on to the next heuristic). But the main purpose of this PR
is to make the code more readable, as this function was getting quite
hard to understand.

Co-authored-by: hauntsaninja <hauntsaninja@gmail.com>
---
 mypy/stubtest.py | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 5946324d46190..0e4c36e684c19 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -346,16 +346,20 @@ def verify_mypyfile(
     imported_symbols = _get_imported_symbol_names(runtime)
 
     def _belongs_to_runtime(r: types.ModuleType, attr: str) -> bool:
+        """Heuristics to determine whether a name originates from another module."""
         obj = getattr(r, attr)
         if isinstance(obj, types.ModuleType):
             return False
         if callable(obj):
+            # It's highly likely to be a class or a function if it's callable,
+            # so the __module__ attribute will give a good indication of which module it comes from
             try:
-                obj_mod = getattr(obj, "__module__", None)
+                obj_mod = obj.__module__
             except Exception:
-                return False
-            if obj_mod is not None:
-                return bool(obj_mod == r.__name__)
+                pass
+            else:
+                if isinstance(obj_mod, str):
+                    return bool(obj_mod == r.__name__)
         if imported_symbols is not None:
             return attr not in imported_symbols
         return True
@@ -367,8 +371,9 @@ def _belongs_to_runtime(r: types.ModuleType, attr: str) -> bool:
             m
             for m in dir(runtime)
             if not is_probably_private(m)
-            # Ensure that the object's module is `runtime`, since in the absence of __all__ we
-            # don't have a good way to detect re-exports at runtime.
+            # Filter out objects that originate from other modules (best effort). Note that in the
+            # absence of __all__, we don't have a way to detect explicit / intentional re-exports
+            # at runtime
             and _belongs_to_runtime(runtime, m)
         }
     )

From 2c225659f3ae3089a597b9ab148050dd97c48cc9 Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Thu, 29 Dec 2022 01:23:44 +0000
Subject: [PATCH 154/231] stubtest: Improve error message for `__all__`-related
 errors (#14362)

This error is *only* emitted if `__all__` is included in the stub, so
the 'if present' clause is unnecessary

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 mypy/stubtest.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index 0e4c36e684c19..bfd8e2b9c81a4 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -267,7 +267,7 @@ def _verify_exported_names(
         object_path + ["__all__"],
         (
             "names exported from the stub do not correspond to the names exported at runtime. "
-            "This is probably due to things being missing from the stub, or if present, an inaccurate `__all__` in the stub"
+            "This is probably due to things being missing from the stub or an inaccurate `__all__` in the stub"
         ),
         # Pass in MISSING instead of the stub and runtime objects, as the line numbers aren't very
         # relevant here, and it makes for a prettier error message

From e51fb561854b5e04c4d5572deca282e1c7d68519 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 29 Dec 2022 10:13:54 +0000
Subject: [PATCH 155/231] A few miscellaneous micro-optimizations (#14366)

These are part of the changes that collectively bring a 6% performance
improvement. These are all pretty minor.
---
 mypy/checker.py   | 10 ++++++----
 mypy/checkexpr.py |  2 +-
 mypy/types.py     |  8 ++++++--
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 7c5fcba1bb09f..c265ac4905fbd 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -378,10 +378,6 @@ def __init__(
         self.path = path
         self.msg = MessageBuilder(errors, modules)
         self.plugin = plugin
-        self.expr_checker = mypy.checkexpr.ExpressionChecker(
-            self, self.msg, self.plugin, per_line_checking_time_ns
-        )
-        self.pattern_checker = PatternChecker(self, self.msg, self.plugin)
         self.tscope = Scope()
         self.scope = CheckerScope(tree)
         self.binder = ConditionalTypeBinder()
@@ -419,6 +415,12 @@ def __init__(
         # example when type-checking class decorators.
         self.allow_abstract_call = False
 
+        # Child checker objects for specific AST node types
+        self.expr_checker = mypy.checkexpr.ExpressionChecker(
+            self, self.msg, self.plugin, per_line_checking_time_ns
+        )
+        self.pattern_checker = PatternChecker(self, self.msg, self.plugin)
+
     @property
     def type_context(self) -> list[Type | None]:
         return self.expr_checker.type_context
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 5993639be4062..2e93a598fb7e2 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -276,7 +276,7 @@ def __init__(
         self.msg = msg
         self.plugin = plugin
         self.per_line_checking_time_ns = per_line_checking_time_ns
-        self.collect_line_checking_stats = self.chk.options.line_checking_stats is not None
+        self.collect_line_checking_stats = chk.options.line_checking_stats is not None
         # Are we already visiting some expression? This is used to avoid double counting
         # time for nested expressions.
         self.in_expression = False
diff --git a/mypy/types.py b/mypy/types.py
index b48280466c3e3..e25630e794db8 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -2623,13 +2623,17 @@ def __init__(
         # We must keep this false to avoid crashes during semantic analysis.
         # TODO: maybe switch this to True during type-checking pass?
         self.items = flatten_nested_unions(items, handle_type_alias_type=False)
-        self.can_be_true = any(item.can_be_true for item in items)
-        self.can_be_false = any(item.can_be_false for item in items)
         # is_evaluated should be set to false for type comments and string literals
         self.is_evaluated = is_evaluated
         # uses_pep604_syntax is True if Union uses OR syntax (X | Y)
         self.uses_pep604_syntax = uses_pep604_syntax
 
+    def can_be_true_default(self) -> bool:
+        return any(item.can_be_true for item in self.items)
+
+    def can_be_false_default(self) -> bool:
+        return any(item.can_be_false for item in self.items)
+
     def __hash__(self) -> int:
         return hash(frozenset(self.items))
 

From 0070071d461dd57e2dc9b8a215333212167e13c8 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 29 Dec 2022 13:40:54 +0000
Subject: [PATCH 156/231] [mypyc] Fixes to union simplification (#14364)

Flatten nested unions before simplifying unions.

Simplify item type unions in loops. This fixes a crash introduced in
#14363.
---
 mypyc/ir/rtypes.py                            | 37 ++++++++++
 mypyc/irbuild/builder.py                      | 13 +++-
 mypyc/irbuild/mapper.py                       | 13 +---
 mypyc/test-data/irbuild-lists.test            | 70 ++++++++++++++++++-
 .../test/{test_subtype.py => test_typeops.py} | 26 ++++++-
 5 files changed, 141 insertions(+), 18 deletions(-)
 rename mypyc/test/{test_subtype.py => test_typeops.py} (64%)

diff --git a/mypyc/ir/rtypes.py b/mypyc/ir/rtypes.py
index 7fe8a940e4c2a..babfe0770f35e 100644
--- a/mypyc/ir/rtypes.py
+++ b/mypyc/ir/rtypes.py
@@ -797,6 +797,30 @@ def __init__(self, items: list[RType]) -> None:
         self.items_set = frozenset(items)
         self._ctype = "PyObject *"
 
+    @staticmethod
+    def make_simplified_union(items: list[RType]) -> RType:
+        """Return a normalized union that covers the given items.
+
+        Flatten nested unions and remove duplicate items.
+
+        Overlapping items are *not* simplified. For example,
+        [object, str] will not be simplified.
+        """
+        items = flatten_nested_unions(items)
+        assert items
+
+        # Remove duplicate items using set + list to preserve item order
+        seen = set()
+        new_items = []
+        for item in items:
+            if item not in seen:
+                new_items.append(item)
+                seen.add(item)
+        if len(new_items) > 1:
+            return RUnion(new_items)
+        else:
+            return new_items[0]
+
     def accept(self, visitor: RTypeVisitor[T]) -> T:
         return visitor.visit_runion(self)
 
@@ -823,6 +847,19 @@ def deserialize(cls, data: JsonDict, ctx: DeserMaps) -> RUnion:
         return RUnion(types)
 
 
+def flatten_nested_unions(types: list[RType]) -> list[RType]:
+    if not any(isinstance(t, RUnion) for t in types):
+        return types  # Fast path
+
+    flat_items: list[RType] = []
+    for t in types:
+        if isinstance(t, RUnion):
+            flat_items.extend(flatten_nested_unions(t.items))
+        else:
+            flat_items.append(t)
+    return flat_items
+
+
 def optional_value_type(rtype: RType) -> RType | None:
     """If rtype is the union of none_rprimitive and another type X, return X.
 
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
index 6310c25c64fb4..792697970785a 100644
--- a/mypyc/irbuild/builder.py
+++ b/mypyc/irbuild/builder.py
@@ -53,6 +53,7 @@
     Type,
     TypeOfAny,
     UninhabitedType,
+    UnionType,
     get_proper_type,
 )
 from mypy.util import split_target
@@ -85,6 +86,7 @@
     RInstance,
     RTuple,
     RType,
+    RUnion,
     bitmap_rprimitive,
     c_int_rprimitive,
     c_pyssize_t_rprimitive,
@@ -864,8 +866,15 @@ def extract_int(self, e: Expression) -> int | None:
             return None
 
     def get_sequence_type(self, expr: Expression) -> RType:
-        target_type = get_proper_type(self.types[expr])
-        assert isinstance(target_type, Instance)
+        return self.get_sequence_type_from_type(self.types[expr])
+
+    def get_sequence_type_from_type(self, target_type: Type) -> RType:
+        target_type = get_proper_type(target_type)
+        if isinstance(target_type, UnionType):
+            return RUnion.make_simplified_union(
+                [self.get_sequence_type_from_type(item) for item in target_type.items]
+            )
+        assert isinstance(target_type, Instance), target_type
         if target_type.type.fullname == "builtins.str":
             return str_rprimitive
         else:
diff --git a/mypyc/irbuild/mapper.py b/mypyc/irbuild/mapper.py
index a108766644ce5..dddb35230fd5c 100644
--- a/mypyc/irbuild/mapper.py
+++ b/mypyc/irbuild/mapper.py
@@ -116,18 +116,7 @@ def type_to_rtype(self, typ: Type | None) -> RType:
         elif isinstance(typ, NoneTyp):
             return none_rprimitive
         elif isinstance(typ, UnionType):
-            # Remove redundant items using set + list to preserve item order
-            seen = set()
-            items = []
-            for item in typ.items:
-                rtype = self.type_to_rtype(item)
-                if rtype not in seen:
-                    items.append(rtype)
-                    seen.add(rtype)
-            if len(items) > 1:
-                return RUnion(items)
-            else:
-                return items[0]
+            return RUnion.make_simplified_union([self.type_to_rtype(item) for item in typ.items])
         elif isinstance(typ, AnyType):
             return object_rprimitive
         elif isinstance(typ, TypeType):
diff --git a/mypyc/test-data/irbuild-lists.test b/mypyc/test-data/irbuild-lists.test
index b82217465fefa..cb9687a2f942b 100644
--- a/mypyc/test-data/irbuild-lists.test
+++ b/mypyc/test-data/irbuild-lists.test
@@ -430,14 +430,20 @@ L5:
     return 1
 
 [case testSimplifyListUnion]
-from typing import List, Union
+from typing import List, Union, Optional
 
-def f(a: Union[List[str], List[bytes], int]) -> int:
+def narrow(a: Union[List[str], List[bytes], int]) -> int:
     if isinstance(a, list):
         return len(a)
     return a
+def loop(a: Union[List[str], List[bytes]]) -> None:
+    for x in a:
+         pass
+def nested_union(a: Union[List[str], List[Optional[str]]]) -> None:
+    for x in a:
+        pass
 [out]
-def f(a):
+def narrow(a):
     a :: union[list, int]
     r0 :: object
     r1 :: int32
@@ -465,3 +471,61 @@ L1:
 L2:
     r8 = unbox(int, a)
     return r8
+def loop(a):
+    a :: list
+    r0 :: short_int
+    r1 :: ptr
+    r2 :: native_int
+    r3 :: short_int
+    r4 :: bit
+    r5 :: object
+    r6, x :: union[str, bytes]
+    r7 :: short_int
+L0:
+    r0 = 0
+L1:
+    r1 = get_element_ptr a ob_size :: PyVarObject
+    r2 = load_mem r1 :: native_int*
+    keep_alive a
+    r3 = r2 << 1
+    r4 = r0 < r3 :: signed
+    if r4 goto L2 else goto L4 :: bool
+L2:
+    r5 = CPyList_GetItemUnsafe(a, r0)
+    r6 = cast(union[str, bytes], r5)
+    x = r6
+L3:
+    r7 = r0 + 2
+    r0 = r7
+    goto L1
+L4:
+    return 1
+def nested_union(a):
+    a :: list
+    r0 :: short_int
+    r1 :: ptr
+    r2 :: native_int
+    r3 :: short_int
+    r4 :: bit
+    r5 :: object
+    r6, x :: union[str, None]
+    r7 :: short_int
+L0:
+    r0 = 0
+L1:
+    r1 = get_element_ptr a ob_size :: PyVarObject
+    r2 = load_mem r1 :: native_int*
+    keep_alive a
+    r3 = r2 << 1
+    r4 = r0 < r3 :: signed
+    if r4 goto L2 else goto L4 :: bool
+L2:
+    r5 = CPyList_GetItemUnsafe(a, r0)
+    r6 = cast(union[str, None], r5)
+    x = r6
+L3:
+    r7 = r0 + 2
+    r0 = r7
+    goto L1
+L4:
+    return 1
diff --git a/mypyc/test/test_subtype.py b/mypyc/test/test_typeops.py
similarity index 64%
rename from mypyc/test/test_subtype.py
rename to mypyc/test/test_typeops.py
index 4a0d8737c8529..f414edd1a2bb9 100644
--- a/mypyc/test/test_subtype.py
+++ b/mypyc/test/test_typeops.py
@@ -1,16 +1,19 @@
-"""Test cases for is_subtype and is_runtime_subtype."""
+"""Test cases for various RType operations."""
 
 from __future__ import annotations
 
 import unittest
 
 from mypyc.ir.rtypes import (
+    RUnion,
     bit_rprimitive,
     bool_rprimitive,
     int32_rprimitive,
     int64_rprimitive,
     int_rprimitive,
+    object_rprimitive,
     short_int_rprimitive,
+    str_rprimitive,
 )
 from mypyc.rt_subtype import is_runtime_subtype
 from mypyc.subtype import is_subtype
@@ -50,3 +53,24 @@ def test_bit(self) -> None:
     def test_bool(self) -> None:
         assert not is_runtime_subtype(bool_rprimitive, bit_rprimitive)
         assert not is_runtime_subtype(bool_rprimitive, int_rprimitive)
+
+
+class TestUnionSimplification(unittest.TestCase):
+    def test_simple_type_result(self) -> None:
+        assert RUnion.make_simplified_union([int_rprimitive]) == int_rprimitive
+
+    def test_remove_duplicate(self) -> None:
+        assert RUnion.make_simplified_union([int_rprimitive, int_rprimitive]) == int_rprimitive
+
+    def test_cannot_simplify(self) -> None:
+        assert RUnion.make_simplified_union(
+            [int_rprimitive, str_rprimitive, object_rprimitive]
+        ) == RUnion([int_rprimitive, str_rprimitive, object_rprimitive])
+
+    def test_nested(self) -> None:
+        assert RUnion.make_simplified_union(
+            [int_rprimitive, RUnion([str_rprimitive, int_rprimitive])]
+        ) == RUnion([int_rprimitive, str_rprimitive])
+        assert RUnion.make_simplified_union(
+            [int_rprimitive, RUnion([str_rprimitive, RUnion([int_rprimitive])])]
+        ) == RUnion([int_rprimitive, str_rprimitive])

From 47747f2f58aef4cac30c0cd9416bc2a521152de5 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 29 Dec 2022 13:41:35 +0000
Subject: [PATCH 157/231] Some semantic analyzer micro-optimizations (#14367)

The biggest change is replacing some calls to bound methods with trait
method calls, which are faster when compiled.

Also remove an unused argument to TypeVarLikeQuery and make a few misc
tweaks.

(Various small optimizations, including these, together netted a 6%
performance improvement in self check.)
---
 mypy/semanal.py      |  6 ++---
 mypy/type_visitor.py |  2 +-
 mypy/typeanal.py     | 58 +++++++++++++++++++++++++++-----------------
 3 files changed, 40 insertions(+), 26 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index eceb96ca63eea..51310e4f3e4d0 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1915,7 +1915,7 @@ def get_all_bases_tvars(
                 except TypeTranslationError:
                     # This error will be caught later.
                     continue
-                base_tvars = base.accept(TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope))
+                base_tvars = base.accept(TypeVarLikeQuery(self, self.tvar_scope))
                 tvars.extend(base_tvars)
         return remove_dups(tvars)
 
@@ -1933,7 +1933,7 @@ def get_and_bind_all_tvars(self, type_exprs: list[Expression]) -> list[TypeVarLi
             except TypeTranslationError:
                 # This error will be caught later.
                 continue
-            base_tvars = base.accept(TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope))
+            base_tvars = base.accept(TypeVarLikeQuery(self, self.tvar_scope))
             tvars.extend(base_tvars)
         tvars = remove_dups(tvars)  # Variables are defined in order of textual appearance.
         tvar_defs = []
@@ -3294,7 +3294,7 @@ def analyze_alias(
             )
             return None, [], set(), []
 
-        found_type_vars = typ.accept(TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope))
+        found_type_vars = typ.accept(TypeVarLikeQuery(self, self.tvar_scope))
         tvar_defs: list[TypeVarLikeType] = []
         namespace = self.qualified_name(name)
         with self.tvar_scope_frame(self.tvar_scope.class_frame(namespace)):
diff --git a/mypy/type_visitor.py b/mypy/type_visitor.py
index 823e74e7e2830..c5324357117b3 100644
--- a/mypy/type_visitor.py
+++ b/mypy/type_visitor.py
@@ -315,7 +315,7 @@ class TypeQuery(SyntheticTypeVisitor[T]):
     # TODO: check that we don't have existing violations of this rule.
     """
 
-    def __init__(self, strategy: Callable[[Iterable[T]], T]) -> None:
+    def __init__(self, strategy: Callable[[list[T]], T]) -> None:
         self.strategy = strategy
         # Keep track of the type aliases already visited. This is needed to avoid
         # infinite recursion on types like A = Union[int, List[A]].
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 28f293613d501..0755b21854de0 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -4,7 +4,6 @@
 
 import itertools
 from contextlib import contextmanager
-from itertools import chain
 from typing import Callable, Iterable, Iterator, List, Sequence, Tuple, TypeVar
 from typing_extensions import Final, Protocol
 
@@ -203,8 +202,6 @@ def __init__(
         allow_type_any: bool = False,
     ) -> None:
         self.api = api
-        self.lookup_qualified = api.lookup_qualified
-        self.lookup_fqn_func = api.lookup_fully_qualified
         self.fail_func = api.fail
         self.note_func = api.note
         self.tvar_scope = tvar_scope
@@ -244,6 +241,14 @@ def __init__(
         # Allow variables typed as Type[Any] and type (useful for base classes).
         self.allow_type_any = allow_type_any
 
+    def lookup_qualified(
+        self, name: str, ctx: Context, suppress_errors: bool = False
+    ) -> SymbolTableNode | None:
+        return self.api.lookup_qualified(name, ctx, suppress_errors)
+
+    def lookup_fully_qualified(self, name: str) -> SymbolTableNode:
+        return self.api.lookup_fully_qualified(name)
+
     def visit_unbound_type(self, t: UnboundType, defining_literal: bool = False) -> Type:
         typ = self.visit_unbound_type_nonoptional(t, defining_literal)
         if t.optional:
@@ -1408,14 +1413,17 @@ def tvar_scope_frame(self) -> Iterator[None]:
         yield
         self.tvar_scope = old_scope
 
+    def find_type_var_likes(self, t: Type, include_callables: bool = True) -> TypeVarLikeList:
+        return t.accept(
+            TypeVarLikeQuery(self.api, self.tvar_scope, include_callables=include_callables)
+        )
+
     def infer_type_variables(self, type: CallableType) -> list[tuple[str, TypeVarLikeExpr]]:
         """Return list of unique type variables referred to in a callable."""
         names: list[str] = []
         tvars: list[TypeVarLikeExpr] = []
         for arg in type.arg_types:
-            for name, tvar_expr in arg.accept(
-                TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope)
-            ):
+            for name, tvar_expr in self.find_type_var_likes(arg):
                 if name not in names:
                     names.append(name)
                     tvars.append(tvar_expr)
@@ -1423,12 +1431,13 @@ def infer_type_variables(self, type: CallableType) -> list[tuple[str, TypeVarLik
         # look inside Callable types.  Type variables only appearing in
         # functions in the return type belong to those functions, not the
         # function we're currently analyzing.
-        for name, tvar_expr in type.ret_type.accept(
-            TypeVarLikeQuery(self.lookup_qualified, self.tvar_scope, include_callables=False)
-        ):
+        for name, tvar_expr in self.find_type_var_likes(type.ret_type, include_callables=False):
             if name not in names:
                 names.append(name)
                 tvars.append(tvar_expr)
+
+        if not names:
+            return []  # Fast path
         return list(zip(names, tvars))
 
     def bind_function_type_variables(
@@ -1546,7 +1555,7 @@ def named_type(
         line: int = -1,
         column: int = -1,
     ) -> Instance:
-        node = self.lookup_fqn_func(fully_qualified_name)
+        node = self.lookup_fully_qualified(fully_qualified_name)
         assert isinstance(node.node, TypeInfo)
         any_type = AnyType(TypeOfAny.special_form)
         if args is not None:
@@ -1785,7 +1794,9 @@ def set_any_tvars(
     return TypeAliasType(node, [any_type] * len(node.alias_tvars), newline, newcolumn)
 
 
-def remove_dups(tvars: Iterable[T]) -> list[T]:
+def remove_dups(tvars: list[T]) -> list[T]:
+    if len(tvars) <= 1:
+        return tvars
     # Get unique elements in order of appearance
     all_tvars: set[T] = set()
     new_tvars: list[T] = []
@@ -1796,8 +1807,13 @@ def remove_dups(tvars: Iterable[T]) -> list[T]:
     return new_tvars
 
 
-def flatten_tvars(ll: Iterable[list[T]]) -> list[T]:
-    return remove_dups(chain.from_iterable(ll))
+def flatten_tvars(lists: list[list[T]]) -> list[T]:
+    result: list[T] = []
+    for lst in lists:
+        for item in lst:
+            if item not in result:
+                result.append(item)
+    return result
 
 
 class TypeVarLikeQuery(TypeQuery[TypeVarLikeList]):
@@ -1805,17 +1821,15 @@ class TypeVarLikeQuery(TypeQuery[TypeVarLikeList]):
 
     def __init__(
         self,
-        lookup: Callable[[str, Context], SymbolTableNode | None],
+        api: SemanticAnalyzerCoreInterface,
         scope: TypeVarLikeScope,
         *,
         include_callables: bool = True,
-        include_bound_tvars: bool = False,
     ) -> None:
-        self.include_callables = include_callables
-        self.lookup = lookup
-        self.scope = scope
-        self.include_bound_tvars = include_bound_tvars
         super().__init__(flatten_tvars)
+        self.api = api
+        self.scope = scope
+        self.include_callables = include_callables
         # Only include type variables in type aliases args. This would be anyway
         # that case if we expand (as target variables would be overridden with args)
         # and it may cause infinite recursion on invalid (diverging) recursive aliases.
@@ -1833,16 +1847,16 @@ def visit_unbound_type(self, t: UnboundType) -> TypeVarLikeList:
         if name.endswith("args"):
             if name.endswith(".args") or name.endswith(".kwargs"):
                 base = ".".join(name.split(".")[:-1])
-                n = self.lookup(base, t)
+                n = self.api.lookup_qualified(base, t)
                 if n is not None and isinstance(n.node, ParamSpecExpr):
                     node = n
                     name = base
         if node is None:
-            node = self.lookup(name, t)
+            node = self.api.lookup_qualified(name, t)
         if (
             node
             and isinstance(node.node, TypeVarLikeExpr)
-            and (self.include_bound_tvars or self.scope.get_binding(node) is None)
+            and self.scope.get_binding(node) is None
         ):
             assert isinstance(node.node, TypeVarLikeExpr)
             return [(name, node.node)]

From 8884f7d38c4ee190068666b633e4433d27c8293e Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 29 Dec 2022 13:42:22 +0000
Subject: [PATCH 158/231] Micro-optimize flatten_nested_unions (#14368)

Avoid constructing a new list if there is nothing to flatten (and the
input is a list, which is often the case).
---
 mypy/types.py | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index e25630e794db8..fa1502f48fa49 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3381,12 +3381,20 @@ def _flattened(types: Iterable[Type]) -> Iterable[Type]:
 
 
 def flatten_nested_unions(
-    types: Iterable[Type], handle_type_alias_type: bool = True
+    types: Sequence[Type], handle_type_alias_type: bool = True
 ) -> list[Type]:
     """Flatten nested unions in a type list."""
+    if not isinstance(types, list):
+        typelist = list(types)
+    else:
+        typelist = cast("list[Type]", types)
+
+    # Fast path: most of the time there is nothing to flatten
+    if not any(isinstance(t, (TypeAliasType, UnionType)) for t in typelist):  # type: ignore[misc]
+        return typelist
+
     flat_items: list[Type] = []
-    # TODO: avoid duplicate types in unions (e.g. using hash)
-    for t in types:
+    for t in typelist:
         tp = get_proper_type(t) if handle_type_alias_type else t
         if isinstance(tp, ProperType) and isinstance(tp, UnionType):
             flat_items.extend(

From 52172a3a0197e2407e666fda5b83161ea8e17183 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 29 Dec 2022 15:17:47 +0000
Subject: [PATCH 159/231] Micro-optimize get_proper_type(s) (#14369)

These are used a lot, so it makes sense to tune them a bit. We now avoid
allocations in a common case, when compiled.

(Various small optimizations, including these, together netted a 6%
performance improvement in self check.)
---
 mypy/checkexpr.py |  9 ++++-----
 mypy/types.py     | 24 ++++++++++++++++++------
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 2e93a598fb7e2..5c6db86964ac9 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -2213,7 +2213,7 @@ def check_overload_call(
                     # we don't want to introduce internal inconsistencies.
                     unioned_result = (
                         make_simplified_union(list(returns), context.line, context.column),
-                        self.combine_function_signatures(inferred_types),
+                        self.combine_function_signatures(get_proper_types(inferred_types)),
                     )
 
         # Step 3: We try checking each branch one-by-one.
@@ -2554,7 +2554,7 @@ def type_overrides_set(
             for expr in exprs:
                 del self.type_overrides[expr]
 
-    def combine_function_signatures(self, types: Sequence[Type]) -> AnyType | CallableType:
+    def combine_function_signatures(self, types: list[ProperType]) -> AnyType | CallableType:
         """Accepts a list of function signatures and attempts to combine them together into a
         new CallableType consisting of the union of all of the given arguments and return types.
 
@@ -2562,10 +2562,9 @@ def combine_function_signatures(self, types: Sequence[Type]) -> AnyType | Callab
         an ambiguity because of Any in arguments).
         """
         assert types, "Trying to merge no callables"
-        types = get_proper_types(types)
         if not all(isinstance(c, CallableType) for c in types):
             return AnyType(TypeOfAny.special_form)
-        callables = cast(Sequence[CallableType], types)
+        callables = cast("list[CallableType]", types)
         if len(callables) == 1:
             return callables[0]
 
@@ -3463,7 +3462,7 @@ def check_op(
             # we call 'combine_function_signature' instead of just unioning the inferred
             # callable types.
             results_final = make_simplified_union(all_results)
-            inferred_final = self.combine_function_signatures(all_inferred)
+            inferred_final = self.combine_function_signatures(get_proper_types(all_inferred))
             return results_final, inferred_final
         else:
             return self.check_method_call_by_name(
diff --git a/mypy/types.py b/mypy/types.py
index fa1502f48fa49..354a740567dc9 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -2888,23 +2888,35 @@ def get_proper_type(typ: Type | None) -> ProperType | None:
         typ = typ.type_guard
     while isinstance(typ, TypeAliasType):
         typ = typ._expand_once()
-    assert isinstance(typ, ProperType), typ
     # TODO: store the name of original type alias on this type, so we can show it in errors.
-    return typ
+    return cast(ProperType, typ)
 
 
 @overload
-def get_proper_types(it: Iterable[Type]) -> list[ProperType]:  # type: ignore[misc]
+def get_proper_types(types: list[Type] | tuple[Type, ...]) -> list[ProperType]:  # type: ignore[misc]
     ...
 
 
 @overload
-def get_proper_types(it: Iterable[Type | None]) -> list[ProperType | None]:
+def get_proper_types(
+    types: list[Type | None] | tuple[Type | None, ...]
+) -> list[ProperType | None]:
     ...
 
 
-def get_proper_types(it: Iterable[Type | None]) -> list[ProperType] | list[ProperType | None]:
-    return [get_proper_type(t) for t in it]
+def get_proper_types(
+    types: list[Type] | list[Type | None] | tuple[Type | None, ...]
+) -> list[ProperType] | list[ProperType | None]:
+    if isinstance(types, list):
+        typelist = types
+        # Optimize for the common case so that we don't need to allocate anything
+        if not any(
+            isinstance(t, (TypeAliasType, TypeGuardedType)) for t in typelist  # type: ignore[misc]
+        ):
+            return cast("list[ProperType]", typelist)
+        return [get_proper_type(t) for t in typelist]
+    else:
+        return [get_proper_type(t) for t in types]
 
 
 # We split off the type visitor base classes to another module

From 9183b28401bd2928d921a068bbbc7e6565e77649 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Thu, 29 Dec 2022 15:18:06 +0000
Subject: [PATCH 160/231] Speed up make_simplified_union (#14370)

If there is only one non-union item, there's nothing interesting to do.
This is pretty common, and it avoids a fairly expensive
`_remove_redundant_union_items` call.

(Various small optimizations, including this, together netted a 6%
performance improvement in self check.)
---
 mypy/typeops.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/mypy/typeops.py b/mypy/typeops.py
index baf5b8552eff8..8c01fb1180765 100644
--- a/mypy/typeops.py
+++ b/mypy/typeops.py
@@ -441,6 +441,7 @@ def make_simplified_union(
     * [int, int] -> int
     * [int, Any] -> Union[int, Any] (Any types are not simplified away!)
     * [Any, Any] -> Any
+    * [int, Union[bytes, str]] -> Union[int, bytes, str]
 
     Note: This must NOT be used during semantic analysis, since TypeInfos may not
           be fully initialized.
@@ -455,10 +456,14 @@ def make_simplified_union(
     # Step 1: expand all nested unions
     items = flatten_nested_unions(items)
 
-    # Step 2: remove redundant unions
+    # Step 2: fast path for single item
+    if len(items) == 1:
+        return get_proper_type(items[0])
+
+    # Step 3: remove redundant unions
     simplified_set: Sequence[Type] = _remove_redundant_union_items(items, keep_erased)
 
-    # Step 3: If more than one literal exists in the union, try to simplify
+    # Step 4: If more than one literal exists in the union, try to simplify
     if (
         contract_literals
         and sum(isinstance(get_proper_type(item), LiteralType) for item in simplified_set) > 1
@@ -471,7 +476,7 @@ def make_simplified_union(
     if nitems > 1 and (
         nitems > 2 or not (type(items[0]) is NoneType or type(items[1]) is NoneType)
     ):
-        # Step 4: At last, we erase any (inconsistent) extra attributes on instances.
+        # Step 5: At last, we erase any (inconsistent) extra attributes on instances.
 
         # Initialize with None instead of an empty set as a micro-optimization. The set
         # is needed very rarely, so we try to avoid constructing it.

From c8316545971833e1f6eafd09de6aa12d9a00278c Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 31 Dec 2022 17:50:18 -0700
Subject: [PATCH 161/231] Sync typeshed (#14375)

Source commit: https://github.com/python/typeshed/commit/46f0d918efc074a3df0d56f94f755e1371d899f0

Co-authored-by: mypybot <>
Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 mypy/typeshed/stdlib/_winapi.pyi              |   1 +
 mypy/typeshed/stdlib/ast.pyi                  |  16 +-
 mypy/typeshed/stdlib/asyncio/subprocess.pyi   |  98 ++++++++++-
 mypy/typeshed/stdlib/asyncio/tasks.pyi        |   2 +-
 mypy/typeshed/stdlib/builtins.pyi             |   8 +-
 mypy/typeshed/stdlib/collections/__init__.pyi |   7 +-
 mypy/typeshed/stdlib/ctypes/__init__.pyi      |   4 +-
 mypy/typeshed/stdlib/datetime.pyi             |  33 +++-
 mypy/typeshed/stdlib/json/__init__.pyi        |   6 +-
 mypy/typeshed/stdlib/json/encoder.pyi         |   4 +-
 mypy/typeshed/stdlib/netrc.pyi                |   6 +-
 mypy/typeshed/stdlib/shutil.pyi               |  25 ++-
 mypy/typeshed/stdlib/subprocess.pyi           | 164 +++++++++---------
 mypy/typeshed/stdlib/types.pyi                |   3 +
 mypy/typeshed/stdlib/unittest/mock.pyi        |   8 +-
 mypy/typeshed/stdlib/zipfile.pyi              |  28 ++-
 mypy/typeshed/stdlib/zipimport.pyi            |   2 +-
 17 files changed, 275 insertions(+), 140 deletions(-)

diff --git a/mypy/typeshed/stdlib/_winapi.pyi b/mypy/typeshed/stdlib/_winapi.pyi
index 3ccac7e6b7e6b..4fbefc33abb1c 100644
--- a/mypy/typeshed/stdlib/_winapi.pyi
+++ b/mypy/typeshed/stdlib/_winapi.pyi
@@ -184,6 +184,7 @@ if sys.platform == "win32":
     def PeekNamedPipe(__handle: int, __size: int = ...) -> tuple[int, int] | tuple[bytes, int, int]: ...
     if sys.version_info >= (3, 10):
         def LCMapStringEx(locale: str, flags: int, src: str) -> str: ...
+        def UnmapViewOfFile(__address: int) -> None: ...
 
     @overload
     def ReadFile(handle: int, size: int, overlapped: Literal[True]) -> tuple[Overlapped, int]: ...
diff --git a/mypy/typeshed/stdlib/ast.pyi b/mypy/typeshed/stdlib/ast.pyi
index b2cff5b00264d..9a5bf0a623fb6 100644
--- a/mypy/typeshed/stdlib/ast.pyi
+++ b/mypy/typeshed/stdlib/ast.pyi
@@ -89,6 +89,7 @@ class NodeVisitor:
     def visit_Constant(self, node: Constant) -> Any: ...
     if sys.version_info >= (3, 8):
         def visit_NamedExpr(self, node: NamedExpr) -> Any: ...
+        def visit_TypeIgnore(self, node: TypeIgnore) -> Any: ...
 
     def visit_Attribute(self, node: Attribute) -> Any: ...
     def visit_Subscript(self, node: Subscript) -> Any: ...
@@ -135,6 +136,19 @@ class NodeVisitor:
     def visit_keyword(self, node: keyword) -> Any: ...
     def visit_alias(self, node: alias) -> Any: ...
     def visit_withitem(self, node: withitem) -> Any: ...
+    if sys.version_info >= (3, 10):
+        def visit_Match(self, node: Match) -> Any: ...
+        def visit_MatchValue(self, node: MatchValue) -> Any: ...
+        def visit_MatchSequence(self, node: MatchSequence) -> Any: ...
+        def visit_MatchStar(self, node: MatchStar) -> Any: ...
+        def visit_MatchMapping(self, node: MatchMapping) -> Any: ...
+        def visit_MatchClass(self, node: MatchClass) -> Any: ...
+        def visit_MatchAs(self, node: MatchAs) -> Any: ...
+        def visit_MatchOr(self, node: MatchOr) -> Any: ...
+
+    if sys.version_info >= (3, 11):
+        def visit_TryStar(self, node: TryStar) -> Any: ...
+
     # visit methods for deprecated nodes
     def visit_ExtSlice(self, node: ExtSlice) -> Any: ...
     def visit_Index(self, node: Index) -> Any: ...
@@ -261,7 +275,7 @@ else:
     def dump(node: AST, annotate_fields: bool = ..., include_attributes: bool = ...) -> str: ...
 
 def fix_missing_locations(node: _T) -> _T: ...
-def get_docstring(node: AST, clean: bool = ...) -> str | None: ...
+def get_docstring(node: AsyncFunctionDef | FunctionDef | ClassDef | Module, clean: bool = ...) -> str | None: ...
 def increment_lineno(node: _T, n: int = ...) -> _T: ...
 def iter_child_nodes(node: AST) -> Iterator[AST]: ...
 def iter_fields(node: AST) -> Iterator[tuple[str, Any]]: ...
diff --git a/mypy/typeshed/stdlib/asyncio/subprocess.pyi b/mypy/typeshed/stdlib/asyncio/subprocess.pyi
index 7fb5883969054..d483f57551b0b 100644
--- a/mypy/typeshed/stdlib/asyncio/subprocess.pyi
+++ b/mypy/typeshed/stdlib/asyncio/subprocess.pyi
@@ -2,7 +2,7 @@ import subprocess
 import sys
 from _typeshed import StrOrBytesPath
 from asyncio import events, protocols, streams, transports
-from collections.abc import Callable
+from collections.abc import Callable, Collection
 from typing import IO, Any
 from typing_extensions import Literal, TypeAlias
 
@@ -40,7 +40,7 @@ class Process:
     def kill(self) -> None: ...
     async def communicate(self, input: bytes | bytearray | memoryview | None = ...) -> tuple[bytes, bytes]: ...
 
-if sys.version_info >= (3, 10):
+if sys.version_info >= (3, 11):
     async def create_subprocess_shell(
         cmd: str | bytes,
         stdin: int | IO[Any] | None = ...,
@@ -65,7 +65,13 @@ if sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
+        group: None | str | int = ...,
+        extra_groups: None | Collection[str | int] = ...,
+        user: None | str | int = ...,
+        umask: int = ...,
+        process_group: int | None = ...,
+        pipesize: int = ...,
     ) -> Process: ...
     async def create_subprocess_exec(
         program: _ExecArg,
@@ -91,10 +97,80 @@ if sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
+        group: None | str | int = ...,
+        extra_groups: None | Collection[str | int] = ...,
+        user: None | str | int = ...,
+        umask: int = ...,
+        process_group: int | None = ...,
+        pipesize: int = ...,
     ) -> Process: ...
 
-else:
+elif sys.version_info >= (3, 10):
+    async def create_subprocess_shell(
+        cmd: str | bytes,
+        stdin: int | IO[Any] | None = ...,
+        stdout: int | IO[Any] | None = ...,
+        stderr: int | IO[Any] | None = ...,
+        limit: int = ...,
+        *,
+        # These parameters are forced to these values by BaseEventLoop.subprocess_shell
+        universal_newlines: Literal[False] = ...,
+        shell: Literal[True] = ...,
+        bufsize: Literal[0] = ...,
+        encoding: None = ...,
+        errors: None = ...,
+        text: Literal[False, None] = ...,
+        # These parameters are taken by subprocess.Popen, which this ultimately delegates to
+        executable: StrOrBytesPath | None = ...,
+        preexec_fn: Callable[[], Any] | None = ...,
+        close_fds: bool = ...,
+        cwd: StrOrBytesPath | None = ...,
+        env: subprocess._ENV | None = ...,
+        startupinfo: Any | None = ...,
+        creationflags: int = ...,
+        restore_signals: bool = ...,
+        start_new_session: bool = ...,
+        pass_fds: Collection[int] = ...,
+        group: None | str | int = ...,
+        extra_groups: None | Collection[str | int] = ...,
+        user: None | str | int = ...,
+        umask: int = ...,
+        pipesize: int = ...,
+    ) -> Process: ...
+    async def create_subprocess_exec(
+        program: _ExecArg,
+        *args: _ExecArg,
+        stdin: int | IO[Any] | None = ...,
+        stdout: int | IO[Any] | None = ...,
+        stderr: int | IO[Any] | None = ...,
+        limit: int = ...,
+        # These parameters are forced to these values by BaseEventLoop.subprocess_shell
+        universal_newlines: Literal[False] = ...,
+        shell: Literal[True] = ...,
+        bufsize: Literal[0] = ...,
+        encoding: None = ...,
+        errors: None = ...,
+        # These parameters are taken by subprocess.Popen, which this ultimately delegates to
+        text: bool | None = ...,
+        executable: StrOrBytesPath | None = ...,
+        preexec_fn: Callable[[], Any] | None = ...,
+        close_fds: bool = ...,
+        cwd: StrOrBytesPath | None = ...,
+        env: subprocess._ENV | None = ...,
+        startupinfo: Any | None = ...,
+        creationflags: int = ...,
+        restore_signals: bool = ...,
+        start_new_session: bool = ...,
+        pass_fds: Collection[int] = ...,
+        group: None | str | int = ...,
+        extra_groups: None | Collection[str | int] = ...,
+        user: None | str | int = ...,
+        umask: int = ...,
+        pipesize: int = ...,
+    ) -> Process: ...
+
+else:  # >= 3.9
     async def create_subprocess_shell(
         cmd: str | bytes,
         stdin: int | IO[Any] | None = ...,
@@ -120,7 +196,11 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
+        group: None | str | int = ...,
+        extra_groups: None | Collection[str | int] = ...,
+        user: None | str | int = ...,
+        umask: int = ...,
     ) -> Process: ...
     async def create_subprocess_exec(
         program: _ExecArg,
@@ -147,5 +227,9 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
+        group: None | str | int = ...,
+        extra_groups: None | Collection[str | int] = ...,
+        user: None | str | int = ...,
+        umask: int = ...,
     ) -> Process: ...
diff --git a/mypy/typeshed/stdlib/asyncio/tasks.pyi b/mypy/typeshed/stdlib/asyncio/tasks.pyi
index 67581eb6a5ad6..43dd020fa99df 100644
--- a/mypy/typeshed/stdlib/asyncio/tasks.pyi
+++ b/mypy/typeshed/stdlib/asyncio/tasks.pyi
@@ -270,7 +270,7 @@ else:
 # While this is true in general, here it's sort-of okay to have a covariant subclass,
 # since the only reason why `asyncio.Future` is invariant is the `set_result()` method,
 # and `asyncio.Task.set_result()` always raises.
-class Task(Future[_T_co], Generic[_T_co]):  # type: ignore[type-var]
+class Task(Future[_T_co], Generic[_T_co]):  # type: ignore[type-var]  # pyright: ignore[reportGeneralTypeIssues]
     if sys.version_info >= (3, 8):
         def __init__(
             self,
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index a47d774467ddd..8fbef893ac57e 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -1,6 +1,6 @@
+import _ast
 import sys
 import types
-from _ast import AST
 from _collections_abc import dict_items, dict_keys, dict_values
 from _typeshed import (
     AnyStr_co,
@@ -1096,7 +1096,7 @@ class property:
 class _NotImplementedType(Any):  # type: ignore[misc]
     # A little weird, but typing the __call__ as NotImplemented makes the error message
     # for NotImplemented() much better
-    __call__: NotImplemented  # type: ignore[valid-type]
+    __call__: NotImplemented  # type: ignore[valid-type]  # pyright: ignore[reportGeneralTypeIssues]
 
 NotImplemented: _NotImplementedType
 
@@ -1131,7 +1131,7 @@ if sys.version_info >= (3, 10):
 # TODO: `compile` has a more precise return type in reality; work on a way of expressing that?
 if sys.version_info >= (3, 8):
     def compile(
-        source: str | ReadableBuffer | AST,
+        source: str | ReadableBuffer | _ast.Module | _ast.Expression | _ast.Interactive,
         filename: str | ReadableBuffer | _PathLike[Any],
         mode: str,
         flags: int = ...,
@@ -1143,7 +1143,7 @@ if sys.version_info >= (3, 8):
 
 else:
     def compile(
-        source: str | ReadableBuffer | AST,
+        source: str | ReadableBuffer | _ast.Module | _ast.Expression | _ast.Interactive,
         filename: str | ReadableBuffer | _PathLike[Any],
         mode: str,
         flags: int = ...,
diff --git a/mypy/typeshed/stdlib/collections/__init__.pyi b/mypy/typeshed/stdlib/collections/__init__.pyi
index 37505c256d9c9..2955aa3b3cd0e 100644
--- a/mypy/typeshed/stdlib/collections/__init__.pyi
+++ b/mypy/typeshed/stdlib/collections/__init__.pyi
@@ -327,16 +327,17 @@ class _OrderedDictValuesView(ValuesView[_VT_co], Reversible[_VT_co]):
 # The C implementations of the "views" classes
 # (At runtime, these are called `odict_keys`, `odict_items` and `odict_values`,
 # but they are not exposed anywhere)
+# pyright doesn't have a specific error code for subclassing error!
 @final
-class _odict_keys(dict_keys[_KT_co, _VT_co], Reversible[_KT_co]):  # type: ignore[misc]
+class _odict_keys(dict_keys[_KT_co, _VT_co], Reversible[_KT_co]):  # type: ignore[misc]  # pyright: ignore
     def __reversed__(self) -> Iterator[_KT_co]: ...
 
 @final
-class _odict_items(dict_items[_KT_co, _VT_co], Reversible[tuple[_KT_co, _VT_co]]):  # type: ignore[misc]
+class _odict_items(dict_items[_KT_co, _VT_co], Reversible[tuple[_KT_co, _VT_co]]):  # type: ignore[misc]  # pyright: ignore
     def __reversed__(self) -> Iterator[tuple[_KT_co, _VT_co]]: ...
 
 @final
-class _odict_values(dict_values[_KT_co, _VT_co], Reversible[_VT_co], Generic[_KT_co, _VT_co]):  # type: ignore[misc]
+class _odict_values(dict_values[_KT_co, _VT_co], Reversible[_VT_co], Generic[_KT_co, _VT_co]):  # type: ignore[misc]  # pyright: ignore
     def __reversed__(self) -> Iterator[_VT_co]: ...
 
 class OrderedDict(dict[_KT, _VT], Reversible[_KT], Generic[_KT, _VT]):
diff --git a/mypy/typeshed/stdlib/ctypes/__init__.pyi b/mypy/typeshed/stdlib/ctypes/__init__.pyi
index 84e4ba07a02ad..2e26a08f81f9d 100644
--- a/mypy/typeshed/stdlib/ctypes/__init__.pyi
+++ b/mypy/typeshed/stdlib/ctypes/__init__.pyi
@@ -64,8 +64,8 @@ class _CDataMeta(type):
     # By default mypy complains about the following two methods, because strictly speaking cls
     # might not be a Type[_CT]. However this can never actually happen, because the only class that
     # uses _CDataMeta as its metaclass is _CData. So it's safe to ignore the errors here.
-    def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc]
-    def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc]
+    def __mul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
+    def __rmul__(cls: type[_CT], other: int) -> type[Array[_CT]]: ...  # type: ignore[misc]  # pyright: ignore[reportGeneralTypeIssues]
 
 class _CData(metaclass=_CDataMeta):
     _b_base: int
diff --git a/mypy/typeshed/stdlib/datetime.pyi b/mypy/typeshed/stdlib/datetime.pyi
index b1b3c17ee25b2..43f5902c3c06d 100644
--- a/mypy/typeshed/stdlib/datetime.pyi
+++ b/mypy/typeshed/stdlib/datetime.pyi
@@ -70,7 +70,14 @@ class date:
     @property
     def day(self) -> int: ...
     def ctime(self) -> str: ...
-    def strftime(self, __format: str) -> str: ...
+    # On <3.12, the name of the parameter in the pure-Python implementation
+    # didn't match the name in the C implementation,
+    # meaning it is only *safe* to pass it as a keyword argument on 3.12+
+    if sys.version_info >= (3, 12):
+        def strftime(self, format: str) -> str: ...
+    else:
+        def strftime(self, __format: str) -> str: ...
+
     def __format__(self, __fmt: str) -> str: ...
     def isoformat(self) -> str: ...
     def timetuple(self) -> struct_time: ...
@@ -140,7 +147,14 @@ class time:
     def isoformat(self, timespec: str = ...) -> str: ...
     @classmethod
     def fromisoformat(cls: type[Self], __time_string: str) -> Self: ...
-    def strftime(self, __format: str) -> str: ...
+    # On <3.12, the name of the parameter in the pure-Python implementation
+    # didn't match the name in the C implementation,
+    # meaning it is only *safe* to pass it as a keyword argument on 3.12+
+    if sys.version_info >= (3, 12):
+        def strftime(self, format: str) -> str: ...
+    else:
+        def strftime(self, __format: str) -> str: ...
+
     def __format__(self, __fmt: str) -> str: ...
     def utcoffset(self) -> timedelta | None: ...
     def tzname(self) -> str | None: ...
@@ -233,11 +247,16 @@ class datetime(date):
     def tzinfo(self) -> _TzInfo | None: ...
     @property
     def fold(self) -> int: ...
-    # The first parameter in `fromtimestamp` is actually positional-or-keyword,
-    # but it is named "timestamp" in the C implementation and "t" in the Python implementation,
-    # so it is only truly *safe* to pass it as a positional argument.
-    @classmethod
-    def fromtimestamp(cls: type[Self], __timestamp: float, tz: _TzInfo | None = ...) -> Self: ...
+    # On <3.12, the name of the first parameter in the pure-Python implementation
+    # didn't match the name in the C implementation,
+    # meaning it is only *safe* to pass it as a keyword argument on 3.12+
+    if sys.version_info >= (3, 12):
+        @classmethod
+        def fromtimestamp(cls: type[Self], timestamp: float, tz: _TzInfo | None = ...) -> Self: ...
+    else:
+        @classmethod
+        def fromtimestamp(cls: type[Self], __timestamp: float, tz: _TzInfo | None = ...) -> Self: ...
+
     @classmethod
     def utcfromtimestamp(cls: type[Self], __t: float) -> Self: ...
     if sys.version_info >= (3, 8):
diff --git a/mypy/typeshed/stdlib/json/__init__.pyi b/mypy/typeshed/stdlib/json/__init__.pyi
index 64ab8a11a45de..73bb5e8b4c1a4 100644
--- a/mypy/typeshed/stdlib/json/__init__.pyi
+++ b/mypy/typeshed/stdlib/json/__init__.pyi
@@ -1,6 +1,6 @@
-from _typeshed import SupportsRead
+from _typeshed import SupportsRead, SupportsWrite
 from collections.abc import Callable
-from typing import IO, Any
+from typing import Any
 
 from .decoder import JSONDecodeError as JSONDecodeError, JSONDecoder as JSONDecoder
 from .encoder import JSONEncoder as JSONEncoder
@@ -23,7 +23,7 @@ def dumps(
 ) -> str: ...
 def dump(
     obj: Any,
-    fp: IO[str],
+    fp: SupportsWrite[str],
     *,
     skipkeys: bool = ...,
     ensure_ascii: bool = ...,
diff --git a/mypy/typeshed/stdlib/json/encoder.pyi b/mypy/typeshed/stdlib/json/encoder.pyi
index 60e82061946b6..0444ae477a960 100644
--- a/mypy/typeshed/stdlib/json/encoder.pyi
+++ b/mypy/typeshed/stdlib/json/encoder.pyi
@@ -20,7 +20,7 @@ class JSONEncoder:
     check_circular: bool
     allow_nan: bool
     sort_keys: bool
-    indent: int
+    indent: int | str
     def __init__(
         self,
         *,
@@ -29,7 +29,7 @@ class JSONEncoder:
         check_circular: bool = ...,
         allow_nan: bool = ...,
         sort_keys: bool = ...,
-        indent: int | None = ...,
+        indent: int | str | None = ...,
         separators: tuple[str, str] | None = ...,
         default: Callable[..., Any] | None = ...,
     ) -> None: ...
diff --git a/mypy/typeshed/stdlib/netrc.pyi b/mypy/typeshed/stdlib/netrc.pyi
index 803c780733485..217c0eb542d07 100644
--- a/mypy/typeshed/stdlib/netrc.pyi
+++ b/mypy/typeshed/stdlib/netrc.pyi
@@ -1,3 +1,4 @@
+import sys
 from _typeshed import StrOrBytesPath
 from typing_extensions import TypeAlias
 
@@ -10,7 +11,10 @@ class NetrcParseError(Exception):
     def __init__(self, msg: str, filename: StrOrBytesPath | None = ..., lineno: int | None = ...) -> None: ...
 
 # (login, account, password) tuple
-_NetrcTuple: TypeAlias = tuple[str, str | None, str | None]
+if sys.version_info >= (3, 11):
+    _NetrcTuple: TypeAlias = tuple[str, str, str]
+else:
+    _NetrcTuple: TypeAlias = tuple[str, str | None, str | None]
 
 class netrc:
     hosts: dict[str, _NetrcTuple]
diff --git a/mypy/typeshed/stdlib/shutil.pyi b/mypy/typeshed/stdlib/shutil.pyi
index 13c706de1cf4d..568879d760036 100644
--- a/mypy/typeshed/stdlib/shutil.pyi
+++ b/mypy/typeshed/stdlib/shutil.pyi
@@ -2,7 +2,7 @@ import os
 import sys
 from _typeshed import BytesPath, StrOrBytesPath, StrPath, SupportsRead, SupportsWrite
 from collections.abc import Callable, Iterable, Sequence
-from typing import Any, AnyStr, NamedTuple, TypeVar, overload
+from typing import Any, AnyStr, NamedTuple, Protocol, TypeVar, overload
 from typing_extensions import TypeAlias
 
 __all__ = [
@@ -84,13 +84,22 @@ else:
 
 _OnErrorCallback: TypeAlias = Callable[[Callable[..., Any], Any, Any], object]
 
-if sys.version_info >= (3, 11):
-    def rmtree(
-        path: StrOrBytesPath, ignore_errors: bool = ..., onerror: _OnErrorCallback | None = ..., *, dir_fd: int | None = ...
-    ) -> None: ...
-
-else:
-    def rmtree(path: StrOrBytesPath, ignore_errors: bool = ..., onerror: _OnErrorCallback | None = ...) -> None: ...
+class _RmtreeType(Protocol):
+    avoids_symlink_attacks: bool
+    if sys.version_info >= (3, 11):
+        def __call__(
+            self,
+            path: StrOrBytesPath,
+            ignore_errors: bool = ...,
+            onerror: _OnErrorCallback | None = ...,
+            *,
+            dir_fd: int | None = ...,
+        ) -> None: ...
+
+    else:
+        def __call__(self, path: StrOrBytesPath, ignore_errors: bool = ..., onerror: _OnErrorCallback | None = ...) -> None: ...
+
+rmtree: _RmtreeType
 
 _CopyFn: TypeAlias = Callable[[str, str], object] | Callable[[StrPath, StrPath], object]
 
diff --git a/mypy/typeshed/stdlib/subprocess.pyi b/mypy/typeshed/stdlib/subprocess.pyi
index 25b988adc52d2..450eb8cd24d10 100644
--- a/mypy/typeshed/stdlib/subprocess.pyi
+++ b/mypy/typeshed/stdlib/subprocess.pyi
@@ -1,6 +1,6 @@
 import sys
 from _typeshed import Self, StrOrBytesPath
-from collections.abc import Callable, Iterable, Mapping, Sequence
+from collections.abc import Callable, Collection, Iterable, Mapping, Sequence
 from types import TracebackType
 from typing import IO, Any, AnyStr, Generic, TypeVar, overload
 from typing_extensions import Literal, TypeAlias
@@ -97,7 +97,7 @@ class CompletedProcess(Generic[_T]):
         args: _CMD,
         returncode: int,
         stdout: _T | None = ...,  # pyright: ignore[reportInvalidTypeVarUse]
-        stderr: _T | None = ...,  # pyright: ignore[reportInvalidTypeVarUse]
+        stderr: _T | None = ...,
     ) -> None: ...
     def check_returncode(self) -> None: ...
     if sys.version_info >= (3, 9):
@@ -123,7 +123,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -157,7 +157,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -191,7 +191,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -226,7 +226,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the *real* keyword only args start
         capture_output: bool = ...,
         check: bool = ...,
@@ -260,7 +260,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -294,7 +294,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -331,7 +331,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -364,7 +364,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -397,7 +397,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -431,7 +431,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the *real* keyword only args start
         capture_output: bool = ...,
         check: bool = ...,
@@ -464,7 +464,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -497,7 +497,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -533,7 +533,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -565,7 +565,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -597,7 +597,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -630,7 +630,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the *real* keyword only args start
         capture_output: bool = ...,
         check: bool = ...,
@@ -662,7 +662,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -694,7 +694,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -728,7 +728,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -756,7 +756,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -784,7 +784,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -813,7 +813,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the *real* keyword only args start
         capture_output: bool = ...,
         check: bool = ...,
@@ -841,7 +841,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -869,7 +869,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         capture_output: bool = ...,
         check: bool = ...,
@@ -900,7 +900,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         text: bool | None = ...,
@@ -931,7 +931,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         text: bool | None = ...,
@@ -961,7 +961,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         text: bool | None = ...,
@@ -989,7 +989,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         text: bool | None = ...,
@@ -1015,7 +1015,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         timeout: float | None = ...,
         *,
         text: bool | None = ...,
@@ -1046,7 +1046,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         timeout: float | None = ...,
         *,
         text: bool | None = ...,
@@ -1076,7 +1076,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         timeout: float | None = ...,
         *,
         text: bool | None = ...,
@@ -1104,7 +1104,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         timeout: float | None = ...,
         *,
         text: bool | None = ...,
@@ -1129,7 +1129,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1160,7 +1160,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1191,7 +1191,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1223,7 +1223,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1254,7 +1254,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1285,7 +1285,7 @@ if sys.version_info >= (3, 11):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1319,7 +1319,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1349,7 +1349,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1379,7 +1379,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1410,7 +1410,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1440,7 +1440,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1470,7 +1470,7 @@ elif sys.version_info >= (3, 10):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1503,7 +1503,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1532,7 +1532,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1561,7 +1561,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1591,7 +1591,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1620,7 +1620,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1649,7 +1649,7 @@ elif sys.version_info >= (3, 9):
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1680,7 +1680,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1705,7 +1705,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1730,7 +1730,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1756,7 +1756,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1781,7 +1781,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1806,7 +1806,7 @@ else:
         creationflags: int = ...,
         restore_signals: bool = ...,
         start_new_session: bool = ...,
-        pass_fds: Any = ...,
+        pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
         input: _TXT | None = ...,
@@ -1873,7 +1873,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str,
@@ -1904,7 +1904,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -1936,7 +1936,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             # where the *real* keyword only args start
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -1967,7 +1967,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[True],
             encoding: str | None = ...,
@@ -1998,7 +1998,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[None, False] = ...,
             encoding: None = ...,
@@ -2029,7 +2029,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2062,7 +2062,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str,
@@ -2092,7 +2092,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2123,7 +2123,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             # where the *real* keyword only args start
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2153,7 +2153,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[True],
             encoding: str | None = ...,
@@ -2183,7 +2183,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[None, False] = ...,
             encoding: None = ...,
@@ -2213,7 +2213,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2245,7 +2245,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str,
@@ -2274,7 +2274,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2304,7 +2304,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             # where the *real* keyword only args start
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2333,7 +2333,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[True],
             encoding: str | None = ...,
@@ -2362,7 +2362,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[None, False] = ...,
             encoding: None = ...,
@@ -2391,7 +2391,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2421,7 +2421,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str,
@@ -2446,7 +2446,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2472,7 +2472,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             # where the *real* keyword only args start
             text: bool | None = ...,
             encoding: str | None = ...,
@@ -2497,7 +2497,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[True],
             encoding: str | None = ...,
@@ -2522,7 +2522,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: Literal[None, False] = ...,
             encoding: None = ...,
@@ -2547,7 +2547,7 @@ class Popen(Generic[AnyStr]):
             creationflags: int = ...,
             restore_signals: bool = ...,
             start_new_session: bool = ...,
-            pass_fds: Any = ...,
+            pass_fds: Collection[int] = ...,
             *,
             text: bool | None = ...,
             encoding: str | None = ...,
diff --git a/mypy/typeshed/stdlib/types.pyi b/mypy/typeshed/stdlib/types.pyi
index a40b6280f47c1..6928032f92b16 100644
--- a/mypy/typeshed/stdlib/types.pyi
+++ b/mypy/typeshed/stdlib/types.pyi
@@ -68,6 +68,9 @@ _V_co = TypeVar("_V_co", covariant=True)
 
 @final
 class _Cell:
+    if sys.version_info >= (3, 8):
+        def __init__(self, __contents: object = ...) -> None: ...
+
     __hash__: ClassVar[None]  # type: ignore[assignment]
     cell_contents: Any
 
diff --git a/mypy/typeshed/stdlib/unittest/mock.pyi b/mypy/typeshed/stdlib/unittest/mock.pyi
index e4cedef1b4256..47535499a9f23 100644
--- a/mypy/typeshed/stdlib/unittest/mock.pyi
+++ b/mypy/typeshed/stdlib/unittest/mock.pyi
@@ -1,6 +1,6 @@
 import sys
 from _typeshed import Self
-from collections.abc import Awaitable, Callable, Iterable, Mapping, Sequence
+from collections.abc import Awaitable, Callable, Coroutine, Iterable, Mapping, Sequence
 from contextlib import _GeneratorContextManager
 from types import TracebackType
 from typing import Any, Generic, TypeVar, overload
@@ -9,6 +9,8 @@ from typing_extensions import Literal, TypeAlias
 _T = TypeVar("_T")
 _TT = TypeVar("_TT", bound=type[Any])
 _R = TypeVar("_R")
+_F = TypeVar("_F", bound=Callable[..., Any])
+_AF = TypeVar("_AF", bound=Callable[..., Coroutine[Any, Any, Any]])
 
 if sys.version_info >= (3, 8):
     __all__ = (
@@ -258,6 +260,10 @@ class _patch_dict:
     clear: Any
     def __init__(self, in_dict: Any, values: Any = ..., clear: Any = ..., **kwargs: Any) -> None: ...
     def __call__(self, f: Any) -> Any: ...
+    if sys.version_info >= (3, 10):
+        def decorate_callable(self, f: _F) -> _F: ...
+        def decorate_async_callable(self, f: _AF) -> _AF: ...
+
     def decorate_class(self, klass: Any) -> Any: ...
     def __enter__(self) -> Any: ...
     def __exit__(self, *args: object) -> Any: ...
diff --git a/mypy/typeshed/stdlib/zipfile.pyi b/mypy/typeshed/stdlib/zipfile.pyi
index 60134c915da70..e964cd6eda871 100644
--- a/mypy/typeshed/stdlib/zipfile.pyi
+++ b/mypy/typeshed/stdlib/zipfile.pyi
@@ -29,7 +29,6 @@ _DateTuple: TypeAlias = tuple[int, int, int, int, int, int]
 _ReadWriteMode: TypeAlias = Literal["r", "w"]
 _ReadWriteBinaryMode: TypeAlias = Literal["r", "w", "rb", "wb"]
 _ZipFileMode: TypeAlias = Literal["r", "w", "x", "a"]
-_CompressionMode: TypeAlias = Literal[0, 8, 12, 14]
 
 class BadZipFile(Exception): ...
 
@@ -101,7 +100,7 @@ class ZipFile:
     fp: IO[bytes] | None
     NameToInfo: dict[str, ZipInfo]
     start_dir: int  # undocumented
-    compression: _CompressionMode  # undocumented
+    compression: int  # undocumented
     compresslevel: int | None  # undocumented
     mode: _ZipFileMode  # undocumented
     pwd: bytes | None  # undocumented
@@ -111,7 +110,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: Literal["r"] = ...,
-            compression: _CompressionMode = ...,
+            compression: int = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
             *,
@@ -123,7 +122,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: _ZipFileMode = ...,
-            compression: _CompressionMode = ...,
+            compression: int = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
             *,
@@ -135,7 +134,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: _ZipFileMode = ...,
-            compression: _CompressionMode = ...,
+            compression: int = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
             *,
@@ -146,7 +145,7 @@ class ZipFile:
             self,
             file: StrPath | IO[bytes],
             mode: _ZipFileMode = ...,
-            compression: _CompressionMode = ...,
+            compression: int = ...,
             allowZip64: bool = ...,
             compresslevel: int | None = ...,
         ) -> None: ...
@@ -185,19 +184,14 @@ class ZipFile:
 
 class PyZipFile(ZipFile):
     def __init__(
-        self,
-        file: str | IO[bytes],
-        mode: _ZipFileMode = ...,
-        compression: _CompressionMode = ...,
-        allowZip64: bool = ...,
-        optimize: int = ...,
+        self, file: str | IO[bytes], mode: _ZipFileMode = ..., compression: int = ..., allowZip64: bool = ..., optimize: int = ...
     ) -> None: ...
     def writepy(self, pathname: str, basename: str = ..., filterfunc: Callable[[str], bool] | None = ...) -> None: ...
 
 class ZipInfo:
     filename: str
     date_time: _DateTuple
-    compress_type: _CompressionMode
+    compress_type: int
     comment: bytes
     extra: bytes
     create_system: int
@@ -275,10 +269,10 @@ if sys.version_info >= (3, 8):
 
 def is_zipfile(filename: StrOrBytesPath | _SupportsReadSeekTell) -> bool: ...
 
-ZIP_STORED: Literal[0]
-ZIP_DEFLATED: Literal[8]
+ZIP_STORED: int
+ZIP_DEFLATED: int
 ZIP64_LIMIT: int
 ZIP_FILECOUNT_LIMIT: int
 ZIP_MAX_COMMENT: int
-ZIP_BZIP2: Literal[12]
-ZIP_LZMA: Literal[14]
+ZIP_BZIP2: int
+ZIP_LZMA: int
diff --git a/mypy/typeshed/stdlib/zipimport.pyi b/mypy/typeshed/stdlib/zipimport.pyi
index d3017f385c0c5..dc2f1aee0752a 100644
--- a/mypy/typeshed/stdlib/zipimport.pyi
+++ b/mypy/typeshed/stdlib/zipimport.pyi
@@ -20,7 +20,7 @@ class zipimporter:
     def find_loader(self, fullname: str, path: str | None = ...) -> tuple[zipimporter | None, list[str]]: ...  # undocumented
     def find_module(self, fullname: str, path: str | None = ...) -> zipimporter | None: ...
     def get_code(self, fullname: str) -> CodeType: ...
-    def get_data(self, pathname: str) -> str: ...
+    def get_data(self, pathname: str) -> bytes: ...
     def get_filename(self, fullname: str) -> str: ...
     def get_resource_reader(self, fullname: str) -> ResourceReader | None: ...  # undocumented
     def get_source(self, fullname: str) -> str | None: ...

From 5f480f37ff3704ed581db944bfdf99c655b3dabe Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Mon, 2 Jan 2023 17:48:48 +0100
Subject: [PATCH 162/231] Fix Unpack imported from typing (#14378)

Add missing check for `typing.Unpack` to fix running with `--python
3.11`.

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
---
 mypy/semanal.py                     |  2 +-
 test-data/unit/check-python311.test | 12 ++++++++++++
 test-data/unit/lib-stub/typing.pyi  |  2 ++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 51310e4f3e4d0..13350b58af874 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1881,7 +1881,7 @@ def analyze_unbound_tvar(self, t: Type) -> tuple[str, TypeVarLikeExpr] | None:
                 # It's bound by our type variable scope
                 return None
             return unbound.name, sym.node
-        if sym and sym.fullname == "typing_extensions.Unpack":
+        if sym and sym.fullname in ("typing.Unpack", "typing_extensions.Unpack"):
             inner_t = unbound.args[0]
             if not isinstance(inner_t, UnboundType):
                 return None
diff --git a/test-data/unit/check-python311.test b/test-data/unit/check-python311.test
index 9bf62b0c489d0..7196f10f88632 100644
--- a/test-data/unit/check-python311.test
+++ b/test-data/unit/check-python311.test
@@ -51,3 +51,15 @@ try:
 except* (RuntimeError, ExceptionGroup) as e:  # E: Exception type in except* cannot derive from BaseExceptionGroup
     reveal_type(e)  # N: Revealed type is "builtins.ExceptionGroup[Union[builtins.RuntimeError, Any]]"
 [builtins fixtures/exception.pyi]
+
+[case testBasicTypeVarTupleGeneric]
+from typing import Generic, TypeVarTuple, Unpack
+
+Ts = TypeVarTuple("Ts")
+
+class Variadic(Generic[Unpack[Ts]]):
+    ...
+
+variadic: Variadic[int, str]
+reveal_type(variadic)  # N: Revealed type is "__main__.Variadic[builtins.int, builtins.str]"
+[builtins fixtures/tuple.pyi]
diff --git a/test-data/unit/lib-stub/typing.pyi b/test-data/unit/lib-stub/typing.pyi
index f3850d3936b45..a306b70f74d74 100644
--- a/test-data/unit/lib-stub/typing.pyi
+++ b/test-data/unit/lib-stub/typing.pyi
@@ -27,6 +27,8 @@ NoReturn = 0
 Never = 0
 NewType = 0
 ParamSpec = 0
+TypeVarTuple = 0
+Unpack = 0
 Self = 0
 TYPE_CHECKING = 0
 

From f104914b9d4f58796042667a8b3d06b5868bee34 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Mon, 2 Jan 2023 23:47:03 -0800
Subject: [PATCH 163/231] Improve performance for errors on class with many
 attributes (#14379)

When checking manticore with `--check-untyped-defs`, this is a 4x total
speedup from master, from ~320s to ~80s (uncompiled).

I looked into this because of
https://github.com/python/typeshed/pull/9443#issuecomment-1369120219
---
 mypy/messages.py                    | 37 +++++++++++++++++++----------
 mypy/semanal.py                     |  2 +-
 test-data/unit/check-kwargs.test    |  6 ++---
 test-data/unit/check-modules.test   |  2 +-
 test-data/unit/semanal-modules.test |  4 ++--
 5 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/mypy/messages.py b/mypy/messages.py
index b8c04fe2b8e98..5d8bf79ec8a32 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -15,7 +15,7 @@
 import re
 from contextlib import contextmanager
 from textwrap import dedent
-from typing import Any, Callable, Iterable, Iterator, List, Sequence, cast
+from typing import Any, Callable, Collection, Iterable, Iterator, List, Sequence, cast
 from typing_extensions import Final
 
 from mypy import errorcodes as codes, message_registry
@@ -440,7 +440,7 @@ def has_no_attr(
                         alternatives.discard(member)
 
                         matches = [m for m in COMMON_MISTAKES.get(member, []) if m in alternatives]
-                        matches.extend(best_matches(member, alternatives)[:3])
+                        matches.extend(best_matches(member, alternatives, n=3))
                         if member == "__aiter__" and matches == ["__iter__"]:
                             matches = []  # Avoid misleading suggestion
                         if matches:
@@ -928,11 +928,11 @@ def unexpected_keyword_argument(
                     matching_type_args.append(callee_arg_name)
                 else:
                     not_matching_type_args.append(callee_arg_name)
-        matches = best_matches(name, matching_type_args)
+        matches = best_matches(name, matching_type_args, n=3)
         if not matches:
-            matches = best_matches(name, not_matching_type_args)
+            matches = best_matches(name, not_matching_type_args, n=3)
         if matches:
-            msg += f"; did you mean {pretty_seq(matches[:3], 'or')}?"
+            msg += f"; did you mean {pretty_seq(matches, 'or')}?"
         self.fail(msg, context, code=codes.CALL_ARG)
         module = find_defining_module(self.modules, callee)
         if module:
@@ -1695,10 +1695,10 @@ def typeddict_key_not_found(
                 context,
                 code=codes.TYPEDDICT_ITEM,
             )
-            matches = best_matches(item_name, typ.items.keys())
+            matches = best_matches(item_name, typ.items.keys(), n=3)
             if matches:
                 self.note(
-                    "Did you mean {}?".format(pretty_seq(matches[:3], "or")),
+                    "Did you mean {}?".format(pretty_seq(matches, "or")),
                     context,
                     code=codes.TYPEDDICT_ITEM,
                 )
@@ -2798,11 +2798,24 @@ def find_defining_module(modules: dict[str, MypyFile], typ: CallableType) -> Myp
 COMMON_MISTAKES: Final[dict[str, Sequence[str]]] = {"add": ("append", "extend")}
 
 
-def best_matches(current: str, options: Iterable[str]) -> list[str]:
-    ratios = {v: difflib.SequenceMatcher(a=current, b=v).ratio() for v in options}
-    return sorted(
-        (o for o in options if ratios[o] > 0.75), reverse=True, key=lambda v: (ratios[v], v)
-    )
+def _real_quick_ratio(a: str, b: str) -> float:
+    # this is an upper bound on difflib.SequenceMatcher.ratio
+    # similar to difflib.SequenceMatcher.real_quick_ratio, but faster since we don't instantiate
+    al = len(a)
+    bl = len(b)
+    return 2.0 * min(al, bl) / (al + bl)
+
+
+def best_matches(current: str, options: Collection[str], n: int) -> list[str]:
+    # narrow down options cheaply
+    assert current
+    options = [o for o in options if _real_quick_ratio(current, o) > 0.75]
+    if len(options) >= 50:
+        options = [o for o in options if abs(len(o) - len(current)) <= 1]
+
+    ratios = {option: difflib.SequenceMatcher(a=current, b=option).ratio() for option in options}
+    options = [option for option, ratio in ratios.items() if ratio > 0.75]
+    return sorted(options, key=lambda v: (-ratios[v], v))[:n]
 
 
 def pretty_seq(args: Sequence[str], conjunction: str) -> str:
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 13350b58af874..a58f4c9df3100 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -2531,7 +2531,7 @@ def report_missing_module_attribute(
                 )
             else:
                 alternatives = set(module.names.keys()).difference({source_id})
-                matches = best_matches(source_id, alternatives)[:3]
+                matches = best_matches(source_id, alternatives, n=3)
                 if matches:
                     suggestion = f"; maybe {pretty_seq(matches, 'or')}?"
                     message += f"{suggestion}"
diff --git a/test-data/unit/check-kwargs.test b/test-data/unit/check-kwargs.test
index e59c295b58ac3..ace28a18a5a81 100644
--- a/test-data/unit/check-kwargs.test
+++ b/test-data/unit/check-kwargs.test
@@ -87,7 +87,7 @@ class A: pass
 
 [case testMultipleKeywordsForMisspelling]
 def f(thing : 'A', other: 'A', atter: 'A', btter: 'B') -> None: pass # N: "f" defined here
-f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other" or "atter"?
+f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "other"?
 class A: pass
 class B: pass
 
@@ -99,7 +99,7 @@ class B: pass
 
 [case testKeywordMisspellingInheritance]
 def f(atter: 'A', btter: 'B', ctter: 'C') -> None: pass # N: "f" defined here
-f(otter=B()) # E: Unexpected keyword argument "otter" for "f"; did you mean "btter" or "atter"?
+f(otter=B()) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "btter"?
 class A: pass
 class B(A): pass
 class C: pass
@@ -107,7 +107,7 @@ class C: pass
 [case testKeywordMisspellingFloatInt]
 def f(atter: float, btter: int) -> None: pass # N: "f" defined here
 x: int = 5
-f(otter=x) # E: Unexpected keyword argument "otter" for "f"; did you mean "btter" or "atter"?
+f(otter=x) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "btter"?
 
 [case testKeywordMisspellingVarArgs]
 def f(other: 'A', *atter: 'A') -> None: pass # N: "f" defined here
diff --git a/test-data/unit/check-modules.test b/test-data/unit/check-modules.test
index 26bd0f92ed9ee..b11a959df4cc1 100644
--- a/test-data/unit/check-modules.test
+++ b/test-data/unit/check-modules.test
@@ -2871,7 +2871,7 @@ aaaaa: int
 
 [case testModuleAttributeThreeSuggestions]
 import m
-m.aaaaa # E: Module has no attribute "aaaaa"; maybe "aabaa", "aaaba", or "aaaab"?
+m.aaaaa # E: Module has no attribute "aaaaa"; maybe "aaaab", "aaaba", or "aabaa"?
 
 [file m.py]
 aaaab: int
diff --git a/test-data/unit/semanal-modules.test b/test-data/unit/semanal-modules.test
index 8ffd7d2488dca..bc381293161fc 100644
--- a/test-data/unit/semanal-modules.test
+++ b/test-data/unit/semanal-modules.test
@@ -814,7 +814,7 @@ def somef_unction():
 [file f.py]
 from m.x import somefunction
 [out]
-tmp/f.py:1: error: Module "m.x" has no attribute "somefunction"; maybe "somef_unction" or "some_function"?
+tmp/f.py:1: error: Module "m.x" has no attribute "somefunction"; maybe "some_function" or "somef_unction"?
 
 [case testImportMisspellingMultipleCandidatesTruncated]
 import f
@@ -831,7 +831,7 @@ def somefun_ction():
 [file f.py]
 from m.x import somefunction
 [out]
-tmp/f.py:1: error: Module "m.x" has no attribute "somefunction"; maybe "somefun_ction", "somefu_nction", or "somef_unction"?
+tmp/f.py:1: error: Module "m.x" has no attribute "somefunction"; maybe "some_function", "somef_unction", or "somefu_nction"?
 
 [case testFromImportAsInStub]
 from m import *

From 692af6d8c87e03c3a16cb67958d84219df823eaa Mon Sep 17 00:00:00 2001
From: johnthagen <johnthagen@users.noreply.github.com>
Date: Tue, 3 Jan 2023 09:38:33 -0500
Subject: [PATCH 164/231] Use secure HTTPS link for Mypy badge (#14383)

Now that the site is accessible via HTTPS

 - #9919

Fetch the badge using a secure link, especially since this will be used
an example for others. Also, non-secure badges will not be shown in some
contexts, such as DockerHub, so this makes the example both more secure
and more generally useful.
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 01d876ead3e4b..9d9618e6bc12d 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ Mypy: Static Typing for Python
 [![Build Status](https://github.com/python/mypy/actions/workflows/test.yml/badge.svg)](https://github.com/python/mypy/actions)
 [![Documentation Status](https://readthedocs.org/projects/mypy/badge/?version=latest)](https://mypy.readthedocs.io/en/latest/?badge=latest)
 [![Chat at https://gitter.im/python/typing](https://badges.gitter.im/python/typing.svg)](https://gitter.im/python/typing?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-[![Checked with mypy](http://www.mypy-lang.org/static/mypy_badge.svg)](http://mypy-lang.org/)
+[![Checked with mypy](https://www.mypy-lang.org/static/mypy_badge.svg)](https://mypy-lang.org/)
 [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
 [![Imports: isort](https://img.shields.io/badge/%20imports-isort-%231674b1?style=flat&labelColor=ef8336)](https://pycqa.github.io/isort/)
 

From 24135782cd460507860c2b9256fb2ac6365e1b69 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Tue, 3 Jan 2023 14:45:46 -0800
Subject: [PATCH 165/231] More helpful error for missing self (#14386)

Fixes #14385
---
 mypy/semanal.py                     |  5 ++++-
 test-data/unit/check-classes.test   |  4 ++--
 test-data/unit/check-functions.test |  2 +-
 test-data/unit/check-super.test     |  2 +-
 test-data/unit/fine-grained.test    | 12 ++++++------
 test-data/unit/semanal-errors.test  |  6 +++---
 6 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index a58f4c9df3100..aee355d7880d5 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -947,7 +947,10 @@ def prepare_method_signature(self, func: FuncDef, info: TypeInfo, has_self_type:
             if func.name in ["__init_subclass__", "__class_getitem__"]:
                 func.is_class = True
             if not func.arguments:
-                self.fail("Method must have at least one argument", func)
+                self.fail(
+                    'Method must have at least one argument. Did you forget the "self" argument?',
+                    func,
+                )
             elif isinstance(functype, CallableType):
                 self_type = get_proper_type(functype.arg_types[0])
                 if isinstance(self_type, AnyType):
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index 8784c73c5b175..b35b2f9e4e94b 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -2901,7 +2901,7 @@ b.bad = 'a'  # E: Incompatible types in assignment (expression has type "str", v
 from typing import Any
 
 class Test:
-    def __setattr__() -> None: ...  # E: Method must have at least one argument # E: Invalid signature "Callable[[], None]" for "__setattr__"
+    def __setattr__() -> None: ...  # E: Method must have at least one argument. Did you forget the "self" argument? # E: Invalid signature "Callable[[], None]" for "__setattr__"
 t = Test()
 t.crash = 'test'  # E: "Test" has no attribute "crash"
 
@@ -7120,7 +7120,7 @@ reveal_type(Foo().y)  # N: Revealed type is "builtins.list[Any]"
 # flags: --check-untyped-defs
 
 class Foo:
-    def bad():  # E: Method must have at least one argument
+    def bad():  # E: Method must have at least one argument. Did you forget the "self" argument?
         self.x = 0  # E: Name "self" is not defined
 
 [case testTypeAfterAttributeAccessWithDisallowAnyExpr]
diff --git a/test-data/unit/check-functions.test b/test-data/unit/check-functions.test
index ae6424f743be4..9afe9189caaaa 100644
--- a/test-data/unit/check-functions.test
+++ b/test-data/unit/check-functions.test
@@ -2708,7 +2708,7 @@ class A:
     @dec
     def e(self) -> int: pass
     @property
-    def g() -> int: pass   # E: Method must have at least one argument
+    def g() -> int: pass   # E: Method must have at least one argument. Did you forget the "self" argument?
     @property
     def h(self, *args, **kwargs) -> int: pass   # OK
 [builtins fixtures/property.pyi]
diff --git a/test-data/unit/check-super.test b/test-data/unit/check-super.test
index 6537f563a99c1..b3379e505be72 100644
--- a/test-data/unit/check-super.test
+++ b/test-data/unit/check-super.test
@@ -365,7 +365,7 @@ class A:
     def f(self) -> None: pass
 
 class B(A):
-    def g() -> None: # E: Method must have at least one argument
+    def g() -> None: # E: Method must have at least one argument. Did you forget the "self" argument?
         super().f() # E: super() requires one or more positional arguments in enclosing function
     def h(self) -> None:
         def a() -> None:
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index 1a318b52a0823..5a7f21d48c20a 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -1586,11 +1586,11 @@ class A:
 [file b.py.3]
 2
 [out]
-a.py:3: error: Method must have at least one argument
+a.py:3: error: Method must have at least one argument. Did you forget the "self" argument?
 ==
-a.py:3: error: Method must have at least one argument
+a.py:3: error: Method must have at least one argument. Did you forget the "self" argument?
 ==
-a.py:3: error: Method must have at least one argument
+a.py:3: error: Method must have at least one argument. Did you forget the "self" argument?
 
 [case testBaseClassDeleted]
 import m
@@ -2007,11 +2007,11 @@ class A:
 class A:
     def foo(self) -> int: pass
 [out]
-a.py:2: error: Method must have at least one argument
+a.py:2: error: Method must have at least one argument. Did you forget the "self" argument?
 ==
-a.py:2: error: Method must have at least one argument
+a.py:2: error: Method must have at least one argument. Did you forget the "self" argument?
 ==
-a.py:2: error: Method must have at least one argument
+a.py:2: error: Method must have at least one argument. Did you forget the "self" argument?
 ==
 
 [case testPreviousErrorInMethodSemanal2]
diff --git a/test-data/unit/semanal-errors.test b/test-data/unit/semanal-errors.test
index 5697d473414ec..fffd02c9c3375 100644
--- a/test-data/unit/semanal-errors.test
+++ b/test-data/unit/semanal-errors.test
@@ -542,7 +542,7 @@ import typing
 class A:
   def f(): pass
 [out]
-main:3: error: Method must have at least one argument
+main:3: error: Method must have at least one argument. Did you forget the "self" argument?
 
 [case testInvalidBaseClass]
 import typing
@@ -564,8 +564,8 @@ class A:
   def f() -> None: pass
   def g(): pass
 [out]
-main:3: error: Method must have at least one argument
-main:4: error: Method must have at least one argument
+main:3: error: Method must have at least one argument. Did you forget the "self" argument?
+main:4: error: Method must have at least one argument. Did you forget the "self" argument?
 
 [case testMultipleMethodDefinition]
 import typing

From ca668055feceba63f2e441ec91ce76dac77eaf5d Mon Sep 17 00:00:00 2001
From: Richard Si <sichard26@gmail.com>
Date: Thu, 5 Jan 2023 17:49:45 -0500
Subject: [PATCH 166/231] [mypyc] Compile away NewType type calls (#14398)

For example, here the call to ID is simply a no-op at runtime, returning
1 unchanged.

    ID = NewType('ID', int)
    person = ID(1)

Resolves https://github.com/mypyc/mypyc/issues/958
---
 mypyc/irbuild/expression.py        |  9 ++++++++-
 mypyc/test-data/irbuild-basic.test | 32 +++++++++++++++++++-----------
 2 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/mypyc/irbuild/expression.py b/mypyc/irbuild/expression.py
index b7d093cde7ee3..b007435957b00 100644
--- a/mypyc/irbuild/expression.py
+++ b/mypyc/irbuild/expression.py
@@ -266,13 +266,20 @@ def transform_super_expr(builder: IRBuilder, o: SuperExpr) -> Value:
 
 
 def transform_call_expr(builder: IRBuilder, expr: CallExpr) -> Value:
+    callee = expr.callee
     if isinstance(expr.analyzed, CastExpr):
         return translate_cast_expr(builder, expr.analyzed)
     elif isinstance(expr.analyzed, AssertTypeExpr):
         # Compile to a no-op.
         return builder.accept(expr.analyzed.expr)
+    elif (
+        isinstance(callee, (NameExpr, MemberExpr))
+        and isinstance(callee.node, TypeInfo)
+        and callee.node.is_newtype
+    ):
+        # A call to a NewType type is a no-op at runtime.
+        return builder.accept(expr.args[0])
 
-    callee = expr.callee
     if isinstance(callee, IndexExpr) and isinstance(callee.analyzed, TypeApplication):
         callee = callee.analyzed.expr  # Unwrap type application
 
diff --git a/mypyc/test-data/irbuild-basic.test b/mypyc/test-data/irbuild-basic.test
index 16b085ad4927e..f72720e59b180 100644
--- a/mypyc/test-data/irbuild-basic.test
+++ b/mypyc/test-data/irbuild-basic.test
@@ -2338,11 +2338,8 @@ def __top_level__():
     r92, r93, r94, r95 :: ptr
     r96 :: dict
     r97 :: str
-    r98, r99 :: object
-    r100 :: dict
-    r101 :: str
-    r102 :: int32
-    r103 :: bit
+    r98 :: int32
+    r99 :: bit
 L0:
     r0 = builtins :: module
     r1 = load_address _Py_NoneStruct
@@ -2454,13 +2451,9 @@ L2:
     set_mem r95, r91 :: builtins.object*
     keep_alive r88
     r96 = __main__.globals :: static
-    r97 = 'Bar'
-    r98 = CPyDict_GetItem(r96, r97)
-    r99 = PyObject_CallFunctionObjArgs(r98, r88, 0)
-    r100 = __main__.globals :: static
-    r101 = 'y'
-    r102 = CPyDict_SetItem(r100, r101, r99)
-    r103 = r102 >= 0 :: signed
+    r97 = 'y'
+    r98 = CPyDict_SetItem(r96, r97, r88)
+    r99 = r98 >= 0 :: signed
     return 1
 
 [case testChainedConditional]
@@ -3584,3 +3577,18 @@ L0:
     r3 = 0.0
     i__redef____redef__ = r3
     return 1
+
+[case testNewType]
+from typing import NewType
+
+class A: pass
+
+N = NewType("N", A)
+
+def f(arg: A) -> N:
+    return N(arg)
+[out]
+def f(arg):
+    arg :: __main__.A
+L0:
+    return arg

From 25ccdfcd0ce788c0499c17e7320037eccaab49a9 Mon Sep 17 00:00:00 2001
From: Ilya Konstantinov <ilya.konstantinov@gmail.com>
Date: Thu, 5 Jan 2023 22:30:53 -0500
Subject: [PATCH 167/231] Document that report generation disables cache
 (#14402)

#6076 made report generation disable cache but we didn't document it.
---
 docs/source/config_file.rst | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/docs/source/config_file.rst b/docs/source/config_file.rst
index abaec31c68885..3b96e6bd7a5a5 100644
--- a/docs/source/config_file.rst
+++ b/docs/source/config_file.rst
@@ -210,7 +210,7 @@ section of the command line docs.
     line.  Mypy *will* recursively type check any submodules of the provided
     package. This flag is identical to :confval:`modules` apart from this
     behavior.
-    
+
     This option may only be set in the global section (``[mypy]``).
 
 .. confval:: exclude
@@ -901,6 +901,12 @@ Report generation
 If these options are set, mypy will generate a report in the specified
 format into the specified directory.
 
+.. warning::
+
+  Generating reports disables incremental mode and can significantly slow down
+  your workflow. It is recommended to enable reporting only for specific runs
+  (e.g. in CI).
+
 .. confval:: any_exprs_report
 
     :type: string

From 98cc165a657a316accb93f1ed57fdc128b086d9f Mon Sep 17 00:00:00 2001
From: Christoph Tyralla <c.tyralla@bjoernsen.de>
Date: Fri, 6 Jan 2023 05:16:13 +0100
Subject: [PATCH 168/231] Fix inference for constrained type variables within
 unions (#14396)

Fixes #3644

Handling of constrained type variables of function `filter_satisfiable`
of module `constraints` was missing (as was indicated by a removed
ToDo).
---
 mypy/constraints.py              |  8 ++++++--
 test-data/unit/check-unions.test | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index fe3c1a19ff181..0dd748ff85e12 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -420,8 +420,12 @@ def filter_satisfiable(option: list[Constraint] | None) -> list[Constraint] | No
         return option
     satisfiable = []
     for c in option:
-        # TODO: add similar logic for TypeVar values (also in various other places)?
-        if mypy.subtypes.is_subtype(c.target, c.origin_type_var.upper_bound):
+        if isinstance(c.origin_type_var, TypeVarType) and c.origin_type_var.values:
+            if any(
+                mypy.subtypes.is_subtype(c.target, value) for value in c.origin_type_var.values
+            ):
+                satisfiable.append(c)
+        elif mypy.subtypes.is_subtype(c.target, c.origin_type_var.upper_bound):
             satisfiable.append(c)
     if not satisfiable:
         return None
diff --git a/test-data/unit/check-unions.test b/test-data/unit/check-unions.test
index a561c29e54f72..4c4fbc32ec3fb 100644
--- a/test-data/unit/check-unions.test
+++ b/test-data/unit/check-unions.test
@@ -1171,6 +1171,25 @@ def foo(
 foo([1])
 [builtins fixtures/list.pyi]
 
+[case testGenericUnionMemberWithTypeVarConstraints]
+
+from typing import Generic, TypeVar, Union
+
+T = TypeVar('T', str, int)
+
+class C(Generic[T]): ...
+
+def f(s: Union[T, C[T]]) -> T:  ...
+
+ci: C[int]
+cs: C[str]
+
+reveal_type(f(1))  # N: Revealed type is "builtins.int"
+reveal_type(f(''))  # N: Revealed type is "builtins.str"
+reveal_type(f(ci))  # N: Revealed type is "builtins.int"
+reveal_type(f(cs))  # N: Revealed type is "builtins.str"
+
+
 [case testNestedInstanceTypeAliasUnsimplifiedUnion]
 from typing import TypeVar, Union, Iterator, List, Any
 T = TypeVar("T")

From 7efe8e5487804014ecf8cb9b6e08f7194f61f963 Mon Sep 17 00:00:00 2001
From: KotlinIsland <65446343+KotlinIsland@users.noreply.github.com>
Date: Mon, 9 Jan 2023 12:43:58 +1000
Subject: [PATCH 169/231] Fix `util.plural_s` for zero and negative (#14411)

While this doesn't currently appear anywhere in usages, it would be
incorrect to say `0 error found` or `-4 line earlier`
---
 mypy/util.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/util.py b/mypy/util.py
index cced4db34fc91..2c225c7fe6510 100644
--- a/mypy/util.py
+++ b/mypy/util.py
@@ -816,7 +816,7 @@ def time_spent_us(t0: int) -> int:
 
 def plural_s(s: int | Sized) -> str:
     count = s if isinstance(s, int) else len(s)
-    if count > 1:
+    if count != 1:
         return "s"
     else:
         return ""

From e959565ae9c8215dc25a82ff394574acd2363b47 Mon Sep 17 00:00:00 2001
From: jhance <jhance@users.noreply.github.com>
Date: Mon, 9 Jan 2023 08:59:57 -0800
Subject: [PATCH 170/231] Begin unifying logic for constraint building (#14406)

Implements support for unpacking varlength tuples from *args, but
because it became apparent that several parts of constraints building
were doing nearly the same thing for typevar tuples, we begin extracting
out some of the logic for re-use. Some existing callsites still should
be switched to the new helpers but it is defered to future PRs.
---
 mypy/checkexpr.py                       |  31 +++-
 mypy/constraints.py                     | 214 ++++++++++++++----------
 mypy/expandtype.py                      | 113 +++++++------
 mypy/subtypes.py                        |  13 +-
 mypy/typeanal.py                        |  14 ++
 mypy/types.py                           |  10 +-
 mypy/typevartuples.py                   |  38 ++++-
 test-data/unit/check-typevar-tuple.test |  90 ++++++++--
 test-data/unit/semanal-errors.test      |  10 +-
 test-data/unit/semanal-types.test       |  25 +++
 10 files changed, 387 insertions(+), 171 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 5c6db86964ac9..e6634e124d30a 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -164,6 +164,7 @@
 )
 from mypy.typestate import type_state
 from mypy.typevars import fill_typevars
+from mypy.typevartuples import find_unpack_in_list
 from mypy.util import split_module_names
 from mypy.visitor import ExpressionVisitor
 
@@ -2064,12 +2065,30 @@ def check_argument_types(
                 actual_kinds = [arg_kinds[a] for a in actuals]
                 if isinstance(orig_callee_arg_type, UnpackType):
                     unpacked_type = get_proper_type(orig_callee_arg_type.type)
-                    # Only case we know of thus far.
-                    assert isinstance(unpacked_type, TupleType)
-                    actual_types = [arg_types[a] for a in actuals]
-                    actual_kinds = [arg_kinds[a] for a in actuals]
-                    callee_arg_types = unpacked_type.items
-                    callee_arg_kinds = [ARG_POS] * len(actuals)
+                    if isinstance(unpacked_type, TupleType):
+                        inner_unpack_index = find_unpack_in_list(unpacked_type.items)
+                        if inner_unpack_index is None:
+                            callee_arg_types = unpacked_type.items
+                            callee_arg_kinds = [ARG_POS] * len(actuals)
+                        else:
+                            inner_unpack = get_proper_type(unpacked_type.items[inner_unpack_index])
+                            assert isinstance(inner_unpack, UnpackType)
+                            inner_unpacked_type = get_proper_type(inner_unpack.type)
+                            # We assume heterogenous tuples are desugared earlier
+                            assert isinstance(inner_unpacked_type, Instance)
+                            assert inner_unpacked_type.type.fullname == "builtins.tuple"
+                            callee_arg_types = (
+                                unpacked_type.items[:inner_unpack_index]
+                                + [inner_unpacked_type.args[0]]
+                                * (len(actuals) - len(unpacked_type.items) + 1)
+                                + unpacked_type.items[inner_unpack_index + 1 :]
+                            )
+                            callee_arg_kinds = [ARG_POS] * len(actuals)
+                    else:
+                        assert isinstance(unpacked_type, Instance)
+                        assert unpacked_type.type.fullname == "builtins.tuple"
+                        callee_arg_types = [unpacked_type.args[0]] * len(actuals)
+                        callee_arg_kinds = [ARG_POS] * len(actuals)
                 else:
                     callee_arg_types = [orig_callee_arg_type] * len(actuals)
                     callee_arg_kinds = [callee.arg_kinds[i]] * len(actuals)
diff --git a/mypy/constraints.py b/mypy/constraints.py
index 0dd748ff85e12..63e1672eb1626 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -52,7 +52,6 @@
 from mypy.typevartuples import (
     extract_unpack,
     find_unpack_in_list,
-    split_with_instance,
     split_with_mapped_and_template,
     split_with_prefix_and_suffix,
 )
@@ -566,7 +565,7 @@ def visit_type_var_tuple(self, template: TypeVarTupleType) -> list[Constraint]:
         raise NotImplementedError
 
     def visit_unpack_type(self, template: UnpackType) -> list[Constraint]:
-        raise NotImplementedError
+        raise RuntimeError("Mypy bug: unpack should be handled at a higher level.")
 
     def visit_parameters(self, template: Parameters) -> list[Constraint]:
         # constraining Any against C[P] turns into infer_against_any([P], Any)
@@ -638,47 +637,22 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                 tvars = mapped.type.defn.type_vars
 
                 if instance.type.has_type_var_tuple_type:
-                    mapped_prefix, mapped_middle, mapped_suffix = split_with_instance(mapped)
-                    instance_prefix, instance_middle, instance_suffix = split_with_instance(
-                        instance
-                    )
-
-                    # Add a constraint for the type var tuple, and then
-                    # remove it for the case below.
-                    instance_unpack = extract_unpack(instance_middle)
-                    if instance_unpack is not None:
-                        if isinstance(instance_unpack, TypeVarTupleType):
-                            res.append(
-                                Constraint(
-                                    instance_unpack,
-                                    SUBTYPE_OF,
-                                    TupleType(list(mapped_middle), instance_unpack.tuple_fallback),
-                                )
-                            )
-                        elif (
-                            isinstance(instance_unpack, Instance)
-                            and instance_unpack.type.fullname == "builtins.tuple"
-                        ):
-                            for item in mapped_middle:
-                                res.extend(
-                                    infer_constraints(
-                                        instance_unpack.args[0], item, self.direction
-                                    )
-                                )
-                        elif isinstance(instance_unpack, TupleType):
-                            if len(instance_unpack.items) == len(mapped_middle):
-                                for instance_arg, item in zip(
-                                    instance_unpack.items, mapped_middle
-                                ):
-                                    res.extend(
-                                        infer_constraints(instance_arg, item, self.direction)
-                                    )
-
-                    mapped_args = mapped_prefix + mapped_suffix
-                    instance_args = instance_prefix + instance_suffix
-
                     assert instance.type.type_var_tuple_prefix is not None
                     assert instance.type.type_var_tuple_suffix is not None
+                    assert mapped.type.type_var_tuple_prefix is not None
+                    assert mapped.type.type_var_tuple_suffix is not None
+
+                    unpack_constraints, mapped_args, instance_args = build_constraints_for_unpack(
+                        mapped.args,
+                        mapped.type.type_var_tuple_prefix,
+                        mapped.type.type_var_tuple_suffix,
+                        instance.args,
+                        instance.type.type_var_tuple_prefix,
+                        instance.type.type_var_tuple_suffix,
+                        self.direction,
+                    )
+                    res.extend(unpack_constraints)
+
                     tvars_prefix, _, tvars_suffix = split_with_prefix_and_suffix(
                         tuple(tvars),
                         instance.type.type_var_tuple_prefix,
@@ -732,57 +706,22 @@ def visit_instance(self, template: Instance) -> list[Constraint]:
                 mapped = map_instance_to_supertype(instance, template.type)
                 tvars = template.type.defn.type_vars
                 if template.type.has_type_var_tuple_type:
-                    mapped_prefix, mapped_middle, mapped_suffix = split_with_instance(mapped)
-                    template_prefix, template_middle, template_suffix = split_with_instance(
-                        template
-                    )
-                    split_result = split_with_mapped_and_template(mapped, template)
-                    assert split_result is not None
-                    (
-                        mapped_prefix,
-                        mapped_middle,
-                        mapped_suffix,
-                        template_prefix,
-                        template_middle,
-                        template_suffix,
-                    ) = split_result
-
-                    # Add a constraint for the type var tuple, and then
-                    # remove it for the case below.
-                    template_unpack = extract_unpack(template_middle)
-                    if template_unpack is not None:
-                        if isinstance(template_unpack, TypeVarTupleType):
-                            res.append(
-                                Constraint(
-                                    template_unpack,
-                                    SUPERTYPE_OF,
-                                    TupleType(list(mapped_middle), template_unpack.tuple_fallback),
-                                )
-                            )
-                        elif (
-                            isinstance(template_unpack, Instance)
-                            and template_unpack.type.fullname == "builtins.tuple"
-                        ):
-                            for item in mapped_middle:
-                                res.extend(
-                                    infer_constraints(
-                                        template_unpack.args[0], item, self.direction
-                                    )
-                                )
-                        elif isinstance(template_unpack, TupleType):
-                            if len(template_unpack.items) == len(mapped_middle):
-                                for template_arg, item in zip(
-                                    template_unpack.items, mapped_middle
-                                ):
-                                    res.extend(
-                                        infer_constraints(template_arg, item, self.direction)
-                                    )
-
-                    mapped_args = mapped_prefix + mapped_suffix
-                    template_args = template_prefix + template_suffix
-
+                    assert mapped.type.type_var_tuple_prefix is not None
+                    assert mapped.type.type_var_tuple_suffix is not None
                     assert template.type.type_var_tuple_prefix is not None
                     assert template.type.type_var_tuple_suffix is not None
+
+                    unpack_constraints, mapped_args, template_args = build_constraints_for_unpack(
+                        mapped.args,
+                        mapped.type.type_var_tuple_prefix,
+                        mapped.type.type_var_tuple_suffix,
+                        template.args,
+                        template.type.type_var_tuple_prefix,
+                        template.type.type_var_tuple_suffix,
+                        self.direction,
+                    )
+                    res.extend(unpack_constraints)
+
                     tvars_prefix, _, tvars_suffix = split_with_prefix_and_suffix(
                         tuple(tvars),
                         template.type.type_var_tuple_prefix,
@@ -945,12 +884,28 @@ def visit_callable_type(self, template: CallableType) -> list[Constraint]:
                 # We can't infer constraints from arguments if the template is Callable[..., T]
                 # (with literal '...').
                 if not template.is_ellipsis_args:
+                    if find_unpack_in_list(template.arg_types) is not None:
+                        (
+                            unpack_constraints,
+                            cactual_args_t,
+                            template_args_t,
+                        ) = find_and_build_constraints_for_unpack(
+                            tuple(cactual.arg_types), tuple(template.arg_types), self.direction
+                        )
+                        template_args = list(template_args_t)
+                        cactual_args = list(cactual_args_t)
+                        res.extend(unpack_constraints)
+                        assert len(template_args) == len(cactual_args)
+                    else:
+                        template_args = template.arg_types
+                        cactual_args = cactual.arg_types
                     # The lengths should match, but don't crash (it will error elsewhere).
-                    for t, a in zip(template.arg_types, cactual.arg_types):
+                    for t, a in zip(template_args, cactual_args):
                         # Negate direction due to function argument type contravariance.
                         res.extend(infer_constraints(t, a, neg_op(self.direction)))
             else:
                 # sometimes, it appears we try to get constraints between two paramspec callables?
+
                 # TODO: Direction
                 # TODO: check the prefixes match
                 prefix = param_spec.prefix
@@ -1197,3 +1152,80 @@ def find_matching_overload_items(
         # it maintains backward compatibility.
         res = items[:]
     return res
+
+
+def find_and_build_constraints_for_unpack(
+    mapped: tuple[Type, ...], template: tuple[Type, ...], direction: int
+) -> tuple[list[Constraint], tuple[Type, ...], tuple[Type, ...]]:
+    mapped_prefix_len = find_unpack_in_list(mapped)
+    if mapped_prefix_len is not None:
+        mapped_suffix_len: int | None = len(mapped) - mapped_prefix_len - 1
+    else:
+        mapped_suffix_len = None
+
+    template_prefix_len = find_unpack_in_list(template)
+    assert template_prefix_len is not None
+    template_suffix_len = len(template) - template_prefix_len - 1
+
+    return build_constraints_for_unpack(
+        mapped,
+        mapped_prefix_len,
+        mapped_suffix_len,
+        template,
+        template_prefix_len,
+        template_suffix_len,
+        direction,
+    )
+
+
+def build_constraints_for_unpack(
+    mapped: tuple[Type, ...],
+    mapped_prefix_len: int | None,
+    mapped_suffix_len: int | None,
+    template: tuple[Type, ...],
+    template_prefix_len: int,
+    template_suffix_len: int,
+    direction: int,
+) -> tuple[list[Constraint], tuple[Type, ...], tuple[Type, ...]]:
+    split_result = split_with_mapped_and_template(
+        mapped,
+        mapped_prefix_len,
+        mapped_suffix_len,
+        template,
+        template_prefix_len,
+        template_suffix_len,
+    )
+    assert split_result is not None
+    (
+        mapped_prefix,
+        mapped_middle,
+        mapped_suffix,
+        template_prefix,
+        template_middle,
+        template_suffix,
+    ) = split_result
+
+    template_unpack = extract_unpack(template_middle)
+    res = []
+
+    if template_unpack is not None:
+        if isinstance(template_unpack, TypeVarTupleType):
+            res.append(
+                Constraint(
+                    template_unpack,
+                    direction,
+                    TupleType(list(mapped_middle), template_unpack.tuple_fallback),
+                )
+            )
+        elif (
+            isinstance(template_unpack, Instance)
+            and template_unpack.type.fullname == "builtins.tuple"
+        ):
+            for item in mapped_middle:
+                res.extend(infer_constraints(template_unpack.args[0], item, direction))
+
+        elif isinstance(template_unpack, TupleType):
+            if len(template_unpack.items) == len(mapped_middle):
+                for template_arg, item in zip(template_unpack.items, mapped_middle):
+                    res.extend(infer_constraints(template_arg, item, direction))
+    return (res, mapped_prefix + mapped_suffix, template_prefix + template_suffix)
diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index ca562ede264f3..1c3553fe5e53a 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -292,59 +292,14 @@ def visit_callable_type(self, t: CallableType) -> Type:
                 expanded_tuple = get_proper_type(var_arg.typ.type.accept(self))
                 # TODO: handle the case that expanded_tuple is a variable length tuple.
                 assert isinstance(expanded_tuple, TupleType)
-                expanded_unpack_index = find_unpack_in_list(expanded_tuple.items)
-                # This is the case where we just have Unpack[Tuple[X1, X2, X3]]
-                # (for example if either the tuple had no unpacks, or the unpack in the
-                # tuple got fully expanded to something with fixed length)
-                if expanded_unpack_index is None:
-                    arg_names = (
-                        t.arg_names[:star_index]
-                        + [None] * len(expanded_tuple.items)
-                        + t.arg_names[star_index + 1 :]
-                    )
-                    arg_kinds = (
-                        t.arg_kinds[:star_index]
-                        + [ARG_POS] * len(expanded_tuple.items)
-                        + t.arg_kinds[star_index + 1 :]
-                    )
-                    arg_types = (
-                        self.expand_types(t.arg_types[:star_index])
-                        + expanded_tuple.items
-                        + self.expand_types(t.arg_types[star_index + 1 :])
-                    )
-                else:
-                    # If Unpack[Ts] simplest form still has an unpack or is a
-                    # homogenous tuple, then only the prefix can be represented as
-                    # positional arguments, and we pass Tuple[Unpack[Ts-1], Y1, Y2]
-                    # as the star arg, for example.
-                    prefix_len = expanded_unpack_index
-                    arg_names = (
-                        t.arg_names[:star_index] + [None] * prefix_len + t.arg_names[star_index:]
-                    )
-                    arg_kinds = (
-                        t.arg_kinds[:star_index]
-                        + [ARG_POS] * prefix_len
-                        + t.arg_kinds[star_index:]
-                    )
-                    arg_types = (
-                        self.expand_types(t.arg_types[:star_index])
-                        + expanded_tuple.items[:prefix_len]
-                        # Constructing the Unpack containing the tuple without the prefix.
-                        + [
-                            UnpackType(
-                                expanded_tuple.copy_modified(
-                                    items=expanded_tuple.items[prefix_len:]
-                                )
-                            )
-                        ]
-                        + self.expand_types(t.arg_types[star_index + 1 :])
-                    )
+                expanded_items = expanded_tuple.items
             else:
-                expanded = self.expand_unpack(var_arg.typ)
-                # Handle other cases later.
-                assert isinstance(expanded, list)
-                assert len(expanded) == 1 and isinstance(expanded[0], UnpackType)
+                expanded_items_res = self.expand_unpack(var_arg.typ)
+                # TODO: can it be anything except a list?
+                assert isinstance(expanded_items_res, list)
+                expanded_items = expanded_items_res
 
+            """
                 # In this case we keep the arg as ARG_STAR.
                 arg_names = t.arg_names
                 arg_kinds = t.arg_kinds
@@ -353,6 +308,62 @@ def visit_callable_type(self, t: CallableType) -> Type:
                     + expanded
                     + self.expand_types(t.arg_types[star_index + 1 :])
                 )
+            """
+
+            expanded_unpack_index = find_unpack_in_list(expanded_items)
+            # This is the case where we just have Unpack[Tuple[X1, X2, X3]]
+            # (for example if either the tuple had no unpacks, or the unpack in the
+            # tuple got fully expanded to something with fixed length)
+            if expanded_unpack_index is None:
+                arg_names = (
+                    t.arg_names[:star_index]
+                    + [None] * len(expanded_items)
+                    + t.arg_names[star_index + 1 :]
+                )
+                arg_kinds = (
+                    t.arg_kinds[:star_index]
+                    + [ARG_POS] * len(expanded_items)
+                    + t.arg_kinds[star_index + 1 :]
+                )
+                arg_types = (
+                    self.expand_types(t.arg_types[:star_index])
+                    + expanded_items
+                    + self.expand_types(t.arg_types[star_index + 1 :])
+                )
+            else:
+                # If Unpack[Ts] simplest form still has an unpack or is a
+                # homogenous tuple, then only the prefix can be represented as
+                # positional arguments, and we pass Tuple[Unpack[Ts-1], Y1, Y2]
+                # as the star arg, for example.
+                expanded_unpack = get_proper_type(expanded_items[expanded_unpack_index])
+                assert isinstance(expanded_unpack, UnpackType)
+
+                # Extract the typevartuple so we can get a tuple fallback from it.
+                expanded_unpacked_tvt = get_proper_type(expanded_unpack.type)
+                assert isinstance(expanded_unpacked_tvt, TypeVarTupleType)
+
+                prefix_len = expanded_unpack_index
+                arg_names = (
+                    t.arg_names[:star_index] + [None] * prefix_len + t.arg_names[star_index:]
+                )
+                arg_kinds = (
+                    t.arg_kinds[:star_index] + [ARG_POS] * prefix_len + t.arg_kinds[star_index:]
+                )
+                arg_types = (
+                    self.expand_types(t.arg_types[:star_index])
+                    + expanded_items[:prefix_len]
+                    # Constructing the Unpack containing the tuple without the prefix.
+                    + [
+                        UnpackType(
+                            TupleType(
+                                expanded_items[prefix_len:], expanded_unpacked_tvt.tuple_fallback
+                            )
+                        )
+                        if len(expanded_items) - prefix_len > 1
+                        else expanded_items[0]
+                    ]
+                    + self.expand_types(t.arg_types[star_index + 1 :])
+                )
         else:
             arg_types = self.expand_types(t.arg_types)
             arg_names = t.arg_names
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 61ba7af5147f4..83cb22d48fabf 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -482,7 +482,18 @@ def visit_instance(self, left: Instance) -> bool:
                     t = erased
                 nominal = True
                 if right.type.has_type_var_tuple_type:
-                    split_result = fully_split_with_mapped_and_template(left, right)
+                    assert left.type.type_var_tuple_prefix is not None
+                    assert left.type.type_var_tuple_suffix is not None
+                    assert right.type.type_var_tuple_prefix is not None
+                    assert right.type.type_var_tuple_suffix is not None
+                    split_result = fully_split_with_mapped_and_template(
+                        left.args,
+                        left.type.type_var_tuple_prefix,
+                        left.type.type_var_tuple_suffix,
+                        right.args,
+                        right.type.type_var_tuple_prefix,
+                        right.type.type_var_tuple_suffix,
+                    )
                     if split_result is None:
                         return False
 
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 0755b21854de0..df74344fb392b 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -1274,6 +1274,7 @@ def analyze_callable_args(
         args: list[Type] = []
         kinds: list[ArgKind] = []
         names: list[str | None] = []
+        found_unpack = False
         for arg in arglist.items:
             if isinstance(arg, CallableArgument):
                 args.append(arg.typ)
@@ -1294,6 +1295,19 @@ def analyze_callable_args(
                     if arg.name is not None and kind.is_star():
                         self.fail(f"{arg.constructor} arguments should not have names", arg)
                         return None
+            elif isinstance(arg, UnboundType):
+                kind = ARG_POS
+                # Potentially a unpack.
+                sym = self.lookup_qualified(arg.name, arg)
+                if sym is not None:
+                    if sym.fullname == "typing_extensions.Unpack":
+                        if found_unpack:
+                            self.fail("Callables can only have a single unpack", arg)
+                        found_unpack = True
+                        kind = ARG_STAR
+                args.append(arg)
+                kinds.append(kind)
+                names.append(None)
             else:
                 args.append(arg)
                 kinds.append(ARG_POS)
diff --git a/mypy/types.py b/mypy/types.py
index 354a740567dc9..7af83b6c11d39 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3568,10 +3568,16 @@ def store_argument_type(
         if isinstance(arg_type, ParamSpecType):
             pass
         elif isinstance(arg_type, UnpackType):
-            if isinstance(get_proper_type(arg_type.type), TupleType):
+            unpacked_type = get_proper_type(arg_type.type)
+            if isinstance(unpacked_type, TupleType):
                 # Instead of using Tuple[Unpack[Tuple[...]]], just use
                 # Tuple[...]
-                arg_type = arg_type.type
+                arg_type = unpacked_type
+            elif (
+                isinstance(unpacked_type, Instance)
+                and unpacked_type.type.fullname == "builtins.tuple"
+            ):
+                arg_type = unpacked_type
             else:
                 arg_type = TupleType(
                     [arg_type],
diff --git a/mypy/typevartuples.py b/mypy/typevartuples.py
index 4b3b5cc2dca7e..29b85dae72eb4 100644
--- a/mypy/typevartuples.py
+++ b/mypy/typevartuples.py
@@ -46,7 +46,12 @@ def split_with_instance(
 
 
 def split_with_mapped_and_template(
-    mapped: Instance, template: Instance
+    mapped: tuple[Type, ...],
+    mapped_prefix_len: int | None,
+    mapped_suffix_len: int | None,
+    template: tuple[Type, ...],
+    template_prefix_len: int,
+    template_suffix_len: int,
 ) -> tuple[
     tuple[Type, ...],
     tuple[Type, ...],
@@ -55,7 +60,14 @@ def split_with_mapped_and_template(
     tuple[Type, ...],
     tuple[Type, ...],
 ] | None:
-    split_result = fully_split_with_mapped_and_template(mapped, template)
+    split_result = fully_split_with_mapped_and_template(
+        mapped,
+        mapped_prefix_len,
+        mapped_suffix_len,
+        template,
+        template_prefix_len,
+        template_suffix_len,
+    )
     if split_result is None:
         return None
 
@@ -83,7 +95,12 @@ def split_with_mapped_and_template(
 
 
 def fully_split_with_mapped_and_template(
-    mapped: Instance, template: Instance
+    mapped: tuple[Type, ...],
+    mapped_prefix_len: int | None,
+    mapped_suffix_len: int | None,
+    template: tuple[Type, ...],
+    template_prefix_len: int,
+    template_suffix_len: int,
 ) -> tuple[
     tuple[Type, ...],
     tuple[Type, ...],
@@ -96,8 +113,19 @@ def fully_split_with_mapped_and_template(
     tuple[Type, ...],
     tuple[Type, ...],
 ] | None:
-    mapped_prefix, mapped_middle, mapped_suffix = split_with_instance(mapped)
-    template_prefix, template_middle, template_suffix = split_with_instance(template)
+    if mapped_prefix_len is not None:
+        assert mapped_suffix_len is not None
+        mapped_prefix, mapped_middle, mapped_suffix = split_with_prefix_and_suffix(
+            tuple(mapped), mapped_prefix_len, mapped_suffix_len
+        )
+    else:
+        mapped_prefix = tuple()
+        mapped_suffix = tuple()
+        mapped_middle = mapped
+
+    template_prefix, template_middle, template_suffix = split_with_prefix_and_suffix(
+        tuple(template), template_prefix_len, template_suffix_len
+    )
 
     unpack_prefix = find_unpack_in_list(template_middle)
     if unpack_prefix is None:
diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test
index d85990293aea0..f61b53dcd2c09 100644
--- a/test-data/unit/check-typevar-tuple.test
+++ b/test-data/unit/check-typevar-tuple.test
@@ -178,7 +178,7 @@ Ts = TypeVarTuple("Ts")
 B = Ts  # E: Type variable "__main__.Ts" is invalid as target for type alias
 [builtins fixtures/tuple.pyi]
 
-[case testPep646ArrayExample]
+[case testTypeVarTuplePep646ArrayExample]
 from typing import Generic, Tuple, TypeVar, Protocol, NewType
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -213,7 +213,7 @@ reveal_type(abs(x))  # N: Revealed type is "__main__.Array[__main__.Height, __ma
 reveal_type(x + x)  # N: Revealed type is "__main__.Array[__main__.Height, __main__.Width]"
 
 [builtins fixtures/tuple.pyi]
-[case testPep646ArrayExampleWithDType]
+[case testTypeVarTuplePep646ArrayExampleWithDType]
 from typing import Generic, Tuple, TypeVar, Protocol, NewType
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -250,7 +250,7 @@ reveal_type(x + x)  # N: Revealed type is "__main__.Array[builtins.float, __main
 
 [builtins fixtures/tuple.pyi]
 
-[case testPep646ArrayExampleInfer]
+[case testTypeVarTuplePep646ArrayExampleInfer]
 from typing import Generic, Tuple, TypeVar, NewType
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -265,7 +265,7 @@ class Array(Generic[Unpack[Shape]]):
 x: Array[float, Height, Width] = Array()
 [builtins fixtures/tuple.pyi]
 
-[case testPep646TypeConcatenation]
+[case testTypeVarTuplePep646TypeConcatenation]
 from typing import Generic, TypeVar, NewType
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -295,7 +295,7 @@ d = add_batch_channels(a)
 reveal_type(d)  # N: Revealed type is "__main__.Array[__main__.Batch, __main__.Height, __main__.Width, __main__.Channels]"
 
 [builtins fixtures/tuple.pyi]
-[case testPep646TypeVarConcatenation]
+[case testTypeVarTuplePep646TypeVarConcatenation]
 from typing import Generic, TypeVar, NewType, Tuple
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -311,7 +311,7 @@ def prefix_tuple(
 z = prefix_tuple(x=0, y=(True, 'a'))
 reveal_type(z)  # N: Revealed type is "Tuple[builtins.int, builtins.bool, builtins.str]"
 [builtins fixtures/tuple.pyi]
-[case testPep646TypeVarTupleUnpacking]
+[case testTypeVarTuplePep646TypeVarTupleUnpacking]
 from typing import Generic, TypeVar, NewType, Any, Tuple
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -367,7 +367,7 @@ reveal_type(bad2)  # N: Revealed type is "def (x: Tuple[builtins.int, Unpack[bui
 
 [builtins fixtures/tuple.pyi]
 
-[case testPep646TypeVarStarArgs]
+[case testTypeVarTuplePep646TypeVarStarArgsBasic]
 from typing import Tuple
 from typing_extensions import TypeVarTuple, Unpack
 
@@ -381,6 +381,13 @@ def args_to_tuple(*args: Unpack[Ts]) -> Tuple[Unpack[Ts]]:
 
 reveal_type(args_to_tuple(1, 'a'))  # N: Revealed type is "Tuple[Literal[1]?, Literal['a']?]"
 
+[builtins fixtures/tuple.pyi]
+[case testTypeVarTuplePep646TypeVarStarArgs]
+from typing import Tuple
+from typing_extensions import TypeVarTuple, Unpack
+
+Ts = TypeVarTuple("Ts")
+
 def with_prefix_suffix(*args: Unpack[Tuple[bool, str, Unpack[Ts], int]]) -> Tuple[bool, str, Unpack[Ts], int]:
     reveal_type(args)  # N: Revealed type is "Tuple[builtins.bool, builtins.str, Unpack[Ts`-1], builtins.int]"
     return args
@@ -404,14 +411,69 @@ with_prefix_suffix(*bad_t)  # E: Too few arguments for "with_prefix_suffix"
 def foo(*args: Unpack[Ts]) -> None:
     reveal_type(with_prefix_suffix(True, "bar", *args, 5))  # N: Revealed type is "Tuple[builtins.bool, builtins.str, Unpack[Ts`-1], builtins.int]"
 
-def concrete(*args: Unpack[Tuple[int, str]]) -> None:
+
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVarTuplePep646TypeVarStarArgsFixedLengthTuple]
+from typing import Tuple
+from typing_extensions import Unpack
+
+def foo(*args: Unpack[Tuple[int, str]]) -> None:
     reveal_type(args)  # N: Revealed type is "Tuple[builtins.int, builtins.str]"
 
-concrete(0, "foo")
-concrete(0, 1)  # E: Argument 2 to "concrete" has incompatible type "int"; expected "Unpack[Tuple[int, str]]"
-concrete("foo", "bar")  # E: Argument 1 to "concrete" has incompatible type "str"; expected "Unpack[Tuple[int, str]]"
-concrete(0, "foo", 1)  # E: Invalid number of arguments
-concrete(0)  # E: Invalid number of arguments
-concrete()  # E: Invalid number of arguments
+foo(0, "foo")
+foo(0, 1)  # E: Argument 2 to "foo" has incompatible type "int"; expected "Unpack[Tuple[int, str]]"
+foo("foo", "bar")  # E: Argument 1 to "foo" has incompatible type "str"; expected "Unpack[Tuple[int, str]]"
+foo(0, "foo", 1)  # E: Invalid number of arguments
+foo(0)  # E: Invalid number of arguments
+foo()  # E: Invalid number of arguments
+foo(*(0, "foo"))
+
+# TODO: fix this case to do something sensible.
+#def foo2(*args: Unpack[Tuple[bool, Unpack[Tuple[int, str]], bool]]) -> None:
+#    reveal_type(args)
+
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVarTuplePep646TypeVarStarArgsVariableLengthTuple]
+from typing import Tuple
+from typing_extensions import Unpack
+
+def foo(*args: Unpack[Tuple[int, ...]]) -> None:
+    reveal_type(args)  # N: Revealed type is "builtins.tuple[builtins.int, ...]"
+
+foo(0, 1, 2)
+# TODO: this should say 'expected "int"' rather than the unpack
+foo(0, 1, "bar")  # E: Argument 3 to "foo" has incompatible type "str"; expected "Unpack[Tuple[int, ...]]" 
+
+
+def foo2(*args: Unpack[Tuple[str, Unpack[Tuple[int, ...]], bool, bool]]) -> None:
+    reveal_type(args)  # N: Revealed type is "Tuple[builtins.str, Unpack[builtins.tuple[builtins.int, ...]], builtins.bool, builtins.bool]"
+    # TODO: generate an error
+    # reveal_type(args[1])
+
+foo2("bar", 1, 2, 3, False, True)
+foo2(0, 1, 2, 3, False, True)  # E: Argument 1 to "foo2" has incompatible type "int"; expected "Unpack[Tuple[str, Unpack[Tuple[int, ...]], bool, bool]]"
+foo2("bar", "bar", 2, 3, False, True)  # E: Argument 2 to "foo2" has incompatible type "str"; expected "Unpack[Tuple[str, Unpack[Tuple[int, ...]], bool, bool]]"
+foo2("bar", 1, 2, 3, 4, True)  # E: Argument 5 to "foo2" has incompatible type "int"; expected "Unpack[Tuple[str, Unpack[Tuple[int, ...]], bool, bool]]"
+foo2(*("bar", 1, 2, 3, False, True))
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVarTuplePep646Callable]
+from typing import Tuple, Callable
+from typing_extensions import Unpack, TypeVarTuple
+
+Ts = TypeVarTuple("Ts")
+
+def call(
+    target: Callable[[ Unpack[Ts]], None],
+    args: Tuple[Unpack[Ts]],
+) -> None:
+    pass
+
+def func(arg1: int, arg2: str) -> None: ...
 
+call(target=func, args=(0, 'foo'))  # Valid
+#call(target=func, args=(True, 'foo', 0))  # Error
+#call(target=func, args=(0, 0, 'foo'))  # Error
 [builtins fixtures/tuple.pyi]
diff --git a/test-data/unit/semanal-errors.test b/test-data/unit/semanal-errors.test
index fffd02c9c3375..a4ed905dcb9f5 100644
--- a/test-data/unit/semanal-errors.test
+++ b/test-data/unit/semanal-errors.test
@@ -1474,4 +1474,12 @@ y: Unpack[TVariadic]  # E: TypeVarTuple "TVariadic" is unbound
 
 class Variadic(Generic[Unpack[TVariadic], Unpack[TVariadic2]]):  # E: Can only use one type var tuple in a class def
     pass
-[builtins fixtures/tuple.pyi]
+
+# TODO: this should generate an error
+#def bad_args(*args: TVariadic):
+#    pass
+
+def bad_kwargs(**kwargs: Unpack[TVariadic]):  # E: Unpack item in ** argument must be a TypedDict
+    pass
+
+[builtins fixtures/dict.pyi]
diff --git a/test-data/unit/semanal-types.test b/test-data/unit/semanal-types.test
index 77ef10a26b133..494d701b758a6 100644
--- a/test-data/unit/semanal-types.test
+++ b/test-data/unit/semanal-types.test
@@ -1560,4 +1560,29 @@ MypyFile:1(
   AssignmentStmt:2(
     NameExpr(TV* [__main__.TV])
     TypeVarTupleExpr:2()))
+
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVarTupleCallable]
+from typing_extensions import TypeVarTuple, Unpack
+from typing import Callable
+Ts = TypeVarTuple("Ts")
+
+def foo(x: Callable[[Unpack[Ts]], None]) -> None:
+    pass
+[out]
+MypyFile:1(
+  ImportFrom:1(typing_extensions, [TypeVarTuple, Unpack])
+  ImportFrom:2(typing, [Callable])
+  AssignmentStmt:3(
+    NameExpr(Ts* [__main__.Ts])
+    TypeVarTupleExpr:3())
+  FuncDef:5(
+    foo
+    Args(
+      Var(x))
+    def [Ts] (x: def (*Unpack[Ts`-1]))
+    Block:5(
+      PassStmt:6())))
+
 [builtins fixtures/tuple.pyi]

From 4ec6ea519f02dc918ad1e55c1096a1009079bfac Mon Sep 17 00:00:00 2001
From: Richard Si <sichard26@gmail.com>
Date: Mon, 9 Jan 2023 12:06:07 -0500
Subject: [PATCH 171/231] [mypyc] Don't load forward ref targets while setting
 up non-ext __annotations__ (#14401)

Take this example:

```
    from typing import NamedTuple

    class VTableMethod(NamedTuple):
        cls: "ClassIR"

    class ClassIR: pass
```

In irbuild::classdef::add_non_ext_class_attr_ann(), mypyc tries to
assign the ClassIR type object to VTableMethod's `__annotations__`.
This causes a segfault as ClassIR won't be initialized and allocated
until *after* the NamedTuple is set up.

Fortunately, AssignmentStmt preserves the unanalyzed type (UnboundType).
If `stmt.unanalyzed_type.orginal_str_expr` is not None, then we know
we're dealing with a forward ref and should just load the string
instead.

Unfortunately, it seems difficult (or impossible?) to infer whether an
annotation is a forward reference when the annotations future is enabled
and the annotation isn't a string.

Fixes https://github.com/mypyc/mypyc/issues/938

Dataclasses are still broken as strings in `__annotations__` cause
dataclass's internals to lookup the module in sys.modules which fails
(as the module hasn't been fully initialized and added to sys.modules
yet!)
---
 mypyc/irbuild/classdef.py       | 15 +++++++++++++--
 mypyc/test-data/run-tuples.test | 10 ++++++----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index b1f2ed1a1a65f..d49c0e580c915 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -24,7 +24,7 @@
     TypeInfo,
     is_class_var,
 )
-from mypy.types import ENUM_REMOVED_PROPS, Instance, get_proper_type
+from mypy.types import ENUM_REMOVED_PROPS, Instance, UnboundType, get_proper_type
 from mypyc.ir.class_ir import ClassIR, NonExtClassInfo
 from mypyc.ir.func_ir import FuncDecl, FuncSignature
 from mypyc.ir.ops import (
@@ -556,6 +556,7 @@ def add_non_ext_class_attr_ann(
     get_type_info: Callable[[AssignmentStmt], TypeInfo | None] | None = None,
 ) -> None:
     """Add a class attribute to __annotations__ of a non-extension class."""
+    # FIXME: try to better preserve the special forms and type parameters of generics.
     typ: Value | None = None
     if get_type_info is not None:
         type_info = get_type_info(stmt)
@@ -565,7 +566,17 @@ def add_non_ext_class_attr_ann(
     if typ is None:
         # FIXME: if get_type_info is not provided, don't fall back to stmt.type?
         ann_type = get_proper_type(stmt.type)
-        if isinstance(ann_type, Instance):
+        if (
+            isinstance(stmt.unanalyzed_type, UnboundType)
+            and stmt.unanalyzed_type.original_str_expr is not None
+        ):
+            # Annotation is a forward reference, so don't attempt to load the actual
+            # type and load the string instead.
+            #
+            # TODO: is it possible to determine whether a non-string annotation is
+            # actually a forward reference due to the __annotations__ future?
+            typ = builder.load_str(stmt.unanalyzed_type.original_str_expr)
+        elif isinstance(ann_type, Instance):
             typ = load_type(builder, ann_type.type, stmt.line)
         else:
             typ = builder.add(LoadAddress(type_object_op.type, type_object_op.src, stmt.line))
diff --git a/mypyc/test-data/run-tuples.test b/mypyc/test-data/run-tuples.test
index 26b0393208443..f6c92b9c720fa 100644
--- a/mypyc/test-data/run-tuples.test
+++ b/mypyc/test-data/run-tuples.test
@@ -99,8 +99,6 @@ assert f(Sub(3, 2)) == 3
 [case testNamedTupleClassSyntax]
 from typing import Dict, List, NamedTuple, Optional, Tuple, Union
 
-class ClassIR: pass
-
 class FuncIR: pass
 
 StealsDescription = Union[bool, List[bool]]
@@ -119,8 +117,12 @@ class Record(NamedTuple):
     ordering: Optional[List[int]]
     extra_int_constants: List[Tuple[int]]
 
+# Make sure mypyc loads the annotation string for this forward reference.
+# Ref: https://github.com/mypyc/mypyc/issues/938
+class ClassIR: pass
+
 [file driver.py]
-from typing import Optional
+from typing import ForwardRef, Optional
 from native import ClassIR, FuncIR, Record
 
 assert Record.__annotations__ == {
@@ -129,7 +131,7 @@ assert Record.__annotations__ == {
     'is_borrowed': bool,
     'hash': str,
     'python_path': tuple,
-    'type': ClassIR,
+    'type': ForwardRef('ClassIR'),
     'method': FuncIR,
     'shadow_method': type,
     'classes': dict,

From e1117c3fc49c0836bf098b5c5dd8027c62b3186c Mon Sep 17 00:00:00 2001
From: Richard Si <sichard26@gmail.com>
Date: Tue, 10 Jan 2023 05:53:43 -0500
Subject: [PATCH 172/231] [mypyc] Precompute set literals for "in" ops against
 / iteration over set literals   (#14409)

Towards https://github.com/mypyc/mypyc/issues/726. (There's a Python
compatibility bug that needs to be fixed before the issue can be
closed.)

For example, the set literals here are now precomputed as frozensets at
module initialization.

```
    x in {1, 2.0, "3"}
    x not in {1, 2.0, "3"}

    for _ in {1, 2.0, "3"}:
        ...
```

Set literal items supported:

- Anything supported by `irbuild.constant_fold.constant_fold_expr()`
  - String and integer literals
  - Final references to int/str values
- Certain int and str unary/binary ops that evaluate to a constant value
- `None`, `True`, and `False`
- Float, byte, and complex literals
- Tuple literals with only items listed above

**Results** (using gcc-9 on 64-bit Ubuntu)

Master @ 98cc165a657a316accb93f1ed57fdc128b086d9f

    running in_set
    ..........
    interpreted: 0.495790s (avg of 5 iterations; stdev 6.8%)
    compiled:    0.810029s (avg of 5 iterations; stdev 1.5%)

    compiled is 0.612x faster

    running set_literal_iteration

.........................................................................................
    interpreted: 0.020255s (avg of 45 iterations; stdev 2.5%)
    compiled:    0.016336s (avg of 45 iterations; stdev 1.8%)

    compiled is 1.240x faster

This PR

    running in_set
    ..........
    interpreted: 0.502020s (avg of 5 iterations; stdev 1.1%)
    compiled:    0.390281s (avg of 5 iterations; stdev 6.2%)

    compiled is 1.286x faster

    running set_literal_iteration

..............................................................................................
    interpreted: 0.019917s (avg of 47 iterations; stdev 2.2%)
    compiled:    0.007134s (avg of 47 iterations; stdev 2.6%)

    compiled is 2.792x faster

Benchmarks can be found here: mypyc/mypyc-benchmarks#32
---
 mypyc/analysis/ircheck.py        |  14 +++
 mypyc/codegen/emitmodule.py      |   5 +-
 mypyc/codegen/literals.py        |  46 +++++---
 mypyc/ir/ops.py                  |   9 +-
 mypyc/ir/pprint.py               |  13 ++-
 mypyc/irbuild/builder.py         |   7 +-
 mypyc/irbuild/expression.py      |  73 ++++++++++++-
 mypyc/irbuild/for_helpers.py     |  15 ++-
 mypyc/irbuild/util.py            |  10 ++
 mypyc/lib-rt/CPy.h               |   3 +-
 mypyc/lib-rt/misc_ops.c          |  21 +++-
 mypyc/primitives/set_ops.py      |   2 +-
 mypyc/test-data/fixtures/ir.py   |   2 +
 mypyc/test-data/irbuild-set.test | 182 +++++++++++++++++++++++++++++++
 mypyc/test-data/run-sets.test    |  33 ++++++
 15 files changed, 403 insertions(+), 32 deletions(-)

diff --git a/mypyc/analysis/ircheck.py b/mypyc/analysis/ircheck.py
index b141784ef9ff2..e96c640fa8a15 100644
--- a/mypyc/analysis/ircheck.py
+++ b/mypyc/analysis/ircheck.py
@@ -252,6 +252,15 @@ def check_tuple_items_valid_literals(self, op: LoadLiteral, t: tuple[object, ...
             if isinstance(x, tuple):
                 self.check_tuple_items_valid_literals(op, x)
 
+    def check_frozenset_items_valid_literals(self, op: LoadLiteral, s: frozenset[object]) -> None:
+        for x in s:
+            if x is None or isinstance(x, (str, bytes, bool, int, float, complex)):
+                pass
+            elif isinstance(x, tuple):
+                self.check_tuple_items_valid_literals(op, x)
+            else:
+                self.fail(op, f"Invalid type for item of frozenset literal: {type(x)})")
+
     def visit_load_literal(self, op: LoadLiteral) -> None:
         expected_type = None
         if op.value is None:
@@ -271,6 +280,11 @@ def visit_load_literal(self, op: LoadLiteral) -> None:
         elif isinstance(op.value, tuple):
             expected_type = "builtins.tuple"
             self.check_tuple_items_valid_literals(op, op.value)
+        elif isinstance(op.value, frozenset):
+            # There's no frozenset_rprimitive type since it'd be pretty useless so we just pretend
+            # it's a set (when it's really a frozenset).
+            expected_type = "builtins.set"
+            self.check_frozenset_items_valid_literals(op, op.value)
 
         assert expected_type is not None, "Missed a case for LoadLiteral check"
 
diff --git a/mypyc/codegen/emitmodule.py b/mypyc/codegen/emitmodule.py
index 5dacaf6acab6c..9f65aa77c47f4 100644
--- a/mypyc/codegen/emitmodule.py
+++ b/mypyc/codegen/emitmodule.py
@@ -669,6 +669,9 @@ def generate_literal_tables(self) -> None:
         # Descriptions of tuple literals
         init_tuple = c_array_initializer(literals.encoded_tuple_values())
         self.declare_global("const int []", "CPyLit_Tuple", initializer=init_tuple)
+        # Descriptions of frozenset literals
+        init_frozenset = c_array_initializer(literals.encoded_frozenset_values())
+        self.declare_global("const int []", "CPyLit_FrozenSet", initializer=init_frozenset)
 
     def generate_export_table(self, decl_emitter: Emitter, code_emitter: Emitter) -> None:
         """Generate the declaration and definition of the group's export struct.
@@ -839,7 +842,7 @@ def generate_globals_init(self, emitter: Emitter) -> None:
         for symbol, fixup in self.simple_inits:
             emitter.emit_line(f"{symbol} = {fixup};")
 
-        values = "CPyLit_Str, CPyLit_Bytes, CPyLit_Int, CPyLit_Float, CPyLit_Complex, CPyLit_Tuple"
+        values = "CPyLit_Str, CPyLit_Bytes, CPyLit_Int, CPyLit_Float, CPyLit_Complex, CPyLit_Tuple, CPyLit_FrozenSet"
         emitter.emit_lines(
             f"if (CPyStatics_Initialize(CPyStatics, {values}) < 0) {{", "return -1;", "}"
         )
diff --git a/mypyc/codegen/literals.py b/mypyc/codegen/literals.py
index 29957d52101c4..784a8ed27c4e4 100644
--- a/mypyc/codegen/literals.py
+++ b/mypyc/codegen/literals.py
@@ -1,12 +1,13 @@
 from __future__ import annotations
 
-from typing import Any, Tuple, Union, cast
+from typing import Any, Dict, FrozenSet, List, Tuple, Union, cast
 from typing_extensions import Final
 
-# Supported Python literal types. All tuple items must have supported
+# Supported Python literal types. All tuple / frozenset items must have supported
 # literal types as well, but we can't represent the type precisely.
-LiteralValue = Union[str, bytes, int, bool, float, complex, Tuple[object, ...], None]
-
+LiteralValue = Union[
+    str, bytes, int, bool, float, complex, Tuple[object, ...], FrozenSet[object], None
+]
 
 # Some literals are singletons and handled specially (None, False and True)
 NUM_SINGLETONS: Final = 3
@@ -23,6 +24,7 @@ def __init__(self) -> None:
         self.float_literals: dict[float, int] = {}
         self.complex_literals: dict[complex, int] = {}
         self.tuple_literals: dict[tuple[object, ...], int] = {}
+        self.frozenset_literals: dict[frozenset[object], int] = {}
 
     def record_literal(self, value: LiteralValue) -> None:
         """Ensure that the literal value is available in generated code."""
@@ -55,6 +57,12 @@ def record_literal(self, value: LiteralValue) -> None:
                 for item in value:
                     self.record_literal(cast(Any, item))
                 tuple_literals[value] = len(tuple_literals)
+        elif isinstance(value, frozenset):
+            frozenset_literals = self.frozenset_literals
+            if value not in frozenset_literals:
+                for item in value:
+                    self.record_literal(cast(Any, item))
+                frozenset_literals[value] = len(frozenset_literals)
         else:
             assert False, "invalid literal: %r" % value
 
@@ -86,6 +94,9 @@ def literal_index(self, value: LiteralValue) -> int:
         n += len(self.complex_literals)
         if isinstance(value, tuple):
             return n + self.tuple_literals[value]
+        n += len(self.tuple_literals)
+        if isinstance(value, frozenset):
+            return n + self.frozenset_literals[value]
         assert False, "invalid literal: %r" % value
 
     def num_literals(self) -> int:
@@ -98,6 +109,7 @@ def num_literals(self) -> int:
             + len(self.float_literals)
             + len(self.complex_literals)
             + len(self.tuple_literals)
+            + len(self.frozenset_literals)
         )
 
     # The following methods return the C encodings of literal values
@@ -119,24 +131,32 @@ def encoded_complex_values(self) -> list[str]:
         return _encode_complex_values(self.complex_literals)
 
     def encoded_tuple_values(self) -> list[str]:
-        """Encode tuple values into a C array.
+        return self._encode_collection_values(self.tuple_literals)
+
+    def encoded_frozenset_values(self) -> List[str]:
+        return self._encode_collection_values(self.frozenset_literals)
+
+    def _encode_collection_values(
+        self, values: dict[tuple[object, ...], int] | dict[frozenset[object], int]
+    ) -> list[str]:
+        """Encode tuple/frozenset values into a C array.
 
         The format of the result is like this:
 
-           <number of tuples>
-           <length of the first tuple>
+           <number of collections>
+           <length of the first collection>
            <literal index of first item>
            ...
            <literal index of last item>
-           <length of the second tuple>
+           <length of the second collection>
            ...
         """
-        values = self.tuple_literals
-        value_by_index = {index: value for value, index in values.items()}
+        # FIXME: https://github.com/mypyc/mypyc/issues/965
+        value_by_index = {index: value for value, index in cast(Dict[Any, int], values).items()}
         result = []
-        num = len(values)
-        result.append(str(num))
-        for i in range(num):
+        count = len(values)
+        result.append(str(count))
+        for i in range(count):
             value = value_by_index[i]
             result.append(str(len(value)))
             for item in value:
diff --git a/mypyc/ir/ops.py b/mypyc/ir/ops.py
index 1f79ba829d767..cc6f542c3e234 100644
--- a/mypyc/ir/ops.py
+++ b/mypyc/ir/ops.py
@@ -39,6 +39,7 @@
 )
 
 if TYPE_CHECKING:
+    from mypyc.codegen.literals import LiteralValue
     from mypyc.ir.class_ir import ClassIR
     from mypyc.ir.func_ir import FuncDecl, FuncIR
 
@@ -588,7 +589,7 @@ class LoadLiteral(RegisterOp):
     This is used to load a static PyObject * value corresponding to
     a literal of one of the supported types.
 
-    Tuple literals must contain only valid literal values as items.
+    Tuple / frozenset literals must contain only valid literal values as items.
 
     NOTE: You can use this to load boxed (Python) int objects. Use
           Integer to load unboxed, tagged integers or fixed-width,
@@ -603,11 +604,7 @@ class LoadLiteral(RegisterOp):
     error_kind = ERR_NEVER
     is_borrowed = True
 
-    def __init__(
-        self,
-        value: None | str | bytes | bool | int | float | complex | tuple[object, ...],
-        rtype: RType,
-    ) -> None:
+    def __init__(self, value: LiteralValue, rtype: RType) -> None:
         self.value = value
         self.type = rtype
 
diff --git a/mypyc/ir/pprint.py b/mypyc/ir/pprint.py
index a9324a8608e40..cb9e4a2d25418 100644
--- a/mypyc/ir/pprint.py
+++ b/mypyc/ir/pprint.py
@@ -106,7 +106,18 @@ def visit_load_literal(self, op: LoadLiteral) -> str:
         # it explicit that this is a Python object.
         if isinstance(op.value, int):
             prefix = "object "
-        return self.format("%r = %s%s", op, prefix, repr(op.value))
+
+        rvalue = repr(op.value)
+        if isinstance(op.value, frozenset):
+            # We need to generate a string representation that won't vary
+            # run-to-run because sets are unordered, otherwise we may get
+            # spurious irbuild test failures.
+            #
+            # Sorting by the item's string representation is a bit of a
+            # hack, but it's stable and won't cause TypeErrors.
+            formatted_items = [repr(i) for i in sorted(op.value, key=str)]
+            rvalue = "frozenset({" + ", ".join(formatted_items) + "})"
+        return self.format("%r = %s%s", op, prefix, rvalue)
 
     def visit_get_attr(self, op: GetAttr) -> str:
         return self.format("%r = %s%r.%s", op, self.borrow_prefix(op), op.obj, op.attr)
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
index 792697970785a..c24207ac64ecb 100644
--- a/mypyc/irbuild/builder.py
+++ b/mypyc/irbuild/builder.py
@@ -118,7 +118,7 @@
     AssignmentTargetRegister,
     AssignmentTargetTuple,
 )
-from mypyc.irbuild.util import is_constant
+from mypyc.irbuild.util import bytes_from_str, is_constant
 from mypyc.options import CompilerOptions
 from mypyc.primitives.dict_ops import dict_get_item_op, dict_set_item_op
 from mypyc.primitives.generic_ops import iter_op, next_op, py_setattr_op
@@ -296,8 +296,7 @@ def load_bytes_from_str_literal(self, value: str) -> Value:
         are stored in BytesExpr.value, whose type is 'str' not 'bytes'.
         Thus we perform a special conversion here.
         """
-        bytes_value = bytes(value, "utf8").decode("unicode-escape").encode("raw-unicode-escape")
-        return self.builder.load_bytes(bytes_value)
+        return self.builder.load_bytes(bytes_from_str(value))
 
     def load_int(self, value: int) -> Value:
         return self.builder.load_int(value)
@@ -886,7 +885,7 @@ def get_dict_base_type(self, expr: Expression) -> Instance:
         This is useful for dict subclasses like SymbolTable.
         """
         target_type = get_proper_type(self.types[expr])
-        assert isinstance(target_type, Instance)
+        assert isinstance(target_type, Instance), target_type
         dict_base = next(base for base in target_type.type.mro if base.fullname == "builtins.dict")
         return map_instance_to_supertype(target_type, dict_base)
 
diff --git a/mypyc/irbuild/expression.py b/mypyc/irbuild/expression.py
index b007435957b00..3f5b795a14363 100644
--- a/mypyc/irbuild/expression.py
+++ b/mypyc/irbuild/expression.py
@@ -6,7 +6,7 @@
 
 from __future__ import annotations
 
-from typing import Callable, cast
+from typing import Callable, Sequence, cast
 
 from mypy.nodes import (
     ARG_POS,
@@ -55,6 +55,7 @@
     ComparisonOp,
     Integer,
     LoadAddress,
+    LoadLiteral,
     RaiseStandardError,
     Register,
     TupleGet,
@@ -63,12 +64,14 @@
 )
 from mypyc.ir.rtypes import (
     RTuple,
+    bool_rprimitive,
     int_rprimitive,
     is_fixed_width_rtype,
     is_int_rprimitive,
     is_list_rprimitive,
     is_none_rprimitive,
     object_rprimitive,
+    set_rprimitive,
 )
 from mypyc.irbuild.ast_helpers import is_borrow_friendly_expr, process_conditional
 from mypyc.irbuild.builder import IRBuilder, int_borrow_friendly_op
@@ -86,6 +89,7 @@
     tokenizer_printf_style,
 )
 from mypyc.irbuild.specialize import apply_function_specialization, apply_method_specialization
+from mypyc.irbuild.util import bytes_from_str
 from mypyc.primitives.bytes_ops import bytes_slice_op
 from mypyc.primitives.dict_ops import dict_get_item_op, dict_new_op, dict_set_item_op
 from mypyc.primitives.generic_ops import iter_op
@@ -93,7 +97,7 @@
 from mypyc.primitives.list_ops import list_append_op, list_extend_op, list_slice_op
 from mypyc.primitives.misc_ops import ellipsis_op, get_module_dict_op, new_slice_op, type_op
 from mypyc.primitives.registry import CFunctionDescription, builtin_names
-from mypyc.primitives.set_ops import set_add_op, set_update_op
+from mypyc.primitives.set_ops import set_add_op, set_in_op, set_update_op
 from mypyc.primitives.str_ops import str_slice_op
 from mypyc.primitives.tuple_ops import list_tuple_op, tuple_slice_op
 
@@ -613,6 +617,54 @@ def transform_conditional_expr(builder: IRBuilder, expr: ConditionalExpr) -> Val
     return target
 
 
+def set_literal_values(builder: IRBuilder, items: Sequence[Expression]) -> list[object] | None:
+    values: list[object] = []
+    for item in items:
+        const_value = constant_fold_expr(builder, item)
+        if const_value is not None:
+            values.append(const_value)
+            continue
+
+        if isinstance(item, RefExpr):
+            if item.fullname == "builtins.None":
+                values.append(None)
+            elif item.fullname == "builtins.True":
+                values.append(True)
+            elif item.fullname == "builtins.False":
+                values.append(False)
+        elif isinstance(item, (BytesExpr, FloatExpr, ComplexExpr)):
+            # constant_fold_expr() doesn't handle these (yet?)
+            v = bytes_from_str(item.value) if isinstance(item, BytesExpr) else item.value
+            values.append(v)
+        elif isinstance(item, TupleExpr):
+            tuple_values = set_literal_values(builder, item.items)
+            if tuple_values is not None:
+                values.append(tuple(tuple_values))
+
+    if len(values) != len(items):
+        # Bail if not all items can be converted into values.
+        return None
+    return values
+
+
+def precompute_set_literal(builder: IRBuilder, s: SetExpr) -> Value | None:
+    """Try to pre-compute a frozenset literal during module initialization.
+
+    Return None if it's not possible.
+
+    Supported items:
+     - Anything supported by irbuild.constant_fold.constant_fold_expr()
+     - None, True, and False
+     - Float, byte, and complex literals
+     - Tuple literals with only items listed above
+    """
+    values = set_literal_values(builder, s.items)
+    if values is not None:
+        return builder.add(LoadLiteral(frozenset(values), set_rprimitive))
+
+    return None
+
+
 def transform_comparison_expr(builder: IRBuilder, e: ComparisonExpr) -> Value:
     # x in (...)/[...]
     # x not in (...)/[...]
@@ -666,6 +718,23 @@ def transform_comparison_expr(builder: IRBuilder, e: ComparisonExpr) -> Value:
             else:
                 return builder.true()
 
+    # x in {...}
+    # x not in {...}
+    if (
+        first_op in ("in", "not in")
+        and len(e.operators) == 1
+        and isinstance(e.operands[1], SetExpr)
+    ):
+        set_literal = precompute_set_literal(builder, e.operands[1])
+        if set_literal is not None:
+            lhs = e.operands[0]
+            result = builder.builder.call_c(
+                set_in_op, [builder.accept(lhs), set_literal], e.line, bool_rprimitive
+            )
+            if first_op == "not in":
+                return builder.unary_op(result, "not", e.line)
+            return result
+
     if len(e.operators) == 1:
         # Special some common simple cases
         if first_op in ("is", "is not"):
diff --git a/mypyc/irbuild/for_helpers.py b/mypyc/irbuild/for_helpers.py
index fc67178af5de6..61dbbe960eb23 100644
--- a/mypyc/irbuild/for_helpers.py
+++ b/mypyc/irbuild/for_helpers.py
@@ -17,6 +17,7 @@
     Lvalue,
     MemberExpr,
     RefExpr,
+    SetExpr,
     TupleExpr,
     TypeAlias,
 )
@@ -469,12 +470,22 @@ def make_for_loop_generator(
             for_dict_gen.init(expr_reg, target_type)
             return for_dict_gen
 
+    iterable_expr_reg: Value | None = None
+    if isinstance(expr, SetExpr):
+        # Special case "for x in <set literal>".
+        from mypyc.irbuild.expression import precompute_set_literal
+
+        set_literal = precompute_set_literal(builder, expr)
+        if set_literal is not None:
+            iterable_expr_reg = set_literal
+
     # Default to a generic for loop.
-    expr_reg = builder.accept(expr)
+    if iterable_expr_reg is None:
+        iterable_expr_reg = builder.accept(expr)
     for_obj = ForIterable(builder, index, body_block, loop_exit, line, nested)
     item_type = builder._analyze_iterable_item_type(expr)
     item_rtype = builder.type_to_rtype(item_type)
-    for_obj.init(expr_reg, item_rtype)
+    for_obj.init(iterable_expr_reg, item_rtype)
     return for_obj
 
 
diff --git a/mypyc/irbuild/util.py b/mypyc/irbuild/util.py
index f50241b96cb3e..ed01a59d1214e 100644
--- a/mypyc/irbuild/util.py
+++ b/mypyc/irbuild/util.py
@@ -177,3 +177,13 @@ def is_constant(e: Expression) -> bool:
             )
         )
     )
+
+
+def bytes_from_str(value: str) -> bytes:
+    """Convert a string representing bytes into actual bytes.
+
+    This is needed because the literal characters of BytesExpr (the
+    characters inside b'') are stored in BytesExpr.value, whose type is
+    'str' not 'bytes'.
+    """
+    return bytes(value, "utf8").decode("unicode-escape").encode("raw-unicode-escape")
diff --git a/mypyc/lib-rt/CPy.h b/mypyc/lib-rt/CPy.h
index 7ee914a037dc4..befa397051efb 100644
--- a/mypyc/lib-rt/CPy.h
+++ b/mypyc/lib-rt/CPy.h
@@ -597,7 +597,8 @@ int CPyStatics_Initialize(PyObject **statics,
                           const char * const *ints,
                           const double *floats,
                           const double *complex_numbers,
-                          const int *tuples);
+                          const int *tuples,
+                          const int *frozensets);
 PyObject *CPy_Super(PyObject *builtins, PyObject *self);
 PyObject *CPy_CallReverseOpMethod(PyObject *left, PyObject *right, const char *op,
                                   _Py_Identifier *method);
diff --git a/mypyc/lib-rt/misc_ops.c b/mypyc/lib-rt/misc_ops.c
index 25f33c5f56c79..5fda78704bbc1 100644
--- a/mypyc/lib-rt/misc_ops.c
+++ b/mypyc/lib-rt/misc_ops.c
@@ -535,7 +535,8 @@ int CPyStatics_Initialize(PyObject **statics,
                           const char * const *ints,
                           const double *floats,
                           const double *complex_numbers,
-                          const int *tuples) {
+                          const int *tuples,
+                          const int *frozensets) {
     PyObject **result = statics;
     // Start with some hard-coded values
     *result++ = Py_None;
@@ -635,6 +636,24 @@ int CPyStatics_Initialize(PyObject **statics,
             *result++ = obj;
         }
     }
+    if (frozensets) {
+        int num = *frozensets++;
+        while (num-- > 0) {
+            int num_items = *frozensets++;
+            PyObject *obj = PyFrozenSet_New(NULL);
+            if (obj == NULL) {
+                return -1;
+            }
+            for (int i = 0; i < num_items; i++) {
+                PyObject *item = statics[*frozensets++];
+                Py_INCREF(item);
+                if (PySet_Add(obj, item) == -1) {
+                    return -1;
+                }
+            }
+            *result++ = obj;
+        }
+    }
     return 0;
 }
 
diff --git a/mypyc/primitives/set_ops.py b/mypyc/primitives/set_ops.py
index 801fdad34ea4d..fcfb7847dc7d5 100644
--- a/mypyc/primitives/set_ops.py
+++ b/mypyc/primitives/set_ops.py
@@ -54,7 +54,7 @@
 )
 
 # item in set
-binary_op(
+set_in_op = binary_op(
     name="in",
     arg_types=[object_rprimitive, set_rprimitive],
     return_type=c_int_rprimitive,
diff --git a/mypyc/test-data/fixtures/ir.py b/mypyc/test-data/fixtures/ir.py
index 0e437f4597eae..2f3c18e9c7311 100644
--- a/mypyc/test-data/fixtures/ir.py
+++ b/mypyc/test-data/fixtures/ir.py
@@ -221,12 +221,14 @@ def clear(self) -> None: pass
     def pop(self) -> T: pass
     def update(self, x: Iterable[S]) -> None: pass
     def __or__(self, s: Union[Set[S], FrozenSet[S]]) -> Set[Union[T, S]]: ...
+    def __xor__(self, s: Union[Set[S], FrozenSet[S]]) -> Set[Union[T, S]]: ...
 
 class frozenset(Generic[T]):
     def __init__(self, i: Optional[Iterable[T]] = None) -> None: pass
     def __iter__(self) -> Iterator[T]: pass
     def __len__(self) -> int: pass
     def __or__(self, s: Union[Set[S], FrozenSet[S]]) -> FrozenSet[Union[T, S]]: ...
+    def __xor__(self, s: Union[Set[S], FrozenSet[S]]) -> FrozenSet[Union[T, S]]: ...
 
 class slice: pass
 
diff --git a/mypyc/test-data/irbuild-set.test b/mypyc/test-data/irbuild-set.test
index fec76751c9154..c567422abac76 100644
--- a/mypyc/test-data/irbuild-set.test
+++ b/mypyc/test-data/irbuild-set.test
@@ -655,3 +655,185 @@ L0:
     r12 = PySet_Add(r0, r11)
     r13 = r12 >= 0 :: signed
     return r0
+
+[case testOperatorInSetLiteral]
+from typing_extensions import Final
+
+CONST: Final = "daylily"
+non_const = 10
+
+def precomputed(i: object) -> bool:
+    return i in {1, 2.0, 1 +2, 4j, "foo", b"bar", CONST, (None, (27,)), (), False}
+def not_precomputed_non_final_name(i: int) -> bool:
+    return i in {non_const}
+def not_precomputed_nested_set(i: int) -> bool:
+    return i in {frozenset({1}), 2}
+[out]
+def precomputed(i):
+    i :: object
+    r0 :: set
+    r1 :: int32
+    r2 :: bit
+    r3 :: bool
+L0:
+    r0 = frozenset({(), (None, (27,)), 1, 2.0, 3, 4j, False, b'bar', 'daylily', 'foo'})
+    r1 = PySet_Contains(r0, i)
+    r2 = r1 >= 0 :: signed
+    r3 = truncate r1: int32 to builtins.bool
+    return r3
+def not_precomputed_non_final_name(i):
+    i :: int
+    r0 :: dict
+    r1 :: str
+    r2 :: object
+    r3 :: int
+    r4 :: set
+    r5 :: object
+    r6 :: int32
+    r7 :: bit
+    r8 :: object
+    r9 :: int32
+    r10 :: bit
+    r11 :: bool
+L0:
+    r0 = __main__.globals :: static
+    r1 = 'non_const'
+    r2 = CPyDict_GetItem(r0, r1)
+    r3 = unbox(int, r2)
+    r4 = PySet_New(0)
+    r5 = box(int, r3)
+    r6 = PySet_Add(r4, r5)
+    r7 = r6 >= 0 :: signed
+    r8 = box(int, i)
+    r9 = PySet_Contains(r4, r8)
+    r10 = r9 >= 0 :: signed
+    r11 = truncate r9: int32 to builtins.bool
+    return r11
+def not_precomputed_nested_set(i):
+    i :: int
+    r0 :: set
+    r1 :: object
+    r2 :: int32
+    r3 :: bit
+    r4 :: object
+    r5 :: set
+    r6 :: int32
+    r7 :: bit
+    r8 :: object
+    r9 :: int32
+    r10 :: bit
+    r11 :: object
+    r12 :: int32
+    r13 :: bit
+    r14 :: bool
+L0:
+    r0 = PySet_New(0)
+    r1 = object 1
+    r2 = PySet_Add(r0, r1)
+    r3 = r2 >= 0 :: signed
+    r4 = PyFrozenSet_New(r0)
+    r5 = PySet_New(0)
+    r6 = PySet_Add(r5, r4)
+    r7 = r6 >= 0 :: signed
+    r8 = object 2
+    r9 = PySet_Add(r5, r8)
+    r10 = r9 >= 0 :: signed
+    r11 = box(int, i)
+    r12 = PySet_Contains(r5, r11)
+    r13 = r12 >= 0 :: signed
+    r14 = truncate r12: int32 to builtins.bool
+    return r14
+
+[case testForSetLiteral]
+from typing_extensions import Final
+
+CONST: Final = 10
+non_const = 20
+
+def precomputed() -> None:
+    for _ in {"None", "True", "False"}:
+        pass
+
+def precomputed2() -> None:
+    for _ in {None, False, 1, 2.0, "4", b"5", (6,), 7j, CONST, CONST + 1}:
+        pass
+
+def not_precomputed() -> None:
+    for not_optimized in {non_const}:
+        pass
+
+[out]
+def precomputed():
+    r0 :: set
+    r1, r2 :: object
+    r3 :: str
+    _ :: object
+    r4 :: bit
+L0:
+    r0 = frozenset({'False', 'None', 'True'})
+    r1 = PyObject_GetIter(r0)
+L1:
+    r2 = PyIter_Next(r1)
+    if is_error(r2) goto L4 else goto L2
+L2:
+    r3 = cast(str, r2)
+    _ = r3
+L3:
+    goto L1
+L4:
+    r4 = CPy_NoErrOccured()
+L5:
+    return 1
+def precomputed2():
+    r0 :: set
+    r1, r2, _ :: object
+    r3 :: bit
+L0:
+    r0 = frozenset({(6,), 1, 10, 11, 2.0, '4', 7j, False, None, b'5'})
+    r1 = PyObject_GetIter(r0)
+L1:
+    r2 = PyIter_Next(r1)
+    if is_error(r2) goto L4 else goto L2
+L2:
+    _ = r2
+L3:
+    goto L1
+L4:
+    r3 = CPy_NoErrOccured()
+L5:
+    return 1
+def not_precomputed():
+    r0 :: dict
+    r1 :: str
+    r2 :: object
+    r3 :: int
+    r4 :: set
+    r5 :: object
+    r6 :: int32
+    r7 :: bit
+    r8, r9 :: object
+    r10, not_optimized :: int
+    r11 :: bit
+L0:
+    r0 = __main__.globals :: static
+    r1 = 'non_const'
+    r2 = CPyDict_GetItem(r0, r1)
+    r3 = unbox(int, r2)
+    r4 = PySet_New(0)
+    r5 = box(int, r3)
+    r6 = PySet_Add(r4, r5)
+    r7 = r6 >= 0 :: signed
+    r8 = PyObject_GetIter(r4)
+L1:
+    r9 = PyIter_Next(r8)
+    if is_error(r9) goto L4 else goto L2
+L2:
+    r10 = unbox(int, r9)
+    not_optimized = r10
+L3:
+    goto L1
+L4:
+    r11 = CPy_NoErrOccured()
+L5:
+    return 1
+
diff --git a/mypyc/test-data/run-sets.test b/mypyc/test-data/run-sets.test
index 98ac92d569b70..56c946933fac4 100644
--- a/mypyc/test-data/run-sets.test
+++ b/mypyc/test-data/run-sets.test
@@ -115,3 +115,36 @@ from native import update
 s = {1, 2, 3}
 update(s, [5, 4, 3])
 assert s == {1, 2, 3, 4, 5}
+
+[case testPrecomputedFrozenSets]
+from typing import Any
+from typing_extensions import Final
+
+CONST: Final = "CONST"
+non_const = "non_const"
+
+def main_set(item: Any) -> bool:
+    return item in {None, False, 1, 2.0, "3", b"4", 5j, (6,), ((7,),), (), CONST}
+
+def main_negated_set(item: Any) -> bool:
+    return item not in {None, False, 1, 2.0, "3", b"4", 5j, (6,), ((7,),), (), CONST}
+
+def non_final_name_set(item: Any) -> bool:
+    return item in {non_const}
+
+s = set()
+for i in {None, False, 1, 2.0, "3", b"4", 5j, (6,), CONST}:
+    s.add(i)
+
+def test_in_set() -> None:
+    for item in (None, False, 1, 2.0, "3", b"4", 5j, (6,), ((7,),), (), CONST):
+        assert main_set(item), f"{item!r} should be in set_main"
+        assert not main_negated_set(item), item
+
+    assert non_final_name_set(non_const)
+    global non_const
+    non_const = "updated"
+    assert non_final_name_set("updated")
+
+def test_for_set() -> None:
+    assert not s ^ {None, False, 1, 2.0, "3", b"4", 5j, (6,), CONST}, s

From 2475643f7e6708ec7da45a753003c13a2baaddce Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 10 Jan 2023 13:18:14 +0000
Subject: [PATCH 173/231] [mypyc] Support attributes that override properties 
 (#14377)

Code like this is now supported by mypyc:
```
class B:
    @property
    def x(self) -> int:
        return 0

class C(B):
    x: int = 0  # Attribute overrides a property
```

The implementation generates implicit getter/setter methods for
attributes as needed and puts them in the vtable. I had to change both
the irbuild "prepare" pass (where we generate declarations), irbuild
main pass (where we generate implicit accessor IRs), and codegen (where
implicit properties aren't visible externally to CPython).

Also fix a minor mypy bug related to overriding properties and multiple
inheritance that I encountered.

This doesn't handle glue methods yet.
---
 mypy/checker.py                  |   9 +-
 mypyc/codegen/emitclass.py       |  16 ++-
 mypyc/ir/class_ir.py             |  12 +-
 mypyc/ir/func_ir.py              |   9 +-
 mypyc/irbuild/classdef.py        |  27 ++++-
 mypyc/irbuild/function.py        |  33 +++++-
 mypyc/irbuild/prepare.py         | 195 ++++++++++++++++++++++---------
 mypyc/irbuild/vtable.py          |   2 +-
 mypyc/sametype.py                |   4 +-
 mypyc/test-data/run-classes.test | 182 +++++++++++++++++++++++++++++
 mypyc/test-data/run-i64.test     |  68 ++++++++++-
 11 files changed, 487 insertions(+), 70 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index c265ac4905fbd..065758cd2be9c 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -2498,8 +2498,13 @@ class C(B, A[int]): ...  # this is unsafe because...
             ok = is_equivalent(first_type, second_type)
             if not ok:
                 second_node = base2[name].node
-                if isinstance(second_node, Decorator) and second_node.func.is_property:
-                    ok = is_subtype(first_type, cast(CallableType, second_type).ret_type)
+                if (
+                    isinstance(second_type, FunctionLike)
+                    and second_node is not None
+                    and is_property(second_node)
+                ):
+                    second_type = get_property_type(second_type)
+                    ok = is_subtype(first_type, second_type)
         else:
             if first_type is None:
                 self.msg.cannot_determine_type_in_base(name, base1.name, ctx)
diff --git a/mypyc/codegen/emitclass.py b/mypyc/codegen/emitclass.py
index 1e774bbd01854..72e16345a3257 100644
--- a/mypyc/codegen/emitclass.py
+++ b/mypyc/codegen/emitclass.py
@@ -824,7 +824,10 @@ def generate_getseter_declarations(cl: ClassIR, emitter: Emitter) -> None:
                 )
             )
 
-    for prop in cl.properties:
+    for prop, (getter, setter) in cl.properties.items():
+        if getter.decl.implicit:
+            continue
+
         # Generate getter declaration
         emitter.emit_line("static PyObject *")
         emitter.emit_line(
@@ -834,7 +837,7 @@ def generate_getseter_declarations(cl: ClassIR, emitter: Emitter) -> None:
         )
 
         # Generate property setter declaration if a setter exists
-        if cl.properties[prop][1]:
+        if setter:
             emitter.emit_line("static int")
             emitter.emit_line(
                 "{}({} *self, PyObject *value, void *closure);".format(
@@ -854,11 +857,13 @@ def generate_getseters_table(cl: ClassIR, name: str, emitter: Emitter) -> None:
                 )
             )
             emitter.emit_line(" NULL, NULL},")
-    for prop in cl.properties:
+    for prop, (getter, setter) in cl.properties.items():
+        if getter.decl.implicit:
+            continue
+
         emitter.emit_line(f'{{"{prop}",')
         emitter.emit_line(f" (getter){getter_name(cl, prop, emitter.names)},")
 
-        setter = cl.properties[prop][1]
         if setter:
             emitter.emit_line(f" (setter){setter_name(cl, prop, emitter.names)},")
             emitter.emit_line("NULL, NULL},")
@@ -878,6 +883,9 @@ def generate_getseters(cl: ClassIR, emitter: Emitter) -> None:
             if i < len(cl.attributes) - 1:
                 emitter.emit_line("")
     for prop, (getter, setter) in cl.properties.items():
+        if getter.decl.implicit:
+            continue
+
         rtype = getter.sig.ret_type
         emitter.emit_line("")
         generate_readonly_getter(cl, prop, rtype, getter, emitter)
diff --git a/mypyc/ir/class_ir.py b/mypyc/ir/class_ir.py
index f0f772306e605..71d61c3f0efa3 100644
--- a/mypyc/ir/class_ir.py
+++ b/mypyc/ir/class_ir.py
@@ -278,10 +278,18 @@ def name_prefix(self, names: NameGenerator) -> str:
     def struct_name(self, names: NameGenerator) -> str:
         return f"{exported_name(self.fullname)}Object"
 
-    def get_method_and_class(self, name: str) -> tuple[FuncIR, ClassIR] | None:
+    def get_method_and_class(
+        self, name: str, *, prefer_method: bool = False
+    ) -> tuple[FuncIR, ClassIR] | None:
         for ir in self.mro:
             if name in ir.methods:
-                return ir.methods[name], ir
+                func_ir = ir.methods[name]
+                if not prefer_method and func_ir.decl.implicit:
+                    # This is an implicit accessor, so there is also an attribute definition
+                    # which the caller prefers. This happens if an attribute overrides a
+                    # property.
+                    return None
+                return func_ir, ir
 
         return None
 
diff --git a/mypyc/ir/func_ir.py b/mypyc/ir/func_ir.py
index 933230a853a80..dbb45fc7ec294 100644
--- a/mypyc/ir/func_ir.py
+++ b/mypyc/ir/func_ir.py
@@ -139,6 +139,7 @@ def __init__(
         kind: int = FUNC_NORMAL,
         is_prop_setter: bool = False,
         is_prop_getter: bool = False,
+        implicit: bool = False,
     ) -> None:
         self.name = name
         self.class_name = class_name
@@ -155,7 +156,11 @@ def __init__(
             else:
                 self.bound_sig = sig.bound_sig()
 
-        # this is optional because this will be set to the line number when the corresponding
+        # If True, not present in the mypy AST and must be synthesized during irbuild
+        # Currently only supported for property getters/setters
+        self.implicit = implicit
+
+        # This is optional because this will be set to the line number when the corresponding
         # FuncIR is created
         self._line: int | None = None
 
@@ -198,6 +203,7 @@ def serialize(self) -> JsonDict:
             "kind": self.kind,
             "is_prop_setter": self.is_prop_setter,
             "is_prop_getter": self.is_prop_getter,
+            "implicit": self.implicit,
         }
 
     # TODO: move this to FuncIR?
@@ -219,6 +225,7 @@ def deserialize(cls, data: JsonDict, ctx: DeserMaps) -> FuncDecl:
             data["kind"],
             data["is_prop_setter"],
             data["is_prop_getter"],
+            data["implicit"],
         )
 
 
diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index d49c0e580c915..4e4263458b3e1 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -25,6 +25,7 @@
     is_class_var,
 )
 from mypy.types import ENUM_REMOVED_PROPS, Instance, UnboundType, get_proper_type
+from mypyc.common import PROPSET_PREFIX
 from mypyc.ir.class_ir import ClassIR, NonExtClassInfo
 from mypyc.ir.func_ir import FuncDecl, FuncSignature
 from mypyc.ir.ops import (
@@ -53,7 +54,13 @@
     object_rprimitive,
 )
 from mypyc.irbuild.builder import IRBuilder
-from mypyc.irbuild.function import handle_ext_method, handle_non_ext_method, load_type
+from mypyc.irbuild.function import (
+    gen_property_getter_ir,
+    gen_property_setter_ir,
+    handle_ext_method,
+    handle_non_ext_method,
+    load_type,
+)
 from mypyc.irbuild.util import dataclass_type, get_func_def, is_constant, is_dataclass_decorator
 from mypyc.primitives.dict_ops import dict_new_op, dict_set_item_op
 from mypyc.primitives.generic_ops import py_hasattr_op, py_setattr_op
@@ -151,6 +158,24 @@ def transform_class_def(builder: IRBuilder, cdef: ClassDef) -> None:
         else:
             builder.error("Unsupported statement in class body", stmt.line)
 
+    # Generate implicit property setters/getters
+    for name, decl in ir.method_decls.items():
+        if decl.implicit and decl.is_prop_getter:
+            getter_ir = gen_property_getter_ir(builder, decl, cdef)
+            builder.functions.append(getter_ir)
+            ir.methods[getter_ir.decl.name] = getter_ir
+
+            setter_ir = None
+            setter_name = PROPSET_PREFIX + name
+            if setter_name in ir.method_decls:
+                setter_ir = gen_property_setter_ir(builder, ir.method_decls[setter_name], cdef)
+                builder.functions.append(setter_ir)
+                ir.methods[setter_name] = setter_ir
+
+            ir.properties[name] = (getter_ir, setter_ir)
+            # TODO: Generate glue method if needed?
+            # TODO: Do we need interpreted glue methods? Maybe not?
+
     cls_builder.finalize(ir)
 
 
diff --git a/mypyc/irbuild/function.py b/mypyc/irbuild/function.py
index 237088791bc9e..5447f945db257 100644
--- a/mypyc/irbuild/function.py
+++ b/mypyc/irbuild/function.py
@@ -28,7 +28,7 @@
     Var,
 )
 from mypy.types import CallableType, get_proper_type
-from mypyc.common import LAMBDA_NAME, SELF_NAME
+from mypyc.common import LAMBDA_NAME, PROPSET_PREFIX, SELF_NAME
 from mypyc.ir.class_ir import ClassIR, NonExtClassInfo
 from mypyc.ir.func_ir import (
     FUNC_CLASSMETHOD,
@@ -1026,3 +1026,34 @@ def get_native_impl_ids(builder: IRBuilder, singledispatch_func: FuncDef) -> dic
     """
     impls = builder.singledispatch_impls[singledispatch_func]
     return {impl: i for i, (typ, impl) in enumerate(impls) if not is_decorated(builder, impl)}
+
+
+def gen_property_getter_ir(builder: IRBuilder, func_decl: FuncDecl, cdef: ClassDef) -> FuncIR:
+    """Generate an implicit trivial property getter for an attribute.
+
+    These are used if an attribute can also be accessed as a property.
+    """
+    name = func_decl.name
+    builder.enter(name)
+    self_reg = builder.add_argument("self", func_decl.sig.args[0].type)
+    value = builder.builder.get_attr(self_reg, name, func_decl.sig.ret_type, -1)
+    builder.add(Return(value))
+    args, _, blocks, ret_type, fn_info = builder.leave()
+    return FuncIR(func_decl, args, blocks)
+
+
+def gen_property_setter_ir(builder: IRBuilder, func_decl: FuncDecl, cdef: ClassDef) -> FuncIR:
+    """Generate an implicit trivial property setter for an attribute.
+
+    These are used if an attribute can also be accessed as a property.
+    """
+    name = func_decl.name
+    builder.enter(name)
+    self_reg = builder.add_argument("self", func_decl.sig.args[0].type)
+    value_reg = builder.add_argument("value", func_decl.sig.args[1].type)
+    assert name.startswith(PROPSET_PREFIX)
+    attr_name = name[len(PROPSET_PREFIX) :]
+    builder.add(SetAttr(self_reg, attr_name, value_reg, -1))
+    builder.add(Return(builder.none()))
+    args, _, blocks, ret_type, fn_info = builder.leave()
+    return FuncIR(func_decl, args, blocks)
diff --git a/mypyc/irbuild/prepare.py b/mypyc/irbuild/prepare.py
index 2399647374c07..eb8288b848182 100644
--- a/mypyc/irbuild/prepare.py
+++ b/mypyc/irbuild/prepare.py
@@ -50,7 +50,7 @@
     RuntimeArg,
 )
 from mypyc.ir.ops import DeserMaps
-from mypyc.ir.rtypes import RInstance, dict_rprimitive, tuple_rprimitive
+from mypyc.ir.rtypes import RInstance, RType, dict_rprimitive, none_rprimitive, tuple_rprimitive
 from mypyc.irbuild.mapper import Mapper
 from mypyc.irbuild.util import (
     get_func_def,
@@ -98,6 +98,12 @@ def build_type_map(
             else:
                 prepare_non_ext_class_def(module.path, module.fullname, cdef, errors, mapper)
 
+    # Prepare implicit attribute accessors as needed if an attribute overrides a property.
+    for module, cdef in classes:
+        class_ir = mapper.type_to_ir[cdef.info]
+        if class_ir.is_ext_class:
+            prepare_implicit_property_accessors(cdef.info, class_ir, module.fullname, mapper)
+
     # Collect all the functions also. We collect from the symbol table
     # so that we can easily pick out the right copy of a function that
     # is conditionally defined.
@@ -168,6 +174,8 @@ def prepare_method_def(
             # works correctly.
             decl.name = PROPSET_PREFIX + decl.name
             decl.is_prop_setter = True
+            # Making the argument implicitly positional-only avoids unnecessary glue methods
+            decl.sig.args[1].pos_only = True
             ir.method_decls[PROPSET_PREFIX + node.name] = decl
 
         if node.func.is_property:
@@ -212,6 +220,11 @@ def can_subclass_builtin(builtin_base: str) -> bool:
 def prepare_class_def(
     path: str, module_name: str, cdef: ClassDef, errors: Errors, mapper: Mapper
 ) -> None:
+    """Populate the interface-level information in a class IR.
+
+    This includes attribute and method declarations, and the MRO, among other things, but
+    method bodies are generated in a later pass.
+    """
 
     ir = mapper.type_to_ir[cdef.info]
     info = cdef.info
@@ -223,8 +236,68 @@ def prepare_class_def(
         # Supports copy.copy and pickle (including subclasses)
         ir._serializable = True
 
-    # We sort the table for determinism here on Python 3.5
-    for name, node in sorted(info.names.items()):
+    # Check for subclassing from builtin types
+    for cls in info.mro:
+        # Special case exceptions and dicts
+        # XXX: How do we handle *other* things??
+        if cls.fullname == "builtins.BaseException":
+            ir.builtin_base = "PyBaseExceptionObject"
+        elif cls.fullname == "builtins.dict":
+            ir.builtin_base = "PyDictObject"
+        elif cls.fullname.startswith("builtins."):
+            if not can_subclass_builtin(cls.fullname):
+                # Note that if we try to subclass a C extension class that
+                # isn't in builtins, bad things will happen and we won't
+                # catch it here! But this should catch a lot of the most
+                # common pitfalls.
+                errors.error(
+                    "Inheriting from most builtin types is unimplemented", path, cdef.line
+                )
+
+    # Set up the parent class
+    bases = [mapper.type_to_ir[base.type] for base in info.bases if base.type in mapper.type_to_ir]
+    if not all(c.is_trait for c in bases[1:]):
+        errors.error("Non-trait bases must appear first in parent list", path, cdef.line)
+    ir.traits = [c for c in bases if c.is_trait]
+
+    mro = []  # All mypyc base classes
+    base_mro = []  # Non-trait mypyc base classes
+    for cls in info.mro:
+        if cls not in mapper.type_to_ir:
+            if cls.fullname != "builtins.object":
+                ir.inherits_python = True
+            continue
+        base_ir = mapper.type_to_ir[cls]
+        if not base_ir.is_trait:
+            base_mro.append(base_ir)
+        mro.append(base_ir)
+
+        if cls.defn.removed_base_type_exprs or not base_ir.is_ext_class:
+            ir.inherits_python = True
+
+    base_idx = 1 if not ir.is_trait else 0
+    if len(base_mro) > base_idx:
+        ir.base = base_mro[base_idx]
+    ir.mro = mro
+    ir.base_mro = base_mro
+
+    prepare_methods_and_attributes(cdef, ir, path, module_name, errors, mapper)
+    prepare_init_method(cdef, ir, module_name, mapper)
+
+    for base in bases:
+        if base.children is not None:
+            base.children.append(ir)
+
+    if is_dataclass(cdef):
+        ir.is_augmented = True
+
+
+def prepare_methods_and_attributes(
+    cdef: ClassDef, ir: ClassIR, path: str, module_name: str, errors: Errors, mapper: Mapper
+) -> None:
+    """Populate attribute and method declarations."""
+    info = cdef.info
+    for name, node in info.names.items():
         # Currently all plugin generated methods are dummies and not included.
         if node.plugin_generated:
             continue
@@ -249,27 +322,73 @@ def prepare_class_def(
                 assert node.node.impl
                 prepare_method_def(ir, module_name, cdef, mapper, node.node.impl)
 
-    # Check for subclassing from builtin types
-    for cls in info.mro:
-        # Special case exceptions and dicts
-        # XXX: How do we handle *other* things??
-        if cls.fullname == "builtins.BaseException":
-            ir.builtin_base = "PyBaseExceptionObject"
-        elif cls.fullname == "builtins.dict":
-            ir.builtin_base = "PyDictObject"
-        elif cls.fullname.startswith("builtins."):
-            if not can_subclass_builtin(cls.fullname):
-                # Note that if we try to subclass a C extension class that
-                # isn't in builtins, bad things will happen and we won't
-                # catch it here! But this should catch a lot of the most
-                # common pitfalls.
-                errors.error(
-                    "Inheriting from most builtin types is unimplemented", path, cdef.line
-                )
-
     if ir.builtin_base:
         ir.attributes.clear()
 
+
+def prepare_implicit_property_accessors(
+    info: TypeInfo, ir: ClassIR, module_name: str, mapper: Mapper
+) -> None:
+    for base in ir.base_mro:
+        for name, attr_rtype in base.attributes.items():
+            add_property_methods_for_attribute_if_needed(
+                info, ir, name, attr_rtype, module_name, mapper
+            )
+
+
+def add_property_methods_for_attribute_if_needed(
+    info: TypeInfo,
+    ir: ClassIR,
+    attr_name: str,
+    attr_rtype: RType,
+    module_name: str,
+    mapper: Mapper,
+) -> None:
+    """Add getter and/or setter for attribute if defined as property in a base class.
+
+    Only add declarations. The body IR will be synthesized later during irbuild.
+    """
+    for base in info.mro[1:]:
+        if base in mapper.type_to_ir:
+            n = base.names.get(attr_name)
+            if n is None:
+                continue
+            node = n.node
+            if isinstance(node, Decorator) and node.name not in ir.method_decls:
+                # Defined as a read-only property in base class/trait
+                add_getter_declaration(ir, attr_name, attr_rtype, module_name)
+            elif isinstance(node, OverloadedFuncDef) and is_valid_multipart_property_def(node):
+                # Defined as a read-write property in base class/trait
+                add_getter_declaration(ir, attr_name, attr_rtype, module_name)
+                add_setter_declaration(ir, attr_name, attr_rtype, module_name)
+
+
+def add_getter_declaration(
+    ir: ClassIR, attr_name: str, attr_rtype: RType, module_name: str
+) -> None:
+    self_arg = RuntimeArg("self", RInstance(ir), pos_only=True)
+    sig = FuncSignature([self_arg], attr_rtype)
+    decl = FuncDecl(attr_name, ir.name, module_name, sig, FUNC_NORMAL)
+    decl.is_prop_getter = True
+    decl.implicit = True  # Triggers synthesization
+    ir.method_decls[attr_name] = decl
+    ir.property_types[attr_name] = attr_rtype  # TODO: Needed??
+
+
+def add_setter_declaration(
+    ir: ClassIR, attr_name: str, attr_rtype: RType, module_name: str
+) -> None:
+    self_arg = RuntimeArg("self", RInstance(ir), pos_only=True)
+    value_arg = RuntimeArg("value", attr_rtype, pos_only=True)
+    sig = FuncSignature([self_arg, value_arg], none_rprimitive)
+    setter_name = PROPSET_PREFIX + attr_name
+    decl = FuncDecl(setter_name, ir.name, module_name, sig, FUNC_NORMAL)
+    decl.is_prop_setter = True
+    decl.implicit = True  # Triggers synthesization
+    ir.method_decls[setter_name] = decl
+
+
+def prepare_init_method(cdef: ClassDef, ir: ClassIR, module_name: str, mapper: Mapper) -> None:
     # Set up a constructor decl
     init_node = cdef.info["__init__"].node
     if not ir.is_trait and not ir.builtin_base and isinstance(init_node, FuncDef):
@@ -298,40 +417,6 @@ def prepare_class_def(
         ir.ctor = FuncDecl(cdef.name, None, module_name, ctor_sig)
         mapper.func_to_decl[cdef.info] = ir.ctor
 
-    # Set up the parent class
-    bases = [mapper.type_to_ir[base.type] for base in info.bases if base.type in mapper.type_to_ir]
-    if not all(c.is_trait for c in bases[1:]):
-        errors.error("Non-trait bases must appear first in parent list", path, cdef.line)
-    ir.traits = [c for c in bases if c.is_trait]
-
-    mro = []
-    base_mro = []
-    for cls in info.mro:
-        if cls not in mapper.type_to_ir:
-            if cls.fullname != "builtins.object":
-                ir.inherits_python = True
-            continue
-        base_ir = mapper.type_to_ir[cls]
-        if not base_ir.is_trait:
-            base_mro.append(base_ir)
-        mro.append(base_ir)
-
-        if cls.defn.removed_base_type_exprs or not base_ir.is_ext_class:
-            ir.inherits_python = True
-
-    base_idx = 1 if not ir.is_trait else 0
-    if len(base_mro) > base_idx:
-        ir.base = base_mro[base_idx]
-    ir.mro = mro
-    ir.base_mro = base_mro
-
-    for base in bases:
-        if base.children is not None:
-            base.children.append(ir)
-
-    if is_dataclass(cdef):
-        ir.is_augmented = True
-
 
 def prepare_non_ext_class_def(
     path: str, module_name: str, cdef: ClassDef, errors: Errors, mapper: Mapper
diff --git a/mypyc/irbuild/vtable.py b/mypyc/irbuild/vtable.py
index a02cd622cee1a..13bc4d46e15df 100644
--- a/mypyc/irbuild/vtable.py
+++ b/mypyc/irbuild/vtable.py
@@ -62,7 +62,7 @@ def specialize_parent_vtable(cls: ClassIR, parent: ClassIR) -> VTableEntries:
         # (This may not be the method in the entry, if it was overridden.)
         orig_parent_method = entry.cls.get_method(entry.name)
         assert orig_parent_method
-        method_cls = cls.get_method_and_class(entry.name)
+        method_cls = cls.get_method_and_class(entry.name, prefer_method=True)
         if method_cls:
             child_method, defining_cls = method_cls
             # TODO: emit a wrapper for __init__ that raises or something
diff --git a/mypyc/sametype.py b/mypyc/sametype.py
index 056ed683e5b87..1b811d4e9041e 100644
--- a/mypyc/sametype.py
+++ b/mypyc/sametype.py
@@ -35,7 +35,9 @@ def is_same_method_signature(a: FuncSignature, b: FuncSignature) -> bool:
         len(a.args) == len(b.args)
         and is_same_type(a.ret_type, b.ret_type)
         and all(
-            is_same_type(t1.type, t2.type) and t1.name == t2.name and t1.optional == t2.optional
+            is_same_type(t1.type, t2.type)
+            and ((t1.pos_only and t2.pos_only) or t1.name == t2.name)
+            and t1.optional == t2.optional
             for t1, t2 in zip(a.args[1:], b.args[1:])
         )
     )
diff --git a/mypyc/test-data/run-classes.test b/mypyc/test-data/run-classes.test
index 2af519dc7aa87..92ec3873bf382 100644
--- a/mypyc/test-data/run-classes.test
+++ b/mypyc/test-data/run-classes.test
@@ -1968,6 +1968,188 @@ import other_interpreted
 
 [out]
 
+[case testAttributeOverridesProperty]
+from typing import Any
+from mypy_extensions import trait
+
+@trait
+class T1:
+    @property
+    def x(self) -> int: ...
+    @property
+    def y(self) -> int: ...
+
+class C1(T1):
+    x: int = 1
+    y: int = 4
+
+def test_read_only_property_in_trait_implemented_as_attribute() -> None:
+    c = C1()
+    c.x = 5
+    assert c.x == 5
+    assert c.y == 4
+    c.y = 6
+    assert c.y == 6
+    t: T1 = C1()
+    assert t.y == 4
+    t = c
+    assert t.x == 5
+    assert t.y == 6
+    a: Any = c
+    assert a.x == 5
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
+class B2:
+    @property
+    def x(self) -> int:
+        return 11
+
+    @property
+    def y(self) -> int:
+        return 25
+
+class C2(B2):
+    x: int = 1
+    y: int = 4
+
+def test_read_only_property_in_class_implemented_as_attribute() -> None:
+    c = C2()
+    c.x = 5
+    assert c.x == 5
+    assert c.y == 4
+    c.y = 6
+    assert c.y == 6
+    b: B2 = C2()
+    assert b.y == 4
+    b = c
+    assert b.x == 5
+    assert b.y == 6
+    a: Any = c
+    assert a.x == 5
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
+@trait
+class T3:
+    @property
+    def x(self) -> int: ...
+    @property
+    def y(self) -> int: ...
+
+class B3:
+    x: int = 1
+    y: int = 4
+
+class C3(B3, T3):
+    pass
+
+def test_read_only_property_implemented_as_attribute_indirectly() -> None:
+    c = C3()
+    c.x = 5
+    assert c.x == 5
+    assert c.y == 4
+    c.y = 6
+    assert c.y == 6
+    t: T3 = C3()
+    assert t.y == 4
+    t = c
+    assert t.x == 5
+    assert t.y == 6
+    a: Any = c
+    assert a.x == 5
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
+@trait
+class T4:
+    @property
+    def x(self) -> int: ...
+    @x.setter
+    def x(self, v1: int) -> None: ...
+
+    @property
+    def y(self) -> int: ...
+    @y.setter
+    def y(self, v2: int) -> None: ...
+
+class C4(T4):
+    x: int = 1
+    y: int = 4
+
+def test_read_write_property_implemented_as_attribute() -> None:
+    c = C4()
+    c.x = 5
+    assert c.x == 5
+    assert c.y == 4
+    c.y = 6
+    assert c.y == 6
+    t: T4 = C4()
+    assert t.y == 4
+    t.x = 5
+    assert t.x == 5
+    t.y = 6
+    assert t.y == 6
+    a: Any = c
+    assert a.x == 5
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
+@trait
+class T5:
+    @property
+    def x(self) -> int: ...
+    @x.setter
+    def x(self, v1: int) -> None: ...
+
+    @property
+    def y(self) -> int: ...
+    @y.setter
+    def y(self, v2: int) -> None: ...
+
+class B5:
+    x: int = 1
+    y: int = 4
+
+class BB5(B5):
+    pass
+
+class C5(BB5, T5):
+    pass
+
+def test_read_write_property_indirectly_implemented_as_attribute() -> None:
+    c = C5()
+    c.x = 5
+    assert c.x == 5
+    assert c.y == 4
+    c.y = 6
+    assert c.y == 6
+    t: T5 = C5()
+    assert t.y == 4
+    t.x = 5
+    assert t.x == 5
+    t.y = 6
+    assert t.y == 6
+    a: Any = c
+    assert a.x == 5
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
 [case testSubclassAttributeAccess]
 from mypy_extensions import trait
 
diff --git a/mypyc/test-data/run-i64.test b/mypyc/test-data/run-i64.test
index 893b3f808f24c..f0c664385d7b5 100644
--- a/mypyc/test-data/run-i64.test
+++ b/mypyc/test-data/run-i64.test
@@ -1223,12 +1223,15 @@ def test_many_locals() -> None:
     assert a32 == 55
     assert a33 == 20
 
-[case testI64GlueMethods]
+[case testI64GlueMethodsAndInheritance]
+from typing import Any
 from typing_extensions import Final
 
 MYPY = False
 if MYPY:
-    from mypy_extensions import i64
+    from mypy_extensions import i64, trait
+
+from testutil import assertRaises
 
 MAGIC: Final = -113
 
@@ -1266,3 +1269,64 @@ def test_derived_switches_arg_to_have_default() -> None:
     b: Base = Derived()
     assert b.hoho(5) == 3
     assert b.hoho(MAGIC) == MAGIC - 2
+
+@trait
+class T:
+    @property
+    def x(self) -> i64: ...
+    @property
+    def y(self) -> i64: ...
+
+class C(T):
+    x: i64 = 1
+    y: i64 = 4
+
+def test_read_only_property_in_trait_implemented_as_attribute() -> None:
+    c = C()
+    c.x = 5
+    assert c.x == 5
+    c.x = MAGIC
+    assert c.x == MAGIC
+    assert c.y == 4
+    c.y = 6
+    assert c.y == 6
+    t: T = C()
+    assert t.y == 4
+    t = c
+    assert t.x == MAGIC
+    c.x = 55
+    assert t.x == 55
+    assert t.y == 6
+    a: Any = c
+    assert a.x == 55
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
+class D(T):
+    xx: i64
+
+    @property
+    def x(self) -> i64:
+        return self.xx
+
+    @property
+    def y(self) -> i64:
+        raise TypeError
+
+def test_read_only_property_in_trait_implemented_as_property() -> None:
+    d = D()
+    d.xx = 5
+    assert d.x == 5
+    d.xx = MAGIC
+    assert d.x == MAGIC
+    with assertRaises(TypeError):
+        d.y
+    t: T = d
+    assert t.x == MAGIC
+    d.xx = 6
+    assert t.x == 6
+    with assertRaises(TypeError):
+        t.y

From e96527598a4271e0a8d59c4abb8bde36e927030a Mon Sep 17 00:00:00 2001
From: Tim Geypens <tim.geypens@gmail.com>
Date: Tue, 10 Jan 2023 22:55:21 +0100
Subject: [PATCH 174/231] Don't read scripts without extensions as modules in
 namespace mode (#14335)

The `FindModuleCache` currently matches files without an extension when
`--namespace_packages` is enabled while [the
docs](https://mypy.readthedocs.io/en/stable/running_mypy.html#mapping-file-paths-to-modules)
don't mention that this should be the case. The "near-miss" logic
collects candidates for modules, which could correctly include a
_directory_ `foo/bar/baz` when looking for `foo/bar/baz`. However, the
current logic also picks up a _file_ `foo/bar/baz`. This means that, if
both a file `foo/bar/baz` and `foo/bar/baz.py` exist, the first one is
actually picked, resulting in unexpected behaviour.

The condition that checks `exists_case` on `foo/bar/baz` should also
check that it is indeed a directory by checking that it is not a file.
I'm open to different fixes of course, but this seemed like the most
obvious and least impactful change to make.

This PR modifies 2 tests:
* add `test-data/packages/modulefinder/pkg1/a` to verify that
`ModuleFinderSuite.test__no_namespace_packages__find_a_in_pkg1` is
indeed working correctly even without the patch because it's not running
in namespace mode.
* add `test-data/packages/modulefinder/nsx-pkg3/nsx/c/c`, making
`ModuleFinderSuite.test__find_nsx_c_c_in_pkg3` fail, which the patch
fixes.

To give one real-world example of this scenario: Bazel's Python rules
construct a wrapper-script with the same name as the main Python-file
without the extension for a `py_binary`-target. If some other Python
rule depends on this `//foo/bar:baz` `py_binary`-target, it sees both
`foo/bar/baz` and `foo/bar/baz.py` in the same directory, incorrectly
picking up the wrapper-script instead of the module. Dependencies on a
`py_binary` might be a bit of an edge-case, but Python execution of
these targets does pick up the right file, so Mypy should probably as
well.
---
 mypy/modulefinder.py                             | 6 +++++-
 test-data/packages/modulefinder/nsx-pkg3/nsx/c/c | 0
 test-data/packages/modulefinder/pkg1/a           | 0
 3 files changed, 5 insertions(+), 1 deletion(-)
 create mode 100644 test-data/packages/modulefinder/nsx-pkg3/nsx/c/c
 create mode 100644 test-data/packages/modulefinder/pkg1/a

diff --git a/mypy/modulefinder.py b/mypy/modulefinder.py
index b2abb4847705b..265d76ed5bb64 100644
--- a/mypy/modulefinder.py
+++ b/mypy/modulefinder.py
@@ -507,7 +507,11 @@ def _find_module(self, id: str, use_typeshed: bool) -> ModuleSearchResult:
 
             # In namespace mode, register a potential namespace package
             if self.options and self.options.namespace_packages:
-                if fscache.exists_case(base_path, dir_prefix) and not has_init:
+                if (
+                    not has_init
+                    and fscache.exists_case(base_path, dir_prefix)
+                    and not fscache.isfile_case(base_path, dir_prefix)
+                ):
                     near_misses.append((base_path, dir_prefix))
 
             # No package, look for module.
diff --git a/test-data/packages/modulefinder/nsx-pkg3/nsx/c/c b/test-data/packages/modulefinder/nsx-pkg3/nsx/c/c
new file mode 100644
index 0000000000000..e69de29bb2d1d
diff --git a/test-data/packages/modulefinder/pkg1/a b/test-data/packages/modulefinder/pkg1/a
new file mode 100644
index 0000000000000..e69de29bb2d1d

From 13e6617448ed5619c8b3512c5eed302f6d9f0f5b Mon Sep 17 00:00:00 2001
From: Anders Kaseorg <andersk@mit.edu>
Date: Tue, 10 Jan 2023 19:25:42 -0500
Subject: [PATCH 175/231] =?UTF-8?q?Move=20truthy-function=20docs=20from=20?=
 =?UTF-8?q?=E2=80=9Coptional=20checks=E2=80=9D=20to=20=E2=80=9Cenabled=20b?=
 =?UTF-8?q?y=20default=E2=80=9D=20(#14380)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This error was enabled by default since its introduction (#13686);
document it in the correct section.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
---
 docs/source/error_code_list.rst  | 13 +++++++++++++
 docs/source/error_code_list2.rst | 13 -------------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/docs/source/error_code_list.rst b/docs/source/error_code_list.rst
index 264badc031075..1a39bf8feb6cb 100644
--- a/docs/source/error_code_list.rst
+++ b/docs/source/error_code_list.rst
@@ -764,6 +764,19 @@ the provided type.
 
    assert_type([1], list[str])  # Error
 
+Check that function isn't used in boolean context [truthy-function]
+-------------------------------------------------------------------
+
+Functions will always evaluate to true in boolean contexts.
+
+.. code-block:: python
+
+    def f():
+        ...
+
+    if f:  # Error: Function "Callable[[], Any]" could always be true in boolean context  [truthy-function]
+        pass
+
 Report syntax errors [syntax]
 -----------------------------
 
diff --git a/docs/source/error_code_list2.rst b/docs/source/error_code_list2.rst
index 0cf96ba9c2e79..85ab76da5cee7 100644
--- a/docs/source/error_code_list2.rst
+++ b/docs/source/error_code_list2.rst
@@ -275,19 +275,6 @@ what the author might have intended. Of course it's possible that ``transform``
 and so there is no error in practice. In such case, it is recommended to annotate ``items: Collection[int]``.
 
 
-Check that function isn't used in boolean context [truthy-function]
--------------------------------------------------------------------
-
-Functions will always evaluate to true in boolean contexts.
-
-.. code-block:: python
-
-    def f():
-        ...
-
-    if f:  # Error: Function "Callable[[], Any]" could always be true in boolean context  [truthy-function]
-        pass
-
 .. _ignore-without-code:
 
 Check that ``# type: ignore`` include an error code [ignore-without-code]

From c4a5f5620763dcfe2b95847806a889d560e2aa51 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 11 Jan 2023 17:23:13 +0000
Subject: [PATCH 176/231] [mypyc] Faster bool and integer conversions (#14422)

Speed up various conversions between bool and integer types. These cases
are covered:
* `bool(x)` for various types
* `int(x)` for `bool` and integer arguments
* Implicit coercion from `bool` to an integer type

Support both regular `int` values and native int values.

(Various small optimizations, including these, together netted a 6%
performance improvement in self check.)
---
 mypyc/irbuild/ll_builder.py        |  93 ++++++++++++++-----
 mypyc/irbuild/specialize.py        |  28 ++++++
 mypyc/test-data/irbuild-basic.test |  34 ++++---
 mypyc/test-data/irbuild-bool.test  | 144 +++++++++++++++++++++++++++++
 mypyc/test-data/irbuild-i64.test   |  26 ++++++
 mypyc/test-data/irbuild-int.test   |  19 ++++
 mypyc/test-data/run-bools.test     |  57 ++++++++++--
 mypyc/test-data/run-i64.test       |  41 ++++++++
 mypyc/test-data/run-integers.test  |  24 +++++
 mypyc/test-data/run-strings.test   |   5 +
 mypyc/test/test_irbuild.py         |   1 +
 11 files changed, 431 insertions(+), 41 deletions(-)
 create mode 100644 mypyc/test-data/irbuild-bool.test

diff --git a/mypyc/irbuild/ll_builder.py b/mypyc/irbuild/ll_builder.py
index 88b35a95c08ca..019f709f0acc4 100644
--- a/mypyc/irbuild/ll_builder.py
+++ b/mypyc/irbuild/ll_builder.py
@@ -326,6 +326,17 @@ def coerce(
             ):
                 # Equivalent types
                 return src
+            elif (
+                is_bool_rprimitive(src_type) or is_bit_rprimitive(src_type)
+            ) and is_int_rprimitive(target_type):
+                shifted = self.int_op(
+                    bool_rprimitive, src, Integer(1, bool_rprimitive), IntOp.LEFT_SHIFT
+                )
+                return self.add(Extend(shifted, int_rprimitive, signed=False))
+            elif (
+                is_bool_rprimitive(src_type) or is_bit_rprimitive(src_type)
+            ) and is_fixed_width_rtype(target_type):
+                return self.add(Extend(src, target_type, signed=False))
             else:
                 # To go from one unboxed type to another, we go through a boxed
                 # in-between value, for simplicity.
@@ -1642,35 +1653,38 @@ def shortcircuit_helper(
         self.activate_block(next_block)
         return target
 
-    def add_bool_branch(self, value: Value, true: BasicBlock, false: BasicBlock) -> None:
-        if is_runtime_subtype(value.type, int_rprimitive):
+    def bool_value(self, value: Value) -> Value:
+        """Return bool(value).
+
+        The result type can be bit_rprimitive or bool_rprimitive.
+        """
+        if is_bool_rprimitive(value.type) or is_bit_rprimitive(value.type):
+            result = value
+        elif is_runtime_subtype(value.type, int_rprimitive):
             zero = Integer(0, short_int_rprimitive)
-            self.compare_tagged_condition(value, zero, "!=", true, false, value.line)
-            return
+            result = self.comparison_op(value, zero, ComparisonOp.NEQ, value.line)
         elif is_fixed_width_rtype(value.type):
             zero = Integer(0, value.type)
-            value = self.add(ComparisonOp(value, zero, ComparisonOp.NEQ))
+            result = self.add(ComparisonOp(value, zero, ComparisonOp.NEQ))
         elif is_same_type(value.type, str_rprimitive):
-            value = self.call_c(str_check_if_true, [value], value.line)
+            result = self.call_c(str_check_if_true, [value], value.line)
         elif is_same_type(value.type, list_rprimitive) or is_same_type(
             value.type, dict_rprimitive
         ):
             length = self.builtin_len(value, value.line)
             zero = Integer(0)
-            value = self.binary_op(length, zero, "!=", value.line)
+            result = self.binary_op(length, zero, "!=", value.line)
         elif (
             isinstance(value.type, RInstance)
             and value.type.class_ir.is_ext_class
             and value.type.class_ir.has_method("__bool__")
         ):
             # Directly call the __bool__ method on classes that have it.
-            value = self.gen_method_call(value, "__bool__", [], bool_rprimitive, value.line)
+            result = self.gen_method_call(value, "__bool__", [], bool_rprimitive, value.line)
         else:
             value_type = optional_value_type(value.type)
             if value_type is not None:
-                is_none = self.translate_is_op(value, self.none_object(), "is not", value.line)
-                branch = Branch(is_none, true, false, Branch.BOOL)
-                self.add(branch)
+                not_none = self.translate_is_op(value, self.none_object(), "is not", value.line)
                 always_truthy = False
                 if isinstance(value_type, RInstance):
                     # check whether X.__bool__ is always just the default (object.__bool__)
@@ -1679,18 +1693,55 @@ def add_bool_branch(self, value: Value, true: BasicBlock, false: BasicBlock) ->
                     ) and value_type.class_ir.is_method_final("__bool__"):
                         always_truthy = True
 
-                if not always_truthy:
-                    # Optional[X] where X may be falsey and requires a check
-                    branch.true = BasicBlock()
-                    self.activate_block(branch.true)
+                if always_truthy:
+                    result = not_none
+                else:
+                    # "X | None" where X may be falsey and requires a check
+                    result = Register(bit_rprimitive)
+                    true, false, end = BasicBlock(), BasicBlock(), BasicBlock()
+                    branch = Branch(not_none, true, false, Branch.BOOL)
+                    self.add(branch)
+                    self.activate_block(true)
                     # unbox_or_cast instead of coerce because we want the
                     # type to change even if it is a subtype.
                     remaining = self.unbox_or_cast(value, value_type, value.line)
-                    self.add_bool_branch(remaining, true, false)
-                return
-            elif not is_bool_rprimitive(value.type) and not is_bit_rprimitive(value.type):
-                value = self.call_c(bool_op, [value], value.line)
-        self.add(Branch(value, true, false, Branch.BOOL))
+                    as_bool = self.bool_value(remaining)
+                    self.add(Assign(result, as_bool))
+                    self.goto(end)
+                    self.activate_block(false)
+                    self.add(Assign(result, Integer(0, bit_rprimitive)))
+                    self.goto(end)
+                    self.activate_block(end)
+            else:
+                result = self.call_c(bool_op, [value], value.line)
+        return result
+
+    def add_bool_branch(self, value: Value, true: BasicBlock, false: BasicBlock) -> None:
+        opt_value_type = optional_value_type(value.type)
+        if opt_value_type is None:
+            bool_value = self.bool_value(value)
+            self.add(Branch(bool_value, true, false, Branch.BOOL))
+        else:
+            # Special-case optional types
+            is_none = self.translate_is_op(value, self.none_object(), "is not", value.line)
+            branch = Branch(is_none, true, false, Branch.BOOL)
+            self.add(branch)
+            always_truthy = False
+            if isinstance(opt_value_type, RInstance):
+                # check whether X.__bool__ is always just the default (object.__bool__)
+                if not opt_value_type.class_ir.has_method(
+                    "__bool__"
+                ) and opt_value_type.class_ir.is_method_final("__bool__"):
+                    always_truthy = True
+
+            if not always_truthy:
+                # Optional[X] where X may be falsey and requires a check
+                branch.true = BasicBlock()
+                self.activate_block(branch.true)
+                # unbox_or_cast instead of coerce because we want the
+                # type to change even if it is a subtype.
+                remaining = self.unbox_or_cast(value, opt_value_type, value.line)
+                self.add_bool_branch(remaining, true, false)
 
     def call_c(
         self,
@@ -1795,7 +1846,7 @@ def matching_call_c(
             return target
         return None
 
-    def int_op(self, type: RType, lhs: Value, rhs: Value, op: int, line: int) -> Value:
+    def int_op(self, type: RType, lhs: Value, rhs: Value, op: int, line: int = -1) -> Value:
         """Generate a native integer binary op.
 
         Use native/C semantics, which sometimes differ from Python
diff --git a/mypyc/irbuild/specialize.py b/mypyc/irbuild/specialize.py
index 5810482cd43d3..06babd2f7e1a9 100644
--- a/mypyc/irbuild/specialize.py
+++ b/mypyc/irbuild/specialize.py
@@ -51,7 +51,10 @@
     dict_rprimitive,
     int32_rprimitive,
     int64_rprimitive,
+    int_rprimitive,
+    is_bool_rprimitive,
     is_dict_rprimitive,
+    is_fixed_width_rtype,
     is_int32_rprimitive,
     is_int64_rprimitive,
     is_int_rprimitive,
@@ -688,3 +691,28 @@ def translate_i32(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value
         val = builder.accept(arg)
         return builder.coerce(val, int32_rprimitive, expr.line)
     return None
+
+
+@specialize_function("builtins.int")
+def translate_int(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value | None:
+    if len(expr.args) != 1 or expr.arg_kinds[0] != ARG_POS:
+        return None
+    arg = expr.args[0]
+    arg_type = builder.node_type(arg)
+    if (
+        is_bool_rprimitive(arg_type)
+        or is_int_rprimitive(arg_type)
+        or is_fixed_width_rtype(arg_type)
+    ):
+        src = builder.accept(arg)
+        return builder.coerce(src, int_rprimitive, expr.line)
+    return None
+
+
+@specialize_function("builtins.bool")
+def translate_bool(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value | None:
+    if len(expr.args) != 1 or expr.arg_kinds[0] != ARG_POS:
+        return None
+    arg = expr.args[0]
+    src = builder.accept(arg)
+    return builder.builder.bool_value(src)
diff --git a/mypyc/test-data/irbuild-basic.test b/mypyc/test-data/irbuild-basic.test
index f72720e59b180..a06977d037b20 100644
--- a/mypyc/test-data/irbuild-basic.test
+++ b/mypyc/test-data/irbuild-basic.test
@@ -1108,7 +1108,9 @@ L0:
     return 1
 
 [case testCallableTypes]
-from typing import Callable
+from typing import Callable, Any
+from m import f
+
 def absolute_value(x: int) -> int:
     return x if x > 0 else -x
 
@@ -1116,7 +1118,7 @@ def call_native_function(x: int) -> int:
     return absolute_value(x)
 
 def call_python_function(x: int) -> int:
-    return int(x)
+    return f(x)
 
 def return_float() -> float:
     return 5.0
@@ -1127,6 +1129,9 @@ def return_callable_type() -> Callable[[], float]:
 def call_callable_type() -> float:
     f = return_callable_type()
     return f()
+[file m.py]
+def f(x: int) -> int:
+    return x
 [out]
 def absolute_value(x):
     x :: int
@@ -1158,14 +1163,18 @@ L0:
     return r0
 def call_python_function(x):
     x :: int
-    r0, r1, r2 :: object
-    r3 :: int
+    r0 :: dict
+    r1 :: str
+    r2, r3, r4 :: object
+    r5 :: int
 L0:
-    r0 = load_address PyLong_Type
-    r1 = box(int, x)
-    r2 = PyObject_CallFunctionObjArgs(r0, r1, 0)
-    r3 = unbox(int, r2)
-    return r3
+    r0 = __main__.globals :: static
+    r1 = 'f'
+    r2 = CPyDict_GetItem(r0, r1)
+    r3 = box(int, x)
+    r4 = PyObject_CallFunctionObjArgs(r2, r3, 0)
+    r5 = unbox(int, r4)
+    return r5
 def return_float():
     r0 :: float
 L0:
@@ -3068,8 +3077,7 @@ def call_sum(l, comparison):
     r1, r2 :: object
     r3, x :: int
     r4, r5 :: object
-    r6 :: bool
-    r7 :: object
+    r6, r7 :: bool
     r8, r9 :: int
     r10 :: bit
 L0:
@@ -3084,8 +3092,8 @@ L2:
     r4 = box(int, x)
     r5 = PyObject_CallFunctionObjArgs(comparison, r4, 0)
     r6 = unbox(bool, r5)
-    r7 = box(bool, r6)
-    r8 = unbox(int, r7)
+    r7 = r6 << 1
+    r8 = extend r7: builtins.bool to builtins.int
     r9 = CPyTagged_Add(r0, r8)
     r0 = r9
 L3:
diff --git a/mypyc/test-data/irbuild-bool.test b/mypyc/test-data/irbuild-bool.test
new file mode 100644
index 0000000000000..407ab8bcda935
--- /dev/null
+++ b/mypyc/test-data/irbuild-bool.test
@@ -0,0 +1,144 @@
+[case testBoolToAndFromInt]
+from mypy_extensions import i64
+
+def bool_to_int(b: bool) -> int:
+    return b
+def int_to_bool(n: int) -> bool:
+    return bool(n)
+def bool_to_i64(b: bool) -> i64:
+    return b
+def i64_to_bool(n: i64) -> bool:
+    return bool(n)
+def bit_to_int(n1: i64, n2: i64) -> int:
+    return bool(n1 == n2)
+def bit_to_i64(n1: i64, n2: i64) -> i64:
+    return bool(n1 == n2)
+[out]
+def bool_to_int(b):
+    b, r0 :: bool
+    r1 :: int
+L0:
+    r0 = b << 1
+    r1 = extend r0: builtins.bool to builtins.int
+    return r1
+def int_to_bool(n):
+    n :: int
+    r0 :: bit
+L0:
+    r0 = n != 0
+    return r0
+def bool_to_i64(b):
+    b :: bool
+    r0 :: int64
+L0:
+    r0 = extend b: builtins.bool to int64
+    return r0
+def i64_to_bool(n):
+    n :: int64
+    r0 :: bit
+L0:
+    r0 = n != 0
+    return r0
+def bit_to_int(n1, n2):
+    n1, n2 :: int64
+    r0 :: bit
+    r1 :: bool
+    r2 :: int
+L0:
+    r0 = n1 == n2
+    r1 = r0 << 1
+    r2 = extend r1: builtins.bool to builtins.int
+    return r2
+def bit_to_i64(n1, n2):
+    n1, n2 :: int64
+    r0 :: bit
+    r1 :: int64
+L0:
+    r0 = n1 == n2
+    r1 = extend r0: bit to int64
+    return r1
+
+[case testConversionToBool]
+from typing import List, Optional
+
+class C: pass
+class D:
+    def __bool__(self) -> bool:
+        return True
+
+def list_to_bool(l: List[str]) -> bool:
+    return bool(l)
+
+def always_truthy_instance_to_bool(o: C) -> bool:
+    return bool(o)
+
+def instance_to_bool(o: D) -> bool:
+    return bool(o)
+
+def optional_truthy_to_bool(o: Optional[C]) -> bool:
+    return bool(o)
+
+def optional_maybe_falsey_to_bool(o: Optional[D]) -> bool:
+    return bool(o)
+[out]
+def D.__bool__(self):
+    self :: __main__.D
+L0:
+    return 1
+def list_to_bool(l):
+    l :: list
+    r0 :: ptr
+    r1 :: native_int
+    r2 :: short_int
+    r3 :: bit
+L0:
+    r0 = get_element_ptr l ob_size :: PyVarObject
+    r1 = load_mem r0 :: native_int*
+    keep_alive l
+    r2 = r1 << 1
+    r3 = r2 != 0
+    return r3
+def always_truthy_instance_to_bool(o):
+    o :: __main__.C
+    r0 :: int32
+    r1 :: bit
+    r2 :: bool
+L0:
+    r0 = PyObject_IsTrue(o)
+    r1 = r0 >= 0 :: signed
+    r2 = truncate r0: int32 to builtins.bool
+    return r2
+def instance_to_bool(o):
+    o :: __main__.D
+    r0 :: bool
+L0:
+    r0 = o.__bool__()
+    return r0
+def optional_truthy_to_bool(o):
+    o :: union[__main__.C, None]
+    r0 :: object
+    r1 :: bit
+L0:
+    r0 = load_address _Py_NoneStruct
+    r1 = o != r0
+    return r1
+def optional_maybe_falsey_to_bool(o):
+    o :: union[__main__.D, None]
+    r0 :: object
+    r1 :: bit
+    r2 :: __main__.D
+    r3 :: bool
+    r4 :: bit
+L0:
+    r0 = load_address _Py_NoneStruct
+    r1 = o != r0
+    if r1 goto L1 else goto L2 :: bool
+L1:
+    r2 = cast(__main__.D, o)
+    r3 = r2.__bool__()
+    r4 = r3
+    goto L3
+L2:
+    r4 = 0
+L3:
+    return r4
diff --git a/mypyc/test-data/irbuild-i64.test b/mypyc/test-data/irbuild-i64.test
index 9c942ea752193..c6b62996bc808 100644
--- a/mypyc/test-data/irbuild-i64.test
+++ b/mypyc/test-data/irbuild-i64.test
@@ -1559,6 +1559,32 @@ L2:
 L3:
     return r3
 
+[case testI64ExplicitConversionToInt_64bit]
+from mypy_extensions import i64
+
+def f(x: i64) -> int:
+    return int(x)
+[out]
+def f(x):
+    x :: int64
+    r0, r1 :: bit
+    r2, r3, r4 :: int
+L0:
+    r0 = x <= 4611686018427387903 :: signed
+    if r0 goto L1 else goto L2 :: bool
+L1:
+    r1 = x >= -4611686018427387904 :: signed
+    if r1 goto L3 else goto L2 :: bool
+L2:
+    r2 = CPyTagged_FromInt64(x)
+    r3 = r2
+    goto L4
+L3:
+    r4 = x << 1
+    r3 = r4
+L4:
+    return r3
+
 [case testI64ExplicitConversionFromLiteral]
 from mypy_extensions import i64
 
diff --git a/mypyc/test-data/irbuild-int.test b/mypyc/test-data/irbuild-int.test
index e193c16ef979d..aebadce5650e7 100644
--- a/mypyc/test-data/irbuild-int.test
+++ b/mypyc/test-data/irbuild-int.test
@@ -203,3 +203,22 @@ L0:
 def f5():
 L0:
     return -2
+
+[case testConvertIntegralToInt]
+def bool_to_int(b: bool) -> int:
+    return int(b)
+
+def int_to_int(n: int) -> int:
+    return int(n)
+[out]
+def bool_to_int(b):
+    b, r0 :: bool
+    r1 :: int
+L0:
+    r0 = b << 1
+    r1 = extend r0: builtins.bool to builtins.int
+    return r1
+def int_to_int(n):
+    n :: int
+L0:
+    return n
diff --git a/mypyc/test-data/run-bools.test b/mypyc/test-data/run-bools.test
index a7afc5f2b1a22..e23b35d82fc57 100644
--- a/mypyc/test-data/run-bools.test
+++ b/mypyc/test-data/run-bools.test
@@ -15,6 +15,8 @@ True
 False
 
 [case testBoolOps]
+from typing import Optional, Any
+
 def f(x: bool) -> bool:
     if x:
         return False
@@ -27,8 +29,8 @@ def test_if() -> None:
 
 def test_bitwise_and() -> None:
     # Use eval() to avoid constand folding
-    t = eval('True')  # type: bool
-    f = eval('False')  # type: bool
+    t: bool = eval('True')
+    f: bool = eval('False')
     assert t & t == True
     assert t & f == False
     assert f & t == False
@@ -40,8 +42,8 @@ def test_bitwise_and() -> None:
 
 def test_bitwise_or() -> None:
     # Use eval() to avoid constand folding
-    t = eval('True')  # type: bool
-    f = eval('False')  # type: bool
+    t: bool = eval('True')
+    f: bool = eval('False')
     assert t | t == True
     assert t | f == True
     assert f | t == True
@@ -53,8 +55,8 @@ def test_bitwise_or() -> None:
 
 def test_bitwise_xor() -> None:
     # Use eval() to avoid constand folding
-    t = eval('True')  # type: bool
-    f = eval('False')  # type: bool
+    t: bool = eval('True')
+    f: bool = eval('False')
     assert t ^ t == False
     assert t ^ f == True
     assert f ^ t == True
@@ -66,7 +68,6 @@ def test_bitwise_xor() -> None:
     f ^= f
     assert f == False
 
-[case testIsinstanceBool]
 def test_isinstance_bool() -> None:
     a = True
     b = 1.0
@@ -76,3 +77,45 @@ def test_isinstance_bool() -> None:
     assert isinstance(b, bool) == False
     assert isinstance(c, bool) == False
     assert isinstance(d, bool) == True
+
+class C: pass
+class D:
+    def __init__(self, b: bool) -> None:
+        self.b = b
+
+    def __bool__(self) -> bool:
+        return self.b
+
+class E: pass
+class F(E):
+    def __init__(self, b: bool) -> None:
+        self.b = b
+
+    def __bool__(self) -> bool:
+        return self.b
+
+def optional_to_bool1(o: Optional[C]) -> bool:
+    return bool(o)
+
+def optional_to_bool2(o: Optional[D]) -> bool:
+    return bool(o)
+
+def optional_to_bool3(o: Optional[E]) -> bool:
+    return bool(o)
+
+def test_optional_to_bool() -> None:
+    assert not optional_to_bool1(None)
+    assert optional_to_bool1(C())
+    assert not optional_to_bool2(None)
+    assert not optional_to_bool2(D(False))
+    assert optional_to_bool2(D(True))
+    assert not optional_to_bool3(None)
+    assert optional_to_bool3(E())
+    assert not optional_to_bool3(F(False))
+    assert optional_to_bool3(F(True))
+
+def test_any_to_bool() -> None:
+    a: Any = int()
+    b: Any = a + 1
+    assert not bool(a)
+    assert bool(b)
diff --git a/mypyc/test-data/run-i64.test b/mypyc/test-data/run-i64.test
index f0c664385d7b5..c2a218156e663 100644
--- a/mypyc/test-data/run-i64.test
+++ b/mypyc/test-data/run-i64.test
@@ -62,6 +62,37 @@ def test_comparisons() -> None:
     assert one != two
     assert not (one != one2)
 
+def is_true(x: i64) -> bool:
+    if x:
+        return True
+    else:
+        return False
+
+def is_true2(x: i64) -> bool:
+    return bool(x)
+
+def is_false(x: i64) -> bool:
+    if not x:
+        return True
+    else:
+        return False
+
+def test_i64_as_bool() -> None:
+    assert not is_true(0)
+    assert not is_true2(0)
+    assert is_false(0)
+    for x in 1, 55, -1, -7, 1 << 40, -(1 << 50):
+        assert is_true(x)
+        assert is_true2(x)
+        assert not is_false(x)
+
+def bool_as_i64(b: bool) -> i64:
+    return b
+
+def test_bool_as_i64() -> None:
+    assert bool_as_i64(False) == 0
+    assert bool_as_i64(True) == 1
+
 def div_by_3(x: i64) -> i64:
     return x // 3
 
@@ -229,6 +260,16 @@ def test_coerce_to_and_from_int() -> None:
                     m: int = x
                     assert m == n
 
+def test_coerce_to_and_from_int2() -> None:
+    for shift in range(0, 64):
+        for sign in 1, -1:
+            for delta in range(-5, 5):
+                n = sign * (1 << shift) + delta
+                if -(1 << 63) <= n < (1 << 63):
+                    x: i64 = i64(n)
+                    m: int = int(x)
+                    assert m == n
+
 def test_explicit_conversion_to_i64() -> None:
     x = i64(5)
     assert x == 5
diff --git a/mypyc/test-data/run-integers.test b/mypyc/test-data/run-integers.test
index 74e7cd6b8fb74..c65f36110b46a 100644
--- a/mypyc/test-data/run-integers.test
+++ b/mypyc/test-data/run-integers.test
@@ -353,6 +353,9 @@ def is_true(x: int) -> bool:
     else:
         return False
 
+def is_true2(x: int) -> bool:
+    return bool(x)
+
 def is_false(x: int) -> bool:
     if not x:
         return True
@@ -361,11 +364,32 @@ def is_false(x: int) -> bool:
 
 def test_int_as_bool() -> None:
     assert not is_true(0)
+    assert not is_true2(0)
     assert is_false(0)
     for x in 1, 55, -1, -7, 1 << 50, 1 << 101, -(1 << 50), -(1 << 101):
         assert is_true(x)
+        assert is_true2(x)
         assert not is_false(x)
 
+def bool_as_int(b: bool) -> int:
+    return b
+
+def bool_as_int2(b: bool) -> int:
+    return int(b)
+
+def test_bool_as_int() -> None:
+    assert bool_as_int(False) == 0
+    assert bool_as_int(True) == 1
+    assert bool_as_int2(False) == 0
+    assert bool_as_int2(True) == 1
+
+def no_op_conversion(n: int) -> int:
+    return int(n)
+
+def test_no_op_conversion() -> None:
+    for x in 1, 55, -1, -7, 1 << 50, 1 << 101, -(1 << 50), -(1 << 101):
+        assert no_op_conversion(x) == x
+
 def test_divide() -> None:
     for x in range(-100, 100):
         for y in range(-100, 100):
diff --git a/mypyc/test-data/run-strings.test b/mypyc/test-data/run-strings.test
index c2b010bdb2bdc..4a20c13ce7899 100644
--- a/mypyc/test-data/run-strings.test
+++ b/mypyc/test-data/run-strings.test
@@ -136,6 +136,9 @@ def is_true(x: str) -> bool:
     else:
         return False
 
+def is_true2(x: str) -> bool:
+    return bool(x)
+
 def is_false(x: str) -> bool:
     if not x:
         return True
@@ -145,8 +148,10 @@ def is_false(x: str) -> bool:
 def test_str_to_bool() -> None:
     assert is_false('')
     assert not is_true('')
+    assert not is_true2('')
     for x in 'a', 'foo', 'bar', 'some string':
         assert is_true(x)
+        assert is_true2(x)
         assert not is_false(x)
 
 def test_str_min_max() -> None:
diff --git a/mypyc/test/test_irbuild.py b/mypyc/test/test_irbuild.py
index 8928f94d62110..cb5e690eed55d 100644
--- a/mypyc/test/test_irbuild.py
+++ b/mypyc/test/test_irbuild.py
@@ -24,6 +24,7 @@
 files = [
     "irbuild-basic.test",
     "irbuild-int.test",
+    "irbuild-bool.test",
     "irbuild-lists.test",
     "irbuild-tuple.test",
     "irbuild-dict.test",

From 3ba22ee43ed8c07667521bf8e97910041d4b31c1 Mon Sep 17 00:00:00 2001
From: Richard Si <sichard26@gmail.com>
Date: Fri, 13 Jan 2023 03:23:59 -0500
Subject: [PATCH 177/231] Use class-based NamedTuples in mypyc (#14442)

---
 mypyc/ir/class_ir.py         |  9 +++++----
 mypyc/ir/ops.py              |  6 +++---
 mypyc/primitives/int_ops.py  | 14 +++++--------
 mypyc/primitives/registry.py | 38 +++++++++++++++++-------------------
 4 files changed, 31 insertions(+), 36 deletions(-)

diff --git a/mypyc/ir/class_ir.py b/mypyc/ir/class_ir.py
index 71d61c3f0efa3..9b73eea3f8e6f 100644
--- a/mypyc/ir/class_ir.py
+++ b/mypyc/ir/class_ir.py
@@ -69,10 +69,11 @@
 # placed in the class's shadow vtable (if it has one).
 
 
-VTableMethod = NamedTuple(
-    "VTableMethod",
-    [("cls", "ClassIR"), ("name", str), ("method", FuncIR), ("shadow_method", Optional[FuncIR])],
-)
+class VTableMethod(NamedTuple):
+    cls: "ClassIR"
+    name: str
+    method: FuncIR
+    shadow_method: Optional[FuncIR]
 
 
 VTableEntries = List[VTableMethod]
diff --git a/mypyc/ir/ops.py b/mypyc/ir/ops.py
index cc6f542c3e234..51a0bffcf3f17 100644
--- a/mypyc/ir/ops.py
+++ b/mypyc/ir/ops.py
@@ -1450,6 +1450,6 @@ def visit_keep_alive(self, op: KeepAlive) -> T:
 #
 # (Serialization and deserialization *will* be used for incremental
 # compilation but so far it is not hooked up to anything.)
-DeserMaps = NamedTuple(
-    "DeserMaps", [("classes", Dict[str, "ClassIR"]), ("functions", Dict[str, "FuncIR"])]
-)
+class DeserMaps(NamedTuple):
+    classes: Dict[str, "ClassIR"]
+    functions: Dict[str, "FuncIR"]
diff --git a/mypyc/primitives/int_ops.py b/mypyc/primitives/int_ops.py
index 55ef16ef54662..382bceb217f47 100644
--- a/mypyc/primitives/int_ops.py
+++ b/mypyc/primitives/int_ops.py
@@ -160,15 +160,11 @@ def int_unary_op(name: str, c_function_name: str) -> CFunctionDescription:
 #   c_func_description: the C function to call when operands are tagged integers
 #   c_func_negated: whether to negate the C function call's result
 #   c_func_swap_operands: whether to swap lhs and rhs when call the function
-IntComparisonOpDescription = NamedTuple(
-    "IntComparisonOpDescription",
-    [
-        ("binary_op_variant", int),
-        ("c_func_description", CFunctionDescription),
-        ("c_func_negated", bool),
-        ("c_func_swap_operands", bool),
-    ],
-)
+class IntComparisonOpDescription(NamedTuple):
+    binary_op_variant: int
+    c_func_description: CFunctionDescription
+    c_func_negated: bool
+    c_func_swap_operands: bool
 
 
 # Equals operation on two boxed tagged integers
diff --git a/mypyc/primitives/registry.py b/mypyc/primitives/registry.py
index d7d171b72ccaa..1e2cf2695ee7c 100644
--- a/mypyc/primitives/registry.py
+++ b/mypyc/primitives/registry.py
@@ -47,29 +47,27 @@
 # is only used for primitives. We translate it away during IR building.
 ERR_NEG_INT: Final = 10
 
-CFunctionDescription = NamedTuple(
-    "CFunctionDescription",
-    [
-        ("name", str),
-        ("arg_types", List[RType]),
-        ("return_type", RType),
-        ("var_arg_type", Optional[RType]),
-        ("truncated_type", Optional[RType]),
-        ("c_function_name", str),
-        ("error_kind", int),
-        ("steals", StealsDescription),
-        ("is_borrowed", bool),
-        ("ordering", Optional[List[int]]),
-        ("extra_int_constants", List[Tuple[int, RType]]),
-        ("priority", int),
-    ],
-)
+
+class CFunctionDescription(NamedTuple):
+    name: str
+    arg_types: List[RType]
+    return_type: RType
+    var_arg_type: Optional[RType]
+    truncated_type: Optional[RType]
+    c_function_name: str
+    error_kind: int
+    steals: StealsDescription
+    is_borrowed: bool
+    ordering: Optional[List[int]]
+    extra_int_constants: List[Tuple[int, RType]]
+    priority: int
 
 
 # A description for C load operations including LoadGlobal and LoadAddress
-LoadAddressDescription = NamedTuple(
-    "LoadAddressDescription", [("name", str), ("type", RType), ("src", str)]
-)  # name of the target to load
+class LoadAddressDescription(NamedTuple):
+    name: str
+    type: RType
+    src: str  # name of the target to load
 
 
 # CallC op for method call(such as 'str.join')

From 87bb1dc912c9fcc449206728d6ca37afb7deb0bd Mon Sep 17 00:00:00 2001
From: KotlinIsland <65446343+KotlinIsland@users.noreply.github.com>
Date: Fri, 13 Jan 2023 19:45:40 +1000
Subject: [PATCH 178/231] =?UTF-8?q?(=F0=9F=94=BC)=20update=20dependencies?=
 =?UTF-8?q?=20(#14433)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

update black and isort, but not flake8, it requires python 3.8

Co-authored-by: KotlinIsland <kotlinisland@users.noreply.github.com>
---
 .pre-commit-config.yaml | 8 ++++----
 test-requirements.txt   | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index af1bb320be6d9..0de686b7eb011 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,10 +1,10 @@
 repos:
   - repo: https://github.com/psf/black
-    rev: 22.10.0  # must match test-requirements.txt
+    rev: 22.12.0  # must match test-requirements.txt
     hooks:
       - id: black
   - repo: https://github.com/pycqa/isort
-    rev: 5.10.1  # must match test-requirements.txt
+    rev: 5.11.4  # must match test-requirements.txt
     hooks:
       - id: isort
   - repo: https://github.com/pycqa/flake8
@@ -12,5 +12,5 @@ repos:
     hooks:
       - id: flake8
         additional_dependencies:
-          - flake8-bugbear==22.9.23  # must match test-requirements.txt
-          - flake8-noqa==1.2.9       # must match test-requirements.txt
+          - flake8-bugbear==22.12.6  # must match test-requirements.txt
+          - flake8-noqa==1.3.0       # must match test-requirements.txt
diff --git a/test-requirements.txt b/test-requirements.txt
index 76255044e2dd5..ac965f4abc520 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,12 +1,12 @@
 -r mypy-requirements.txt
 -r build-requirements.txt
 attrs>=18.0
-black==22.10.0  # must match version in .pre-commit-config.yaml
+black==22.12.0  # must match version in .pre-commit-config.yaml
 filelock>=3.3.0
 flake8==5.0.4           # must match version in .pre-commit-config.yaml
-flake8-bugbear==22.9.23 # must match version in .pre-commit-config.yaml
-flake8-noqa==1.2.9      # must match version in .pre-commit-config.yaml
-isort[colors]==5.10.1   # must match version in .pre-commit-config.yaml
+flake8-bugbear==22.12.6 # must match version in .pre-commit-config.yaml
+flake8-noqa==1.3.0      # must match version in .pre-commit-config.yaml
+isort[colors]==5.11.4   # must match version in .pre-commit-config.yaml
 lxml>=4.9.1; (python_version<'3.11' or sys_platform!='win32') and python_version<'3.12'
 psutil>=4.0
 # pytest 6.2.3 does not support Python 3.10

From 1c5eeb817998518f1789b06dcafd7c207f8553d6 Mon Sep 17 00:00:00 2001
From: KotlinIsland <65446343+KotlinIsland@users.noreply.github.com>
Date: Fri, 13 Jan 2023 19:47:02 +1000
Subject: [PATCH 179/231] =?UTF-8?q?(=F0=9F=A7=B9)=20cleanup=20config=20fil?=
 =?UTF-8?q?e=20(#14432)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

These two options in the config file are redundant.

Co-authored-by: KotlinIsland <kotlinisland@users.noreply.github.com>
---
 mypy_self_check.ini | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mypy_self_check.ini b/mypy_self_check.ini
index 719148240c89b..d20fcd60a9cb4 100644
--- a/mypy_self_check.ini
+++ b/mypy_self_check.ini
@@ -1,8 +1,6 @@
 [mypy]
 
 strict = True
-warn_no_return = True
-strict_optional = True
 disallow_any_unimported = True
 show_traceback = True
 pretty = True

From 28e5436bbba16c8a217dace56b951898e53532f9 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Fri, 13 Jan 2023 11:39:21 +0000
Subject: [PATCH 180/231] Refactoring: make the type of fullname str instead of
 Bogus[str] (#14435)

The type Bogus[X] is treated as Any when the code is compiled with
mypyc, while it's equivalent to X when only type checking. They are
sometimes used when X is not actually the real type of a value, but
changing it to the correct type would be complicated.

Bogus[str] types are pretty awkward, since we are lying to the type
checker and mypyc only sees Any types.

An empty fullname is now represented by "" instead of None, so we no
longer need a Bogus[str] type.

This might break some plugins, so we should document this in release
notes and the relevant issue that tracks plugin incompatibilities.

(Various small optimizations, including this, together netted a 6%
performance improvement in self check.)
---
 mypy/checker.py                       |  4 +-
 mypy/checkexpr.py                     | 14 +++----
 mypy/nodes.py                         | 58 +++++++++++++++------------
 mypy/partially_defined.py             |  2 +-
 mypy/semanal.py                       | 12 +++---
 mypy/server/aststrip.py               |  2 +-
 mypy/server/deps.py                   | 14 +++----
 mypy/strconv.py                       |  2 +-
 mypy/stubtest.py                      |  2 +-
 mypy/test/testsemanal.py              |  2 +-
 mypy/tvar_scope.py                    |  2 +-
 mypy/typeanal.py                      |  2 +-
 mypyc/irbuild/builder.py              |  6 +--
 mypyc/irbuild/function.py             |  2 +-
 test-data/unit/plugins/customentry.py |  2 +-
 15 files changed, 65 insertions(+), 61 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 065758cd2be9c..61104756b2979 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -2178,7 +2178,7 @@ def visit_class_def(self, defn: ClassDef) -> None:
                     temp = self.temp_node(sig, context=decorator)
                     fullname = None
                     if isinstance(decorator, RefExpr):
-                        fullname = decorator.fullname
+                        fullname = decorator.fullname or None
 
                     # TODO: Figure out how to have clearer error messages.
                     # (e.g. "class decorator must be a function that accepts a type."
@@ -4598,7 +4598,7 @@ def visit_decorator(self, e: Decorator) -> None:
             temp = self.temp_node(sig, context=e)
             fullname = None
             if isinstance(d, RefExpr):
-                fullname = d.fullname
+                fullname = d.fullname or None
             # if this is a expression like @b.a where b is an object, get the type of b
             # so we can pass it the method hook in the plugins
             object_type: Type | None = None
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index e6634e124d30a..1c25b8ea7a12b 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -216,8 +216,8 @@ def extract_refexpr_names(expr: RefExpr) -> set[str]:
     Note that currently, the only two subclasses of RefExpr are NameExpr and
     MemberExpr."""
     output: set[str] = set()
-    while isinstance(expr.node, MypyFile) or expr.fullname is not None:
-        if isinstance(expr.node, MypyFile) and expr.fullname is not None:
+    while isinstance(expr.node, MypyFile) or expr.fullname:
+        if isinstance(expr.node, MypyFile) and expr.fullname:
             # If it's None, something's wrong (perhaps due to an
             # import cycle or a suppressed error).  For now we just
             # skip it.
@@ -228,7 +228,7 @@ def extract_refexpr_names(expr: RefExpr) -> set[str]:
             if isinstance(expr.node, TypeInfo):
                 # Reference to a class or a nested class
                 output.update(split_module_names(expr.node.module_name))
-            elif expr.fullname is not None and "." in expr.fullname and not is_suppressed_import:
+            elif "." in expr.fullname and not is_suppressed_import:
                 # Everything else (that is not a silenced import within a class)
                 output.add(expr.fullname.rsplit(".", 1)[0])
             break
@@ -526,7 +526,7 @@ def visit_call_expr_inner(self, e: CallExpr, allow_none_return: bool = False) ->
             # There are two special cases where plugins might act:
             # * A "static" reference/alias to a class or function;
             #   get_function_hook() will be invoked for these.
-            fullname = e.callee.fullname
+            fullname = e.callee.fullname or None
             if isinstance(e.callee.node, TypeAlias):
                 target = get_proper_type(e.callee.node.target)
                 if isinstance(target, Instance):
@@ -536,7 +536,7 @@ def visit_call_expr_inner(self, e: CallExpr, allow_none_return: bool = False) ->
             #   get_method_hook() and get_method_signature_hook() will
             #   be invoked for these.
             if (
-                fullname is None
+                not fullname
                 and isinstance(e.callee, MemberExpr)
                 and self.chk.has_type(e.callee.expr)
             ):
@@ -605,7 +605,7 @@ def method_fullname(self, object_type: Type, method_name: str) -> str | None:
         elif isinstance(object_type, TupleType):
             type_name = tuple_fallback(object_type).type.fullname
 
-        if type_name is not None:
+        if type_name:
             return f"{type_name}.{method_name}"
         else:
             return None
@@ -5489,7 +5489,7 @@ def type_info_from_type(typ: Type) -> TypeInfo | None:
 
 
 def is_operator_method(fullname: str | None) -> bool:
-    if fullname is None:
+    if not fullname:
         return False
     short_name = fullname.split(".")[-1]
     return (
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 80ab787f4a9cf..85bb9ce4a8dee 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -25,7 +25,6 @@
 from mypy_extensions import trait
 
 import mypy.strconv
-from mypy.bogus_type import Bogus
 from mypy.util import short_type
 from mypy.visitor import ExpressionVisitor, NodeVisitor, StatementVisitor
 
@@ -247,12 +246,10 @@ class SymbolNode(Node):
     def name(self) -> str:
         pass
 
-    # fullname can often be None even though the type system
-    # disagrees. We mark this with Bogus to let mypyc know not to
-    # worry about it.
+    # Fully qualified name
     @property
     @abstractmethod
-    def fullname(self) -> Bogus[str]:
+    def fullname(self) -> str:
         pass
 
     @abstractmethod
@@ -294,7 +291,7 @@ class MypyFile(SymbolNode):
     __match_args__ = ("name", "path", "defs")
 
     # Fully qualified module name
-    _fullname: Bogus[str]
+    _fullname: str
     # Path to the file (empty string if not known)
     path: str
     # Top-level definitions and statements
@@ -361,7 +358,7 @@ def name(self) -> str:
         return "" if not self._fullname else self._fullname.split(".")[-1]
 
     @property
-    def fullname(self) -> Bogus[str]:
+    def fullname(self) -> str:
         return self._fullname
 
     def accept(self, visitor: NodeVisitor[T]) -> T:
@@ -526,8 +523,7 @@ def __init__(self) -> None:
         self.is_static = False
         self.is_final = False
         # Name with module prefix
-        # TODO: Type should be Optional[str]
-        self._fullname = cast(Bogus[str], None)
+        self._fullname = ""
 
     @property
     @abstractmethod
@@ -535,7 +531,7 @@ def name(self) -> str:
         pass
 
     @property
-    def fullname(self) -> Bogus[str]:
+    def fullname(self) -> str:
         return self._fullname
 
 
@@ -871,7 +867,7 @@ def name(self) -> str:
         return self.func.name
 
     @property
-    def fullname(self) -> Bogus[str]:
+    def fullname(self) -> str:
         return self.func.fullname
 
     @property
@@ -967,7 +963,7 @@ def __init__(self, name: str, type: mypy.types.Type | None = None) -> None:
         super().__init__()
         self._name = name  # Name without module prefix
         # TODO: Should be Optional[str]
-        self._fullname = cast("Bogus[str]", None)  # Name with module prefix
+        self._fullname = ""  # Name with module prefix
         # TODO: Should be Optional[TypeInfo]
         self.info = VAR_NO_INFO
         self.type: mypy.types.Type | None = type  # Declared or inferred type, or None
@@ -1019,7 +1015,7 @@ def name(self) -> str:
         return self._name
 
     @property
-    def fullname(self) -> Bogus[str]:
+    def fullname(self) -> str:
         return self._fullname
 
     def accept(self, visitor: NodeVisitor[T]) -> T:
@@ -1057,7 +1053,7 @@ class ClassDef(Statement):
 
     __slots__ = (
         "name",
-        "fullname",
+        "_fullname",
         "defs",
         "type_vars",
         "base_type_exprs",
@@ -1075,7 +1071,7 @@ class ClassDef(Statement):
     __match_args__ = ("name", "defs")
 
     name: str  # Name of the class without module prefix
-    fullname: Bogus[str]  # Fully qualified name of the class
+    _fullname: str  # Fully qualified name of the class
     defs: Block
     type_vars: list[mypy.types.TypeVarLikeType]
     # Base class expressions (not semantically analyzed -- can be arbitrary expressions)
@@ -1102,7 +1098,7 @@ def __init__(
     ) -> None:
         super().__init__()
         self.name = name
-        self.fullname = None  # type: ignore[assignment]
+        self._fullname = ""
         self.defs = defs
         self.type_vars = type_vars or []
         self.base_type_exprs = base_type_exprs or []
@@ -1117,6 +1113,14 @@ def __init__(
         self.deco_line: int | None = None
         self.removed_statements = []
 
+    @property
+    def fullname(self) -> str:
+        return self._fullname
+
+    @fullname.setter
+    def fullname(self, v: str) -> None:
+        self._fullname = v
+
     def accept(self, visitor: StatementVisitor[T]) -> T:
         return visitor.visit_class_def(self)
 
@@ -1725,7 +1729,7 @@ class RefExpr(Expression):
     __slots__ = (
         "kind",
         "node",
-        "fullname",
+        "_fullname",
         "is_new_def",
         "is_inferred_def",
         "is_alias_rvalue",
@@ -1739,7 +1743,7 @@ def __init__(self) -> None:
         # Var, FuncDef or TypeInfo that describes this
         self.node: SymbolNode | None = None
         # Fully qualified name (or name if not global)
-        self.fullname: str | None = None
+        self._fullname = ""
         # Does this define a new name?
         self.is_new_def = False
         # Does this define a new name with inferred type?
@@ -1752,6 +1756,14 @@ def __init__(self) -> None:
         # Cache type guard from callable_type.type_guard
         self.type_guard: mypy.types.Type | None = None
 
+    @property
+    def fullname(self) -> str:
+        return self._fullname
+
+    @fullname.setter
+    def fullname(self, v: str) -> None:
+        self._fullname = v
+
 
 class NameExpr(RefExpr):
     """Name expression
@@ -2806,7 +2818,7 @@ class is generic then it will be a type constructor of higher kind.
         "self_type",
     )
 
-    _fullname: Bogus[str]  # Fully qualified name
+    _fullname: str  # Fully qualified name
     # Fully qualified name for the module this type was defined in. This
     # information is also in the fullname, but is harder to extract in the
     # case of nested class definitions.
@@ -3023,7 +3035,7 @@ def name(self) -> str:
         return self.defn.name
 
     @property
-    def fullname(self) -> Bogus[str]:
+    def fullname(self) -> str:
         return self._fullname
 
     def is_generic(self) -> bool:
@@ -3739,11 +3751,7 @@ def serialize(self, prefix: str, name: str) -> JsonDict:
             if prefix is not None:
                 fullname = self.node.fullname
                 if (
-                    # See the comment above SymbolNode.fullname -- fullname can often be None,
-                    # but for complex reasons it's annotated as being `Bogus[str]` instead of `str | None`,
-                    # meaning mypy erroneously thinks the `fullname is not None` check here is redundant
-                    fullname is not None  # type: ignore[redundant-expr]
-                    and "." in fullname
+                    "." in fullname
                     and fullname != prefix + "." + name
                     and not (isinstance(self.node, Var) and self.node.from_module_getattr)
                 ):
diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index c63c62c3e3937..9a58df04371f8 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -287,7 +287,7 @@ def is_undefined(self, name: str) -> bool:
 
 
 def refers_to_builtin(o: RefExpr) -> bool:
-    return o.fullname is not None and o.fullname.startswith("builtins.")
+    return o.fullname.startswith("builtins.")
 
 
 class Loop:
diff --git a/mypy/semanal.py b/mypy/semanal.py
index aee355d7880d5..acc485a609e0c 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -3022,13 +3022,13 @@ def analyze_lvalues(self, s: AssignmentStmt) -> None:
     def apply_dynamic_class_hook(self, s: AssignmentStmt) -> None:
         if not isinstance(s.rvalue, CallExpr):
             return
-        fname = None
+        fname = ""
         call = s.rvalue
         while True:
             if isinstance(call.callee, RefExpr):
                 fname = call.callee.fullname
             # check if method call
-            if fname is None and isinstance(call.callee, MemberExpr):
+            if not fname and isinstance(call.callee, MemberExpr):
                 callee_expr = call.callee.expr
                 if isinstance(callee_expr, RefExpr) and callee_expr.fullname:
                     method_name = call.callee.name
@@ -4624,7 +4624,7 @@ def bind_name_expr(self, expr: NameExpr, sym: SymbolTableNode) -> None:
         else:
             expr.kind = sym.kind
             expr.node = sym.node
-            expr.fullname = sym.fullname
+            expr.fullname = sym.fullname or ""
 
     def visit_super_expr(self, expr: SuperExpr) -> None:
         if not self.type and not expr.call.args:
@@ -4849,7 +4849,7 @@ def visit_member_expr(self, expr: MemberExpr) -> None:
                     self.process_placeholder(expr.name, "attribute", expr)
                     return
                 expr.kind = sym.kind
-                expr.fullname = sym.fullname
+                expr.fullname = sym.fullname or ""
                 expr.node = sym.node
         elif isinstance(base, RefExpr):
             # This branch handles the case C.bar (or cls.bar or self.bar inside
@@ -4881,7 +4881,7 @@ def visit_member_expr(self, expr: MemberExpr) -> None:
                     if not n:
                         return
                     expr.kind = n.kind
-                    expr.fullname = n.fullname
+                    expr.fullname = n.fullname or ""
                     expr.node = n.node
 
     def visit_op_expr(self, expr: OpExpr) -> None:
@@ -5341,7 +5341,7 @@ def is_overloaded_item(self, node: SymbolNode, statement: Statement) -> bool:
         return False
 
     def is_defined_in_current_module(self, fullname: str | None) -> bool:
-        if fullname is None:
+        if not fullname:
             return False
         return module_prefix(self.modules, fullname) == self.cur_mod_id
 
diff --git a/mypy/server/aststrip.py b/mypy/server/aststrip.py
index b0666f8e1ff4d..05af6a3d53a11 100644
--- a/mypy/server/aststrip.py
+++ b/mypy/server/aststrip.py
@@ -230,7 +230,7 @@ def visit_op_expr(self, node: OpExpr) -> None:
     def strip_ref_expr(self, node: RefExpr) -> None:
         node.kind = None
         node.node = None
-        node.fullname = None
+        node.fullname = ""
         node.is_new_def = False
         node.is_inferred_def = False
 
diff --git a/mypy/server/deps.py b/mypy/server/deps.py
index eb40737061bf0..50b66b70b8aaf 100644
--- a/mypy/server/deps.py
+++ b/mypy/server/deps.py
@@ -289,13 +289,9 @@ def visit_decorator(self, o: Decorator) -> None:
             # all call sites, making them all `Any`.
             for d in o.decorators:
                 tname: str | None = None
-                if isinstance(d, RefExpr) and d.fullname is not None:
+                if isinstance(d, RefExpr) and d.fullname:
                     tname = d.fullname
-                if (
-                    isinstance(d, CallExpr)
-                    and isinstance(d.callee, RefExpr)
-                    and d.callee.fullname is not None
-                ):
+                if isinstance(d, CallExpr) and isinstance(d.callee, RefExpr) and d.callee.fullname:
                     tname = d.callee.fullname
                 if tname is not None:
                     self.add_dependency(make_trigger(tname), make_trigger(o.func.fullname))
@@ -500,7 +496,7 @@ def visit_assignment_stmt(self, o: AssignmentStmt) -> None:
             if (
                 isinstance(rvalue, CallExpr)
                 and isinstance(rvalue.callee, RefExpr)
-                and rvalue.callee.fullname is not None
+                and rvalue.callee.fullname
             ):
                 fname: str | None = None
                 if isinstance(rvalue.callee.node, TypeInfo):
@@ -510,7 +506,7 @@ def visit_assignment_stmt(self, o: AssignmentStmt) -> None:
                         fname = init.node.fullname
                 else:
                     fname = rvalue.callee.fullname
-                if fname is None:
+                if not fname:
                     return
                 for lv in o.lvalues:
                     if isinstance(lv, RefExpr) and lv.fullname and lv.is_new_def:
@@ -638,7 +634,7 @@ def visit_del_stmt(self, o: DelStmt) -> None:
     # Expressions
 
     def process_global_ref_expr(self, o: RefExpr) -> None:
-        if o.fullname is not None:
+        if o.fullname:
             self.add_dependency(make_trigger(o.fullname))
 
         # If this is a reference to a type, generate a dependency to its
diff --git a/mypy/strconv.py b/mypy/strconv.py
index 861a7c9b7fa08..b2e9da5dbf6ae 100644
--- a/mypy/strconv.py
+++ b/mypy/strconv.py
@@ -367,7 +367,7 @@ def pretty_name(
             id = ""
         if isinstance(target_node, mypy.nodes.MypyFile) and name == fullname:
             n += id
-        elif kind == mypy.nodes.GDEF or (fullname != name and fullname is not None):
+        elif kind == mypy.nodes.GDEF or (fullname != name and fullname):
             # Append fully qualified name for global references.
             n += f" [{fullname}{id}]"
         elif kind == mypy.nodes.LDEF:
diff --git a/mypy/stubtest.py b/mypy/stubtest.py
index bfd8e2b9c81a4..774f03cbbdd0d 100644
--- a/mypy/stubtest.py
+++ b/mypy/stubtest.py
@@ -1147,7 +1147,7 @@ def apply_decorator_to_funcitem(
     ) -> nodes.FuncItem | None:
         if not isinstance(decorator, nodes.RefExpr):
             return None
-        if decorator.fullname is None:
+        if not decorator.fullname:
             # Happens with namedtuple
             return None
         if (
diff --git a/mypy/test/testsemanal.py b/mypy/test/testsemanal.py
index 6cfd53f09beb4..71ebc43df8c26 100644
--- a/mypy/test/testsemanal.py
+++ b/mypy/test/testsemanal.py
@@ -202,7 +202,7 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
             for f in result.files.values():
                 for n in f.names.values():
                     if isinstance(n.node, TypeInfo):
-                        assert n.fullname is not None
+                        assert n.fullname
                         typeinfos[n.fullname] = n.node
 
             # The output is the symbol table converted into a string.
diff --git a/mypy/tvar_scope.py b/mypy/tvar_scope.py
index db83768bf68ab..9b432d8e68ec5 100644
--- a/mypy/tvar_scope.py
+++ b/mypy/tvar_scope.py
@@ -129,7 +129,7 @@ def bind_existing(self, tvar_def: TypeVarLikeType) -> None:
 
     def get_binding(self, item: str | SymbolTableNode) -> TypeVarLikeType | None:
         fullname = item.fullname if isinstance(item, SymbolTableNode) else item
-        assert fullname is not None
+        assert fullname
         if fullname in self.scope:
             return self.scope[fullname]
         elif self.parent is not None:
diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index df74344fb392b..07720afeff888 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -1123,7 +1123,7 @@ def visit_type_type(self, t: TypeType) -> Type:
         return TypeType.make_normalized(self.anal_type(t.item), line=t.line)
 
     def visit_placeholder_type(self, t: PlaceholderType) -> Type:
-        n = None if t.fullname is None else self.api.lookup_fully_qualified(t.fullname)
+        n = None if not t.fullname else self.api.lookup_fully_qualified(t.fullname)
         if not n or isinstance(n.node, PlaceholderNode):
             self.api.defer()  # Still incomplete
             return t
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
index c24207ac64ecb..f2a70d4e8691e 100644
--- a/mypyc/irbuild/builder.py
+++ b/mypyc/irbuild/builder.py
@@ -1001,7 +1001,7 @@ def call_refexpr_with_args(
     ) -> Value:
 
         # Handle data-driven special-cased primitive call ops.
-        if callee.fullname is not None and expr.arg_kinds == [ARG_POS] * len(arg_values):
+        if callee.fullname and expr.arg_kinds == [ARG_POS] * len(arg_values):
             call_c_ops_candidates = function_ops.get(callee.fullname, [])
             target = self.builder.matching_call_c(
                 call_c_ops_candidates, arg_values, expr.line, self.node_type(expr)
@@ -1026,7 +1026,7 @@ def call_refexpr_with_args(
             callee_node = callee_node.func
         if (
             callee_node is not None
-            and callee.fullname is not None
+            and callee.fullname
             and callee_node in self.mapper.func_to_decl
             and all(kind in (ARG_POS, ARG_NAMED) for kind in expr.arg_kinds)
         ):
@@ -1240,7 +1240,7 @@ def load_global(self, expr: NameExpr) -> Value:
             and isinstance(expr.node, TypeInfo)
             and not self.is_synthetic_type(expr.node)
         ):
-            assert expr.fullname is not None
+            assert expr.fullname
             return self.load_native_type_object(expr.fullname)
         return self.load_global_str(expr.name, expr.line)
 
diff --git a/mypyc/irbuild/function.py b/mypyc/irbuild/function.py
index 5447f945db257..523f8c299c2fd 100644
--- a/mypyc/irbuild/function.py
+++ b/mypyc/irbuild/function.py
@@ -789,7 +789,7 @@ def load_type(builder: IRBuilder, typ: TypeInfo, line: int) -> Value:
 
 
 def load_func(builder: IRBuilder, func_name: str, fullname: str | None, line: int) -> Value:
-    if fullname is not None and not fullname.startswith(builder.current_module):
+    if fullname and not fullname.startswith(builder.current_module):
         # we're calling a function in a different module
 
         # We can't use load_module_attr_by_fullname here because we need to load the function using
diff --git a/test-data/unit/plugins/customentry.py b/test-data/unit/plugins/customentry.py
index f8b86c33dcfc4..b3dacfd4cf443 100644
--- a/test-data/unit/plugins/customentry.py
+++ b/test-data/unit/plugins/customentry.py
@@ -4,7 +4,7 @@ class MyPlugin(Plugin):
     def get_function_hook(self, fullname):
         if fullname == '__main__.f':
             return my_hook
-        assert fullname is not None
+        assert fullname
         return None
 
 def my_hook(ctx):

From f37a0aeeb89b87de2d2bcdb7a749e4e6f63a3185 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 14 Jan 2023 18:54:57 -0800
Subject: [PATCH 181/231] Sync typeshed (#14449)

Source commit:

https://github.com/python/typeshed/commit/ea0ae2155e8a04c9837903c3aff8dd5ad5f36ebc

Note that you will need to close and re-open the PR in order to trigger
CI.

Co-authored-by: mypybot <>
Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 mypy/typeshed/stdlib/_typeshed/__init__.pyi   |   4 +
 mypy/typeshed/stdlib/builtins.pyi             |  17 +-
 mypy/typeshed/stdlib/compileall.pyi           |  40 ++-
 mypy/typeshed/stdlib/contextlib.pyi           |   4 +-
 mypy/typeshed/stdlib/distutils/dist.pyi       |   4 +-
 mypy/typeshed/stdlib/email/message.pyi        |   4 +-
 mypy/typeshed/stdlib/genericpath.pyi          |  18 +-
 mypy/typeshed/stdlib/http/server.pyi          |  29 +--
 mypy/typeshed/stdlib/io.pyi                   |   6 +-
 mypy/typeshed/stdlib/itertools.pyi            |   6 +
 .../multiprocessing/resource_tracker.pyi      |   4 +-
 mypy/typeshed/stdlib/os/__init__.pyi          |  39 +--
 mypy/typeshed/stdlib/posixpath.pyi            |   8 +-
 mypy/typeshed/stdlib/shutil.pyi               |   4 +-
 mypy/typeshed/stdlib/socketserver.pyi         |  59 +++--
 mypy/typeshed/stdlib/ssl.pyi                  |  40 ++-
 mypy/typeshed/stdlib/subprocess.pyi           | 245 +++++++++---------
 mypy/typeshed/stdlib/sysconfig.pyi            |   8 +-
 mypy/typeshed/stdlib/tokenize.pyi             |   4 +-
 mypy/typeshed/stdlib/urllib/parse.pyi         |   6 +-
 mypy/typeshed/stdlib/venv/__init__.pyi        |   3 +
 .../stdlib/xml/etree/ElementInclude.pyi       |   4 +-
 .../typeshed/stdlib/xml/etree/ElementTree.pyi |   6 +-
 23 files changed, 315 insertions(+), 247 deletions(-)

diff --git a/mypy/typeshed/stdlib/_typeshed/__init__.pyi b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
index f01db74caf40a..68ac2a9b1900c 100644
--- a/mypy/typeshed/stdlib/_typeshed/__init__.pyi
+++ b/mypy/typeshed/stdlib/_typeshed/__init__.pyi
@@ -36,6 +36,9 @@ AnyStr_co = TypeVar("AnyStr_co", str, bytes, covariant=True)  # noqa: Y001
 # "Incomplete | None" instead of "Any | None".
 Incomplete: TypeAlias = Any
 
+# To describe a function parameter that is unused and will work with anything.
+Unused: TypeAlias = object
+
 # stable
 class IdentityFunction(Protocol):
     def __call__(self, __x: _T) -> _T: ...
@@ -205,6 +208,7 @@ class HasFileno(Protocol):
 
 FileDescriptor: TypeAlias = int  # stable
 FileDescriptorLike: TypeAlias = int | HasFileno  # stable
+FileDescriptorOrPath: TypeAlias = int | StrOrBytesPath
 
 # stable
 class SupportsRead(Protocol[_T_co]):
diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
index 8fbef893ac57e..b2241bb60527d 100644
--- a/mypy/typeshed/stdlib/builtins.pyi
+++ b/mypy/typeshed/stdlib/builtins.pyi
@@ -4,6 +4,7 @@ import types
 from _collections_abc import dict_items, dict_keys, dict_values
 from _typeshed import (
     AnyStr_co,
+    FileDescriptorOrPath,
     OpenBinaryMode,
     OpenBinaryModeReading,
     OpenBinaryModeUpdating,
@@ -11,7 +12,6 @@ from _typeshed import (
     OpenTextMode,
     ReadableBuffer,
     Self,
-    StrOrBytesPath,
     SupportsAdd,
     SupportsAiter,
     SupportsAnext,
@@ -1320,13 +1320,12 @@ def next(__i: SupportsNext[_T]) -> _T: ...
 def next(__i: SupportsNext[_T], __default: _VT) -> _T | _VT: ...
 def oct(__number: int | SupportsIndex) -> str: ...
 
-_OpenFile = StrOrBytesPath | int  # noqa: Y026  # TODO: Use TypeAlias once mypy bugs are fixed
 _Opener: TypeAlias = Callable[[str, int], int]
 
 # Text mode: always returns a TextIOWrapper
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: OpenTextMode = ...,
     buffering: int = ...,
     encoding: str | None = ...,
@@ -1339,7 +1338,7 @@ def open(
 # Unbuffered binary mode: returns a FileIO
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: OpenBinaryMode,
     buffering: Literal[0],
     encoding: None = ...,
@@ -1352,7 +1351,7 @@ def open(
 # Buffering is on: return BufferedRandom, BufferedReader, or BufferedWriter
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: OpenBinaryModeUpdating,
     buffering: Literal[-1, 1] = ...,
     encoding: None = ...,
@@ -1363,7 +1362,7 @@ def open(
 ) -> BufferedRandom: ...
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: OpenBinaryModeWriting,
     buffering: Literal[-1, 1] = ...,
     encoding: None = ...,
@@ -1374,7 +1373,7 @@ def open(
 ) -> BufferedWriter: ...
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: OpenBinaryModeReading,
     buffering: Literal[-1, 1] = ...,
     encoding: None = ...,
@@ -1387,7 +1386,7 @@ def open(
 # Buffering cannot be determined: fall back to BinaryIO
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: OpenBinaryMode,
     buffering: int = ...,
     encoding: None = ...,
@@ -1400,7 +1399,7 @@ def open(
 # Fallback if mode is not specified
 @overload
 def open(
-    file: _OpenFile,
+    file: FileDescriptorOrPath,
     mode: str,
     buffering: int = ...,
     encoding: str | None = ...,
diff --git a/mypy/typeshed/stdlib/compileall.pyi b/mypy/typeshed/stdlib/compileall.pyi
index dd1de3f496e7f..4621500eda963 100644
--- a/mypy/typeshed/stdlib/compileall.pyi
+++ b/mypy/typeshed/stdlib/compileall.pyi
@@ -8,7 +8,7 @@ __all__ = ["compile_dir", "compile_file", "compile_path"]
 class _SupportsSearch(Protocol):
     def search(self, string: str) -> Any: ...
 
-if sys.version_info >= (3, 9):
+if sys.version_info >= (3, 10):
     def compile_dir(
         dir: StrPath,
         maxlevels: int | None = ...,
@@ -21,7 +21,7 @@ if sys.version_info >= (3, 9):
         workers: int = ...,
         invalidation_mode: PycInvalidationMode | None = ...,
         *,
-        stripdir: str | None = ...,  # TODO: change to StrPath | None once https://bugs.python.org/issue40447 is resolved
+        stripdir: StrPath | None = ...,
         prependdir: StrPath | None = ...,
         limit_sl_dest: StrPath | None = ...,
         hardlink_dupes: bool = ...,
@@ -36,7 +36,41 @@ if sys.version_info >= (3, 9):
         optimize: int = ...,
         invalidation_mode: PycInvalidationMode | None = ...,
         *,
-        stripdir: str | None = ...,  # TODO: change to StrPath | None once https://bugs.python.org/issue40447 is resolved
+        stripdir: StrPath | None = ...,
+        prependdir: StrPath | None = ...,
+        limit_sl_dest: StrPath | None = ...,
+        hardlink_dupes: bool = ...,
+    ) -> int: ...
+
+elif sys.version_info >= (3, 9):
+    def compile_dir(
+        dir: StrPath,
+        maxlevels: int | None = ...,
+        ddir: StrPath | None = ...,
+        force: bool = ...,
+        rx: _SupportsSearch | None = ...,
+        quiet: int = ...,
+        legacy: bool = ...,
+        optimize: int = ...,
+        workers: int = ...,
+        invalidation_mode: PycInvalidationMode | None = ...,
+        *,
+        stripdir: str | None = ...,  # https://bugs.python.org/issue40447
+        prependdir: StrPath | None = ...,
+        limit_sl_dest: StrPath | None = ...,
+        hardlink_dupes: bool = ...,
+    ) -> int: ...
+    def compile_file(
+        fullname: StrPath,
+        ddir: StrPath | None = ...,
+        force: bool = ...,
+        rx: _SupportsSearch | None = ...,
+        quiet: int = ...,
+        legacy: bool = ...,
+        optimize: int = ...,
+        invalidation_mode: PycInvalidationMode | None = ...,
+        *,
+        stripdir: str | None = ...,  # https://bugs.python.org/issue40447
         prependdir: StrPath | None = ...,
         limit_sl_dest: StrPath | None = ...,
         hardlink_dupes: bool = ...,
diff --git a/mypy/typeshed/stdlib/contextlib.pyi b/mypy/typeshed/stdlib/contextlib.pyi
index ca88304395385..1a6642b643e30 100644
--- a/mypy/typeshed/stdlib/contextlib.pyi
+++ b/mypy/typeshed/stdlib/contextlib.pyi
@@ -1,6 +1,6 @@
 import abc
 import sys
-from _typeshed import Self, StrOrBytesPath
+from _typeshed import FileDescriptorOrPath, Self
 from abc import abstractmethod
 from collections.abc import AsyncGenerator, AsyncIterator, Awaitable, Callable, Generator, Iterator
 from types import TracebackType
@@ -193,7 +193,7 @@ else:
         def __exit__(self, *exctype: object) -> None: ...
 
 if sys.version_info >= (3, 11):
-    _T_fd_or_any_path = TypeVar("_T_fd_or_any_path", bound=int | StrOrBytesPath)
+    _T_fd_or_any_path = TypeVar("_T_fd_or_any_path", bound=FileDescriptorOrPath)
 
     class chdir(AbstractContextManager[None], Generic[_T_fd_or_any_path]):
         path: _T_fd_or_any_path
diff --git a/mypy/typeshed/stdlib/distutils/dist.pyi b/mypy/typeshed/stdlib/distutils/dist.pyi
index ef47e4e4d15a7..fc1bce261e57f 100644
--- a/mypy/typeshed/stdlib/distutils/dist.pyi
+++ b/mypy/typeshed/stdlib/distutils/dist.pyi
@@ -1,10 +1,10 @@
-from _typeshed import StrOrBytesPath, SupportsWrite
+from _typeshed import FileDescriptorOrPath, SupportsWrite
 from collections.abc import Iterable, Mapping
 from distutils.cmd import Command
 from typing import IO, Any
 
 class DistributionMetadata:
-    def __init__(self, path: int | StrOrBytesPath | None = ...) -> None: ...
+    def __init__(self, path: FileDescriptorOrPath | None = ...) -> None: ...
     name: str | None
     version: str | None
     author: str | None
diff --git a/mypy/typeshed/stdlib/email/message.pyi b/mypy/typeshed/stdlib/email/message.pyi
index c6b77cdde0544..58b1c1cd8f3d5 100644
--- a/mypy/typeshed/stdlib/email/message.pyi
+++ b/mypy/typeshed/stdlib/email/message.pyi
@@ -76,8 +76,8 @@ class Message:
     ) -> None: ...
     def __init__(self, policy: Policy = ...) -> None: ...
     # The following two methods are undocumented, but a source code comment states that they are public API
-    def set_raw(self, name: str, value: str) -> None: ...
-    def raw_items(self) -> Iterator[tuple[str, str]]: ...
+    def set_raw(self, name: str, value: _HeaderType) -> None: ...
+    def raw_items(self) -> Iterator[tuple[str, _HeaderType]]: ...
 
 class MIMEPart(Message):
     def __init__(self, policy: Policy | None = ...) -> None: ...
diff --git a/mypy/typeshed/stdlib/genericpath.pyi b/mypy/typeshed/stdlib/genericpath.pyi
index 911d582fd538f..46426b63c852a 100644
--- a/mypy/typeshed/stdlib/genericpath.pyi
+++ b/mypy/typeshed/stdlib/genericpath.pyi
@@ -1,5 +1,5 @@
 import os
-from _typeshed import BytesPath, StrOrBytesPath, StrPath, SupportsRichComparisonT
+from _typeshed import BytesPath, FileDescriptorOrPath, StrPath, SupportsRichComparisonT
 from collections.abc import Sequence
 from typing import overload
 from typing_extensions import Literal, LiteralString
@@ -31,16 +31,16 @@ def commonprefix(m: Sequence[BytesPath]) -> bytes | Literal[""]: ...
 def commonprefix(m: Sequence[list[SupportsRichComparisonT]]) -> Sequence[SupportsRichComparisonT]: ...
 @overload
 def commonprefix(m: Sequence[tuple[SupportsRichComparisonT, ...]]) -> Sequence[SupportsRichComparisonT]: ...
-def exists(path: StrOrBytesPath | int) -> bool: ...
-def getsize(filename: StrOrBytesPath | int) -> int: ...
-def isfile(path: StrOrBytesPath | int) -> bool: ...
-def isdir(s: StrOrBytesPath | int) -> bool: ...
+def exists(path: FileDescriptorOrPath) -> bool: ...
+def getsize(filename: FileDescriptorOrPath) -> int: ...
+def isfile(path: FileDescriptorOrPath) -> bool: ...
+def isdir(s: FileDescriptorOrPath) -> bool: ...
 
 # These return float if os.stat_float_times() == True,
 # but int is a subclass of float.
-def getatime(filename: StrOrBytesPath | int) -> float: ...
-def getmtime(filename: StrOrBytesPath | int) -> float: ...
-def getctime(filename: StrOrBytesPath | int) -> float: ...
-def samefile(f1: StrOrBytesPath | int, f2: StrOrBytesPath | int) -> bool: ...
+def getatime(filename: FileDescriptorOrPath) -> float: ...
+def getmtime(filename: FileDescriptorOrPath) -> float: ...
+def getctime(filename: FileDescriptorOrPath) -> float: ...
+def samefile(f1: FileDescriptorOrPath, f2: FileDescriptorOrPath) -> bool: ...
 def sameopenfile(fp1: int, fp2: int) -> bool: ...
 def samestat(s1: os.stat_result, s2: os.stat_result) -> bool: ...
diff --git a/mypy/typeshed/stdlib/http/server.pyi b/mypy/typeshed/stdlib/http/server.pyi
index 011d464b46531..04ac28c3278ee 100644
--- a/mypy/typeshed/stdlib/http/server.pyi
+++ b/mypy/typeshed/stdlib/http/server.pyi
@@ -1,3 +1,4 @@
+import _socket
 import email.message
 import io
 import socketserver
@@ -52,25 +53,15 @@ class BaseHTTPRequestHandler(socketserver.StreamRequestHandler):
 class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):
     extensions_map: dict[str, str]
     if sys.version_info >= (3, 12):
-        def __init__(
-            self,
-            request: socketserver._RequestType,
-            client_address: socketserver._AddressType,
-            server: socketserver.BaseServer,
-            *,
-            directory: str | None = ...,
-            index_pages: Sequence[str] | None = ...,
-        ) -> None: ...
-    else:
-        def __init__(
-            self,
-            request: socketserver._RequestType,
-            client_address: socketserver._AddressType,
-            server: socketserver.BaseServer,
-            *,
-            directory: str | None = ...,
-        ) -> None: ...
-
+        index_pages: ClassVar[tuple[str, ...]]
+    def __init__(
+        self,
+        request: socketserver._RequestType,
+        client_address: _socket._RetAddress,
+        server: socketserver.BaseServer,
+        *,
+        directory: str | None = ...,
+    ) -> None: ...
     def do_GET(self) -> None: ...
     def do_HEAD(self) -> None: ...
     def send_head(self) -> io.BytesIO | BinaryIO | None: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/io.pyi b/mypy/typeshed/stdlib/io.pyi
index 9c4c769fe34bc..c1889300f9818 100644
--- a/mypy/typeshed/stdlib/io.pyi
+++ b/mypy/typeshed/stdlib/io.pyi
@@ -2,7 +2,7 @@ import abc
 import builtins
 import codecs
 import sys
-from _typeshed import ReadableBuffer, Self, StrOrBytesPath, WriteableBuffer
+from _typeshed import FileDescriptorOrPath, ReadableBuffer, Self, WriteableBuffer
 from collections.abc import Callable, Iterable, Iterator
 from os import _Opener
 from types import TracebackType
@@ -92,9 +92,9 @@ class BufferedIOBase(IOBase):
 
 class FileIO(RawIOBase, BinaryIO):
     mode: str
-    name: StrOrBytesPath | int  # type: ignore[assignment]
+    name: FileDescriptorOrPath  # type: ignore[assignment]
     def __init__(
-        self, file: StrOrBytesPath | int, mode: str = ..., closefd: bool = ..., opener: _Opener | None = ...
+        self, file: FileDescriptorOrPath, mode: str = ..., closefd: bool = ..., opener: _Opener | None = ...
     ) -> None: ...
     @property
     def closefd(self) -> bool: ...
diff --git a/mypy/typeshed/stdlib/itertools.pyi b/mypy/typeshed/stdlib/itertools.pyi
index 7299ee8200db0..3cc1bd00de792 100644
--- a/mypy/typeshed/stdlib/itertools.pyi
+++ b/mypy/typeshed/stdlib/itertools.pyi
@@ -271,3 +271,9 @@ if sys.version_info >= (3, 10):
         def __new__(cls, __iterable: Iterable[_T]) -> pairwise[tuple[_T, _T]]: ...
         def __iter__(self: Self) -> Self: ...
         def __next__(self) -> _T_co: ...
+
+if sys.version_info >= (3, 12):
+    class batched(Iterator[_T_co], Generic[_T_co]):
+        def __new__(cls: type[Self], iterable: Iterable[_T_co], n: int) -> Self: ...
+        def __iter__(self: Self) -> Self: ...
+        def __next__(self) -> tuple[_T_co, ...]: ...
diff --git a/mypy/typeshed/stdlib/multiprocessing/resource_tracker.pyi b/mypy/typeshed/stdlib/multiprocessing/resource_tracker.pyi
index 50f3db67467bd..e2b940796126f 100644
--- a/mypy/typeshed/stdlib/multiprocessing/resource_tracker.pyi
+++ b/mypy/typeshed/stdlib/multiprocessing/resource_tracker.pyi
@@ -1,4 +1,4 @@
-from _typeshed import Incomplete, StrOrBytesPath
+from _typeshed import FileDescriptorOrPath, Incomplete
 from collections.abc import Sized
 
 __all__ = ["ensure_running", "register", "unregister"]
@@ -15,4 +15,4 @@ register = _resource_tracker.register
 unregister = _resource_tracker.unregister
 getfd = _resource_tracker.getfd
 
-def main(fd: StrOrBytesPath | int) -> None: ...
+def main(fd: FileDescriptorOrPath) -> None: ...
diff --git a/mypy/typeshed/stdlib/os/__init__.pyi b/mypy/typeshed/stdlib/os/__init__.pyi
index 590d20576665e..ec31cc5e2a76e 100644
--- a/mypy/typeshed/stdlib/os/__init__.pyi
+++ b/mypy/typeshed/stdlib/os/__init__.pyi
@@ -3,6 +3,7 @@ from _typeshed import (
     AnyStr_co,
     BytesPath,
     FileDescriptorLike,
+    FileDescriptorOrPath,
     GenericPath,
     OpenBinaryMode,
     OpenBinaryModeReading,
@@ -370,9 +371,6 @@ def listdir(path: StrPath | None = ...) -> list[str]: ...
 def listdir(path: BytesPath) -> list[bytes]: ...
 @overload
 def listdir(path: int) -> list[str]: ...
-
-_FdOrAnyPath: TypeAlias = int | StrOrBytesPath
-
 @final
 class DirEntry(Generic[AnyStr]):
     # This is what the scandir iterator yields
@@ -676,16 +674,16 @@ if sys.platform != "win32":
 
 def write(__fd: int, __data: ReadableBuffer) -> int: ...
 def access(
-    path: _FdOrAnyPath, mode: int, *, dir_fd: int | None = ..., effective_ids: bool = ..., follow_symlinks: bool = ...
+    path: FileDescriptorOrPath, mode: int, *, dir_fd: int | None = ..., effective_ids: bool = ..., follow_symlinks: bool = ...
 ) -> bool: ...
-def chdir(path: _FdOrAnyPath) -> None: ...
+def chdir(path: FileDescriptorOrPath) -> None: ...
 
 if sys.platform != "win32":
     def fchdir(fd: FileDescriptorLike) -> None: ...
 
 def getcwd() -> str: ...
 def getcwdb() -> bytes: ...
-def chmod(path: _FdOrAnyPath, mode: int, *, dir_fd: int | None = ..., follow_symlinks: bool = ...) -> None: ...
+def chmod(path: FileDescriptorOrPath, mode: int, *, dir_fd: int | None = ..., follow_symlinks: bool = ...) -> None: ...
 
 if sys.platform != "win32" and sys.platform != "linux":
     def chflags(path: StrOrBytesPath, flags: int, follow_symlinks: bool = ...) -> None: ...  # some flavors of Unix
@@ -694,7 +692,9 @@ if sys.platform != "win32" and sys.platform != "linux":
 
 if sys.platform != "win32":
     def chroot(path: StrOrBytesPath) -> None: ...
-    def chown(path: _FdOrAnyPath, uid: int, gid: int, *, dir_fd: int | None = ..., follow_symlinks: bool = ...) -> None: ...
+    def chown(
+        path: FileDescriptorOrPath, uid: int, gid: int, *, dir_fd: int | None = ..., follow_symlinks: bool = ...
+    ) -> None: ...
     def lchown(path: StrOrBytesPath, uid: int, gid: int) -> None: ...
 
 def link(
@@ -718,7 +718,7 @@ if sys.platform != "win32":
     def major(__device: int) -> int: ...
     def minor(__device: int) -> int: ...
     def makedev(__major: int, __minor: int) -> int: ...
-    def pathconf(path: _FdOrAnyPath, name: str | int) -> int: ...  # Unix only
+    def pathconf(path: FileDescriptorOrPath, name: str | int) -> int: ...  # Unix only
 
 def readlink(path: GenericPath[AnyStr], *, dir_fd: int | None = ...) -> AnyStr: ...
 def remove(path: StrOrBytesPath, *, dir_fd: int | None = ...) -> None: ...
@@ -739,20 +739,20 @@ def scandir(path: None = ...) -> _ScandirIterator[str]: ...
 def scandir(path: int) -> _ScandirIterator[str]: ...
 @overload
 def scandir(path: GenericPath[AnyStr]) -> _ScandirIterator[AnyStr]: ...
-def stat(path: _FdOrAnyPath, *, dir_fd: int | None = ..., follow_symlinks: bool = ...) -> stat_result: ...
+def stat(path: FileDescriptorOrPath, *, dir_fd: int | None = ..., follow_symlinks: bool = ...) -> stat_result: ...
 
 if sys.platform != "win32":
-    def statvfs(path: _FdOrAnyPath) -> statvfs_result: ...  # Unix only
+    def statvfs(path: FileDescriptorOrPath) -> statvfs_result: ...  # Unix only
 
 def symlink(src: StrOrBytesPath, dst: StrOrBytesPath, target_is_directory: bool = ..., *, dir_fd: int | None = ...) -> None: ...
 
 if sys.platform != "win32":
     def sync() -> None: ...  # Unix only
 
-def truncate(path: _FdOrAnyPath, length: int) -> None: ...  # Unix only up to version 3.4
+def truncate(path: FileDescriptorOrPath, length: int) -> None: ...  # Unix only up to version 3.4
 def unlink(path: StrOrBytesPath, *, dir_fd: int | None = ...) -> None: ...
 def utime(
-    path: _FdOrAnyPath,
+    path: FileDescriptorOrPath,
     times: tuple[int, int] | tuple[float, float] | None = ...,
     *,
     ns: tuple[int, int] = ...,
@@ -786,11 +786,16 @@ if sys.platform != "win32":
         dir_fd: int | None = ...,
     ) -> Iterator[tuple[bytes, list[bytes], list[bytes], int]]: ...
     if sys.platform == "linux":
-        def getxattr(path: _FdOrAnyPath, attribute: StrOrBytesPath, *, follow_symlinks: bool = ...) -> bytes: ...
-        def listxattr(path: _FdOrAnyPath | None = ..., *, follow_symlinks: bool = ...) -> list[str]: ...
-        def removexattr(path: _FdOrAnyPath, attribute: StrOrBytesPath, *, follow_symlinks: bool = ...) -> None: ...
+        def getxattr(path: FileDescriptorOrPath, attribute: StrOrBytesPath, *, follow_symlinks: bool = ...) -> bytes: ...
+        def listxattr(path: FileDescriptorOrPath | None = ..., *, follow_symlinks: bool = ...) -> list[str]: ...
+        def removexattr(path: FileDescriptorOrPath, attribute: StrOrBytesPath, *, follow_symlinks: bool = ...) -> None: ...
         def setxattr(
-            path: _FdOrAnyPath, attribute: StrOrBytesPath, value: ReadableBuffer, flags: int = ..., *, follow_symlinks: bool = ...
+            path: FileDescriptorOrPath,
+            attribute: StrOrBytesPath,
+            value: ReadableBuffer,
+            flags: int = ...,
+            *,
+            follow_symlinks: bool = ...,
         ) -> None: ...
 
 def abort() -> NoReturn: ...
@@ -825,7 +830,7 @@ _ExecVArgs: TypeAlias = (
 _ExecEnv: TypeAlias = Mapping[bytes, bytes | str] | Mapping[str, bytes | str]
 
 def execv(__path: StrOrBytesPath, __argv: _ExecVArgs) -> NoReturn: ...
-def execve(path: _FdOrAnyPath, argv: _ExecVArgs, env: _ExecEnv) -> NoReturn: ...
+def execve(path: FileDescriptorOrPath, argv: _ExecVArgs, env: _ExecEnv) -> NoReturn: ...
 def execvp(file: StrOrBytesPath, args: _ExecVArgs) -> NoReturn: ...
 def execvpe(file: StrOrBytesPath, args: _ExecVArgs, env: _ExecEnv) -> NoReturn: ...
 def _exit(status: int) -> NoReturn: ...
diff --git a/mypy/typeshed/stdlib/posixpath.pyi b/mypy/typeshed/stdlib/posixpath.pyi
index 8d880a072dfb6..ff9c2482ace5a 100644
--- a/mypy/typeshed/stdlib/posixpath.pyi
+++ b/mypy/typeshed/stdlib/posixpath.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import AnyOrLiteralStr, BytesPath, StrOrBytesPath, StrPath
+from _typeshed import AnyOrLiteralStr, BytesPath, FileDescriptorOrPath, StrOrBytesPath, StrPath
 from collections.abc import Sequence
 from genericpath import (
     commonprefix as commonprefix,
@@ -147,6 +147,6 @@ def splitext(p: PathLike[AnyStr]) -> tuple[AnyStr, AnyStr]: ...
 @overload
 def splitext(p: AnyOrLiteralStr) -> tuple[AnyOrLiteralStr, AnyOrLiteralStr]: ...
 def isabs(s: StrOrBytesPath) -> bool: ...
-def islink(path: StrOrBytesPath | int) -> bool: ...
-def ismount(path: StrOrBytesPath | int) -> bool: ...
-def lexists(path: StrOrBytesPath | int) -> bool: ...
+def islink(path: FileDescriptorOrPath) -> bool: ...
+def ismount(path: FileDescriptorOrPath) -> bool: ...
+def lexists(path: FileDescriptorOrPath) -> bool: ...
diff --git a/mypy/typeshed/stdlib/shutil.pyi b/mypy/typeshed/stdlib/shutil.pyi
index 568879d760036..6dbfbcc069980 100644
--- a/mypy/typeshed/stdlib/shutil.pyi
+++ b/mypy/typeshed/stdlib/shutil.pyi
@@ -1,6 +1,6 @@
 import os
 import sys
-from _typeshed import BytesPath, StrOrBytesPath, StrPath, SupportsRead, SupportsWrite
+from _typeshed import BytesPath, FileDescriptorOrPath, StrOrBytesPath, StrPath, SupportsRead, SupportsWrite
 from collections.abc import Callable, Iterable, Sequence
 from typing import Any, AnyStr, NamedTuple, Protocol, TypeVar, overload
 from typing_extensions import TypeAlias
@@ -118,7 +118,7 @@ class _ntuple_diskusage(NamedTuple):
     used: int
     free: int
 
-def disk_usage(path: int | StrOrBytesPath) -> _ntuple_diskusage: ...
+def disk_usage(path: FileDescriptorOrPath) -> _ntuple_diskusage: ...
 
 # While chown can be imported on Windows, it doesn't actually work;
 # see https://bugs.python.org/issue33140. We keep it here because it's
diff --git a/mypy/typeshed/stdlib/socketserver.pyi b/mypy/typeshed/stdlib/socketserver.pyi
index e597818ef7da9..b5147d356ffed 100644
--- a/mypy/typeshed/stdlib/socketserver.pyi
+++ b/mypy/typeshed/stdlib/socketserver.pyi
@@ -1,6 +1,7 @@
 import sys
 import types
-from _typeshed import Self
+from _socket import _Address, _RetAddress
+from _typeshed import ReadableBuffer, Self
 from collections.abc import Callable
 from socket import socket as _socket
 from typing import Any, BinaryIO, ClassVar, Union
@@ -29,38 +30,39 @@ if sys.platform != "win32":
     ]
 
 _RequestType: TypeAlias = Union[_socket, tuple[bytes, _socket]]
-_AddressType: TypeAlias = Union[tuple[str, int], str]
+_AfUnixAddress: TypeAlias = str | ReadableBuffer  # adddress acceptable for an AF_UNIX socket
+_AfInetAddress: TypeAlias = tuple[str | bytes | bytearray, int]  # address acceptable for an AF_INET socket
 
 # This can possibly be generic at some point:
 class BaseServer:
     address_family: int
-    server_address: tuple[str, int]
+    server_address: _Address
     socket: _socket
     allow_reuse_address: bool
     request_queue_size: int
     socket_type: int
     timeout: float | None
     def __init__(
-        self: Self, server_address: Any, RequestHandlerClass: Callable[[Any, Any, Self], BaseRequestHandler]
+        self: Self, server_address: _Address, RequestHandlerClass: Callable[[Any, _RetAddress, Self], BaseRequestHandler]
     ) -> None: ...
     # It is not actually a `@property`, but we need a `Self` type:
     @property
-    def RequestHandlerClass(self: Self) -> Callable[[Any, Any, Self], BaseRequestHandler]: ...
+    def RequestHandlerClass(self: Self) -> Callable[[Any, _RetAddress, Self], BaseRequestHandler]: ...
     @RequestHandlerClass.setter
-    def RequestHandlerClass(self: Self, val: Callable[[Any, Any, Self], BaseRequestHandler]) -> None: ...
+    def RequestHandlerClass(self: Self, val: Callable[[Any, _RetAddress, Self], BaseRequestHandler]) -> None: ...
     def fileno(self) -> int: ...
     def handle_request(self) -> None: ...
     def serve_forever(self, poll_interval: float = ...) -> None: ...
     def shutdown(self) -> None: ...
     def server_close(self) -> None: ...
-    def finish_request(self, request: _RequestType, client_address: _AddressType) -> None: ...
+    def finish_request(self, request: _RequestType, client_address: _RetAddress) -> None: ...
     def get_request(self) -> tuple[Any, Any]: ...
-    def handle_error(self, request: _RequestType, client_address: _AddressType) -> None: ...
+    def handle_error(self, request: _RequestType, client_address: _RetAddress) -> None: ...
     def handle_timeout(self) -> None: ...
-    def process_request(self, request: _RequestType, client_address: _AddressType) -> None: ...
+    def process_request(self, request: _RequestType, client_address: _RetAddress) -> None: ...
     def server_activate(self) -> None: ...
     def server_bind(self) -> None: ...
-    def verify_request(self, request: _RequestType, client_address: _AddressType) -> bool: ...
+    def verify_request(self, request: _RequestType, client_address: _RetAddress) -> bool: ...
     def __enter__(self: Self) -> Self: ...
     def __exit__(
         self, exc_type: type[BaseException] | None, exc_val: BaseException | None, exc_tb: types.TracebackType | None
@@ -72,32 +74,35 @@ class BaseServer:
 class TCPServer(BaseServer):
     if sys.version_info >= (3, 11):
         allow_reuse_port: bool
+    server_address: _AfInetAddress  # type: ignore[assignment]
     def __init__(
         self: Self,
-        server_address: tuple[str, int],
-        RequestHandlerClass: Callable[[Any, Any, Self], BaseRequestHandler],
+        server_address: _AfInetAddress,
+        RequestHandlerClass: Callable[[Any, _RetAddress, Self], BaseRequestHandler],
         bind_and_activate: bool = ...,
     ) -> None: ...
-    def get_request(self) -> tuple[_socket, Any]: ...
+    def get_request(self) -> tuple[_socket, _RetAddress]: ...
 
 class UDPServer(TCPServer):
     max_packet_size: ClassVar[int]
-    def get_request(self) -> tuple[tuple[bytes, _socket], Any]: ...  # type: ignore[override]
+    def get_request(self) -> tuple[tuple[bytes, _socket], _RetAddress]: ...  # type: ignore[override]
 
 if sys.platform != "win32":
     class UnixStreamServer(BaseServer):
+        server_address: _AfUnixAddress  # type: ignore[assignment]
         def __init__(
             self: Self,
-            server_address: str | bytes,
-            RequestHandlerClass: Callable[[Any, Any, Self], BaseRequestHandler],
+            server_address: _AfUnixAddress,
+            RequestHandlerClass: Callable[[Any, _RetAddress, Self], BaseRequestHandler],
             bind_and_activate: bool = ...,
         ) -> None: ...
 
     class UnixDatagramServer(BaseServer):
+        server_address: _AfUnixAddress  # type: ignore[assignment]
         def __init__(
             self: Self,
-            server_address: str | bytes,
-            RequestHandlerClass: Callable[[Any, Any, Self], BaseRequestHandler],
+            server_address: _AfUnixAddress,
+            RequestHandlerClass: Callable[[Any, _RetAddress, Self], BaseRequestHandler],
             bind_and_activate: bool = ...,
         ) -> None: ...
 
@@ -110,14 +115,14 @@ if sys.platform != "win32":
         def collect_children(self, *, blocking: bool = ...) -> None: ...  # undocumented
         def handle_timeout(self) -> None: ...  # undocumented
         def service_actions(self) -> None: ...  # undocumented
-        def process_request(self, request: _RequestType, client_address: _AddressType) -> None: ...
+        def process_request(self, request: _RequestType, client_address: _RetAddress) -> None: ...
         def server_close(self) -> None: ...
 
 class ThreadingMixIn:
     daemon_threads: bool
     block_on_close: bool
-    def process_request_thread(self, request: _RequestType, client_address: _AddressType) -> None: ...  # undocumented
-    def process_request(self, request: _RequestType, client_address: _AddressType) -> None: ...
+    def process_request_thread(self, request: _RequestType, client_address: _RetAddress) -> None: ...  # undocumented
+    def process_request(self, request: _RequestType, client_address: _RetAddress) -> None: ...
     def server_close(self) -> None: ...
 
 if sys.platform != "win32":
@@ -132,16 +137,16 @@ if sys.platform != "win32":
     class ThreadingUnixDatagramServer(ThreadingMixIn, UnixDatagramServer): ...
 
 class BaseRequestHandler:
-    # Those are technically of types, respectively:
-    # * _RequestType
-    # * _AddressType
-    # But there are some concerns that having unions here would cause
+    # `request` is technically of type _RequestType,
+    # but there are some concerns that having a union here would cause
     # too much inconvenience to people using it (see
     # https://github.com/python/typeshed/pull/384#issuecomment-234649696)
+    #
+    # Note also that _RetAddress is also just an alias for `Any`
     request: Any
-    client_address: Any
+    client_address: _RetAddress
     server: BaseServer
-    def __init__(self, request: _RequestType, client_address: _AddressType, server: BaseServer) -> None: ...
+    def __init__(self, request: _RequestType, client_address: _RetAddress, server: BaseServer) -> None: ...
     def setup(self) -> None: ...
     def handle(self) -> None: ...
     def finish(self) -> None: ...
diff --git a/mypy/typeshed/stdlib/ssl.pyi b/mypy/typeshed/stdlib/ssl.pyi
index 91844e8369df3..6d7df5e1c202e 100644
--- a/mypy/typeshed/stdlib/ssl.pyi
+++ b/mypy/typeshed/stdlib/ssl.pyi
@@ -63,18 +63,34 @@ def create_default_context(
     capath: StrOrBytesPath | None = ...,
     cadata: str | ReadableBuffer | None = ...,
 ) -> SSLContext: ...
-def _create_unverified_context(
-    protocol: int = ...,
-    *,
-    cert_reqs: int = ...,
-    check_hostname: bool = ...,
-    purpose: Purpose = ...,
-    certfile: StrOrBytesPath | None = ...,
-    keyfile: StrOrBytesPath | None = ...,
-    cafile: StrOrBytesPath | None = ...,
-    capath: StrOrBytesPath | None = ...,
-    cadata: str | ReadableBuffer | None = ...,
-) -> SSLContext: ...
+
+if sys.version_info >= (3, 10):
+    def _create_unverified_context(
+        protocol: int | None = None,
+        *,
+        cert_reqs: int = ...,
+        check_hostname: bool = ...,
+        purpose: Purpose = ...,
+        certfile: StrOrBytesPath | None = ...,
+        keyfile: StrOrBytesPath | None = ...,
+        cafile: StrOrBytesPath | None = ...,
+        capath: StrOrBytesPath | None = ...,
+        cadata: str | ReadableBuffer | None = ...,
+    ) -> SSLContext: ...
+
+else:
+    def _create_unverified_context(
+        protocol: int = ...,
+        *,
+        cert_reqs: int = ...,
+        check_hostname: bool = ...,
+        purpose: Purpose = ...,
+        certfile: StrOrBytesPath | None = ...,
+        keyfile: StrOrBytesPath | None = ...,
+        cafile: StrOrBytesPath | None = ...,
+        capath: StrOrBytesPath | None = ...,
+        cadata: str | ReadableBuffer | None = ...,
+    ) -> SSLContext: ...
 
 _create_default_https_context: Callable[..., SSLContext]
 
diff --git a/mypy/typeshed/stdlib/subprocess.pyi b/mypy/typeshed/stdlib/subprocess.pyi
index 450eb8cd24d10..c0b10a7781c3a 100644
--- a/mypy/typeshed/stdlib/subprocess.pyi
+++ b/mypy/typeshed/stdlib/subprocess.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import Self, StrOrBytesPath
+from _typeshed import ReadableBuffer, Self, StrOrBytesPath
 from collections.abc import Callable, Collection, Iterable, Mapping, Sequence
 from types import TracebackType
 from typing import IO, Any, AnyStr, Generic, TypeVar, overload
@@ -63,13 +63,13 @@ if sys.platform == "win32":
 # except TimeoutError as e:
 #    reveal_type(e.cmd)  # Any, but morally is _CMD
 _FILE: TypeAlias = None | int | IO[Any]
-_TXT: TypeAlias = bytes | str
+_InputString: TypeAlias = ReadableBuffer | str
 if sys.version_info >= (3, 8):
     _CMD: TypeAlias = StrOrBytesPath | Sequence[StrOrBytesPath]
 else:
     # Python 3.7 doesn't support _CMD being a single PathLike.
     # See: https://bugs.python.org/issue31961
-    _CMD: TypeAlias = _TXT | Sequence[StrOrBytesPath]
+    _CMD: TypeAlias = str | bytes | Sequence[StrOrBytesPath]
 if sys.platform == "win32":
     _ENV: TypeAlias = Mapping[str, str]
 else:
@@ -118,7 +118,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -152,7 +152,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -186,7 +186,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -255,7 +255,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -266,7 +266,7 @@ if sys.version_info >= (3, 11):
         check: bool = ...,
         encoding: None = ...,
         errors: None = ...,
-        input: bytes | None = ...,
+        input: ReadableBuffer | None = ...,
         text: Literal[None, False] = ...,
         timeout: float | None = ...,
         user: str | int | None = ...,
@@ -289,7 +289,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -300,7 +300,7 @@ if sys.version_info >= (3, 11):
         check: bool = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         text: bool | None = ...,
         timeout: float | None = ...,
         user: str | int | None = ...,
@@ -326,7 +326,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -359,7 +359,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -392,7 +392,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -459,7 +459,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -470,7 +470,7 @@ elif sys.version_info >= (3, 10):
         check: bool = ...,
         encoding: None = ...,
         errors: None = ...,
-        input: bytes | None = ...,
+        input: ReadableBuffer | None = ...,
         text: Literal[None, False] = ...,
         timeout: float | None = ...,
         user: str | int | None = ...,
@@ -492,7 +492,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -503,7 +503,7 @@ elif sys.version_info >= (3, 10):
         check: bool = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         text: bool | None = ...,
         timeout: float | None = ...,
         user: str | int | None = ...,
@@ -528,7 +528,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -560,7 +560,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -592,7 +592,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -657,7 +657,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -668,7 +668,7 @@ elif sys.version_info >= (3, 9):
         check: bool = ...,
         encoding: None = ...,
         errors: None = ...,
-        input: bytes | None = ...,
+        input: ReadableBuffer | None = ...,
         text: Literal[None, False] = ...,
         timeout: float | None = ...,
         user: str | int | None = ...,
@@ -689,7 +689,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -700,7 +700,7 @@ elif sys.version_info >= (3, 9):
         check: bool = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         text: bool | None = ...,
         timeout: float | None = ...,
         user: str | int | None = ...,
@@ -723,7 +723,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -751,7 +751,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -779,7 +779,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -836,7 +836,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -847,7 +847,7 @@ else:
         check: bool = ...,
         encoding: None = ...,
         errors: None = ...,
-        input: bytes | None = ...,
+        input: ReadableBuffer | None = ...,
         text: Literal[None, False] = ...,
         timeout: float | None = ...,
     ) -> CompletedProcess[bytes]: ...
@@ -864,7 +864,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -875,7 +875,7 @@ else:
         check: bool = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         text: bool | None = ...,
         timeout: float | None = ...,
     ) -> CompletedProcess[Any]: ...
@@ -895,7 +895,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -926,7 +926,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -956,7 +956,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -984,7 +984,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1010,7 +1010,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1041,7 +1041,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1071,7 +1071,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1099,7 +1099,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1124,7 +1124,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1132,7 +1132,7 @@ if sys.version_info >= (3, 11):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: Literal[True],
@@ -1155,7 +1155,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1163,7 +1163,7 @@ if sys.version_info >= (3, 11):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1186,7 +1186,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1194,7 +1194,7 @@ if sys.version_info >= (3, 11):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str,
         text: bool | None = ...,
@@ -1226,7 +1226,7 @@ if sys.version_info >= (3, 11):
         pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1249,7 +1249,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1257,7 +1257,7 @@ if sys.version_info >= (3, 11):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: None = ...,
         errors: None = ...,
         text: Literal[None, False] = ...,
@@ -1280,7 +1280,7 @@ if sys.version_info >= (3, 11):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1288,7 +1288,7 @@ if sys.version_info >= (3, 11):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1298,7 +1298,7 @@ if sys.version_info >= (3, 11):
         umask: int = ...,
         pipesize: int = ...,
         process_group: int | None = ...,
-    ) -> Any: ...  # morally: -> _TXT
+    ) -> Any: ...  # morally: -> str | bytes
 
 elif sys.version_info >= (3, 10):
     # 3.10 adds "pipesize" argument
@@ -1314,7 +1314,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1322,7 +1322,7 @@ elif sys.version_info >= (3, 10):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: Literal[True],
@@ -1344,7 +1344,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1352,7 +1352,7 @@ elif sys.version_info >= (3, 10):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1374,7 +1374,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1382,7 +1382,7 @@ elif sys.version_info >= (3, 10):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str,
         text: bool | None = ...,
@@ -1413,7 +1413,7 @@ elif sys.version_info >= (3, 10):
         pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1435,7 +1435,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1443,7 +1443,7 @@ elif sys.version_info >= (3, 10):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: None = ...,
         errors: None = ...,
         text: Literal[None, False] = ...,
@@ -1465,7 +1465,7 @@ elif sys.version_info >= (3, 10):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1473,7 +1473,7 @@ elif sys.version_info >= (3, 10):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1482,7 +1482,7 @@ elif sys.version_info >= (3, 10):
         extra_groups: Iterable[str | int] | None = ...,
         umask: int = ...,
         pipesize: int = ...,
-    ) -> Any: ...  # morally: -> _TXT
+    ) -> Any: ...  # morally: -> str | bytes
 
 elif sys.version_info >= (3, 9):
     # 3.9 adds arguments "user", "group", "extra_groups" and "umask"
@@ -1498,7 +1498,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1506,7 +1506,7 @@ elif sys.version_info >= (3, 9):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: Literal[True],
@@ -1527,7 +1527,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1535,7 +1535,7 @@ elif sys.version_info >= (3, 9):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1556,7 +1556,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1564,7 +1564,7 @@ elif sys.version_info >= (3, 9):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str,
         text: bool | None = ...,
@@ -1594,7 +1594,7 @@ elif sys.version_info >= (3, 9):
         pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1615,7 +1615,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1623,7 +1623,7 @@ elif sys.version_info >= (3, 9):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: None = ...,
         errors: None = ...,
         text: Literal[None, False] = ...,
@@ -1644,7 +1644,7 @@ elif sys.version_info >= (3, 9):
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1652,7 +1652,7 @@ elif sys.version_info >= (3, 9):
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1660,7 +1660,7 @@ elif sys.version_info >= (3, 9):
         group: str | int | None = ...,
         extra_groups: Iterable[str | int] | None = ...,
         umask: int = ...,
-    ) -> Any: ...  # morally: -> _TXT
+    ) -> Any: ...  # morally: -> str | bytes
 
 else:
     @overload
@@ -1675,7 +1675,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1683,7 +1683,7 @@ else:
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: Literal[True],
@@ -1700,7 +1700,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1708,7 +1708,7 @@ else:
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1725,7 +1725,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1733,7 +1733,7 @@ else:
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str,
         text: bool | None = ...,
@@ -1759,7 +1759,7 @@ else:
         pass_fds: Collection[int] = ...,
         # where the real keyword only ones start
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
@@ -1776,7 +1776,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: Literal[False] = ...,
+        universal_newlines: Literal[False, None] = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1784,7 +1784,7 @@ else:
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: None = ...,
         errors: None = ...,
         text: Literal[None, False] = ...,
@@ -1801,7 +1801,7 @@ else:
         shell: bool = ...,
         cwd: StrOrBytesPath | None = ...,
         env: _ENV | None = ...,
-        universal_newlines: bool = ...,
+        universal_newlines: bool | None = ...,
         startupinfo: Any = ...,
         creationflags: int = ...,
         restore_signals: bool = ...,
@@ -1809,11 +1809,11 @@ else:
         pass_fds: Collection[int] = ...,
         *,
         timeout: float | None = ...,
-        input: _TXT | None = ...,
+        input: _InputString | None = ...,
         encoding: str | None = ...,
         errors: str | None = ...,
         text: bool | None = ...,
-    ) -> Any: ...  # morally: -> _TXT
+    ) -> Any: ...  # morally: -> str | bytes
 
 PIPE: int
 STDOUT: int
@@ -1822,11 +1822,11 @@ DEVNULL: int
 class SubprocessError(Exception): ...
 
 class TimeoutExpired(SubprocessError):
-    def __init__(self, cmd: _CMD, timeout: float, output: _TXT | None = ..., stderr: _TXT | None = ...) -> None: ...
+    def __init__(self, cmd: _CMD, timeout: float, output: str | bytes | None = ..., stderr: str | bytes | None = ...) -> None: ...
     # morally: _CMD
     cmd: Any
     timeout: float
-    # morally: _TXT | None
+    # morally: str | bytes | None
     output: Any
     stdout: bytes | None
     stderr: bytes | None
@@ -1835,13 +1835,15 @@ class CalledProcessError(SubprocessError):
     returncode: int
     # morally: _CMD
     cmd: Any
-    # morally: _TXT | None
+    # morally: str | bytes | None
     output: Any
 
-    # morally: _TXT | None
+    # morally: str | bytes | None
     stdout: Any
     stderr: Any
-    def __init__(self, returncode: int, cmd: _CMD, output: _TXT | None = ..., stderr: _TXT | None = ...) -> None: ...
+    def __init__(
+        self, returncode: int, cmd: _CMD, output: str | bytes | None = ..., stderr: str | bytes | None = ...
+    ) -> None: ...
 
 class Popen(Generic[AnyStr]):
     args: _CMD
@@ -1868,7 +1870,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -1899,7 +1901,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -1962,7 +1964,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -1993,7 +1995,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: Literal[False] = ...,
+            universal_newlines: Literal[False, None] = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2024,7 +2026,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2057,7 +2059,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2087,7 +2089,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2148,7 +2150,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2178,7 +2180,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: Literal[False] = ...,
+            universal_newlines: Literal[False, None] = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2208,7 +2210,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2240,7 +2242,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2269,7 +2271,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2328,7 +2330,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2357,7 +2359,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: Literal[False] = ...,
+            universal_newlines: Literal[False, None] = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2386,7 +2388,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2416,7 +2418,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2441,7 +2443,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2492,7 +2494,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2517,7 +2519,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: Literal[False] = ...,
+            universal_newlines: Literal[False, None] = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2542,7 +2544,7 @@ class Popen(Generic[AnyStr]):
             shell: bool = ...,
             cwd: StrOrBytesPath | None = ...,
             env: _ENV | None = ...,
-            universal_newlines: bool = ...,
+            universal_newlines: bool | None = ...,
             startupinfo: Any | None = ...,
             creationflags: int = ...,
             restore_signals: bool = ...,
@@ -2556,13 +2558,10 @@ class Popen(Generic[AnyStr]):
 
     def poll(self) -> int | None: ...
     def wait(self, timeout: float | None = ...) -> int: ...
-    # Return str/bytes
-    def communicate(
-        self,
-        input: AnyStr | None = ...,
-        timeout: float | None = ...,
-        # morally this should be optional
-    ) -> tuple[AnyStr, AnyStr]: ...
+    # morally the members of the returned tuple should be optional
+    # TODO this should allow ReadableBuffer for Popen[bytes], but adding
+    # overloads for that runs into a mypy bug (python/mypy#14070).
+    def communicate(self, input: AnyStr | None = ..., timeout: float | None = ...) -> tuple[AnyStr, AnyStr]: ...
     def send_signal(self, sig: int) -> None: ...
     def terminate(self) -> None: ...
     def kill(self) -> None: ...
@@ -2575,12 +2574,12 @@ class Popen(Generic[AnyStr]):
 
 # The result really is always a str.
 if sys.version_info >= (3, 11):
-    def getstatusoutput(cmd: _TXT, *, encoding: str | None = ..., errors: str | None = ...) -> tuple[int, str]: ...
-    def getoutput(cmd: _TXT, *, encoding: str | None = ..., errors: str | None = ...) -> str: ...
+    def getstatusoutput(cmd: str | bytes, *, encoding: str | None = ..., errors: str | None = ...) -> tuple[int, str]: ...
+    def getoutput(cmd: str | bytes, *, encoding: str | None = ..., errors: str | None = ...) -> str: ...
 
 else:
-    def getstatusoutput(cmd: _TXT) -> tuple[int, str]: ...
-    def getoutput(cmd: _TXT) -> str: ...
+    def getstatusoutput(cmd: str | bytes) -> tuple[int, str]: ...
+    def getoutput(cmd: str | bytes) -> str: ...
 
 if sys.version_info >= (3, 8):
     def list2cmdline(seq: Iterable[StrOrBytesPath]) -> str: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/sysconfig.pyi b/mypy/typeshed/stdlib/sysconfig.pyi
index 895abc2cd0477..4b6257b5f62e0 100644
--- a/mypy/typeshed/stdlib/sysconfig.pyi
+++ b/mypy/typeshed/stdlib/sysconfig.pyi
@@ -32,7 +32,13 @@ def get_path(name: str, scheme: str = ..., vars: dict[str, Any] | None = ..., ex
 def get_paths(scheme: str = ..., vars: dict[str, Any] | None = ..., expand: bool = ...) -> dict[str, str]: ...
 def get_python_version() -> str: ...
 def get_platform() -> str: ...
-def is_python_build(check_home: bool = ...) -> bool: ...
+
+if sys.version_info >= (3, 11):
+    def is_python_build(check_home: object = None) -> bool: ...
+
+else:
+    def is_python_build(check_home: bool = False) -> bool: ...
+
 def parse_config_h(fp: IO[Any], vars: dict[str, Any] | None = ...) -> dict[str, Any]: ...
 def get_config_h_filename() -> str: ...
 def get_makefile_filename() -> str: ...
diff --git a/mypy/typeshed/stdlib/tokenize.pyi b/mypy/typeshed/stdlib/tokenize.pyi
index 7c00b507a528b..ba57402fb8455 100644
--- a/mypy/typeshed/stdlib/tokenize.pyi
+++ b/mypy/typeshed/stdlib/tokenize.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import StrOrBytesPath
+from _typeshed import FileDescriptorOrPath
 from collections.abc import Callable, Generator, Iterable, Sequence
 from re import Pattern
 from token import *
@@ -125,7 +125,7 @@ def untokenize(iterable: Iterable[_Token]) -> Any: ...
 def detect_encoding(readline: Callable[[], bytes | bytearray]) -> tuple[str, Sequence[bytes]]: ...
 def tokenize(readline: Callable[[], bytes | bytearray]) -> Generator[TokenInfo, None, None]: ...
 def generate_tokens(readline: Callable[[], str]) -> Generator[TokenInfo, None, None]: ...  # undocumented
-def open(filename: StrOrBytesPath | int) -> TextIO: ...
+def open(filename: FileDescriptorOrPath) -> TextIO: ...
 def group(*choices: str) -> str: ...  # undocumented
 def any(*choices: str) -> str: ...  # undocumented
 def maybe(*choices: str) -> str: ...  # undocumented
diff --git a/mypy/typeshed/stdlib/urllib/parse.pyi b/mypy/typeshed/stdlib/urllib/parse.pyi
index efb91a4b34fff..8fe5d8b37ac06 100644
--- a/mypy/typeshed/stdlib/urllib/parse.pyi
+++ b/mypy/typeshed/stdlib/urllib/parse.pyi
@@ -158,10 +158,10 @@ _Q = TypeVar("_Q", bound=str | Iterable[int])
 
 def urlencode(
     query: Mapping[Any, Any] | Mapping[Any, Sequence[Any]] | Sequence[tuple[Any, Any]] | Sequence[tuple[Any, Sequence[Any]]],
-    doseq: bool = ...,
+    doseq: bool = False,
     safe: _Q = ...,
-    encoding: str = ...,
-    errors: str = ...,
+    encoding: str | None = None,
+    errors: str | None = None,
     quote_via: Callable[[AnyStr, _Q, str, str], str] = ...,
 ) -> str: ...
 def urljoin(base: AnyStr, url: AnyStr | None, allow_fragments: bool = ...) -> AnyStr: ...
diff --git a/mypy/typeshed/stdlib/venv/__init__.pyi b/mypy/typeshed/stdlib/venv/__init__.pyi
index 2e34aed4c6934..dfa0b69b08702 100644
--- a/mypy/typeshed/stdlib/venv/__init__.pyi
+++ b/mypy/typeshed/stdlib/venv/__init__.pyi
@@ -1,8 +1,11 @@
+import logging
 import sys
 from _typeshed import StrOrBytesPath
 from collections.abc import Sequence
 from types import SimpleNamespace
 
+logger: logging.Logger
+
 if sys.version_info >= (3, 9):
     CORE_VENV_DEPS: tuple[str, ...]
 
diff --git a/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi b/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi
index 3e3e3f2662065..43b394bd67ec4 100644
--- a/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi
+++ b/mypy/typeshed/stdlib/xml/etree/ElementInclude.pyi
@@ -1,5 +1,5 @@
 import sys
-from _typeshed import StrOrBytesPath
+from _typeshed import FileDescriptorOrPath
 from collections.abc import Callable
 from xml.etree.ElementTree import Element
 
@@ -12,7 +12,7 @@ if sys.version_info >= (3, 9):
 
 class FatalIncludeError(SyntaxError): ...
 
-def default_loader(href: StrOrBytesPath | int, parse: str, encoding: str | None = ...) -> str | Element: ...
+def default_loader(href: FileDescriptorOrPath, parse: str, encoding: str | None = ...) -> str | Element: ...
 
 # TODO: loader is of type default_loader ie it takes a callable that has the
 # same signature as default_loader. But default_loader has a keyword argument
diff --git a/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi b/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
index c063c1fd34883..2b6191a395c39 100644
--- a/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
+++ b/mypy/typeshed/stdlib/xml/etree/ElementTree.pyi
@@ -1,6 +1,6 @@
 import sys
 from _collections_abc import dict_keys
-from _typeshed import FileDescriptor, ReadableBuffer, StrOrBytesPath, SupportsRead, SupportsWrite
+from _typeshed import FileDescriptorOrPath, ReadableBuffer, SupportsRead, SupportsWrite
 from collections.abc import Callable, Generator, ItemsView, Iterable, Iterator, Mapping, Sequence
 from typing import Any, TypeVar, overload
 from typing_extensions import Literal, SupportsIndex, TypeAlias, TypeGuard
@@ -38,8 +38,8 @@ if sys.version_info >= (3, 9):
     __all__ += ["indent"]
 
 _T = TypeVar("_T")
-_FileRead: TypeAlias = StrOrBytesPath | FileDescriptor | SupportsRead[bytes] | SupportsRead[str]
-_FileWriteC14N: TypeAlias = StrOrBytesPath | FileDescriptor | SupportsWrite[bytes]
+_FileRead: TypeAlias = FileDescriptorOrPath | SupportsRead[bytes] | SupportsRead[str]
+_FileWriteC14N: TypeAlias = FileDescriptorOrPath | SupportsWrite[bytes]
 _FileWrite: TypeAlias = _FileWriteC14N | SupportsWrite[str]
 
 VERSION: str

From e9f5858c44b61c2d02819940debe3c31d099f9d5 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 16 Jan 2023 08:30:42 +0000
Subject: [PATCH 182/231] Run lint in parallel in runtest.py (#14448)

Give flake8 3 parallel processes. Previously it was sequential.

Assuming that most developers have a machine with at least 4 cores, we
have at least one left for self check, which is run in parallel with
lint.
---
 runtests.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/runtests.py b/runtests.py
index be4ad4add08a3..ade0a8adee5e9 100755
--- a/runtests.py
+++ b/runtests.py
@@ -50,7 +50,7 @@
     # Self type check
     "self": [executable, "-m", "mypy", "--config-file", "mypy_self_check.ini", "-p", "mypy"],
     # Lint
-    "lint": ["flake8", "-j0"],
+    "lint": ["flake8", "-j3"],
     "format-black": ["black", "."],
     "format-isort": ["isort", "."],
     # Fast test cases only (this is the bulk of the test suite)

From e88f4a471f31c7b730477266244505fb7715f463 Mon Sep 17 00:00:00 2001
From: Richard Si <sichard26@gmail.com>
Date: Mon, 16 Jan 2023 05:24:27 -0500
Subject: [PATCH 183/231] [mypyc] Always emit warnings (#14451)

For example the warning for "treating generator comprehension as list"
doesn't get printed unless there were errors too. This was due to the
fact mypyc/build.py was only checking errors.num_errors to decide
whether to print messages to STDOUT.

To be honest, the generate_c() logic was pretty messy, so I broke out
the message printing logic into a separate helper function and made
liberal use of early exits.

Fixes https://github.com/mypyc/mypyc/issues/873#issuecomment-871055474.
---
 mypyc/build.py                   | 51 +++++++++++++++-----------------
 mypyc/test-data/commandline.test |  6 ++++
 mypyc/test/test_commandline.py   |  5 ++++
 3 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/mypyc/build.py b/mypyc/build.py
index a9aa16f5dfee3..cc03eba95b4ee 100644
--- a/mypyc/build.py
+++ b/mypyc/build.py
@@ -85,6 +85,15 @@ def fail(message: str) -> NoReturn:
     sys.exit(message)
 
 
+def emit_messages(options: Options, messages: list[str], dt: float, serious: bool = False) -> None:
+    # ... you know, just in case.
+    if options.junit_xml:
+        py_version = f"{options.python_version[0]}_{options.python_version[1]}"
+        write_junit_xml(dt, serious, messages, options.junit_xml, py_version, options.platform)
+    if messages:
+        print("\n".join(messages))
+
+
 def get_mypy_config(
     mypy_options: list[str],
     only_compile_paths: Iterable[str] | None,
@@ -191,47 +200,35 @@ def generate_c(
     """
     t0 = time.time()
 
-    # Do the actual work now
-    serious = False
-    result = None
     try:
         result = emitmodule.parse_and_typecheck(
             sources, options, compiler_options, groups, fscache
         )
-        messages = result.errors
     except CompileError as e:
-        messages = e.messages
-        if not e.use_stdout:
-            serious = True
+        emit_messages(options, e.messages, time.time() - t0, serious=(not e.use_stdout))
+        sys.exit(1)
 
     t1 = time.time()
+    if result.errors:
+        emit_messages(options, result.errors, t1 - t0)
+        sys.exit(1)
+
     if compiler_options.verbose:
         print(f"Parsed and typechecked in {t1 - t0:.3f}s")
 
-    if not messages and result:
-        errors = Errors()
-        modules, ctext = emitmodule.compile_modules_to_c(
-            result, compiler_options=compiler_options, errors=errors, groups=groups
-        )
-
-        if errors.num_errors:
-            messages.extend(errors.new_messages())
-
+    errors = Errors()
+    modules, ctext = emitmodule.compile_modules_to_c(
+        result, compiler_options=compiler_options, errors=errors, groups=groups
+    )
     t2 = time.time()
+    emit_messages(options, errors.new_messages(), t2 - t1)
+    if errors.num_errors:
+        # No need to stop the build if only warnings were emitted.
+        sys.exit(1)
+
     if compiler_options.verbose:
         print(f"Compiled to C in {t2 - t1:.3f}s")
 
-    # ... you know, just in case.
-    if options.junit_xml:
-        py_version = f"{options.python_version[0]}_{options.python_version[1]}"
-        write_junit_xml(
-            t2 - t0, serious, messages, options.junit_xml, py_version, options.platform
-        )
-
-    if messages:
-        print("\n".join(messages))
-        sys.exit(1)
-
     return ctext, "\n".join(format_modules(modules))
 
 
diff --git a/mypyc/test-data/commandline.test b/mypyc/test-data/commandline.test
index bc2713a20f7dd..e7ba11192d286 100644
--- a/mypyc/test-data/commandline.test
+++ b/mypyc/test-data/commandline.test
@@ -223,3 +223,9 @@ def h(arg: str) -> None:
 @a.register
 def i(arg: Foo) -> None:
     pass
+
+[case testOnlyWarningOutput]
+# cmd: test.py
+
+[file test.py]
+names = (str(v) for v in [1, 2, 3])  # W: Treating generator comprehension as list
diff --git a/mypyc/test/test_commandline.py b/mypyc/test/test_commandline.py
index aafe1e4adc1b1..f66ca2ec8ff02 100644
--- a/mypyc/test/test_commandline.py
+++ b/mypyc/test/test_commandline.py
@@ -58,6 +58,11 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
             )
             if "ErrorOutput" in testcase.name or cmd.returncode != 0:
                 out += cmd.stdout
+            elif "WarningOutput" in testcase.name:
+                # Strip out setuptools build related output since we're only
+                # interested in the messages emitted during compilation.
+                messages, _, _ = cmd.stdout.partition(b"running build_ext")
+                out += messages
 
             if cmd.returncode == 0:
                 # Run main program

From f957a39f4338e6532dd7381230d07cf51c72f265 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 16 Jan 2023 11:07:21 +0000
Subject: [PATCH 184/231] Add scripts for running mypy and mypyc tests inside a
 Docker container (#14454)

This speeds up running `pytest mypyc/test/test_run.py` by over 3x on a
Mac mini M1. Mypy test performance is fairly similar to running
natively.

Example of how to use these on macOS:
```
$ colima start -c 8  # Start VM
$ python3 misc/docker/build.py  # Build Ubuntu container with test dependencies
$ misc/docker/run.sh pytest mypyc/test/test_run.py  # Run tests in container
```

Also add a README that documents how to use these.

Closes #14453.
---
 misc/docker/Dockerfile     |  12 +++++
 misc/docker/README.md      | 101 +++++++++++++++++++++++++++++++++++++
 misc/docker/build.py       |  46 +++++++++++++++++
 misc/docker/run-wrapper.sh |  13 +++++
 misc/docker/run.sh         |  15 ++++++
 5 files changed, 187 insertions(+)
 create mode 100644 misc/docker/Dockerfile
 create mode 100644 misc/docker/README.md
 create mode 100644 misc/docker/build.py
 create mode 100755 misc/docker/run-wrapper.sh
 create mode 100755 misc/docker/run.sh

diff --git a/misc/docker/Dockerfile b/misc/docker/Dockerfile
new file mode 100644
index 0000000000000..3327f9e38815e
--- /dev/null
+++ b/misc/docker/Dockerfile
@@ -0,0 +1,12 @@
+FROM ubuntu:latest
+
+WORKDIR /mypy
+
+RUN apt-get update
+RUN apt-get install -y python3 python3-pip clang
+
+COPY mypy-requirements.txt .
+COPY test-requirements.txt .
+COPY build-requirements.txt .
+
+RUN pip3 install -r test-requirements.txt
diff --git a/misc/docker/README.md b/misc/docker/README.md
new file mode 100644
index 0000000000000..839f9761cb03a
--- /dev/null
+++ b/misc/docker/README.md
@@ -0,0 +1,101 @@
+Running mypy and mypyc tests in a Docker container
+==================================================
+
+This directory contains scripts for running mypy and mypyc tests in a
+Linux Docker container. This allows running Linux tests on a different
+operating system that supports Docker, or running tests in an
+isolated, predictable environment on a Linux host operating system.
+
+Why use Docker?
+---------------
+
+Mypyc tests can be significantly faster in a Docker container than
+running natively on macOS.
+
+Also, if it's inconvient to install the necessary dependencies on the
+host operating system, or there are issues getting some tests to pass
+on the host operating system, using a container can be an easy
+workaround.
+
+Prerequisites
+-------------
+
+First install Docker. On macOS, both Docker Desktop (proprietary, but
+with a free of charge subscription for some use cases) and Colima (MIT
+license) should work as runtimes.
+
+You may have to explicitly start the runtime first. Colima example
+(replace '8' with the number of CPU cores you have):
+
+```
+$ colima start -c 8
+
+```
+
+How to run tests
+----------------
+
+You need to build the container with all necessary dependencies before
+you can run tests:
+
+```
+$ python3 misc/docker/build.py
+```
+
+This creates a `mypy-test` Docker container that you can use to run
+tests.
+
+You may need to run the script as root:
+
+```
+$ sudo python3 misc/docker/build.py
+```
+
+If you have a stale container which isn't up-to-date, use `--no-cache`
+`--pull` to force rebuilding everything:
+
+```
+$ python3 misc/docker/build.py --no-cache --pull
+```
+
+Now you can run tests by using the `misc/docker/run.sh` script. Give
+it the pytest command line you want to run as arguments. For example,
+you can run mypyc tests like this:
+
+```
+$ misc/docker/run.sh pytest mypyc
+```
+
+You can also use `-k <filter>`, `-n0`, `-q`, etc.
+
+Again, you may need to run `run.sh` as root:
+
+```
+$ sudo misc/docker/run.sh pytest mypyc
+```
+
+You can also use `runtests.py` in the container. Example:
+
+```
+$ misc/docker/run.sh ./runtests.py self lint
+```
+
+Notes
+-----
+
+File system changes within the container are not visible to the host
+system. You can't use the container to format code using Black, for
+example.
+
+On a mac, you may want to give additional CPU to the VM used to run
+the container. The default allocation may be way too low (e.g. 2 CPU
+cores). For example, use the `-c` option when starting the VM if you
+use Colima:
+
+```
+$ colima start -c 8
+```
+
+Giving access to all available CPUs to the Linux VM tends to provide
+the best performance. This is not needed on a Linux host, since the
+container is not run in a VM.
diff --git a/misc/docker/build.py b/misc/docker/build.py
new file mode 100644
index 0000000000000..2103be3f110fc
--- /dev/null
+++ b/misc/docker/build.py
@@ -0,0 +1,46 @@
+"""Build a "mypy-test" Linux Docker container for running mypy/mypyc tests.
+
+This allows running Linux tests under a non-Linux operating system. Mypyc
+tests can also run much faster under Linux that the host OS.
+
+NOTE: You may need to run this as root (using sudo).
+
+Run with "--no-cache" to force reinstallation of mypy dependencies.
+Run with "--pull" to force update of the Linux (Ubuntu) base image.
+
+After you've built the container, use "run.sh" to run tests. Example:
+
+  misc/docker/run.sh pytest mypyc/
+"""
+
+import argparse
+import os
+import subprocess
+import sys
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="""Build a 'mypy-test' Docker container for running mypy/mypyc tests. You may
+                       need to run this as root (using sudo)."""
+    )
+    parser.add_argument("--no-cache", action="store_true", help="Force rebuilding")
+    parser.add_argument("--pull", action="store_true", help="Force pulling fresh Linux base image")
+    args = parser.parse_args()
+
+    dockerdir = os.path.dirname(os.path.abspath(__file__))
+    dockerfile = os.path.join(dockerdir, "Dockerfile")
+    rootdir = os.path.join(dockerdir, "..", "..")
+
+    cmdline = ["docker", "build", "-t", "mypy-test", "-f", dockerfile]
+    if args.no_cache:
+        cmdline.append("--no-cache")
+    if args.pull:
+        cmdline.append("--pull")
+    cmdline.append(rootdir)
+    result = subprocess.run(cmdline)
+    sys.exit(result.returncode)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/misc/docker/run-wrapper.sh b/misc/docker/run-wrapper.sh
new file mode 100755
index 0000000000000..77e77d99af342
--- /dev/null
+++ b/misc/docker/run-wrapper.sh
@@ -0,0 +1,13 @@
+#!/bin/bash
+# Internal wrapper script used to run commands in a container
+
+# Copy all the files we need from the mypy repo directory shared with
+# the host to a local directory. Accessing files using a shared
+# directory on a mac can be *very* slow.
+echo "copying files to the container..."
+cp -R /repo/{mypy,mypyc,test-data,misc} .
+cp /repo/{pytest.ini,conftest.py,runtests.py,pyproject.toml,setup.cfg} .
+cp /repo/{mypy_self_check.ini,mypy_bootstrap.ini} .
+
+# Run the wrapped command
+"$@"
diff --git a/misc/docker/run.sh b/misc/docker/run.sh
new file mode 100755
index 0000000000000..c8fc0e510e8e3
--- /dev/null
+++ b/misc/docker/run.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+# Run mypy or mypyc tests in a Docker container that was built using misc/docker/build.py.
+#
+# Usage: misc/docker/run.sh <command> <arg>...
+#
+# For example, run mypyc tests like this:
+#
+#   misc/docker/run.sh pytest mypyc
+#
+# NOTE: You may need to run this as root (using sudo).
+
+SCRIPT_DIR=$(cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd)
+MYPY_DIR="$SCRIPT_DIR/../.."
+
+docker run -ti --rm -v "$MYPY_DIR:/repo" mypy-test /repo/misc/docker/run-wrapper.sh "$@"

From f6256025c4af14f606da7aa0a3699c2417647686 Mon Sep 17 00:00:00 2001
From: jhance <jhance@users.noreply.github.com>
Date: Tue, 17 Jan 2023 08:17:38 -0800
Subject: [PATCH 185/231] Re-use constraints helper in constraints visitor
 (#14444)

The visit_tuple_type method of the constraints visitor does similar
logic to the new helper for building constraints for typevar tuples, so
we reimplement it using that. This also fixes a bug that was uncovered
in the implementation of the helper.
---
 mypy/constraints.py          | 101 ++++++++++++++++++-----------------
 mypy/test/testconstraints.py |   8 +++
 2 files changed, 60 insertions(+), 49 deletions(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index 63e1672eb1626..697e793cb11d0 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -995,58 +995,53 @@ def infer_against_overloaded(
         return infer_constraints(template, item, self.direction)
 
     def visit_tuple_type(self, template: TupleType) -> list[Constraint]:
+
         actual = self.actual
-        # TODO: Support subclasses of Tuple
+        unpack_index = find_unpack_in_list(template.items)
         is_varlength_tuple = (
             isinstance(actual, Instance) and actual.type.fullname == "builtins.tuple"
         )
-        unpack_index = find_unpack_in_list(template.items)
 
-        if unpack_index is not None:
-            unpack_item = get_proper_type(template.items[unpack_index])
-            assert isinstance(unpack_item, UnpackType)
-
-            unpacked_type = get_proper_type(unpack_item.type)
-            if isinstance(unpacked_type, TypeVarTupleType):
+        if isinstance(actual, TupleType) or is_varlength_tuple:
+            res: list[Constraint] = []
+            if unpack_index is not None:
                 if is_varlength_tuple:
-                    # This case is only valid when the unpack is the only
-                    # item in the tuple.
-                    #
-                    # TODO: We should support this in the case that all the items
-                    # in the tuple besides the unpack have the same type as the
-                    # varlength tuple's type. E.g. Tuple[int, ...] should be valid
-                    # where we expect Tuple[int, Unpack[Ts]], but not for Tuple[str, Unpack[Ts]].
-                    assert len(template.items) == 1
-
-                if isinstance(actual, (TupleType, AnyType)) or is_varlength_tuple:
-                    modified_actual = actual
-                    if isinstance(actual, TupleType):
-                        # Exclude the items from before and after the unpack index.
-                        # TODO: Support including constraints from the prefix/suffix.
-                        _, actual_items, _ = split_with_prefix_and_suffix(
-                            tuple(actual.items),
-                            unpack_index,
-                            len(template.items) - unpack_index - 1,
-                        )
-                        modified_actual = actual.copy_modified(items=list(actual_items))
-                    return [
-                        Constraint(
-                            type_var=unpacked_type, op=self.direction, target=modified_actual
-                        )
-                    ]
+                    unpack_type = template.items[unpack_index]
+                    assert isinstance(unpack_type, UnpackType)
+                    unpacked_type = unpack_type.type
+                    assert isinstance(unpacked_type, TypeVarTupleType)
+                    return [Constraint(type_var=unpacked_type, op=self.direction, target=actual)]
+                else:
+                    assert isinstance(actual, TupleType)
+                    (
+                        unpack_constraints,
+                        actual_items,
+                        template_items,
+                    ) = find_and_build_constraints_for_unpack(
+                        tuple(actual.items), tuple(template.items), self.direction
+                    )
+                    res.extend(unpack_constraints)
+            elif isinstance(actual, TupleType):
+                actual_items = tuple(actual.items)
+                template_items = tuple(template.items)
+            else:
+                return res
 
-        if isinstance(actual, TupleType) and len(actual.items) == len(template.items):
-            if (
-                actual.partial_fallback.type.is_named_tuple
-                and template.partial_fallback.type.is_named_tuple
-            ):
-                # For named tuples using just the fallbacks usually gives better results.
-                return infer_constraints(
-                    template.partial_fallback, actual.partial_fallback, self.direction
-                )
-            res: list[Constraint] = []
-            for i in range(len(template.items)):
-                res.extend(infer_constraints(template.items[i], actual.items[i], self.direction))
+            # Cases above will return if actual wasn't a TupleType.
+            assert isinstance(actual, TupleType)
+            if len(actual_items) == len(template_items):
+                if (
+                    actual.partial_fallback.type.is_named_tuple
+                    and template.partial_fallback.type.is_named_tuple
+                ):
+                    # For named tuples using just the fallbacks usually gives better results.
+                    return res + infer_constraints(
+                        template.partial_fallback, actual.partial_fallback, self.direction
+                    )
+                for i in range(len(template_items)):
+                    res.extend(
+                        infer_constraints(template_items[i], actual_items[i], self.direction)
+                    )
             return res
         elif isinstance(actual, AnyType):
             return self.infer_against_any(template.items, actual)
@@ -1079,10 +1074,13 @@ def visit_type_alias_type(self, template: TypeAliasType) -> list[Constraint]:
     def infer_against_any(self, types: Iterable[Type], any_type: AnyType) -> list[Constraint]:
         res: list[Constraint] = []
         for t in types:
-            # Note that we ignore variance and simply always use the
-            # original direction. This is because for Any targets direction is
-            # irrelevant in most cases, see e.g. is_same_constraint().
-            res.extend(infer_constraints(t, any_type, self.direction))
+            if isinstance(t, UnpackType) and isinstance(t.type, TypeVarTupleType):
+                res.append(Constraint(t.type, self.direction, any_type))
+            else:
+                # Note that we ignore variance and simply always use the
+                # original direction. This is because for Any targets direction is
+                # irrelevant in most cases, see e.g. is_same_constraint().
+                res.extend(infer_constraints(t, any_type, self.direction))
         return res
 
     def visit_overloaded(self, template: Overloaded) -> list[Constraint]:
@@ -1187,6 +1185,11 @@ def build_constraints_for_unpack(
     template_suffix_len: int,
     direction: int,
 ) -> tuple[list[Constraint], tuple[Type, ...], tuple[Type, ...]]:
+    if mapped_prefix_len is None:
+        mapped_prefix_len = template_prefix_len
+    if mapped_suffix_len is None:
+        mapped_suffix_len = template_suffix_len
+
     split_result = split_with_mapped_and_template(
         mapped,
         mapped_prefix_len,
diff --git a/mypy/test/testconstraints.py b/mypy/test/testconstraints.py
index fc6960e0d8a0a..b46f313271501 100644
--- a/mypy/test/testconstraints.py
+++ b/mypy/test/testconstraints.py
@@ -151,3 +151,11 @@ def test_unpack_tuple_length_non_match(self) -> None:
             Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.a),
             Constraint(type_var=fx.u, op=SUPERTYPE_OF, target=fx.d),
         }
+
+    def test_var_length_tuple_with_fixed_length_tuple(self) -> None:
+        fx = self.fx
+        assert not infer_constraints(
+            TupleType([fx.t, fx.s], fallback=Instance(fx.std_tuplei, [fx.o])),
+            Instance(fx.std_tuplei, [fx.a]),
+            SUPERTYPE_OF,
+        )

From acf26f43e9d26066fdcbe7850bbfab87b98cf8e0 Mon Sep 17 00:00:00 2001
From: Richard Si <sichard26@gmail.com>
Date: Wed, 18 Jan 2023 05:14:41 -0500
Subject: [PATCH 186/231] [mypyc] Optimize int()/float()/complex() on native
 classes (#14450)

int() and float() calls on native classes can simply call the associated
dunder if the RInstance defines it, no need to load the type and call
it.

bool() calls were already optimized merely a few days ago, but there
wasn't an IRbuild test verifying this so I added one.

---

Follow up to https://github.com/python/mypy/pull/14422. I saw the PR and
it reminded me that I had this old patch laying around :)
---
 mypy/nodes.py                        |  2 +-
 mypyc/irbuild/specialize.py          | 16 ++++++++----
 mypyc/test-data/irbuild-dunders.test | 38 +++++++++++++++++++++-------
 3 files changed, 41 insertions(+), 15 deletions(-)

diff --git a/mypy/nodes.py b/mypy/nodes.py
index 85bb9ce4a8dee..4a4de9d4503db 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -1777,7 +1777,7 @@ class NameExpr(RefExpr):
 
     def __init__(self, name: str) -> None:
         super().__init__()
-        self.name = name  # Name referred to (may be qualified)
+        self.name = name  # Name referred to
         # Is this a l.h.s. of a special form assignment like typed dict or type variable?
         self.is_special_form = False
 
diff --git a/mypyc/irbuild/specialize.py b/mypyc/irbuild/specialize.py
index 06babd2f7e1a9..e62350778f548 100644
--- a/mypyc/irbuild/specialize.py
+++ b/mypyc/irbuild/specialize.py
@@ -157,14 +157,20 @@ def translate_globals(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Va
 
 
 @specialize_function("builtins.abs")
-def translate_abs(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value | None:
-    """Specialize calls on native classes that implement __abs__."""
-    if len(expr.args) == 1 and expr.arg_kinds == [ARG_POS]:
+@specialize_function("builtins.int")
+@specialize_function("builtins.float")
+@specialize_function("builtins.complex")
+def translate_builtins_with_unary_dunder(
+    builder: IRBuilder, expr: CallExpr, callee: RefExpr
+) -> Value | None:
+    """Specialize calls on native classes that implement the associated dunder."""
+    if len(expr.args) == 1 and expr.arg_kinds == [ARG_POS] and isinstance(callee, NameExpr):
         arg = expr.args[0]
         arg_typ = builder.node_type(arg)
-        if isinstance(arg_typ, RInstance) and arg_typ.class_ir.has_method("__abs__"):
+        method = f"__{callee.name}__"
+        if isinstance(arg_typ, RInstance) and arg_typ.class_ir.has_method(method):
             obj = builder.accept(arg)
-            return builder.gen_method_call(obj, "__abs__", [], None, expr.line)
+            return builder.gen_method_call(obj, method, [], None, expr.line)
 
     return None
 
diff --git a/mypyc/test-data/irbuild-dunders.test b/mypyc/test-data/irbuild-dunders.test
index 24e7089133542..82f04dcdf6870 100644
--- a/mypyc/test-data/irbuild-dunders.test
+++ b/mypyc/test-data/irbuild-dunders.test
@@ -154,6 +154,12 @@ class C:
     def __abs__(self) -> int:
         return 6
 
+    def __bool__(self) -> bool:
+        return False
+
+    def __complex__(self) -> complex:
+        return 7j
+
 def f(c: C) -> None:
     -c
     ~c
@@ -161,6 +167,8 @@ def f(c: C) -> None:
     float(c)
     +c
     abs(c)
+    bool(c)
+    complex(c)
 [out]
 def C.__neg__(self):
     self :: __main__.C
@@ -188,19 +196,31 @@ def C.__abs__(self):
     self :: __main__.C
 L0:
     return 12
+def C.__bool__(self):
+    self :: __main__.C
+L0:
+    return 0
+def C.__complex__(self):
+    self :: __main__.C
+    r0 :: object
+L0:
+    r0 = 7j
+    return r0
 def f(c):
     c :: __main__.C
-    r0, r1 :: int
-    r2, r3, r4, r5 :: object
-    r6, r7 :: int
+    r0, r1, r2 :: int
+    r3 :: float
+    r4, r5 :: int
+    r6 :: bool
+    r7 :: object
 L0:
     r0 = c.__neg__()
     r1 = c.__invert__()
-    r2 = load_address PyLong_Type
-    r3 = PyObject_CallFunctionObjArgs(r2, c, 0)
-    r4 = load_address PyFloat_Type
-    r5 = PyObject_CallFunctionObjArgs(r4, c, 0)
-    r6 = c.__pos__()
-    r7 = c.__abs__()
+    r2 = c.__int__()
+    r3 = c.__float__()
+    r4 = c.__pos__()
+    r5 = c.__abs__()
+    r6 = c.__bool__()
+    r7 = c.__complex__()
     return 1
 

From 914901f14e0e6223077a8433388c367138717451 Mon Sep 17 00:00:00 2001
From: jhance <jhance@users.noreply.github.com>
Date: Wed, 18 Jan 2023 02:19:42 -0800
Subject: [PATCH 187/231] Improve CallableType handling with typevar tuples
 (#14465)

Mainly adds some tests that were previously disabled since they failed,
as well as tests for handling prefices. Suffices tests are not added yet
because when a suffix is involved we can't use the existing solution
since it will construct positional args after *args, when we really need
something like `*tuple[*args, <suffix>]` in order to encode this in the
type info.

We also refactor out the manipulation of the arg names/kinds/types into
its own helper which will make control flow less annoying to deal with.

We are deferring the implementation of suffices until more parts of the
PEP are implemented since it doesn't seem as important (e.g. in other
parts of the language this is not supported)
---
 mypy/expandtype.py                      | 168 ++++++++++++------------
 test-data/unit/check-typevar-tuple.test |  43 +++++-
 2 files changed, 126 insertions(+), 85 deletions(-)

diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 1c3553fe5e53a..203c71b4e8243 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -3,7 +3,7 @@
 from typing import Iterable, Mapping, Sequence, TypeVar, cast, overload
 from typing_extensions import Final
 
-from mypy.nodes import ARG_POS, ARG_STAR, Var
+from mypy.nodes import ARG_POS, ARG_STAR, ArgKind, Var
 from mypy.type_visitor import TypeTranslator
 from mypy.types import (
     ANY_STRATEGY,
@@ -258,6 +258,90 @@ def expand_unpack(self, t: UnpackType) -> list[Type] | Instance | AnyType | None
     def visit_parameters(self, t: Parameters) -> Type:
         return t.copy_modified(arg_types=self.expand_types(t.arg_types))
 
+    def interpolate_args_for_unpack(
+        self, t: CallableType, var_arg: UnpackType
+    ) -> tuple[list[str | None], list[ArgKind], list[Type]]:
+        star_index = t.arg_kinds.index(ARG_STAR)
+
+        # We have something like Unpack[Tuple[X1, X2, Unpack[Ts], Y1, Y2]]
+        if isinstance(get_proper_type(var_arg.type), TupleType):
+            expanded_tuple = get_proper_type(var_arg.type.accept(self))
+            # TODO: handle the case that expanded_tuple is a variable length tuple.
+            assert isinstance(expanded_tuple, TupleType)
+            expanded_items = expanded_tuple.items
+        else:
+            expanded_items_res = self.expand_unpack(var_arg)
+            if isinstance(expanded_items_res, list):
+                expanded_items = expanded_items_res
+            elif (
+                isinstance(expanded_items_res, Instance)
+                and expanded_items_res.type.fullname == "builtins.tuple"
+            ):
+                # TODO: We shouldnt't simply treat this as a *arg because of suffix handling
+                # (there cannot be positional args after a *arg)
+                arg_types = (
+                    t.arg_types[:star_index]
+                    + [expanded_items_res.args[0]]
+                    + t.arg_types[star_index + 1 :]
+                )
+                return (t.arg_names, t.arg_kinds, arg_types)
+            else:
+                return (t.arg_names, t.arg_kinds, t.arg_types)
+
+        expanded_unpack_index = find_unpack_in_list(expanded_items)
+        # This is the case where we just have Unpack[Tuple[X1, X2, X3]]
+        # (for example if either the tuple had no unpacks, or the unpack in the
+        # tuple got fully expanded to something with fixed length)
+        if expanded_unpack_index is None:
+            arg_names = (
+                t.arg_names[:star_index]
+                + [None] * len(expanded_items)
+                + t.arg_names[star_index + 1 :]
+            )
+            arg_kinds = (
+                t.arg_kinds[:star_index]
+                + [ARG_POS] * len(expanded_items)
+                + t.arg_kinds[star_index + 1 :]
+            )
+            arg_types = (
+                self.expand_types(t.arg_types[:star_index])
+                + expanded_items
+                + self.expand_types(t.arg_types[star_index + 1 :])
+            )
+        else:
+            # If Unpack[Ts] simplest form still has an unpack or is a
+            # homogenous tuple, then only the prefix can be represented as
+            # positional arguments, and we pass Tuple[Unpack[Ts-1], Y1, Y2]
+            # as the star arg, for example.
+            expanded_unpack = get_proper_type(expanded_items[expanded_unpack_index])
+            assert isinstance(expanded_unpack, UnpackType)
+
+            # Extract the typevartuple so we can get a tuple fallback from it.
+            expanded_unpacked_tvt = get_proper_type(expanded_unpack.type)
+            assert isinstance(expanded_unpacked_tvt, TypeVarTupleType)
+
+            prefix_len = expanded_unpack_index
+            arg_names = t.arg_names[:star_index] + [None] * prefix_len + t.arg_names[star_index:]
+            arg_kinds = (
+                t.arg_kinds[:star_index] + [ARG_POS] * prefix_len + t.arg_kinds[star_index:]
+            )
+            arg_types = (
+                self.expand_types(t.arg_types[:star_index])
+                + expanded_items[:prefix_len]
+                # Constructing the Unpack containing the tuple without the prefix.
+                + [
+                    UnpackType(
+                        TupleType(
+                            expanded_items[prefix_len:], expanded_unpacked_tvt.tuple_fallback
+                        )
+                    )
+                    if len(expanded_items) - prefix_len > 1
+                    else expanded_items[0]
+                ]
+                + self.expand_types(t.arg_types[star_index + 1 :])
+            )
+        return (arg_names, arg_kinds, arg_types)
+
     def visit_callable_type(self, t: CallableType) -> Type:
         param_spec = t.param_spec()
         if param_spec is not None:
@@ -285,89 +369,11 @@ def visit_callable_type(self, t: CallableType) -> Type:
 
         var_arg = t.var_arg()
         if var_arg is not None and isinstance(var_arg.typ, UnpackType):
-            star_index = t.arg_kinds.index(ARG_STAR)
-
-            # We have something like Unpack[Tuple[X1, X2, Unpack[Ts], Y1, Y2]]
-            if isinstance(get_proper_type(var_arg.typ.type), TupleType):
-                expanded_tuple = get_proper_type(var_arg.typ.type.accept(self))
-                # TODO: handle the case that expanded_tuple is a variable length tuple.
-                assert isinstance(expanded_tuple, TupleType)
-                expanded_items = expanded_tuple.items
-            else:
-                expanded_items_res = self.expand_unpack(var_arg.typ)
-                # TODO: can it be anything except a list?
-                assert isinstance(expanded_items_res, list)
-                expanded_items = expanded_items_res
-
-            """
-                # In this case we keep the arg as ARG_STAR.
-                arg_names = t.arg_names
-                arg_kinds = t.arg_kinds
-                arg_types = (
-                    self.expand_types(t.arg_types[:star_index])
-                    + expanded
-                    + self.expand_types(t.arg_types[star_index + 1 :])
-                )
-            """
-
-            expanded_unpack_index = find_unpack_in_list(expanded_items)
-            # This is the case where we just have Unpack[Tuple[X1, X2, X3]]
-            # (for example if either the tuple had no unpacks, or the unpack in the
-            # tuple got fully expanded to something with fixed length)
-            if expanded_unpack_index is None:
-                arg_names = (
-                    t.arg_names[:star_index]
-                    + [None] * len(expanded_items)
-                    + t.arg_names[star_index + 1 :]
-                )
-                arg_kinds = (
-                    t.arg_kinds[:star_index]
-                    + [ARG_POS] * len(expanded_items)
-                    + t.arg_kinds[star_index + 1 :]
-                )
-                arg_types = (
-                    self.expand_types(t.arg_types[:star_index])
-                    + expanded_items
-                    + self.expand_types(t.arg_types[star_index + 1 :])
-                )
-            else:
-                # If Unpack[Ts] simplest form still has an unpack or is a
-                # homogenous tuple, then only the prefix can be represented as
-                # positional arguments, and we pass Tuple[Unpack[Ts-1], Y1, Y2]
-                # as the star arg, for example.
-                expanded_unpack = get_proper_type(expanded_items[expanded_unpack_index])
-                assert isinstance(expanded_unpack, UnpackType)
-
-                # Extract the typevartuple so we can get a tuple fallback from it.
-                expanded_unpacked_tvt = get_proper_type(expanded_unpack.type)
-                assert isinstance(expanded_unpacked_tvt, TypeVarTupleType)
-
-                prefix_len = expanded_unpack_index
-                arg_names = (
-                    t.arg_names[:star_index] + [None] * prefix_len + t.arg_names[star_index:]
-                )
-                arg_kinds = (
-                    t.arg_kinds[:star_index] + [ARG_POS] * prefix_len + t.arg_kinds[star_index:]
-                )
-                arg_types = (
-                    self.expand_types(t.arg_types[:star_index])
-                    + expanded_items[:prefix_len]
-                    # Constructing the Unpack containing the tuple without the prefix.
-                    + [
-                        UnpackType(
-                            TupleType(
-                                expanded_items[prefix_len:], expanded_unpacked_tvt.tuple_fallback
-                            )
-                        )
-                        if len(expanded_items) - prefix_len > 1
-                        else expanded_items[0]
-                    ]
-                    + self.expand_types(t.arg_types[star_index + 1 :])
-                )
+            arg_names, arg_kinds, arg_types = self.interpolate_args_for_unpack(t, var_arg.typ)
         else:
-            arg_types = self.expand_types(t.arg_types)
             arg_names = t.arg_names
             arg_kinds = t.arg_kinds
+            arg_types = self.expand_types(t.arg_types)
 
         return t.copy_modified(
             arg_types=arg_types,
diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test
index f61b53dcd2c09..9afe709ed19b8 100644
--- a/test-data/unit/check-typevar-tuple.test
+++ b/test-data/unit/check-typevar-tuple.test
@@ -466,14 +466,49 @@ from typing_extensions import Unpack, TypeVarTuple
 Ts = TypeVarTuple("Ts")
 
 def call(
-    target: Callable[[ Unpack[Ts]], None],
+    target: Callable[[Unpack[Ts]], None],
     args: Tuple[Unpack[Ts]],
 ) -> None:
     pass
 
 def func(arg1: int, arg2: str) -> None: ...
+def func2(arg1: int, arg2: int) -> None: ...
+def func3(*args: int) -> None: ...
+
+vargs: Tuple[int, ...]
+vargs_str: Tuple[str, ...]
+
+call(target=func, args=(0, 'foo'))
+call(target=func, args=('bar', 'foo'))  # E: Argument "target" to "call" has incompatible type "Callable[[int, str], None]"; expected "Callable[[object, str], None]"
+call(target=func, args=(True, 'foo', 0))  # E: Argument "target" to "call" has incompatible type "Callable[[int, str], None]"; expected "Callable[[VarArg(object)], None]"
+call(target=func, args=(0, 0, 'foo'))  # E: Argument "target" to "call" has incompatible type "Callable[[int, str], None]"; expected "Callable[[VarArg(object)], None]"
+call(target=func, args=vargs)  # E: Argument "target" to "call" has incompatible type "Callable[[int, str], None]"; expected "Callable[[VarArg(object)], None]"
+
+# NOTE: This behavior may be a bit contentious, it is maybe inconsistent with our handling of
+# PEP646 but consistent with our handling of callable constraints.
+call(target=func2, args=vargs)  # E: Argument "target" to "call" has incompatible type "Callable[[int, int], None]"; expected "Callable[[VarArg(int)], None]"
+call(target=func3, args=vargs)
+call(target=func3, args=(0,1))
+call(target=func3, args=(0,'foo'))  # E: Argument "target" to "call" has incompatible type "Callable[[VarArg(int)], None]"; expected "Callable[[VarArg(object)], None]"
+call(target=func3, args=vargs_str)  # E: Argument "target" to "call" has incompatible type "Callable[[VarArg(int)], None]"; expected "Callable[[VarArg(object)], None]"
+[builtins fixtures/tuple.pyi]
+
+[case testTypeVarTuplePep646CallableWithPrefixSuffix]
+from typing import Tuple, Callable
+from typing_extensions import Unpack, TypeVarTuple
+
+Ts = TypeVarTuple("Ts")
 
-call(target=func, args=(0, 'foo'))  # Valid
-#call(target=func, args=(True, 'foo', 0))  # Error
-#call(target=func, args=(0, 0, 'foo'))  # Error
+def call_prefix(
+    target: Callable[[bytes, Unpack[Ts]], None],
+    args: Tuple[Unpack[Ts]],
+) -> None:
+    pass
+
+def func_prefix(arg0: bytes, arg1: int, arg2: str) -> None: ...
+def func2_prefix(arg0: str, arg1: int, arg2: str) -> None: ...
+
+call_prefix(target=func_prefix, args=(0, 'foo'))
+call_prefix(target=func2_prefix, args=(0, 'foo'))  # E: Argument "target" to "call_prefix" has incompatible type "Callable[[str, int, str], None]"; expected "Callable[[bytes, int, str], None]"
 [builtins fixtures/tuple.pyi]
+

From 83660d0ad72ab5a61cea5fe5955e66c33ef54111 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Fri, 20 Jan 2023 03:10:01 -0800
Subject: [PATCH 188/231] Enable use-before-def error code by default (#14166)

This enables the error code added in #14163.
---
 mypy/errorcodes.py                          |   5 +-
 test-data/unit/check-abstract.test          |   8 +-
 test-data/unit/check-basic.test             |  79 ++-----
 test-data/unit/check-classes.test           | 161 +++++--------
 test-data/unit/check-columns.test           |   2 +-
 test-data/unit/check-dataclasses.test       |   4 +-
 test-data/unit/check-dynamic-typing.test    |  69 +++---
 test-data/unit/check-enum.test              |   2 +-
 test-data/unit/check-errorcodes.test        |   6 +-
 test-data/unit/check-expressions.test       |  74 +++---
 test-data/unit/check-flags.test             |   6 +-
 test-data/unit/check-functions.test         |  26 +-
 test-data/unit/check-generics.test          |  31 +--
 test-data/unit/check-incremental.test       |  10 +-
 test-data/unit/check-inference-context.test | 170 +++++++------
 test-data/unit/check-inference.test         | 146 ++++++------
 test-data/unit/check-kwargs.test            |  94 ++++----
 test-data/unit/check-namedtuple.test        |   4 +-
 test-data/unit/check-newsemanal.test        | 249 ++++++++++----------
 test-data/unit/check-overloading.test       |  37 +--
 test-data/unit/check-protocols.test         |   2 +-
 test-data/unit/check-python39.test          |   2 +-
 test-data/unit/check-recursive-types.test   |   9 +
 test-data/unit/check-selftype.test          |   8 +-
 test-data/unit/check-statements.test        |  61 ++---
 test-data/unit/check-tuples.test            |  32 ++-
 test-data/unit/check-type-aliases.test      |   7 +-
 test-data/unit/check-typeddict.test         |   4 +-
 test-data/unit/check-varargs.test           | 223 ++++++++----------
 test-data/unit/fine-grained.test            |  55 +++--
 test-data/unit/semanal-basic.test           |  15 +-
 test-data/unit/semanal-statements.test      |  35 ++-
 test-data/unit/typexport-basic.test         | 168 +++++++------
 33 files changed, 850 insertions(+), 954 deletions(-)

diff --git a/mypy/errorcodes.py b/mypy/errorcodes.py
index 6b266cc7b4299..5696763ec9d14 100644
--- a/mypy/errorcodes.py
+++ b/mypy/errorcodes.py
@@ -193,10 +193,7 @@ def __str__(self) -> str:
     default_enabled=False,
 )
 USED_BEFORE_DEF: Final[ErrorCode] = ErrorCode(
-    "used-before-def",
-    "Warn about variables that are used before they are defined",
-    "General",
-    default_enabled=False,
+    "used-before-def", "Warn about variables that are used before they are defined", "General"
 )
 
 
diff --git a/test-data/unit/check-abstract.test b/test-data/unit/check-abstract.test
index f67d9859397e8..98be314b9c276 100644
--- a/test-data/unit/check-abstract.test
+++ b/test-data/unit/check-abstract.test
@@ -102,16 +102,16 @@ class B(A, I): pass
 
 from abc import abstractmethod, ABCMeta
 
+class I(metaclass=ABCMeta):
+  @abstractmethod
+  def f(self): pass
+
 o = None # type: object
 t = None # type: type
 
 o = I
 t = I
 
-class I(metaclass=ABCMeta):
-  @abstractmethod
-  def f(self): pass
-
 [case testAbstractClassInCasts]
 from typing import cast
 from abc import abstractmethod, ABCMeta
diff --git a/test-data/unit/check-basic.test b/test-data/unit/check-basic.test
index a4056c8cb5768..c16b9e40122dd 100644
--- a/test-data/unit/check-basic.test
+++ b/test-data/unit/check-basic.test
@@ -12,25 +12,26 @@ class A: pass
 class B: pass
 
 [case testConstructionAndAssignment]
-x = None # type: A
-x = A()
-if int():
-    x = B() # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 class A:
     def __init__(self): pass
 class B:
     def __init__(self): pass
 
+x = None # type: A
+x = A()
+if int():
+    x = B() # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 [case testInheritInitFromObject]
+class A(object): pass
+class B(object): pass
 x = None # type: A
 if int():
     x = A()
 if int():
     x = B() # E: Incompatible types in assignment (expression has type "B", variable has type "A")
-class A(object): pass
-class B(object): pass
-
 [case testImplicitInheritInitFromObject]
+class A: pass
+class B: pass
 x = None # type: A
 o = None # type: object
 if int():
@@ -39,10 +40,6 @@ if int():
     x = A()
 if int():
     o = x
-class A: pass
-class B: pass
-[out]
-
 [case testTooManyConstructorArgs]
 import typing
 object(object())
@@ -51,21 +48,15 @@ main:2: error: Too many arguments for "object"
 
 [case testVarDefWithInit]
 import typing
-a = A() # type: A
-b = object() # type: A
 class A: pass
-[out]
-main:3: error: Incompatible types in assignment (expression has type "object", variable has type "A")
-
+a = A() # type: A
+b = object() # type: A  # E: Incompatible types in assignment (expression has type "object", variable has type "A")
 [case testInheritanceBasedSubtyping]
 import typing
-x = B() # type: A
-y = A() # type: B # Fail
 class A: pass
 class B(A): pass
-[out]
-main:3: error: Incompatible types in assignment (expression has type "A", variable has type "B")
-
+x = B() # type: A
+y = A() # type: B  # E: Incompatible types in assignment (expression has type "A", variable has type "B")
 [case testDeclaredVariableInParentheses]
 
 (x) = None # type: int
@@ -101,32 +92,22 @@ w = 1  # E: Incompatible types in assignment (expression has type "int", variabl
 
 [case testFunction]
 import typing
-def f(x: 'A') -> None: pass
-f(A())
-f(B()) # Fail
 class A: pass
 class B: pass
-[out]
-main:4: error: Argument 1 to "f" has incompatible type "B"; expected "A"
-
+def f(x: 'A') -> None: pass
+f(A())
+f(B()) # E: Argument 1 to "f" has incompatible type "B"; expected "A"
 [case testNotCallable]
 import typing
-A()()
 class A: pass
-[out]
-main:2: error: "A" not callable
-
+A()()  # E: "A" not callable
 [case testSubtypeArgument]
 import typing
-def f(x: 'A', y: 'B') -> None: pass
-f(B(), A()) # Fail
-f(B(), B())
-
 class A: pass
 class B(A): pass
-[out]
-main:3: error: Argument 2 to "f" has incompatible type "A"; expected "B"
-
+def f(x: 'A', y: 'B') -> None: pass
+f(B(), A()) # E: Argument 2 to "f" has incompatible type "A"; expected "B"
+f(B(), B())
 [case testInvalidArgumentCount]
 import typing
 def f(x, y) -> None: pass
@@ -194,12 +175,10 @@ main:4: error: Incompatible types in assignment (expression has type "B", variab
 
 [case testVariableInitializationWithSubtype]
 import typing
-x = B() # type: A
-y = A() # type: B # Fail
 class A: pass
 class B(A): pass
-[out]
-main:3: error: Incompatible types in assignment (expression has type "A", variable has type "B")
+x = B() # type: A
+y = A() # type: B # E: Incompatible types in assignment (expression has type "A", variable has type "B")
 
 
 -- Misc
@@ -217,15 +196,11 @@ main:3: error: Incompatible return value type (got "B", expected "A")
 
 [case testTopLevelContextAndInvalidReturn]
 import typing
-def f() -> 'A':
-  return B()
-a = B() # type: A
 class A: pass
 class B: pass
-[out]
-main:3: error: Incompatible return value type (got "B", expected "A")
-main:4: error: Incompatible types in assignment (expression has type "B", variable has type "A")
-
+def f() -> 'A':
+  return B()  # E: Incompatible return value type (got "B", expected "A")
+a = B() # type: A  # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 [case testEmptyReturnInAnyTypedFunction]
 from typing import Any
 def f() -> Any:
@@ -252,6 +227,8 @@ reveal_type(__annotations__)  # N: Revealed type is "builtins.dict[builtins.str,
 
 
 [case testLocalVariableShadowing]
+class A: pass
+class B: pass
 a = None # type: A
 if int():
     a = B()  # E: Incompatible types in assignment (expression has type "B", variable has type "A")
@@ -263,10 +240,6 @@ def f() -> None:
       a = B()
 a = B()       # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 a = A()
-
-class A: pass
-class B: pass
-
 [case testGlobalDefinedInBlockWithType]
 class A: pass
 while A:
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index b35b2f9e4e94b..fce1aa1768f91 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -3,64 +3,56 @@
 
 
 [case testMethodCall]
+class A:
+    def foo(self, x: 'A') -> None: pass
+class B:
+    def bar(self, x: 'B', y: A) -> None: pass
 
 a = None # type: A
 b = None # type: B
 
-a.foo(B())        # Fail
-a.bar(B(), A())   # Fail
+a.foo(B())  # E: Argument 1 to "foo" of "A" has incompatible type "B"; expected "A"
+a.bar(B(), A())  # E: "A" has no attribute "bar"
 
 a.foo(A())
 b.bar(B(), A())
 
+[case testMethodCallWithSubtype]
 class A:
     def foo(self, x: 'A') -> None: pass
-class B:
-    def bar(self, x: 'B', y: A) -> None: pass
-[out]
-main:5: error: Argument 1 to "foo" of "A" has incompatible type "B"; expected "A"
-main:6: error: "A" has no attribute "bar"
-
-[case testMethodCallWithSubtype]
+    def bar(self, x: 'B') -> None: pass
+class B(A): pass
 
 a = None # type: A
 a.foo(A())
 a.foo(B())
-a.bar(A()) # Fail
+a.bar(A()) # E: Argument 1 to "bar" of "A" has incompatible type "A"; expected "B"
 a.bar(B())
 
+[case testInheritingMethod]
 class A:
-    def foo(self, x: 'A') -> None: pass
-    def bar(self, x: 'B') -> None: pass
+    def foo(self, x: 'B') -> None: pass
 class B(A): pass
-[out]
-main:5: error: Argument 1 to "bar" of "A" has incompatible type "A"; expected "B"
-
-[case testInheritingMethod]
 
 a = None # type: B
 a.foo(A()) # Fail
 a.foo(B())
 
-class A:
-    def foo(self, x: 'B') -> None: pass
-class B(A): pass
-[targets __main__, __main__, __main__.A.foo]
+[targets __main__, __main__.A.foo]
 [out]
-main:3: error: Argument 1 to "foo" of "A" has incompatible type "A"; expected "B"
+main:6: error: Argument 1 to "foo" of "A" has incompatible type "A"; expected "B"
 
 [case testMethodCallWithInvalidNumberOfArguments]
+class A:
+    def foo(self, x: 'A') -> None: pass
 
 a = None # type: A
 a.foo()               # Fail
 a.foo(object(), A())  # Fail
-
-class A:
-    def foo(self, x: 'A') -> None: pass
 [out]
-main:3: error: Missing positional argument "x" in call to "foo" of "A"
-main:4: error: Too many arguments for "foo" of "A"
-main:4: error: Argument 1 to "foo" of "A" has incompatible type "object"; expected "A"
+main:5: error: Missing positional argument "x" in call to "foo" of "A"
+main:6: error: Too many arguments for "foo" of "A"
+main:6: error: Argument 1 to "foo" of "A" has incompatible type "object"; expected "A"
 
 [case testMethodBody]
 import typing
@@ -216,13 +208,11 @@ main:11: error: "B" has no attribute "a"
 
 [case testExplicitAttributeInBody]
 
-a = None # type: A
-a.x = object() # Fail
-a.x = A()
 class A:
   x = None # type: A
-[out]
-main:3: error: Incompatible types in assignment (expression has type "object", variable has type "A")
+a = None # type: A
+a.x = object() # E: Incompatible types in assignment (expression has type "object", variable has type "A")
+a.x = A()
 
 [case testAttributeDefinedInNonInitMethod]
 import typing
@@ -629,64 +619,50 @@ class B(A):
 
 
 [case testTrivialConstructor]
-import typing
-a = A() # type: A
-b = A() # type: B # Fail
 class A:
     def __init__(self) -> None: pass
-class B: pass
-[out]
-main:3: error: Incompatible types in assignment (expression has type "A", variable has type "B")
 
+a = A() # type: A
+b = A() # type: B # E: Incompatible types in assignment (expression has type "A", variable has type "B")
+class B: pass
 [case testConstructor]
-import typing
-a = A(B()) # type: A
-aa = A(object()) # type: A  # Fail
-b = A(B()) # type: B       # Fail
 class A:
     def __init__(self, x: 'B') -> None: pass
 class B: pass
-[out]
-main:3: error: Argument 1 to "A" has incompatible type "object"; expected "B"
-main:4: error: Incompatible types in assignment (expression has type "A", variable has type "B")
 
-[case testConstructorWithTwoArguments]
-import typing
-a = A(C(), B()) # type: A  # Fail
+a = A(B()) # type: A
+aa = A(object()) # type: A  # E: Argument 1 to "A" has incompatible type "object"; expected "B"
+b = A(B()) # type: B # E: Incompatible types in assignment (expression has type "A", variable has type "B")
 
+[case testConstructorWithTwoArguments]
 class A:
     def __init__(self, x: 'B', y: 'C') -> None: pass
 class B: pass
 class C(B): pass
-[out]
-main:2: error: Argument 2 to "A" has incompatible type "B"; expected "C"
+
+a = A(C(), B()) # type: A  # E: Argument 2 to "A" has incompatible type "B"; expected "C"
 
 [case testInheritedConstructor]
-import typing
-b = B(C()) # type: B
-a = B(D()) # type: A # Fail
-class A:
-    def __init__(self, x: 'C') -> None: pass
 class B(A): pass
 class C: pass
 class D: pass
-[out]
-main:3: error: Argument 1 to "B" has incompatible type "D"; expected "C"
+
+b = B(C()) # type: B
+a = B(D()) # type: A # E: Argument 1 to "B" has incompatible type "D"; expected "C"
+class A:
+    def __init__(self, x: 'C') -> None: pass
 
 [case testOverridingWithIncompatibleConstructor]
-import typing
-A()    # Fail
-B(C()) # Fail
-A(C())
-B()
 class A:
     def __init__(self, x: 'C') -> None: pass
 class B(A):
     def __init__(self) -> None: pass
 class C: pass
-[out]
-main:2: error: Missing positional argument "x" in call to "A"
-main:3: error: Too many arguments for "B"
+
+A()    # E: Missing positional argument "x" in call to "A"
+B(C()) # E: Too many arguments for "B"
+A(C())
+B()
 
 [case testConstructorWithReturnValueType]
 import typing
@@ -826,15 +802,12 @@ class Foo:
         pass
 
 [case testGlobalFunctionInitWithReturnType]
-import typing
-a = __init__() # type: A
-b = __init__() # type: B # Fail
-def __init__() -> 'A': pass
 class A: pass
 class B: pass
-[out]
-main:3: error: Incompatible types in assignment (expression has type "A", variable has type "B")
+def __init__() -> 'A': pass
 
+a = __init__() # type: A
+b = __init__() # type: B # E: Incompatible types in assignment (expression has type "A", variable has type "B")
 [case testAccessingInit]
 from typing import Any, cast
 class A:
@@ -844,7 +817,12 @@ a.__init__(a)  # E: Accessing "__init__" on an instance is unsound, since instan
 (cast(Any, a)).__init__(a)
 
 [case testDeepInheritanceHierarchy]
-import typing
+class A: pass
+class B(A): pass
+class C(B): pass
+class D(C): pass
+class D2(C): pass
+
 d = C() # type: D  # E: Incompatible types in assignment (expression has type "C", variable has type "D")
 if int():
     d = B()      # E: Incompatible types in assignment (expression has type "B", variable has type "D")
@@ -859,12 +837,6 @@ b = D() # type: B
 if int():
     b = D2()
 
-class A: pass
-class B(A): pass
-class C(B): pass
-class D(C): pass
-class D2(C): pass
-
 [case testConstructorJoinsWithCustomMetaclass]
 # flags: --strict-optional
 from typing import TypeVar
@@ -1030,7 +1002,7 @@ A.B = None # E: Cannot assign to a type
 [targets __main__]
 
 [case testAccessingClassAttributeWithTypeInferenceIssue]
-x = C.x # E: Cannot determine type of "x"
+x = C.x # E: Cannot determine type of "x" # E: Name "C" is used before definition
 def f() -> int: return 1
 class C:
     x = f()
@@ -1209,13 +1181,9 @@ class A:
 
 
 [case testMultipleClassDefinition]
-import typing
-A()
-class A: pass
 class A: pass
-[out]
-main:4: error: Name "A" already defined on line 3
-
+class A: pass  # E: Name "A" already defined on line 1
+A()
 [case testDocstringInClass]
 import typing
 class A:
@@ -2351,7 +2319,7 @@ reveal_type(Fraction() + Fraction())  # N: Revealed type is "builtins.str"
 
 [case testReverseOperatorTypeVar2b]
 from typing import TypeVar
-T = TypeVar("T", Real, Fraction)
+T = TypeVar("T", "Real", "Fraction")
 class Real:
     def __add__(self, other: Fraction) -> str: ...
 class Fraction(Real):
@@ -2955,7 +2923,11 @@ c.__setattr__("x", 42, p=True)
 
 
 [case testCallableObject]
-import typing
+class A:
+    def __call__(self, x: 'A') -> 'A':
+        pass
+class B: pass
+
 a = A()
 b = B()
 
@@ -2968,11 +2940,6 @@ if int():
 if int():
     b = a(a)  # E: Incompatible types in assignment (expression has type "A", variable has type "B")
 
-class A:
-    def __call__(self, x: A) -> A:
-        pass
-class B: pass
-
 
 -- __new__
 -- --------
@@ -4933,7 +4900,7 @@ reveal_type(x.frob) # N: Revealed type is "def (foos: builtins.dict[Any, __main_
 [case testNewTypeFromForwardNamedTuple]
 from typing import NewType, NamedTuple, Tuple
 
-NT = NewType('NT', N)
+NT = NewType('NT', 'N')
 class N(NamedTuple):
     x: int
 
@@ -4947,7 +4914,7 @@ x = NT(N(1))
 from typing import NewType, Tuple
 from mypy_extensions import TypedDict
 
-NT = NewType('NT', N) # E: Argument 2 to NewType(...) must be subclassable (got "N")
+NT = NewType('NT', 'N') # E: Argument 2 to NewType(...) must be subclassable (got "N")
 class N(TypedDict):
     x: int
 [builtins fixtures/dict.pyi]
@@ -5060,7 +5027,7 @@ def foo(node: Node) -> Node:
 [case testForwardReferencesInNewTypeMRORecomputed]
 from typing import NewType
 x: Foo
-Foo = NewType('Foo', B)
+Foo = NewType('Foo', 'B')
 class A:
     x: int
 class B(A):
@@ -5445,7 +5412,7 @@ class F:
 
 [case testCorrectEnclosingClassPushedInDeferred2]
 from typing import TypeVar
-T = TypeVar('T', bound=C)
+T = TypeVar('T', bound='C')
 class C:
     def m(self: T) -> T:
         class Inner:
@@ -7059,7 +7026,7 @@ reveal_type(C.__new__)  # N: Revealed type is "def (cls: Type[__main__.C]) -> An
 [case testOverrideGenericSelfClassMethod]
 from typing import Generic, TypeVar, Type, List
 
-T = TypeVar('T', bound=A)
+T = TypeVar('T', bound='A')
 
 class A:
     @classmethod
diff --git a/test-data/unit/check-columns.test b/test-data/unit/check-columns.test
index 7c4681c7a7097..6748646b65aa7 100644
--- a/test-data/unit/check-columns.test
+++ b/test-data/unit/check-columns.test
@@ -211,7 +211,7 @@ y: Dict[int, int] = {
 [builtins fixtures/dict.pyi]
 
 [case testColumnCannotDetermineType]
-(x)  # E:2: Cannot determine type of "x"
+(x)  # E:2: Cannot determine type of "x"  # E:2: Name "x" is used before definition
 x = None
 
 [case testColumnInvalidIndexing]
diff --git a/test-data/unit/check-dataclasses.test b/test-data/unit/check-dataclasses.test
index c248f8db85854..631a92f9963b0 100644
--- a/test-data/unit/check-dataclasses.test
+++ b/test-data/unit/check-dataclasses.test
@@ -1929,9 +1929,9 @@ reveal_type(D)  # N: Revealed type is "def (x: builtins.list[b.C]) -> a.D"
 [file b.py]
 from typing import List
 import a
-B = List[C]
-class C(CC): ...
 class CC: ...
+class C(CC): ...
+B = List[C]
 [builtins fixtures/dataclasses.pyi]
 
 [case testDataclassSelfType]
diff --git a/test-data/unit/check-dynamic-typing.test b/test-data/unit/check-dynamic-typing.test
index 7b016c342e95f..7e62c0d0b0e83 100644
--- a/test-data/unit/check-dynamic-typing.test
+++ b/test-data/unit/check-dynamic-typing.test
@@ -47,6 +47,10 @@ class B: pass
 
 [case testCallingFunctionWithDynamicArgumentTypes]
 from typing import Any
+
+def f(x: Any) -> 'A':
+    pass
+
 a, b = None, None # type: (A, B)
 
 if int():
@@ -61,15 +65,16 @@ if int():
 if int():
     a = f(f)
 
-def f(x: Any) -> 'A':
-    pass
-
 class A: pass
 class B: pass
 [builtins fixtures/tuple.pyi]
 
 [case testCallingWithDynamicReturnType]
 from typing import Any
+
+def f(x: 'A') -> Any:
+    pass
+
 a, b = None, None # type: (A, B)
 
 a = f(b) # E: Argument 1 to "f" has incompatible type "B"; expected "A"
@@ -77,9 +82,6 @@ a = f(b) # E: Argument 1 to "f" has incompatible type "B"; expected "A"
 a = f(a)
 b = f(a)
 
-def f(x: 'A') -> Any:
-    pass
-
 class A: pass
 class B: pass
 [builtins fixtures/tuple.pyi]
@@ -283,6 +285,8 @@ class A: pass
 from typing import Any, cast
 class A: pass
 class B: pass
+def f() -> None: pass
+
 d = None # type: Any
 a = None # type: A
 b = None # type: B
@@ -294,10 +298,15 @@ if int():
     b = cast(Any, d)
 if int():
     a = cast(Any, f())
-def f() -> None: pass
-
 [case testCompatibilityOfDynamicWithOtherTypes]
 from typing import Any, Tuple
+
+def g(a: 'A') -> None:
+    pass
+
+class A: pass
+class B: pass
+
 d = None # type: Any
 t = None # type: Tuple[A, A]
 # TODO: callable types, overloaded functions
@@ -308,12 +317,6 @@ d = g
 d = A
 t = d
 f = d
-
-def g(a: 'A') -> None:
-    pass
-
-class A: pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 
@@ -362,6 +365,8 @@ a = None # type: A
 g = None # type: Callable[[], None]
 h = None # type: Callable[[A], None]
 
+def f(x): pass
+
 f()     # E: Missing positional argument "x" in call to "f"
 f(x, x) # E: Too many arguments for "f"
 if int():
@@ -373,8 +378,6 @@ if int():
 if int():
     h = f
 
-def f(x): pass
-
 class A: pass
 
 [case testImplicitGlobalFunctionSignatureWithDifferentArgCounts]
@@ -384,6 +387,9 @@ g1 = None # type: Callable[[A], None]
 g2 = None # type: Callable[[A, A], None]
 a = None # type: A
 
+def f0(): pass
+def f2(x, y): pass
+
 if int():
     g1 = f0 # E: Incompatible types in assignment (expression has type "Callable[[], Any]", variable has type "Callable[[A], None]")
 if int():
@@ -400,16 +406,18 @@ if int():
 f0()
 f2(a, a)
 
-def f0(): pass
-
-def f2(x, y): pass
-
 class A: pass
 
 [case testImplicitGlobalFunctionSignatureWithDefaultArgs]
 from typing import Callable
+class A: pass
+class B: pass
+
 a, b = None, None # type: (A, B)
 
+def f01(x = b): pass
+def f13(x, y = b, z = b): pass
+
 g0 = None # type: Callable[[], None]
 g1 = None # type: Callable[[A], None]
 g2 = None # type: Callable[[A, A], None]
@@ -443,11 +451,6 @@ if int():
 if int():
     g3 = f13
 
-def f01(x = b): pass
-def f13(x, y = b, z = b): pass
-
-class A: pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 [case testSkipTypeCheckingWithImplicitSignature]
@@ -550,6 +553,10 @@ f(o, o, o)
 
 [case testInitMethodWithImplicitSignature]
 from typing import Callable
+
+class A:
+  def __init__(self, a, b): pass
+
 f1 = None # type: Callable[[A], A]
 f2 = None # type: Callable[[A, A], A]
 a = None # type: A
@@ -562,20 +569,14 @@ A(a, a)
 if int():
     f2 = A
 
-class A:
-  def __init__(self, a, b): pass
-
 [case testUsingImplicitTypeObjectWithIs]
-
-t = None # type: type
-t = A
-t = B
-
 class A: pass
 class B:
     def __init__(self): pass
 
-
+t = None # type: type
+t = A
+t = B
 -- Type compatibility
 -- ------------------
 
diff --git a/test-data/unit/check-enum.test b/test-data/unit/check-enum.test
index db86434550993..9343e8d5c5628 100644
--- a/test-data/unit/check-enum.test
+++ b/test-data/unit/check-enum.test
@@ -549,7 +549,7 @@ reveal_type(list(Color))  # N: Revealed type is "builtins.list[__main__.Color]"
 
 [case testEnumWorkWithForward]
 from enum import Enum
-a: E = E.x
+a: E = E.x  # type: ignore[used-before-def]
 class E(Enum):
     x = 1
     y = 2
diff --git a/test-data/unit/check-errorcodes.test b/test-data/unit/check-errorcodes.test
index 798c52629a35b..d966eb44b6e39 100644
--- a/test-data/unit/check-errorcodes.test
+++ b/test-data/unit/check-errorcodes.test
@@ -77,8 +77,8 @@ a = 'x'.foobar(b)  # type: ignore[xyz, w, attr-defined]  # E: Name "b" is not de
     # N: Error code "name-defined" not covered by "type: ignore" comment
 
 [case testErrorCodeIgnoreMultiple2]
-a = 'x'.foobar(b) # type: int # type: ignore[name-defined, attr-defined]
-b = 'x'.foobar(b) # type: int # type: ignore[name-defined, xyz]  # E: "str" has no attribute "foobar"  [attr-defined] \
+a = 'x'.foobar(c) # type: int # type: ignore[name-defined, attr-defined]
+b = 'x'.foobar(c) # type: int # type: ignore[name-defined, xyz]  # E: "str" has no attribute "foobar"  [attr-defined] \
     # N: Error code "attr-defined" not covered by "type: ignore" comment
 
 [case testErrorCodeWarnUnusedIgnores1]
@@ -477,7 +477,7 @@ a['other_commonpart'] = 3  # type: ignore[typeddict-item]
 [typing fixtures/typing-typeddict.pyi]
 
 [case testErrorCodeCannotDetermineType]
-y = x  # E: Cannot determine type of "x"  [has-type]
+y = x  # E: Cannot determine type of "x"  [has-type]  # E: Name "x" is used before definition  [used-before-def]
 reveal_type(y)  # N: Revealed type is "Any"
 x = None
 
diff --git a/test-data/unit/check-expressions.test b/test-data/unit/check-expressions.test
index 6b42141b2b155..78ef78e9ad980 100644
--- a/test-data/unit/check-expressions.test
+++ b/test-data/unit/check-expressions.test
@@ -692,6 +692,7 @@ tmp/m.py:8: error: Invalid index type "int" for "A"; expected type "str"
 
 
 [case testDivmod]
+# flags: --disable-error-code=used-before-def
 from typing import Tuple, Union, SupportsInt
 _Decimal = Union[Decimal, int]
 class Decimal(SupportsInt):
@@ -991,6 +992,15 @@ assert_type(reduce_it(True), Scalar)
 
 
 [case testNoneReturnTypeBasics]
+def f() -> None:
+    pass
+
+class A:
+    def g(self, x: object) -> None:
+        pass
+    def __call__(self) -> None:
+        pass
+
 a, o = None, None # type: (A, object)
 if int():
     a = f()         # E: "f" does not return a value
@@ -1004,40 +1014,30 @@ A().g(f())      # E: "f" does not return a value
 x: A = f()      # E: "f" does not return a value
 f()
 A().g(a)
-
-def f() -> None:
-    pass
-
-class A:
-    def g(self, x: object) -> None:
-        pass
-    def __call__(self) -> None:
-        pass
 [builtins fixtures/tuple.pyi]
 
 [case testNoneReturnTypeWithStatements]
 import typing
-if f():   # Fail
+def f() -> None: pass
+
+if f():   # E: "f" does not return a value
     pass
-elif f(): # Fail
+elif f(): # E: "f" does not return a value
     pass
-while f(): # Fail
+while f(): # E: "f" does not return a value
     pass
 def g() -> object:
-    return f() # Fail
-raise f() # Fail
-
-def f() -> None: pass
+    return f() # E: "f" does not return a value
+raise f() # E: "f" does not return a value
 [builtins fixtures/exception.pyi]
-[out]
-main:2: error: "f" does not return a value
-main:4: error: "f" does not return a value
-main:6: error: "f" does not return a value
-main:9: error: "f" does not return a value
-main:10: error: "f" does not return a value
 
 [case testNoneReturnTypeWithExpressions]
 from typing import cast
+
+def f() -> None: pass
+class A:
+    def __add__(self, x: 'A') -> 'A': pass
+
 a = None # type: A
 [f()]       # E: "f" does not return a value
 f() + a     # E: "f" does not return a value
@@ -1046,15 +1046,16 @@ f() == a    # E: "f" does not return a value
 a != f()    # E: "f" does not return a value
 cast(A, f())
 f().foo     # E: "f" does not return a value
-
-def f() -> None: pass
-class A:
-    def __add__(self, x: 'A') -> 'A': pass
 [builtins fixtures/list.pyi]
 
 [case testNoneReturnTypeWithExpressions2]
 import typing
 
+def f() -> None: pass
+class A:
+    def __add__(self, x: 'A') -> 'A':
+        pass
+
 a, b = None, None # type: (A, bool)
 f() in a   # E: "f" does not return a value  # E: Unsupported right operand type for in ("A")
 a < f()    # E: "f" does not return a value
@@ -1064,11 +1065,6 @@ a in f()   # E: "f" does not return a value
 not f()    # E: "f" does not return a value
 f() and b  # E: "f" does not return a value
 b or f()   # E: "f" does not return a value
-
-def f() -> None: pass
-class A:
-    def __add__(self, x: 'A') -> 'A':
-        pass
 [builtins fixtures/bool.pyi]
 
 
@@ -1424,19 +1420,13 @@ z = x.append(y) if bool() else x.append(y) # E: "append" of "list" does not retu
 from typing import cast
 class A:
     def __add__(self, a: 'A') -> 'A': pass
-a = None # type: A
-None + a   # Fail
-f + a      # Fail
-a + f      # Fail
-cast(A, f)
-
 def f() -> None:
     pass
-[out]
-main:5: error: Unsupported left operand type for + ("None")
-main:6: error: Unsupported left operand type for + ("Callable[[], None]")
-main:7: error: Unsupported operand types for + ("A" and "Callable[[], None]")
-
+a = None # type: A
+None + a   # E: Unsupported left operand type for + ("None")
+f + a      # E: Unsupported left operand type for + ("Callable[[], None]")
+a + f      # E: Unsupported operand types for + ("A" and "Callable[[], None]")
+cast(A, f)
 [case testOperatorMethodWithInvalidArgCount]
 
 a = None # type: A
diff --git a/test-data/unit/check-flags.test b/test-data/unit/check-flags.test
index a76463e3106bf..ebb3744e9f08d 100644
--- a/test-data/unit/check-flags.test
+++ b/test-data/unit/check-flags.test
@@ -1152,13 +1152,13 @@ from typing import Any
 def f(s):
     yield s
 
+def g(x) -> Any:
+    yield x  # E: Expression has type "Any"
+
 x = f(0)  # E: Expression has type "Any"
 for x in f(0):  # E: Expression has type "Any"
     g(x)  # E: Expression has type "Any"
 
-def g(x) -> Any:
-    yield x  # E: Expression has type "Any"
-
 l = [1, 2, 3]
 l[f(0)]  # E: Expression has type "Any"
 f(l)
diff --git a/test-data/unit/check-functions.test b/test-data/unit/check-functions.test
index 9afe9189caaaa..c23bbb77f6435 100644
--- a/test-data/unit/check-functions.test
+++ b/test-data/unit/check-functions.test
@@ -337,6 +337,11 @@ class A: pass
 [out]
 
 [case testCompatibilityOfSimpleTypeObjectWithStdType]
+class A:
+    def __init__(self, a: 'A') -> None: pass
+
+def f() -> None: pass
+
 t = None # type: type
 a = None # type: A
 
@@ -347,11 +352,6 @@ if int():
 if int():
     t = A
 
-class A:
-    def __init__(self, a: 'A') -> None: pass
-
-def f() -> None: pass
-
 [case testFunctionTypesWithOverloads]
 from foo import *
 [file foo.pyi]
@@ -466,6 +466,11 @@ if int():
 
 [case testCallingFunctionsWithDefaultArgumentValues]
 # flags: --implicit-optional --no-strict-optional
+class A: pass
+class AA(A): pass
+class B: pass
+
+def f(x: 'A'  =  None) -> 'B': pass
 
 a, b = None, None # type: (A, B)
 if int():
@@ -482,11 +487,6 @@ if int():
 if int():
     b = f(AA())
 
-def f(x: 'A'  =  None) -> 'B': pass
-
-class A: pass
-class AA(A): pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 [case testDefaultArgumentExpressions]
@@ -1133,6 +1133,7 @@ def dec(f: T) -> T:
 [out]
 
 [case testForwardReferenceToFunctionWithMultipleDecorators]
+# flags: --disable-error-code=used-before-def
 def f(self) -> None:
     g()
     g(1)
@@ -1167,6 +1168,7 @@ def dec(f): return f
 [builtins fixtures/staticmethod.pyi]
 
 [case testForwardRefereceToDecoratedFunctionWithCallExpressionDecorator]
+# flags: --disable-error-code=used-before-def
 def f(self) -> None:
     g()
     g(1)
@@ -2608,9 +2610,9 @@ import p
 def f() -> int: ...
 
 [case testLambdaDefaultTypeErrors]
-lambda a=nonsense: a  # E: Name "nonsense" is not defined
 lambda a=(1 + 'asdf'): a  # E: Unsupported operand types for + ("int" and "str")
-def f(x: int = i):  # E: Name "i" is not defined
+lambda a=nonsense: a  # E: Name "nonsense" is not defined
+def f(x: int = i):  # E: Name "i" is not defined  # E: Name "i" is used before definition
     i = 42
 
 [case testRevealTypeOfCallExpressionReturningNoneWorks]
diff --git a/test-data/unit/check-generics.test b/test-data/unit/check-generics.test
index 27441ce908fe8..1be3145b3b10e 100644
--- a/test-data/unit/check-generics.test
+++ b/test-data/unit/check-generics.test
@@ -20,21 +20,19 @@ class C: pass
 [case testGenericMethodArgument]
 from typing import TypeVar, Generic
 T = TypeVar('T')
-a.f(c) # Fail
-a.f(b)
+
+class A(Generic[T]):
+    def f(self, a: T) -> None: pass
 
 a = None # type: A[B]
 b = None # type: B
 c = None # type: C
 
-class A(Generic[T]):
-    def f(self, a: T) -> None: pass
+a.f(c) # E: Argument 1 to "f" of "A" has incompatible type "C"; expected "B"
+a.f(b)
 
 class B: pass
 class C: pass
-[out]
-main:3: error: Argument 1 to "f" of "A" has incompatible type "C"; expected "B"
-
 [case testGenericMemberVariable]
 from typing import TypeVar, Generic
 T = TypeVar('T')
@@ -661,10 +659,10 @@ main:3: error: Type argument "float" of "Array" must be a subtype of "generic"
 [file other.py]
 from typing import Any, Generic, TypeVar
 
-DT = TypeVar("DT", covariant=True, bound=dtype[Any])
-DTS = TypeVar("DTS", covariant=True, bound=generic)
+DT = TypeVar("DT", covariant=True, bound='dtype[Any]')
+DTS = TypeVar("DTS", covariant=True, bound='generic')
 S = TypeVar("S", bound=Any)
-ST = TypeVar("ST", bound=generic, covariant=True)
+ST = TypeVar("ST", bound='generic', covariant=True)
 
 class common: pass
 class generic(common): pass
@@ -1383,10 +1381,11 @@ Z = TypeVar('Z')
 class OO: pass
 a = None # type: A[object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object]
 
-f(a) # E: Argument 1 to "f" has incompatible type "A[object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object]"; expected "OO"
-
 def f(a: OO) -> None:
     pass
+
+f(a) # E: Argument 1 to "f" has incompatible type "A[object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object, object]"; expected "OO"
+
 class A(Generic[B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z]): pass
 
 [case testErrorWithShorterGenericTypeName]
@@ -1394,9 +1393,10 @@ from typing import TypeVar, Generic
 S = TypeVar('S')
 T = TypeVar('T')
 a = None # type: A[object, B]
+def f(a: 'B') -> None: pass
+
 f(a) # E: Argument 1 to "f" has incompatible type "A[object, B]"; expected "B"
 
-def f(a: 'B') -> None: pass
 class A(Generic[S, T]): pass
 class B: pass
 
@@ -1405,9 +1405,10 @@ from typing import Callable, TypeVar, Generic
 S = TypeVar('S')
 T = TypeVar('T')
 a = None # type: A[object, Callable[[], None]]
+def f(a: 'B') -> None: pass
+
 f(a) # E: Argument 1 to "f" has incompatible type "A[object, Callable[[], None]]"; expected "B"
 
-def f(a: 'B') -> None: pass
 class A(Generic[S, T]): pass
 class B: pass
 
@@ -2143,7 +2144,7 @@ from typing import Generic, TypeVar, Any, Tuple, Type
 
 T = TypeVar('T')
 S = TypeVar('S')
-Q = TypeVar('Q', bound=A[Any])
+Q = TypeVar('Q', bound='A[Any]')
 
 class A(Generic[T]):
     @classmethod
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index e5b69fb6fb9d4..60917db041a1f 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -2507,7 +2507,7 @@ A = Tuple[int]
 [case testNewTypeFromForwardNamedTupleIncremental]
 from typing import NewType, NamedTuple, Tuple
 
-NT = NewType('NT', N)
+NT = NewType('NT', 'N')
 class N(NamedTuple):
     x: int
 
@@ -2591,8 +2591,8 @@ class C(NamedTuple): # type: ignore
 from typing import TypeVar, Generic
 T = TypeVar('T')
 S = TypeVar('S')
-IntNode = Node[int, S]
-AnyNode = Node[S, T]
+IntNode = Node[int, S]  # type: ignore[used-before-def]
+AnyNode = Node[S, T]  # type: ignore[used-before-def]
 
 class Node(Generic[T, S]):
     def __init__(self, x: T, y: S) -> None:
@@ -2642,8 +2642,8 @@ class G(Generic[T]):
     x: T
 
 yg: G[M]
-z: int = G[M]().x.x
-z = G[M]().x[0]
+z: int = G[M]().x.x  # type: ignore[used-before-def]
+z = G[M]().x[0]  # type: ignore[used-before-def]
 M = NamedTuple('M', [('x', int)])
 [builtins fixtures/tuple.pyi]
 [out]
diff --git a/test-data/unit/check-inference-context.test b/test-data/unit/check-inference-context.test
index f80f93eb26159..625ab091a6a99 100644
--- a/test-data/unit/check-inference-context.test
+++ b/test-data/unit/check-inference-context.test
@@ -7,6 +7,12 @@
 [case testBasicContextInference]
 from typing import TypeVar, Generic
 T = TypeVar('T')
+
+def f() -> 'A[T]': pass
+
+class A(Generic[T]): pass
+class B: pass
+
 ab = None # type: A[B]
 ao = None # type: A[object]
 b = None # type: B
@@ -17,15 +23,11 @@ if int():
     ab = f()
 if int():
     b = f() # E: Incompatible types in assignment (expression has type "A[<nothing>]", variable has type "B")
-
-def f() -> 'A[T]': pass
-
-class A(Generic[T]): pass
-class B: pass
-
 [case testBasicContextInferenceForConstructor]
 from typing import TypeVar, Generic
 T = TypeVar('T')
+class A(Generic[T]): pass
+class B: pass
 ab = None # type: A[B]
 ao = None # type: A[object]
 b = None # type: B
@@ -36,13 +38,16 @@ if int():
     ab = A()
 if int():
     b = A() # E: Incompatible types in assignment (expression has type "A[<nothing>]", variable has type "B")
-
-class A(Generic[T]): pass
-class B: pass
-
 [case testIncompatibleContextInference]
 from typing import TypeVar, Generic
 T = TypeVar('T')
+def f(a: T) -> 'A[T]':
+    pass
+
+class A(Generic[T]): pass
+
+class B: pass
+class C: pass
 b = None # type: B
 c = None # type: C
 ab = None # type: A[B]
@@ -63,14 +68,6 @@ if int():
 if int():
     ac = f(c)
 
-def f(a: T) -> 'A[T]':
-    pass
-
-class A(Generic[T]): pass
-
-class B: pass
-class C: pass
-
 
 -- Local variables
 -- ---------------
@@ -159,6 +156,12 @@ class B: pass
 [case testInferenceWithTypeVariableTwiceInReturnType]
 from typing import TypeVar, Tuple, Generic
 T = TypeVar('T')
+
+def f(a: T) -> 'Tuple[A[T], A[T]]': pass
+
+class A(Generic[T]): pass
+class B: pass
+
 b = None # type: B
 o = None # type: object
 ab = None # type: A[B]
@@ -175,17 +178,20 @@ if int():
     ab, ab = f(b)
 if int():
     ao, ao = f(o)
-
-def f(a: T) -> 'Tuple[A[T], A[T]]': pass
-
-class A(Generic[T]): pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 [case testInferenceWithTypeVariableTwiceInReturnTypeAndMultipleVariables]
 from typing import TypeVar, Tuple, Generic
 S = TypeVar('S')
 T = TypeVar('T')
+
+def f(a: S, b: T) -> 'Tuple[A[S], A[T], A[T]]': pass
+def g(a: S, b: T) -> 'Tuple[A[S], A[S], A[T]]': pass
+def h(a: S, b: T) -> 'Tuple[A[S], A[S], A[T], A[T]]': pass
+
+class A(Generic[T]): pass
+class B: pass
+
 b = None # type: B
 o = None # type: object
 ab = None # type: A[B]
@@ -206,13 +212,6 @@ if int():
     ab, ab, ao = g(b, b)
 if int():
     ab, ab, ab, ab = h(b, b)
-
-def f(a: S, b: T) -> 'Tuple[A[S], A[T], A[T]]': pass
-def g(a: S, b: T) -> 'Tuple[A[S], A[S], A[T]]': pass
-def h(a: S, b: T) -> 'Tuple[A[S], A[S], A[T], A[T]]': pass
-
-class A(Generic[T]): pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 
@@ -223,6 +222,13 @@ class B: pass
 [case testMultipleTvatInstancesInArgs]
 from typing import TypeVar, Generic
 T = TypeVar('T')
+
+def f(a: T, b: T) -> 'A[T]': pass
+
+class A(Generic[T]): pass
+class B: pass
+class C(B): pass
+
 ac = None # type: A[C]
 ab = None # type: A[B]
 ao = None # type: A[object]
@@ -246,12 +252,6 @@ if int():
 if int():
     ab = f(c, b)
 
-def f(a: T, b: T) -> 'A[T]': pass
-
-class A(Generic[T]): pass
-class B: pass
-class C(B): pass
-
 
 -- Nested generic function calls
 -- -----------------------------
@@ -260,6 +260,12 @@ class C(B): pass
 [case testNestedGenericFunctionCall1]
 from typing import TypeVar, Generic
 T = TypeVar('T')
+
+def f(a: T) -> 'A[T]': pass
+
+class A(Generic[T]): pass
+class B: pass
+
 aab = None # type: A[A[B]]
 aao = None # type: A[A[object]]
 ao = None # type: A[object]
@@ -273,15 +279,16 @@ if int():
     aab = f(f(b))
     aao = f(f(b))
     ao = f(f(b))
+[case testNestedGenericFunctionCall2]
+from typing import TypeVar, Generic
+T = TypeVar('T')
 
-def f(a: T) -> 'A[T]': pass
+def f(a: T) -> T: pass
+def g(a: T) -> 'A[T]': pass
 
 class A(Generic[T]): pass
 class B: pass
 
-[case testNestedGenericFunctionCall2]
-from typing import TypeVar, Generic
-T = TypeVar('T')
 ab = None # type: A[B]
 ao = None # type: A[object]
 b = None # type: B
@@ -293,17 +300,16 @@ if int():
 if int():
     ab = f(g(b))
     ao = f(g(b))
-
-def f(a: T) -> T: pass
+[case testNestedGenericFunctionCall3]
+from typing import TypeVar, Generic
+T = TypeVar('T')
+def f(a: T, b: T) -> T:
+    pass
 
 def g(a: T) -> 'A[T]': pass
 
 class A(Generic[T]): pass
 class B: pass
-
-[case testNestedGenericFunctionCall3]
-from typing import TypeVar, Generic
-T = TypeVar('T')
 ab = None # type: A[B]
 ao = None # type: A[object]
 b = None # type: B
@@ -320,14 +326,6 @@ if int():
 if int():
     ao = f(g(o), g(b))
 
-def f(a: T, b: T) -> T:
-    pass
-
-def g(a: T) -> 'A[T]': pass
-
-class A(Generic[T]): pass
-class B: pass
-
 
 -- Method calls
 -- ------------
@@ -339,6 +337,13 @@ T = TypeVar('T')
 o = None # type: object
 b = None # type: B
 c = None # type: C
+def f(a: T) -> 'A[T]': pass
+
+class A(Generic[T]):
+    def g(self, a: 'A[T]') -> 'A[T]': pass
+
+class B: pass
+class C(B): pass
 ao = None # type: A[object]
 ab = None # type: A[B]
 ac = None # type: A[C]
@@ -353,14 +358,6 @@ if int():
     ab = f(b).g(f(c))
 ab.g(f(c))
 
-def f(a: T) -> 'A[T]': pass
-
-class A(Generic[T]):
-    def g(self, a: 'A[T]') -> 'A[T]': pass
-
-class B: pass
-class C(B): pass
-
 
 -- List expressions
 -- ----------------
@@ -461,8 +458,8 @@ class B: pass
 
 [case testParenthesesAndContext]
 from typing import List
-l = ([A()]) # type: List[object]
 class A: pass
+l = ([A()]) # type: List[object]
 [builtins fixtures/list.pyi]
 
 [case testComplexTypeInferenceWithTuple]
@@ -470,14 +467,15 @@ from typing import TypeVar, Tuple, Generic
 k = TypeVar('k')
 t = TypeVar('t')
 v = TypeVar('v')
-def f(x: Tuple[k]) -> 'A[k]': pass
-
-d = f((A(),)) # type: A[A[B]]
 
 class A(Generic[t]): pass
 class B: pass
 class C: pass
 class D(Generic[k, v]): pass
+
+def f(x: Tuple[k]) -> 'A[k]': pass
+
+d = f((A(),)) # type: A[A[B]]
 [builtins fixtures/list.pyi]
 
 
@@ -505,12 +503,12 @@ d = {A() : a_c,
 [case testInitializationWithInferredGenericType]
 from typing import TypeVar, Generic
 T = TypeVar('T')
-c = f(A()) # type: C[A] # E: Argument 1 to "f" has incompatible type "A"; expected "C[A]"
 
 def f(x: T) -> T: pass
 class C(Generic[T]): pass
 class A: pass
 
+c = f(A()) # type: C[A] # E: Argument 1 to "f" has incompatible type "A"; expected "C[A]"
 [case testInferredGenericTypeAsReturnValue]
 from typing import TypeVar, Generic
 T = TypeVar('T')
@@ -544,9 +542,6 @@ class B: pass
 from typing import TypeVar, Generic
 from abc import abstractmethod, ABCMeta
 t = TypeVar('t')
-x = A() # type: I[int]
-a_object = A() # type: A[object]
-y = a_object # type: I[int] # E: Incompatible types in assignment (expression has type "A[object]", variable has type "I[int]")
 
 class I(Generic[t]):
     @abstractmethod
@@ -554,16 +549,20 @@ class I(Generic[t]):
 class A(I[t], Generic[t]):
     def f(self): pass
 
+x = A() # type: I[int]
+a_object = A() # type: A[object]
+y = a_object # type: I[int] # E: Incompatible types in assignment (expression has type "A[object]", variable has type "I[int]")
+
 [case testInferenceWithAbstractClassContext2]
 from typing import TypeVar, Generic
 from abc import abstractmethod, ABCMeta
 t = TypeVar('t')
-a = f(A()) # type: A[int]
-a_int = A() # type: A[int]
-aa = f(a_int)
 class I(Generic[t]): pass
 class A(I[t], Generic[t]): pass
 def f(i: I[t]) -> A[t]: pass
+a = f(A()) # type: A[int]
+a_int = A() # type: A[int]
+aa = f(a_int)
 
 [case testInferenceWithAbstractClassContext3]
 from typing import TypeVar, Generic, Iterable
@@ -585,9 +584,9 @@ if int():
 from typing import Any, TypeVar, Generic
 s = TypeVar('s')
 t = TypeVar('t')
+class C(Generic[s, t]): pass
 x = [] # type: Any
 y = C() # type: Any
-class C(Generic[s, t]): pass
 [builtins fixtures/list.pyi]
 
 
@@ -737,6 +736,9 @@ a = m # type: List[A] # E: Incompatible types in assignment (expression has type
 
 [case testOrOperationInferredFromContext]
 from typing import List
+class A: pass
+class B: pass
+class C(B): pass
 a, b, c = None, None, None # type: (List[A], List[B], List[C])
 if int():
     a = a or []
@@ -748,10 +750,6 @@ if int():
     a = a or b # E: Incompatible types in assignment (expression has type "Union[List[A], List[B]]", variable has type "List[A]")
 if int():
     b = b or c # E: Incompatible types in assignment (expression has type "Union[List[B], List[C]]", variable has type "List[B]")
-
-class A: pass
-class B: pass
-class C(B): pass
 [builtins fixtures/list.pyi]
 
 
@@ -765,38 +763,38 @@ t = TypeVar('t')
 s = TypeVar('s')
 # Some type variables can be inferred using context, but not all of them.
 a = None # type: List[A]
+def f(a: s, b: t) -> List[s]: pass
+class A: pass
+class B: pass
 if int():
     a = f(A(), B())
 if int():
     a = f(B(), B()) # E: Argument 1 to "f" has incompatible type "B"; expected "A"
-def f(a: s, b: t) -> List[s]: pass
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testSomeTypeVarsInferredFromContext2]
 from typing import List, TypeVar
 s = TypeVar('s')
 t = TypeVar('t')
+def f(a: s, b: t) -> List[s]: pass
+class A: pass
+class B: pass
 # Like testSomeTypeVarsInferredFromContext, but tvars in different order.
 a = None # type: List[A]
 if int():
     a = f(A(), B())
 if int():
     a = f(B(), B()) # E: Argument 1 to "f" has incompatible type "B"; expected "A"
-def f(a: s, b: t) -> List[s]: pass
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testLambdaInListAndHigherOrderFunction]
 from typing import TypeVar, Callable, List
 t = TypeVar('t')
 s = TypeVar('s')
-map(
-  [lambda x: x], [])
 def map(f: List[Callable[[t], s]], a: List[t]) -> List[s]: pass
 class A: pass
+map(
+  [lambda x: x], [])
 [builtins fixtures/list.pyi]
 [out]
 
diff --git a/test-data/unit/check-inference.test b/test-data/unit/check-inference.test
index 45a833e5210c5..41fe942b83397 100644
--- a/test-data/unit/check-inference.test
+++ b/test-data/unit/check-inference.test
@@ -3,7 +3,9 @@
 
 
 [case testInferSimpleGvarType]
-import typing
+class A: pass
+class B: pass
+
 x = A()
 y = B()
 if int():
@@ -14,9 +16,6 @@ if int():
     x = y   # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 if int():
     x = x
-class A: pass
-class B: pass
-
 [case testInferSimpleLvarType]
 import typing
 def f() -> None:
@@ -401,6 +400,8 @@ a = None # type: A
 b = None # type: B
 c = None # type: Tuple[A, object]
 
+def id(a: T) -> T: pass
+
 if int():
     b = id(a) # E: Incompatible types in assignment (expression has type "A", variable has type "B")
     a = id(b) # E: Incompatible types in assignment (expression has type "B", variable has type "A")
@@ -412,8 +413,6 @@ if int():
     b = id(b)
     c = id(c)
 
-def id(a: T) -> T: pass
-
 class A: pass
 class B: pass
 [builtins fixtures/tuple.pyi]
@@ -444,20 +443,26 @@ def ff() -> None:
     x = f() # E: Need type annotation for "x"
     reveal_type(x) # N: Revealed type is "Any"
 
+def f() -> T: pass # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
+def g(a: T) -> None: pass
+
 g(None) # Ok
 f()     # Ok because not used to infer local variable type
 g(a)
-
-def f() -> T: pass # E: A function returning TypeVar should receive at least one argument containing the same TypeVar
-def g(a: T) -> None: pass
 [out]
 
 [case testInferenceWithMultipleConstraints]
 from typing import TypeVar
+
+class A: pass
+class B(A): pass
+
 T = TypeVar('T')
 a = None # type: A
 b = None # type: B
 
+def f(a: T, b: T) -> T: pass
+
 if int():
     b = f(a, b) # E: Incompatible types in assignment (expression has type "A", variable has type "B")
 if int():
@@ -467,15 +472,16 @@ if int():
 if int():
     a = f(b, a)
 
-def f(a: T, b: T) -> T: pass
-
-class A: pass
-class B(A): pass
-
 [case testInferenceWithMultipleVariables]
 from typing import Tuple, TypeVar
 T = TypeVar('T')
 S = TypeVar('S')
+
+def f(a: T, b: S) -> Tuple[T, S]: pass
+
+class A: pass
+class B: pass
+
 a, b = None, None # type: (A, B)
 taa = None # type: Tuple[A, A]
 tab = None # type: Tuple[A, B]
@@ -493,11 +499,6 @@ if int():
     tab = f(a, b)
 if int():
     tba = f(b, a)
-
-def f(a: T, b: S) -> Tuple[T, S]: pass
-
-class A: pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 [case testConstraintSolvingWithSimpleGenerics]
@@ -507,6 +508,14 @@ ao = None # type: A[object]
 ab = None # type: A[B]
 ac = None # type: A[C]
 
+def f(a: 'A[T]') -> 'A[T]': pass
+
+def g(a: T) -> T: pass
+
+class A(Generic[T]): pass
+class B: pass
+class C: pass
+
 if int():
     ab = f(ao) # E: Argument 1 to "f" has incompatible type "A[object]"; expected "A[B]"
     ao = f(ab) # E: Argument 1 to "f" has incompatible type "A[B]"; expected "A[object]"
@@ -524,37 +533,33 @@ if int():
 if int():
     ab = g(ab)
     ao = g(ao)
-
-def f(a: 'A[T]') -> 'A[T]': pass
-
-def g(a: T) -> T: pass
-
-class A(Generic[T]): pass
-class B: pass
-class C: pass
-
 [case testConstraintSolvingFailureWithSimpleGenerics]
 from typing import TypeVar, Generic
 T = TypeVar('T')
 ao = None # type: A[object]
 ab = None # type: A[B]
 
-f(ao, ab) # E: Cannot infer type argument 1 of "f"
-f(ab, ao) # E: Cannot infer type argument 1 of "f"
-f(ao, ao)
-f(ab, ab)
-
 def f(a: 'A[T]', b: 'A[T]') -> None: pass
 
 class A(Generic[T]): pass
 class B: pass
 
+
+f(ao, ab) # E: Cannot infer type argument 1 of "f"
+f(ab, ao) # E: Cannot infer type argument 1 of "f"
+f(ao, ao)
+f(ab, ab)
 [case testTypeInferenceWithCalleeDefaultArgs]
 from typing import TypeVar
 T = TypeVar('T')
 a = None # type: A
 o = None # type: object
 
+def f(a: T = None) -> T: pass
+def g(a: T, b: T = None) -> T: pass
+
+class A: pass
+
 if int():
     a = f(o)    # E: Incompatible types in assignment (expression has type "object", variable has type "A")
 if int():
@@ -569,11 +574,6 @@ if int():
 if int():
     a = g(a)
 
-def f(a: T = None) -> T: pass
-def g(a: T, b: T = None) -> T: pass
-
-class A: pass
-
 
 -- Generic function inference with multiple inheritance
 -- ----------------------------------------------------
@@ -655,6 +655,12 @@ g(c)
 [case testPrecedenceOfFirstBaseAsInferenceResult]
 from typing import TypeVar
 from abc import abstractmethod, ABCMeta
+class A: pass
+class B(A, I, J): pass
+class C(A, I, J): pass
+
+def f(a: T, b: T) -> T: pass
+
 T = TypeVar('T')
 a, i, j = None, None, None # type: (A, I, J)
 
@@ -663,11 +669,7 @@ a = f(B(), C())
 class I(metaclass=ABCMeta): pass
 class J(metaclass=ABCMeta): pass
 
-def f(a: T, b: T) -> T: pass
 
-class A: pass
-class B(A, I, J): pass
-class C(A, I, J): pass
 [builtins fixtures/tuple.pyi]
 
 
@@ -966,6 +968,9 @@ list_2 = [f, h]
 [case testInferenceOfFor1]
 a, b = None, None # type: (A, B)
 
+class A: pass
+class B: pass
+
 for x in [A()]:
     b = x # E: Incompatible types in assignment (expression has type "A", variable has type "B")
     a = x
@@ -973,40 +978,32 @@ for x in [A()]:
 for y in []: # E: Need type annotation for "y"
     a = y
     reveal_type(y)  # N: Revealed type is "Any"
-
-class A: pass
-class B: pass
 [builtins fixtures/for.pyi]
 
 [case testInferenceOfFor2]
+class A: pass
+class B: pass
+class C: pass
 
 a, b, c = None, None, None # type: (A, B, C)
 for x, (y, z) in [(A(), (B(), C()))]:
-    b = x # Fail
-    c = y # Fail
-    a = z # Fail
+    b = x # E: Incompatible types in assignment (expression has type "A", variable has type "B")
+    c = y # E: Incompatible types in assignment (expression has type "B", variable has type "C")
+    a = z # E: Incompatible types in assignment (expression has type "C", variable has type "A")
     a = x
     b = y
     c = z
-for xx, yy, zz in [(A(), B())]: # Fail
+for xx, yy, zz in [(A(), B())]: # E: Need more than 2 values to unpack (3 expected)
     pass
-for xx, (yy, zz) in [(A(), B())]: # Fail
+for xx, (yy, zz) in [(A(), B())]: # E: "B" object is not iterable
     pass
 for xxx, yyy in [(None, None)]:
     pass
-
-class A: pass
-class B: pass
-class C: pass
 [builtins fixtures/for.pyi]
-[out]
-main:4: error: Incompatible types in assignment (expression has type "A", variable has type "B")
-main:5: error: Incompatible types in assignment (expression has type "B", variable has type "C")
-main:6: error: Incompatible types in assignment (expression has type "C", variable has type "A")
-main:10: error: Need more than 2 values to unpack (3 expected)
-main:12: error: "B" object is not iterable
 
 [case testInferenceOfFor3]
+class A: pass
+class B: pass
 
 a, b = None, None # type: (A, B)
 
@@ -1021,19 +1018,21 @@ for e, f in [[]]:  # E: Need type annotation for "e" \
     reveal_type(e)  # N: Revealed type is "Any"
     reveal_type(f)  # N: Revealed type is "Any"
 
-class A: pass
-class B: pass
 [builtins fixtures/for.pyi]
 
 [case testForStatementInferenceWithVoid]
-import typing
+def f() -> None: pass
+
 for x in f(): # E: "f" does not return a value
     pass
-def f() -> None: pass
 [builtins fixtures/for.pyi]
 
 [case testReusingInferredForIndex]
 import typing
+
+class A: pass
+class B: pass
+
 for a in [A()]: pass
 a = A()
 if int():
@@ -1041,8 +1040,6 @@ if int():
     for a in []: pass
     a = A()
     a = B() # E: Incompatible types in assignment (expression has type "B", variable has type "A")
-class A: pass
-class B: pass
 [builtins fixtures/for.pyi]
 
 [case testReusingInferredForIndex2]
@@ -1128,15 +1125,15 @@ if int():
 class A: pass
 
 [case testInferGlobalDefinedInBlock]
-import typing
+class A: pass
+class B: pass
+
 if A:
     a = A()
     if int():
         a = A()
     if int():
         a = B() # E: Incompatible types in assignment (expression has type "B", variable has type "A")
-class A: pass
-class B: pass
 
 [case testAssigningAnyStrToNone]
 from typing import Tuple, TypeVar
@@ -1314,7 +1311,7 @@ class A: pass
 
 [case testAccessGlobalVarBeforeItsTypeIsAvailable]
 import typing
-x.y  # E: Cannot determine type of "x"
+x.y  # E: Cannot determine type of "x"  # E: Name "x" is used before definition
 x = object()
 x.y  # E: "object" has no attribute "y"
 
@@ -1977,7 +1974,7 @@ class A:
 [out]
 
 [case testMultipassAndTopLevelVariable]
-y = x # E: Cannot determine type of "x"
+y = x # E: Cannot determine type of "x"  # E: Name "x" is used before definition
 y()
 x = 1+int()
 [out]
@@ -2160,7 +2157,7 @@ from typing import TypeVar, Callable
 T = TypeVar('T')
 def dec() -> Callable[[T], T]: pass
 
-A.g  # E: Cannot determine type of "g"
+A.g  # E: Cannot determine type of "g"  # E: Name "A" is used before definition
 
 class A:
     @classmethod
@@ -2990,13 +2987,14 @@ class C:
 [case testUnionGenericWithBoundedVariable]
 from typing import Generic, TypeVar, Union
 
+class A: ...
+class B(A): ...
+
 T = TypeVar('T', bound=A)
 class Z(Generic[T]):
     def __init__(self, y: T) -> None:
         self.y = y
 
-class A: ...
-class B(A): ...
 F = TypeVar('F', bound=A)
 
 def q1(x: Union[F, Z[F]]) -> F:
diff --git a/test-data/unit/check-kwargs.test b/test-data/unit/check-kwargs.test
index ace28a18a5a81..e0fe389bbbd9f 100644
--- a/test-data/unit/check-kwargs.test
+++ b/test-data/unit/check-kwargs.test
@@ -8,24 +8,27 @@ f(o=None()) # E: "None" not callable
 
 [case testSimpleKeywordArgument]
 import typing
+class A: pass
 def f(a: 'A') -> None: pass
 f(a=A())
 f(a=object()) # E: Argument "a" to "f" has incompatible type "object"; expected "A"
-class A: pass
 
 [case testTwoKeywordArgumentsNotInOrder]
 import typing
+class A: pass
+class B: pass
 def f(a: 'A', b: 'B') -> None: pass
 f(b=A(), a=A()) # E: Argument "b" to "f" has incompatible type "A"; expected "B"
 f(b=B(), a=B()) # E: Argument "a" to "f" has incompatible type "B"; expected "A"
 f(a=A(), b=B())
 f(b=B(), a=A())
-class A: pass
-class B: pass
 
 [case testOneOfSeveralOptionalKeywordArguments]
 # flags: --implicit-optional
 import typing
+class A: pass
+class B: pass
+class C: pass
 def f(a: 'A' = None, b: 'B' = None, c: 'C' = None) -> None: pass
 f(a=A())
 f(b=B())
@@ -35,39 +38,34 @@ f(a=B()) # E: Argument "a" to "f" has incompatible type "B"; expected "Optional[
 f(b=A()) # E: Argument "b" to "f" has incompatible type "A"; expected "Optional[B]"
 f(c=B()) # E: Argument "c" to "f" has incompatible type "B"; expected "Optional[C]"
 f(b=B(), c=A()) # E: Argument "c" to "f" has incompatible type "A"; expected "Optional[C]"
-class A: pass
-class B: pass
-class C: pass
-
 [case testBothPositionalAndKeywordArguments]
 import typing
+class A: pass
+class B: pass
 def f(a: 'A', b: 'B') -> None: pass
 f(A(), b=A()) # E: Argument "b" to "f" has incompatible type "A"; expected "B"
 f(A(), b=B())
-class A: pass
-class B: pass
 
 [case testContextSensitiveTypeInferenceForKeywordArg]
 from typing import List
+class A: pass
 def f(a: 'A', b: 'List[A]') -> None: pass
 f(b=[], a=A())
-class A: pass
 [builtins fixtures/list.pyi]
 
 [case testGivingArgumentAsPositionalAndKeywordArg]
 import typing
-def f(a: 'A', b: 'B' = None) -> None: pass
-f(A(), a=A()) # E: "f" gets multiple values for keyword argument "a"
 class A: pass
 class B: pass
+def f(a: 'A', b: 'B' = None) -> None: pass
+f(A(), a=A()) # E: "f" gets multiple values for keyword argument "a"
 
 [case testGivingArgumentAsPositionalAndKeywordArg2]
 import typing
-def f(a: 'A' = None, b: 'B' = None) -> None: pass
-f(A(), a=A()) # E: "f" gets multiple values for keyword argument "a"
 class A: pass
 class B: pass
-
+def f(a: 'A' = None, b: 'B' = None) -> None: pass
+f(A(), a=A()) # E: "f" gets multiple values for keyword argument "a"
 [case testPositionalAndKeywordForSameArg]
 # This used to crash in check_argument_count(). See #1095.
 def f(a: int): pass
@@ -81,28 +79,28 @@ f(b=object()) # E: Unexpected keyword argument "b" for "f"
 class A: pass
 
 [case testKeywordMisspelling]
+class A: pass
 def f(other: 'A') -> None: pass # N: "f" defined here
 f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other"?
-class A: pass
 
 [case testMultipleKeywordsForMisspelling]
-def f(thing : 'A', other: 'A', atter: 'A', btter: 'B') -> None: pass # N: "f" defined here
-f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "other"?
 class A: pass
 class B: pass
+def f(thing : 'A', other: 'A', atter: 'A', btter: 'B') -> None: pass # N: "f" defined here
+f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "other"?
 
 [case testKeywordMisspellingDifferentType]
-def f(other: 'A') -> None: pass # N: "f" defined here
-f(otter=B()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other"?
 class A: pass
 class B: pass
+def f(other: 'A') -> None: pass # N: "f" defined here
+f(otter=B()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other"?
 
 [case testKeywordMisspellingInheritance]
-def f(atter: 'A', btter: 'B', ctter: 'C') -> None: pass # N: "f" defined here
-f(otter=B()) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "btter"?
 class A: pass
 class B(A): pass
 class C: pass
+def f(atter: 'A', btter: 'B', ctter: 'C') -> None: pass # N: "f" defined here
+f(otter=B()) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "btter"?
 
 [case testKeywordMisspellingFloatInt]
 def f(atter: float, btter: int) -> None: pass # N: "f" defined here
@@ -110,28 +108,28 @@ x: int = 5
 f(otter=x) # E: Unexpected keyword argument "otter" for "f"; did you mean "atter" or "btter"?
 
 [case testKeywordMisspellingVarArgs]
+class A: pass
 def f(other: 'A', *atter: 'A') -> None: pass # N: "f" defined here
 f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other"?
-class A: pass
 [builtins fixtures/tuple.pyi]
 
 [case testKeywordMisspellingOnlyVarArgs]
+class A: pass
 def f(*other: 'A') -> None: pass # N: "f" defined here
 f(otter=A()) # E: Unexpected keyword argument "otter" for "f"
-class A: pass
 [builtins fixtures/tuple.pyi]
 
 [case testKeywordMisspellingVarArgsDifferentTypes]
-def f(other: 'B', *atter: 'A') -> None: pass # N: "f" defined here
-f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other"?
 class A: pass
 class B: pass
+def f(other: 'B', *atter: 'A') -> None: pass # N: "f" defined here
+f(otter=A()) # E: Unexpected keyword argument "otter" for "f"; did you mean "other"?
 [builtins fixtures/tuple.pyi]
 
 [case testKeywordMisspellingVarKwargs]
+class A: pass
 def f(other: 'A', **atter: 'A') -> None: pass
 f(otter=A()) # E: Missing positional argument "other" in call to "f"
-class A: pass
 [builtins fixtures/dict.pyi]
 
 [case testKeywordArgumentsWithDynamicallyTypedCallable]
@@ -143,18 +141,15 @@ f(x=None)
 
 [case testKeywordArgumentWithFunctionObject]
 from typing import Callable
-f = None # type: Callable[[A, B], None]
-f(a=A(), b=B())
-f(A(), b=B())
 class A: pass
 class B: pass
-[out]
-main:3: error: Unexpected keyword argument "a"
-main:3: error: Unexpected keyword argument "b"
-main:4: error: Unexpected keyword argument "b"
-
+f = None # type: Callable[[A, B], None]
+f(a=A(), b=B())  # E: Unexpected keyword argument "a"  # E: Unexpected keyword argument "b"
+f(A(), b=B())  # E: Unexpected keyword argument "b"
 [case testKeywordOnlyArguments]
 import typing
+class A: pass
+class B: pass
 def f(a: 'A', *, b: 'B' = None) -> None: pass
 def g(a: 'A', *, b: 'B') -> None: pass
 def h(a: 'A', *, b: 'B', aa: 'A') -> None: pass
@@ -177,13 +172,12 @@ i(A(), b=B())
 i(A(), aa=A()) # E: Missing named argument "b" for "i"
 i(A(), b=B(), aa=A())
 i(A(), aa=A(), b=B())
+[case testKeywordOnlyArgumentsFastparse]
+import typing
 
 class A: pass
 class B: pass
 
-[case testKeywordOnlyArgumentsFastparse]
-
-import typing
 def f(a: 'A', *, b: 'B' = None) -> None: pass
 def g(a: 'A', *, b: 'B') -> None: pass
 def h(a: 'A', *, b: 'B', aa: 'A') -> None: pass
@@ -206,10 +200,6 @@ i(A(), b=B())
 i(A(), aa=A()) # E: Missing named argument "b" for "i"
 i(A(), b=B(), aa=A())
 i(A(), aa=A(), b=B())
-
-class A: pass
-class B: pass
-
 [case testKwargsAfterBareArgs]
 from typing import Tuple, Any
 def f(a, *, b=None) -> None: pass
@@ -222,6 +212,8 @@ f(a, **b)
 [case testKeywordArgAfterVarArgs]
 # flags: --implicit-optional
 import typing
+class A: pass
+class B: pass
 def f(*a: 'A', b: 'B' = None) -> None: pass
 f()
 f(A())
@@ -232,13 +224,13 @@ f(A(), A(), b=B())
 f(B())      # E: Argument 1 to "f" has incompatible type "B"; expected "A"
 f(A(), B()) # E: Argument 2 to "f" has incompatible type "B"; expected "A"
 f(b=A())    # E: Argument "b" to "f" has incompatible type "A"; expected "Optional[B]"
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testKeywordArgAfterVarArgsWithBothCallerAndCalleeVarArgs]
 # flags: --implicit-optional --no-strict-optional
 from typing import List
+class A: pass
+class B: pass
 def f(*a: 'A', b: 'B' = None) -> None: pass
 a = None # type: List[A]
 f(*a)
@@ -249,18 +241,16 @@ f(A(), *a, b=B())
 f(A(), B())   # E: Argument 2 to "f" has incompatible type "B"; expected "A"
 f(A(), b=A()) # E: Argument "b" to "f" has incompatible type "A"; expected "Optional[B]"
 f(*a, b=A())  # E: Argument "b" to "f" has incompatible type "A"; expected "Optional[B]"
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testCallingDynamicallyTypedFunctionWithKeywordArgs]
 import typing
+class A: pass
 def f(x, y=A()): pass  # N: "f" defined here
 f(x=A(), y=A())
 f(y=A(), x=A())
 f(y=A())      # E: Missing positional argument "x" in call to "f"
 f(A(), z=A()) # E: Unexpected keyword argument "z" for "f"
-class A: pass
 
 [case testKwargsArgumentInFunctionBody]
 from typing import Dict, Any
@@ -284,6 +274,8 @@ class A: pass
 
 [case testCallingFunctionThatAcceptsVarKwargs]
 import typing
+class A: pass
+class B: pass
 def f( **kwargs: 'A') -> None: pass
 f()
 f(x=A())
@@ -291,12 +283,12 @@ f(y=A(), z=A())
 f(x=B()) # E: Argument "x" to "f" has incompatible type "B"; expected "A"
 f(A())   # E: Too many arguments for "f"
 # Perhaps a better message would be "Too many *positional* arguments..."
-class A: pass
-class B: pass
 [builtins fixtures/dict.pyi]
 
 [case testCallingFunctionWithKeywordVarArgs]
 from typing import Dict
+class A: pass
+class B: pass
 def f( **kwargs: 'A') -> None: pass
 d = None # type: Dict[str, A]
 f(**d)
@@ -305,8 +297,6 @@ d2 = None # type: Dict[str, B]
 f(**d2)         # E: Argument 1 to "f" has incompatible type "**Dict[str, B]"; expected "A"
 f(x=A(), **d2)  # E: Argument 2 to "f" has incompatible type "**Dict[str, B]"; expected "A"
 f(**{'x': B()}) # E: Argument 1 to "f" has incompatible type "**Dict[str, B]"; expected "A"
-class A: pass
-class B: pass
 [builtins fixtures/dict.pyi]
 
 [case testKwargsAllowedInDunderCall]
@@ -355,11 +345,11 @@ class A: pass
 [case testInvalidTypeForKeywordVarArg]
 # flags: --strict-optional
 from typing import Dict, Any, Optional
+class A: pass
 def f(**kwargs: 'A') -> None: pass
 d = {} # type: Dict[A, A]
 f(**d)         # E: Keywords must be strings
 f(**A())       # E: Argument after ** must be a mapping, not "A"
-class A: pass
 kwargs: Optional[Any]
 f(**kwargs)    # E: Argument after ** must be a mapping, not "Optional[Any]"
 [builtins fixtures/dict.pyi]
diff --git a/test-data/unit/check-namedtuple.test b/test-data/unit/check-namedtuple.test
index 4eda14c2c592e..6b9f139f541cc 100644
--- a/test-data/unit/check-namedtuple.test
+++ b/test-data/unit/check-namedtuple.test
@@ -561,6 +561,7 @@ A  # E: Name "A" is not defined
 [builtins fixtures/tuple.pyi]
 
 [case testNamedTupleForwardAsUpperBound]
+# flags: --disable-error-code=used-before-def
 from typing import NamedTuple, TypeVar, Generic
 T = TypeVar('T', bound='M')
 class G(Generic[T]):
@@ -723,7 +724,7 @@ reveal_type(n.y[0]) # N: Revealed type is "Any"
 from typing import NamedTuple
 
 B = NamedTuple('B', [
-        ('x', A), # E: Cannot resolve name "A" (possible cyclic definition)
+        ('x', A), # E: Cannot resolve name "A" (possible cyclic definition)  # E: Name "A" is used before definition
         ('y', int),
     ])
 A = NamedTuple('A', [
@@ -904,6 +905,7 @@ if not b:
 [builtins fixtures/tuple.pyi]
 
 [case testNamedTupleDoubleForward]
+# flags: --disable-error-code=used-before-def
 from typing import Union, Mapping, NamedTuple
 
 class MyBaseTuple(NamedTuple):
diff --git a/test-data/unit/check-newsemanal.test b/test-data/unit/check-newsemanal.test
index 97cf1ef1494dd..99f4141a4d649 100644
--- a/test-data/unit/check-newsemanal.test
+++ b/test-data/unit/check-newsemanal.test
@@ -434,7 +434,7 @@ def main() -> None:
             x  # E: Name "x" is not defined
 
 [case testNewAnalyzerCyclicDefinitions]
-# flags: --disable-recursive-aliases
+# flags: --disable-recursive-aliases --disable-error-code used-before-def
 gx = gy  # E: Cannot resolve name "gy" (possible cyclic definition)
 gy = gx
 def main() -> None:
@@ -521,12 +521,6 @@ reveal_type(b.x) # N: Revealed type is "builtins.int"
 reveal_type(b.f()) # N: Revealed type is "builtins.str"
 
 [case testNewAnalyzerNestedClass2]
-b: A.B
-b = A.B('') # E: Argument 1 to "B" has incompatible type "str"; expected "int"
-reveal_type(b) # N: Revealed type is "__main__.A.B"
-reveal_type(b.x) # N: Revealed type is "builtins.int"
-reveal_type(b.f()) # N: Revealed type is "builtins.str"
-
 class A:
     class B:
         x: int
@@ -537,17 +531,14 @@ class A:
         def f(self) -> str:
             return self.x # E: Incompatible return value type (got "int", expected "str")
 
+b: A.B
+b = A.B('') # E: Argument 1 to "B" has incompatible type "str"; expected "int"
+reveal_type(b) # N: Revealed type is "__main__.A.B"
+reveal_type(b.x) # N: Revealed type is "builtins.int"
+reveal_type(b.f()) # N: Revealed type is "builtins.str"
 [case testNewAnalyzerGenerics]
 from typing import TypeVar, Generic
 
-c: C[int]
-c2: C[int, str] # E: "C" expects 1 type argument, but 2 given
-c3: C
-c = C('') # E: Argument 1 to "C" has incompatible type "str"; expected "int"
-reveal_type(c.get()) # N: Revealed type is "builtins.int"
-reveal_type(c2) # N: Revealed type is "__main__.C[Any]"
-reveal_type(c3) # N: Revealed type is "__main__.C[Any]"
-
 T = TypeVar('T')
 
 class C(Generic[T]):
@@ -557,6 +548,13 @@ class C(Generic[T]):
     def get(self) -> T:
         return self.x
 
+c: C[int]
+c2: C[int, str] # E: "C" expects 1 type argument, but 2 given
+c3: C
+c = C('') # E: Argument 1 to "C" has incompatible type "str"; expected "int"
+reveal_type(c.get()) # N: Revealed type is "builtins.int"
+reveal_type(c2) # N: Revealed type is "__main__.C[Any]"
+reveal_type(c3) # N: Revealed type is "__main__.C[Any]"
 [case testNewAnalyzerGenericsTypeVarForwardRef]
 from typing import TypeVar, Generic
 
@@ -577,6 +575,12 @@ reveal_type(c.get()) # N: Revealed type is "builtins.int"
 [case testNewAnalyzerTypeAlias]
 from typing import Union, TypeVar, Generic
 
+T = TypeVar('T')
+S = TypeVar('S')
+class D(Generic[T, S]): pass
+
+class C: pass
+
 C2 = C
 U = Union[C, int]
 G = D[T, C]
@@ -587,13 +591,6 @@ u: U
 reveal_type(u) # N: Revealed type is "Union[__main__.C, builtins.int]"
 g: G[int]
 reveal_type(g) # N: Revealed type is "__main__.D[builtins.int, __main__.C]"
-
-class C: pass
-
-T = TypeVar('T')
-S = TypeVar('S')
-class D(Generic[T, S]): pass
-
 [case testNewAnalyzerTypeAlias2]
 from typing import Union
 
@@ -678,13 +675,14 @@ a.f(1.0) # E: No overload variant of "f" of "A" matches argument type "float" \
          # N:     def f(self, x: str) -> str
 
 [case testNewAnalyzerPromotion]
+def f(x: float) -> None: pass
 y: int
 f(y)
 f(1)
-def f(x: float) -> None: pass
 [builtins fixtures/primitives.pyi]
 
 [case testNewAnalyzerFunctionDecorator]
+# flags: --disable-error-code used-before-def
 from typing import Callable
 
 @dec
@@ -702,6 +700,7 @@ reveal_type(f1('')) # N: Revealed type is "builtins.str"
 f2(1) # E: Argument 1 to "f2" has incompatible type "int"; expected "str"
 
 [case testNewAnalyzerTypeVarForwardReference]
+# flags: --disable-error-code used-before-def
 from typing import TypeVar, Generic
 
 T = TypeVar('T')
@@ -721,7 +720,7 @@ y: D[Y]
 from typing import TypeVar, Generic
 
 T = TypeVar('T')
-XY = TypeVar('XY', X, Y)
+XY = TypeVar('XY', 'X', 'Y')
 
 class C(Generic[T]): pass
 
@@ -737,7 +736,7 @@ y: D[Y]
 from typing import TypeVar, Generic
 
 T = TypeVar('T')
-XY = TypeVar('XY', X, Y)
+XY = TypeVar('XY', 'X', 'Y')
 
 class C(Generic[T]): pass
 
@@ -755,7 +754,7 @@ y: D[Y]
 from typing import TypeVar, Generic
 
 T = TypeVar('T')
-TY = TypeVar('TY', bound=Y)
+TY = TypeVar('TY', bound='Y')
 
 class C(Generic[T]): pass
 
@@ -775,7 +774,7 @@ class C(Generic[T]):
 def func(x: U) -> U: ...
 
 U = TypeVar('U', asdf, asdf)  # E: Name "asdf" is not defined
-T = TypeVar('T', bound=asdf)  # E: Name "asdf" is not defined
+T = TypeVar('T', bound='asdf')  # E: Name "asdf" is not defined
 
 reveal_type(C)  # N: Revealed type is "def [T <: Any] (x: T`1) -> __main__.C[T`1]"
 reveal_type(func)  # N: Revealed type is "def [U in (Any, Any)] (x: U`-1) -> U`-1"
@@ -799,16 +798,16 @@ T = TypeVar('T')
 
 class A(Generic[T]): pass
 
-a1: A[C] = C()
-a2: A[D] = C() \
-    # E: Incompatible types in assignment (expression has type "C", variable has type "A[D]")
-
 class C(A[C]):
     pass
 
-class D(A[D]):
+class D(A['D']):
     pass
 
+a1: A[C] = C()
+a2: A[D] = C() \
+    # E: Incompatible types in assignment (expression has type "C", variable has type "A[D]")
+
 [case testNewAnalyzerTypeVarBoundForwardRef]
 from typing import TypeVar
 
@@ -855,19 +854,17 @@ def f(): pass
 [case testNewAnalyzerNamedTupleCall]
 from typing import NamedTuple
 
-o: Out
-i: In
 
+class Other: pass
+In = NamedTuple('In', [('s', str), ('t', Other)])
 Out = NamedTuple('Out', [('x', In), ('y', Other)])
-
+o: Out
+i: In
 reveal_type(o)  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other, fallback=__main__.In], __main__.Other, fallback=__main__.Out]"
 reveal_type(o.x)  # N: Revealed type is "Tuple[builtins.str, __main__.Other, fallback=__main__.In]"
 reveal_type(o.y)  # N: Revealed type is "__main__.Other"
 reveal_type(o.x.t)  # N: Revealed type is "__main__.Other"
 reveal_type(i.t)  # N: Revealed type is "__main__.Other"
-
-In = NamedTuple('In', [('s', str), ('t', Other)])
-class Other: pass
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerNamedTupleClass]
@@ -936,29 +933,23 @@ class C:
 [case testNewAnalyzerNamedTupleCallNestedMethod]
 from typing import NamedTuple
 
-c = C()
-reveal_type(c.o)  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other@12, fallback=__main__.C.In@11], __main__.Other@12, fallback=__main__.C.Out@10]"
-reveal_type(c.o.x)  # N: Revealed type is "Tuple[builtins.str, __main__.Other@12, fallback=__main__.C.In@11]"
-
 class C:
     def get_tuple(self) -> None:
-        self.o: Out
-        Out = NamedTuple('Out', [('x', In), ('y', Other)])
-        In = NamedTuple('In', [('s', str), ('t', Other)])
+        Out = NamedTuple('Out', [('x', 'In'), ('y', 'Other')])
+        In = NamedTuple('In', [('s', str), ('t', 'Other')])
         class Other: pass
+        self.o: Out
+
+c = C()
+reveal_type(c.o)  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other@7, fallback=__main__.C.In@6], __main__.Other@7, fallback=__main__.C.Out@5]"
+reveal_type(c.o.x)  # N: Revealed type is "Tuple[builtins.str, __main__.Other@7, fallback=__main__.C.In@6]"
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerNamedTupleClassNestedMethod]
 from typing import NamedTuple
 
-c = C()
-reveal_type(c.o)  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other@18, fallback=__main__.C.In@15], __main__.Other@18, fallback=__main__.C.Out@11]"
-reveal_type(c.o.x)  # N: Revealed type is "Tuple[builtins.str, __main__.Other@18, fallback=__main__.C.In@15]"
-reveal_type(c.o.method())  # N: Revealed type is "Tuple[builtins.str, __main__.Other@18, fallback=__main__.C.In@15]"
-
 class C:
     def get_tuple(self) -> None:
-        self.o: Out
         class Out(NamedTuple):
             x: In
             y: Other
@@ -967,6 +958,12 @@ class C:
             s: str
             t: Other
         class Other: pass
+        self.o: Out
+
+c = C()
+reveal_type(c.o)  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other@12, fallback=__main__.C.In@9], __main__.Other@12, fallback=__main__.C.Out@5]"
+reveal_type(c.o.x)  # N: Revealed type is "Tuple[builtins.str, __main__.Other@12, fallback=__main__.C.In@9]"
+reveal_type(c.o.method())  # N: Revealed type is "Tuple[builtins.str, __main__.Other@12, fallback=__main__.C.In@9]"
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerNamedTupleClassForwardMethod]
@@ -988,34 +985,31 @@ class Other(NamedTuple):
 [case testNewAnalyzerNamedTupleSpecialMethods]
 from typing import NamedTuple
 
+class Other: pass
+In = NamedTuple('In', [('s', str), ('t', Other)])
+Out = NamedTuple('Out', [('x', In), ('y', Other)])
+class SubO(Out): pass
+
 o: SubO
 
 reveal_type(SubO._make)  # N: Revealed type is "def (iterable: typing.Iterable[Any], *, new: Any =, len: Any =) -> Tuple[Tuple[builtins.str, __main__.Other, fallback=__main__.In], __main__.Other, fallback=__main__.SubO]"
 reveal_type(o._replace(y=Other()))  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other, fallback=__main__.In], __main__.Other, fallback=__main__.SubO]"
-
-class SubO(Out): pass
-
-Out = NamedTuple('Out', [('x', In), ('y', Other)])
-In = NamedTuple('In', [('s', str), ('t', Other)])
-class Other: pass
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerNamedTupleBaseClass]
 from typing import NamedTuple
+class Other: pass
+class In(NamedTuple):
+    s: str
+    t: Other
+class Out(NamedTuple('Out', [('x', In), ('y', Other)])):
+    pass
 
 o: Out
 reveal_type(o)  # N: Revealed type is "Tuple[Tuple[builtins.str, __main__.Other, fallback=__main__.In], __main__.Other, fallback=__main__.Out]"
 reveal_type(o.x)  # N: Revealed type is "Tuple[builtins.str, __main__.Other, fallback=__main__.In]"
 reveal_type(o.x.t)  # N: Revealed type is "__main__.Other"
 reveal_type(Out._make)  # N: Revealed type is "def (iterable: typing.Iterable[Any], *, new: Any =, len: Any =) -> Tuple[Tuple[builtins.str, __main__.Other, fallback=__main__.In], __main__.Other, fallback=__main__.Out]"
-
-class Out(NamedTuple('Out', [('x', In), ('y', Other)])):
-    pass
-
-class In(NamedTuple):
-    s: str
-    t: Other
-class Other: pass
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerIncompleteRefShadowsBuiltin1]
@@ -1134,7 +1128,11 @@ class B(type):
 reveal_type(A.f()) # N: Revealed type is "builtins.int"
 
 [case testNewAnalyzerMetaclass2]
-reveal_type(A.f()) # N: Revealed type is "builtins.int"
+class B(type):
+    def f(cls) -> int:
+        return 0
+
+class C: pass
 
 class A(metaclass=B):
     pass
@@ -1142,12 +1140,7 @@ class A(metaclass=B):
 class AA(metaclass=C): # E: Metaclasses not inheriting from "type" are not supported
     pass
 
-class B(type):
-    def f(cls) -> int:
-        return 0
-
-class C: pass
-
+reveal_type(A.f()) # N: Revealed type is "builtins.int"
 [case testNewAnalyzerMetaclassPlaceholder]
 class B(C): pass
 
@@ -1211,14 +1204,14 @@ class B(type):
     def f(cls) -> int:
         return 0
 
-reveal_type(A.f()) # N: Revealed type is "builtins.int"
-reveal_type(A.x) # N: Revealed type is "builtins.str"
-
 class A(six.with_metaclass(B, Defer)):
     pass
 
 class Defer:
     x: str
+
+reveal_type(A.f()) # N: Revealed type is "builtins.int"
+reveal_type(A.x) # N: Revealed type is "builtins.str"
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerMetaclassFuture1]
@@ -1252,6 +1245,7 @@ reveal_type(A.x) # N: Revealed type is "builtins.str"
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerMetaclassFuture4]
+# flags: --disable-error-code used-before-def
 import future.utils
 
 class B(type):
@@ -1271,31 +1265,32 @@ class Defer:
 [case testNewAnalyzerFinalDefiningModuleVar]
 from typing import Final
 
+class D(C): ...
+class C: ...
+
 x: Final = C()
 y: Final[C] = D()
 bad: Final[D] = C()  # E: Incompatible types in assignment (expression has type "C", variable has type "D")
 
 reveal_type(x)  # N: Revealed type is "__main__.C"
 reveal_type(y)  # N: Revealed type is "__main__.C"
-class D(C): ...
-class C: ...
-
 [case testNewAnalyzerFinalDefiningInstanceVar]
 from typing import Final
 
+class D: ...
+class E(C): ...
+
 class C:
     def __init__(self, x: D) -> None:
         self.x: Final = x
         self.y: Final[C] = E(D())
 reveal_type(C(D()).x)  # N: Revealed type is "__main__.D"
 reveal_type(C(D()).y)  # N: Revealed type is "__main__.C"
-
-class D: ...
-class E(C): ...
-
 [case testNewAnalyzerFinalReassignModuleVar]
 from typing import Final
 
+class A: ...
+
 x: Final = A()
 x = A()  # E: Cannot assign to final name "x"
 
@@ -1308,8 +1303,6 @@ def f2() -> None:
     def g() -> None:
         f()
 
-class A: ...
-
 [case testNewAnalyzerFinalReassignModuleReexport]
 import a
 [file a.py]
@@ -1382,6 +1375,7 @@ reveal_type(x[0][0])  # N: Revealed type is "__main__.A"
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerAliasToNotReadyClass3]
+# flags: --disable-error-code used-before-def
 from typing import List
 
 x: B
@@ -1461,13 +1455,13 @@ from typing import List, TypeVar, Union
 T = TypeVar('T')
 
 x: B[int]
-B = A[List[T]]
 A = Union[int, T]
+B = A[List[T]]
 class C(List[B[int]]): pass
 
+y: C
 reveal_type(x)  # N: Revealed type is "Union[builtins.int, builtins.list[builtins.int]]"
 reveal_type(y[0])  # N: Revealed type is "Union[builtins.int, builtins.list[builtins.int]]"
-y: C
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerForwardAliasFromUnion]
@@ -1488,6 +1482,7 @@ class C:
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerAliasToNotReadyTwoDeferrals]
+# flags: --disable-error-code used-before-def
 from typing import List
 
 x: B
@@ -1500,7 +1495,7 @@ reveal_type(x[0][0])  # N: Revealed type is "__main__.C"
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerAliasToNotReadyDirectBase]
-# flags: --disable-recursive-aliases
+# flags: --disable-recursive-aliases --disable-error-code used-before-def
 from typing import List
 
 x: B
@@ -1518,6 +1513,7 @@ main:8: note: Revealed type is "Any"
 main:9: note: Revealed type is "Any"
 
 [case testNewAnalyzerAliasToNotReadyTwoDeferralsFunction]
+# flags: --disable-error-code used-before-def
 import a
 [file a.py]
 from typing import List
@@ -1534,7 +1530,7 @@ reveal_type(f)  # N: Revealed type is "def (x: builtins.list[a.C]) -> builtins.l
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerAliasToNotReadyDirectBaseFunction]
-# flags: --disable-recursive-aliases
+# flags: --disable-recursive-aliases --disable-error-code used-before-def
 import a
 [file a.py]
 from typing import List
@@ -1558,11 +1554,11 @@ tmp/a.py:5: error: Cannot resolve name "C" (possible cyclic definition)
 from typing import List, Union
 x: A
 
-A = Union[B, C]
-
 class B(List[A]): pass
 class C(List[A]): pass
 
+A = Union[B, C]
+
 reveal_type(x)  # N: Revealed type is "Union[__main__.B, __main__.C]"
 reveal_type(x[0])  # N: Revealed type is "Union[__main__.B, __main__.C]"
 [builtins fixtures/list.pyi]
@@ -1578,19 +1574,18 @@ reveal_type(func())  # N: Revealed type is "builtins.list[Tuple[b.C, b.C]]"
 from typing import List, Tuple
 from a import func
 
-B = List[Tuple[C, C]]
-
-class C(A): ...
 class A: ...
+class C(A): ...
+B = List[Tuple[C, C]]
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerListComprehension]
 from typing import List
+class A: pass
+class B: pass
 a: List[A]
 a = [x for x in a]
 b: List[B] = [x for x in a] # E: List comprehension has incompatible type List[A]; expected List[B]
-class A: pass
-class B: pass
 [builtins fixtures/for.pyi]
 
 [case testNewAnalyzerDictionaryComprehension]
@@ -1796,23 +1791,26 @@ a.y = 1  # E: Incompatible types in assignment (expression has type "int", varia
 
 [case testNewAnalyzerAliasesFixedFew]
 from typing import List, Generic, TypeVar
+T = TypeVar('T')
+class C(Generic[T]):
+    ...
+A = List[C]
+x: A
 
 def func(x: List[C[T]]) -> T:
     ...
-x: A
-A = List[C]
 
 reveal_type(x)  # N: Revealed type is "builtins.list[__main__.C[Any]]"
 reveal_type(func(x))  # N: Revealed type is "Any"
-class C(Generic[T]):
-    ...
-
-T = TypeVar('T')
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerAliasesFixedMany]
 from typing import List, Generic, TypeVar
 
+T = TypeVar('T')
+class C(Generic[T]):
+    ...
+
 def func(x: List[C[T]]) -> T:
     ...
 
@@ -1822,9 +1820,7 @@ A = List[C[int, str]]  # E: "C" expects 1 type argument, but 2 given
 reveal_type(x)  # N: Revealed type is "builtins.list[__main__.C[Any]]"
 reveal_type(func(x))  # N: Revealed type is "Any"
 
-class C(Generic[T]):
-    ...
-T = TypeVar('T')
+
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerBuiltinAliasesFixed]
@@ -1973,7 +1969,7 @@ class A: pass
 class B: pass
 class C(B): pass
 
-S = TypeVar('S', bound=Tuple[G[A], ...])
+S = TypeVar('S', bound='Tuple[G[A], ...]')
 
 class GG(Generic[S]): pass
 
@@ -2060,12 +2056,12 @@ class C(Tuple[int, str]):
 class Meta(type):
     x = int()
 
-y = C.x
-reveal_type(y)  # N: Revealed type is "builtins.int"
-
 class C(metaclass=Meta):
     pass
 
+y = C.x
+reveal_type(y)  # N: Revealed type is "builtins.int"
+
 [case testNewAnalyzerFunctionError]
 def f(x: asdf) -> None:  # E: Name "asdf" is not defined
     pass
@@ -2089,7 +2085,7 @@ from typing import NewType, List
 x: C
 reveal_type(x[0])  # N: Revealed type is "__main__.C"
 
-C = NewType('C', B)
+C = NewType('C', 'B')
 
 class B(List[C]):
     pass
@@ -2101,8 +2097,8 @@ from typing import NewType, List
 x: D
 reveal_type(x[0])  # N: Revealed type is "__main__.C"
 
+C = NewType('C', 'B')
 D = C
-C = NewType('C', B)
 
 class B(List[D]):
     pass
@@ -2114,22 +2110,22 @@ from typing import NewType, List
 x: D
 reveal_type(x[0][0])  # N: Revealed type is "__main__.C"
 
-D = C
-C = NewType('C', List[B])
+D = C  # E: Name "C" is used before definition
+C = NewType('C', 'List[B]')
 
 class B(List[C]):
     pass
 [builtins fixtures/list.pyi]
 
 [case testNewAnalyzerNewTypeForwardClassAliasDirect]
-# flags: --disable-recursive-aliases
+# flags: --disable-recursive-aliases --disable-error-code used-before-def
 from typing import NewType, List
 
 x: D
 reveal_type(x[0][0])
 
 D = List[C]
-C = NewType('C', B)
+C = NewType('C', 'B')
 
 class B(D):
     pass
@@ -2178,9 +2174,9 @@ reveal_type(x)  # N: Revealed type is "__main__.G[Tuple[builtins.int, fallback=_
 [case testNewAnalyzerDuplicateTypeVar]
 from typing import TypeVar, Generic, Any
 
-T = TypeVar('T', bound=B[Any])
+T = TypeVar('T', bound='B[Any]')
 # The "int" error is because of typing fixture.
-T = TypeVar('T', bound=C)  # E: Cannot redefine "T" as a type variable \
+T = TypeVar('T', bound='C')  # E: Cannot redefine "T" as a type variable \
                            # E: Invalid assignment target \
                            # E: "int" not callable
 
@@ -2193,6 +2189,7 @@ y: B[B[Any]]
 reveal_type(y.x)  # N: Revealed type is "__main__.B[Any]"
 
 [case testNewAnalyzerDuplicateTypeVarImportCycle]
+# flags: --disable-error-code used-before-def
 import a
 [file a.py]
 from typing import TypeVar, Any
@@ -2220,6 +2217,7 @@ tmp/a.py:5: error: Invalid assignment target
 tmp/a.py:5: error: "int" not callable
 
 [case testNewAnalyzerDuplicateTypeVarImportCycleWithAliases]
+# flags: --disable-error-code used-before-def
 import a
 [file a.py]
 from typing import TypeVar, Any
@@ -2313,6 +2311,7 @@ C = NamedTuple('C', [('x', int)])
 [builtins fixtures/tuple.pyi]
 
 [case testNewAnalyzerApplicationForward1]
+# flags: --disable-error-code used-before-def
 from typing import Generic, TypeVar
 
 x = C[int]()
@@ -2335,15 +2334,14 @@ class A: ...
 [case testNewAnalyzerApplicationForward3]
 from typing import Generic, TypeVar
 
-x = C[A]()
-reveal_type(x)  # N: Revealed type is "__main__.C[__main__.A]"
-
+class A: ...
 T = TypeVar('T')
 class C(Generic[T]): ...
-
-class A: ...
+x = C[A]()
+reveal_type(x)  # N: Revealed type is "__main__.C[__main__.A]"
 
 [case testNewAnalyzerApplicationForward4]
+# flags: --disable-error-code used-before-def
 from typing import Generic, TypeVar
 
 x = C[A]()  # E: Value of type variable "T" of "C" cannot be "A"
@@ -2474,6 +2472,9 @@ else:
         y()  # E: "str" not callable
 
 [case testNewAnalyzerFirstAliasTargetWins]
+class DesiredTarget:
+    attr: int
+
 if int():
     Alias = DesiredTarget
 else:
@@ -2483,12 +2484,8 @@ else:
 
 x: Alias
 reveal_type(x.attr)  # N: Revealed type is "builtins.int"
-
-class DesiredTarget:
-    attr: int
-
 [case testNewAnalyzerFirstVarDefinitionWins]
-x = y
+x = y  # E: Name "y" is used before definition
 x = 1
 
 # We want to check that the first definition creates the variable.
diff --git a/test-data/unit/check-overloading.test b/test-data/unit/check-overloading.test
index a5e6cefc2af0e..4209f4ec91640 100644
--- a/test-data/unit/check-overloading.test
+++ b/test-data/unit/check-overloading.test
@@ -25,6 +25,9 @@ main:6: error: Name "f" already defined on line 2
 
 [case testTypeCheckOverloadWithImplementation]
 from typing import overload, Any
+class A: pass
+class B: pass
+
 @overload
 def f(x: 'A') -> 'B': ...
 @overload
@@ -35,14 +38,14 @@ def f(x: Any) -> Any:
 
 reveal_type(f(A())) # N: Revealed type is "__main__.B"
 reveal_type(f(B())) # N: Revealed type is "__main__.A"
-
-class A: pass
-class B: pass
 [builtins fixtures/isinstance.pyi]
 
 [case testTypingExtensionsOverload]
 from typing import Any
 from typing_extensions import overload
+class A: pass
+class B: pass
+
 @overload
 def f(x: 'A') -> 'B': ...
 @overload
@@ -53,13 +56,14 @@ def f(x: Any) -> Any:
 
 reveal_type(f(A())) # N: Revealed type is "__main__.B"
 reveal_type(f(B())) # N: Revealed type is "__main__.A"
-
-class A: pass
-class B: pass
 [builtins fixtures/isinstance.pyi]
 
 [case testOverloadNeedsImplementation]
 from typing import overload, Any
+
+class A: pass
+class B: pass
+
 @overload  # E: An overloaded function outside a stub file must have an implementation
 def f(x: 'A') -> 'B': ...
 @overload
@@ -67,9 +71,6 @@ def f(x: 'B') -> 'A': ...
 
 reveal_type(f(A())) # N: Revealed type is "__main__.B"
 reveal_type(f(B())) # N: Revealed type is "__main__.A"
-
-class A: pass
-class B: pass
 [builtins fixtures/isinstance.pyi]
 
 [case testSingleOverloadNoImplementation]
@@ -84,6 +85,9 @@ class B: pass
 [case testOverloadByAnyOtherName]
 from typing import overload as rose
 from typing import Any
+class A: pass
+class B: pass
+
 @rose
 def f(x: 'A') -> 'B': ...
 @rose
@@ -94,14 +98,14 @@ def f(x: Any) -> Any:
 
 reveal_type(f(A())) # N: Revealed type is "__main__.B"
 reveal_type(f(B())) # N: Revealed type is "__main__.A"
-
-class A: pass
-class B: pass
 [builtins fixtures/isinstance.pyi]
 
 [case testTypeCheckOverloadWithDecoratedImplementation]
 from typing import overload, Any
 
+class A: pass
+class B: pass
+
 def deco(fun): ...
 
 @overload
@@ -115,9 +119,6 @@ def f(x: Any) -> Any:
 
 reveal_type(f(A())) # N: Revealed type is "__main__.B"
 reveal_type(f(B())) # N: Revealed type is "__main__.A"
-
-class A: pass
-class B: pass
 [builtins fixtures/isinstance.pyi]
 
 [case testOverloadDecoratedImplementationNotLast]
@@ -174,6 +175,9 @@ class B: pass
 [case testTypeCheckOverloadWithImplementationError]
 from typing import overload, Any
 
+class A: pass
+class B: pass
+
 @overload
 def f(x: 'A') -> 'B': ...
 @overload
@@ -196,9 +200,6 @@ def g(x):
 
 reveal_type(f(A()))  # N: Revealed type is "__main__.B"
 reveal_type(f(B()))  # N: Revealed type is "__main__.A"
-
-class A: pass
-class B: pass
 [builtins fixtures/isinstance.pyi]
 
 [case testTypeCheckOverloadWithUntypedImplAndMultipleVariants]
diff --git a/test-data/unit/check-protocols.test b/test-data/unit/check-protocols.test
index 8c4aef9b5be01..e490457ff25c0 100644
--- a/test-data/unit/check-protocols.test
+++ b/test-data/unit/check-protocols.test
@@ -794,7 +794,7 @@ main:18: note:         def attr2(self) -> str
 [case testSelfTypesWithProtocolsBehaveAsWithNominal]
 from typing import Protocol, TypeVar
 
-T = TypeVar('T', bound=Shape)
+T = TypeVar('T', bound='Shape')
 class Shape(Protocol):
     def combine(self: T, other: T) -> T:
         pass
diff --git a/test-data/unit/check-python39.test b/test-data/unit/check-python39.test
index d169f40010156..105051a840bbf 100644
--- a/test-data/unit/check-python39.test
+++ b/test-data/unit/check-python39.test
@@ -4,9 +4,9 @@
 # most important test, to deal with this we'll only run this test with Python 3.9 and later.
 import typing
 def f(a: 'A', b: 'B') -> None: pass
-f(a=A(), b=B(), a=A()) # E: "f" gets multiple values for keyword argument "a"
 class A: pass
 class B: pass
+f(a=A(), b=B(), a=A()) # E: "f" gets multiple values for keyword argument "a"
 
 
 [case testPEP614]
diff --git a/test-data/unit/check-recursive-types.test b/test-data/unit/check-recursive-types.test
index 0aa3c4c18be30..53811521f4422 100644
--- a/test-data/unit/check-recursive-types.test
+++ b/test-data/unit/check-recursive-types.test
@@ -88,6 +88,7 @@ A = int | list[A]
 -- Tests duplicating some existing type alias tests with recursive aliases enabled
 
 [case testRecursiveAliasesMutual]
+# flags: --disable-error-code used-before-def
 from typing import Type, Callable, Union
 
 A = Union[B, int]
@@ -120,6 +121,7 @@ B = List[A]
 [builtins fixtures/list.pyi]
 
 [case testRecursiveAliasViaBaseClass]
+# flags: --disable-error-code used-before-def
 from typing import List
 
 x: B
@@ -131,6 +133,7 @@ reveal_type(x[0][0])  # N: Revealed type is "__main__.C"
 [builtins fixtures/list.pyi]
 
 [case testRecursiveAliasViaBaseClass2]
+# flags: --disable-error-code used-before-def
 from typing import NewType, List
 
 x: D
@@ -162,6 +165,7 @@ reveal_type(x)  # N: Revealed type is "__main__.G[Tuple[builtins.int, fallback=_
 [builtins fixtures/list.pyi]
 
 [case testRecursiveAliasViaBaseClassImported]
+# flags: --disable-error-code used-before-def
 import a
 [file a.py]
 from typing import List
@@ -376,6 +380,7 @@ x: A
 y: str = x[0]  # E: Incompatible types in assignment (expression has type "Optional[A]", variable has type "str")
 
 [case testRecursiveAliasesProhibitBadAliases]
+# flags: --disable-error-code used-before-def
 from typing import Union, Type, List, TypeVar
 
 NR = List[int]
@@ -502,6 +507,8 @@ reveal_type(bnt.y)  # N: Revealed type is "builtins.int"
 -- Tests duplicating some existing named tuple tests with recursive aliases enabled
 
 [case testMutuallyRecursiveNamedTuples]
+# flags: --disable-error-code used-before-def
+
 from typing import Tuple, NamedTuple, TypeVar, Union
 
 A = NamedTuple('A', [('x', str), ('y', Tuple[B, ...])])
@@ -565,6 +572,7 @@ t = m  # E: Incompatible types in assignment (expression has type "B", variable
 [builtins fixtures/tuple.pyi]
 
 [case testMutuallyRecursiveNamedTuplesCalls]
+# flags: --disable-error-code used-before-def
 from typing import NamedTuple
 
 B = NamedTuple('B', [('x', A), ('y', int)])
@@ -862,6 +870,7 @@ reveal_type(Sub)  # N: Revealed type is "def [ValueT] (element: Union[ValueT`1,
 reveal_type(Sub(x))  # N: Revealed type is "__main__.Sub[typing.Iterable[builtins.str]]"
 
 [case testNoRecursiveExpandInstanceUnionCrashInference]
+# flags: --disable-error-code used-before-def
 from typing import TypeVar, Union, Generic, List
 
 T = TypeVar("T")
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index b002746a33972..dd177e143aaa0 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -428,7 +428,7 @@ class C:
 [case testSelfTypeNew]
 from typing import TypeVar, Type
 
-T = TypeVar('T', bound=A)
+T = TypeVar('T', bound='A')
 class A:
     def __new__(cls: Type[T]) -> T:
         return cls()
@@ -998,7 +998,7 @@ reveal_type(ab.x)  # N: Revealed type is "builtins.int"
 from typing import Generic, List, Optional, TypeVar, Any
 
 Q = TypeVar("Q")
-T = TypeVar("T", bound=Super[Any])
+T = TypeVar("T", bound='Super[Any]')
 
 class Super(Generic[Q]):
     @classmethod
@@ -1157,7 +1157,7 @@ from typing import Optional, Type, TypeVar, overload, Union
 
 Id = int
 
-A = TypeVar("A", bound=AClass)
+A = TypeVar("A", bound='AClass')
 
 class AClass:
     @overload
@@ -1682,7 +1682,7 @@ class This: ...
 [case testTypingSelfAttrOldVsNewStyle]
 from typing import Self, TypeVar
 
-T = TypeVar("T", bound=C)
+T = TypeVar("T", bound='C')
 class C:
     x: Self
     def foo(self: T) -> T:
diff --git a/test-data/unit/check-statements.test b/test-data/unit/check-statements.test
index 3450f8593d27d..d1a2469efa56b 100644
--- a/test-data/unit/check-statements.test
+++ b/test-data/unit/check-statements.test
@@ -140,20 +140,15 @@ main:5: error: Incompatible types in assignment (expression has type "bool", var
 main:7: error: Incompatible types in assignment (expression has type "bool", variable has type "A")
 
 [case testForStatement]
+class A: pass
 
 a = None # type: A
 b = None # type: object
 for a in [A()]:
-    a = b    # Fail
+    a = b  # E: Incompatible types in assignment (expression has type "object", variable has type "A")
 else:
-    a = b    # Fail
-
-class A: pass
+    a = b  # E: Incompatible types in assignment (expression has type "object", variable has type "A")
 [builtins fixtures/list.pyi]
-[out]
-main:5: error: Incompatible types in assignment (expression has type "object", variable has type "A")
-main:7: error: Incompatible types in assignment (expression has type "object", variable has type "A")
-
 [case testBreakStatement]
 import typing
 while None:
@@ -520,15 +515,15 @@ class B: pass
 main:7: error: Incompatible types in assignment (expression has type "object", variable has type "BaseException")
 
 [case testTypeErrorInBlock]
+class A: pass
+class B: pass
 while object:
     x = None # type: A
     if int():
         x = object() # E: Incompatible types in assignment (expression has type "object", variable has type "A")
         x = B() # E: Incompatible types in assignment (expression has type "B", variable has type "A")
-class A: pass
-class B: pass
-
 [case testTypeErrorInvolvingBaseException]
+class A: pass
 
 x, a = None, None # type: (BaseException, A)
 if int():
@@ -541,7 +536,6 @@ if int():
     x = A()              # E: Incompatible types in assignment (expression has type "A", variable has type "BaseException")
 if int():
     x = BaseException()
-class A: pass
 [builtins fixtures/exception.pyi]
 
 [case testSimpleTryExcept2]
@@ -557,49 +551,38 @@ main:5: error: Incompatible types in assignment (expression has type "object", v
 
 [case testBaseClassAsExceptionTypeInExcept]
 import typing
+class Err(BaseException): pass
 try:
   pass
 except Err as e:
-  e = BaseException() # Fail
+  e = BaseException()  # E: Incompatible types in assignment (expression has type "BaseException", variable has type "Err")
   e = Err()
-class Err(BaseException): pass
 [builtins fixtures/exception.pyi]
-[out]
-main:5: error: Incompatible types in assignment (expression has type "BaseException", variable has type "Err")
-
 [case testMultipleExceptHandlers]
 import typing
+class Err(BaseException): pass
 try:
     pass
 except BaseException as e:
     pass
 except Err as f:
-    f = BaseException() # Fail
+    f = BaseException()  # E: Incompatible types in assignment (expression has type "BaseException", variable has type "Err")
     f = Err()
-class Err(BaseException): pass
 [builtins fixtures/exception.pyi]
-[out]
-main:7: error: Incompatible types in assignment (expression has type "BaseException", variable has type "Err")
-
 [case testTryExceptStatement]
 import typing
+class A: pass
+class B: pass
+class Err(BaseException): pass
 try:
-    a = B() # type: A       # Fail
+    a = B() # type: A  # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 except BaseException as e:
-    e = A()             # Fail
+    e = A()  # E: Incompatible types in assignment (expression has type "A", variable has type "BaseException")
     e = Err()
 except Err as f:
-    f = BaseException() # Fail
+    f = BaseException()  # E: Incompatible types in assignment (expression has type "BaseException", variable has type "Err")
     f = Err()
-class A: pass
-class B: pass
-class Err(BaseException): pass
 [builtins fixtures/exception.pyi]
-[out]
-main:3: error: Incompatible types in assignment (expression has type "B", variable has type "A")
-main:5: error: Incompatible types in assignment (expression has type "A", variable has type "BaseException")
-main:8: error: Incompatible types in assignment (expression has type "BaseException", variable has type "Err")
-
 [case testTryExceptWithinFunction]
 import typing
 def f() -> None:
@@ -823,7 +806,7 @@ try: pass
 except E1 as e: pass
 try: pass
 except E2 as e: pass
-e + 1 # E: Trying to read deleted variable "e"
+e + 1 # E: Trying to read deleted variable "e"  # E: Name "e" is used before definition
 e = E1() # E: Assignment to variable "e" outside except: block
 [builtins fixtures/exception.pyi]
 
@@ -2052,16 +2035,12 @@ foo = int
 
 [case testTypeOfGlobalUsed]
 import typing
+class A(): pass
+class B(): pass
 g = A()
 def f() -> None:
     global g
-    g = B()
-
-class A(): pass
-class B(): pass
-[out]
-main:5: error: Incompatible types in assignment (expression has type "B", variable has type "A")
-
+    g = B()  # E: Incompatible types in assignment (expression has type "B", variable has type "A")
 [case testTypeOfNonlocalUsed]
 import typing
 def f() -> None:
diff --git a/test-data/unit/check-tuples.test b/test-data/unit/check-tuples.test
index cdb27d10fe0c2..535a8ae5007ef 100644
--- a/test-data/unit/check-tuples.test
+++ b/test-data/unit/check-tuples.test
@@ -164,10 +164,10 @@ class C(B): pass
 
 [case testVoidValueInTuple]
 import typing
+def f() -> None: pass
+
 (None, f()) # E: "f" does not return a value
 (f(), None) # E: "f" does not return a value
-
-def f() -> None: pass
 [builtins fixtures/tuple.pyi]
 
 
@@ -247,15 +247,16 @@ class B: pass
 
 [case testAssigningToTupleItems]
 from typing import Tuple
+
+class A: pass
+class B: pass
+
 t = None # type: Tuple[A, B]
 n = 0
 
 t[0] = A() # E: Unsupported target for indexed assignment ("Tuple[A, B]")
 t[2] = A() # E: Unsupported target for indexed assignment ("Tuple[A, B]")
 t[n] = A() # E: Unsupported target for indexed assignment ("Tuple[A, B]")
-
-class A: pass
-class B: pass
 [builtins fixtures/tuple.pyi]
 
 
@@ -532,13 +533,12 @@ if int():
 
 [case testAssignmentToStarFromAny]
 from typing import Any, cast
+class C: pass
+
 a, c = cast(Any, 1), C()
 p, *q = a
 c = a
 c = q
-
-class C: pass
-
 [case testAssignmentToComplexStar]
 from typing import List
 li = None # type: List[int]
@@ -572,6 +572,7 @@ class A: pass
 
 [case testAssignmentToStarFromTupleInference]
 from typing import List
+class A: pass
 li = None # type: List[int]
 la = None # type: List[A]
 a, *l = A(), A()
@@ -579,13 +580,14 @@ if int():
     l = li  # E: Incompatible types in assignment (expression has type "List[int]", variable has type "List[A]")
 if int():
     l = la
-
-class A: pass
 [builtins fixtures/list.pyi]
 [out]
 
 [case testAssignmentToStarFromListInference]
 from typing import List
+
+class A: pass
+
 li = None # type: List[int]
 la = None # type: List[A]
 a, *l = [A(), A()]
@@ -593,8 +595,6 @@ if int():
     l = li  # E: Incompatible types in assignment (expression has type "List[int]", variable has type "List[A]")
 if int():
     l = la
-
-class A: pass
 [builtins fixtures/list.pyi]
 [out]
 
@@ -710,6 +710,9 @@ class C: pass
 
 
 [case testTupleErrorMessages]
+class A:
+    def __add__(self, x: 'A') -> 'A': pass
+def f(x: 'A') -> None: pass
 
 a = None # type: A
 
@@ -717,11 +720,6 @@ a = None # type: A
 a + (a, a)  # E: Unsupported operand types for + ("A" and "Tuple[A, A]")
 f((a, a))   # E: Argument 1 to "f" has incompatible type "Tuple[A, A]"; expected "A"
 (a, a).foo  # E: "Tuple[A, A]" has no attribute "foo"
-
-def f(x: 'A') -> None: pass
-
-class A:
-    def __add__(self, x: 'A') -> 'A': pass
 [builtins fixtures/tuple.pyi]
 
 [case testLargeTuplesInErrorMessages]
diff --git a/test-data/unit/check-type-aliases.test b/test-data/unit/check-type-aliases.test
index e5d9bf94873ad..d7cccd2d6ba6e 100644
--- a/test-data/unit/check-type-aliases.test
+++ b/test-data/unit/check-type-aliases.test
@@ -206,7 +206,7 @@ B = Callable[[B], int] # E: Cannot resolve name "B" (possible cyclic definition)
 C = Type[C] # E: Cannot resolve name "C" (possible cyclic definition)
 
 [case testRecursiveAliasesErrors2]
-# flags: --disable-recursive-aliases
+# flags: --disable-recursive-aliases --disable-error-code=used-before-def
 # Recursive aliases are not supported yet.
 from typing import Type, Callable, Union
 
@@ -224,6 +224,7 @@ main:7: error: Cannot resolve name "C" (possible cyclic definition)
 main:9: note: Revealed type is "Union[Any, builtins.int]"
 
 [case testDoubleForwardAlias]
+# flags: --disable-error-code=used-before-def
 from typing import List
 x: A
 A = List[B]
@@ -233,6 +234,7 @@ reveal_type(x) # N: Revealed type is "builtins.list[builtins.list[builtins.int]]
 [out]
 
 [case testDoubleForwardAliasWithNamedTuple]
+# flags: --disable-error-code=used-before-def
 from typing import List, NamedTuple
 x: A
 A = List[B]
@@ -254,6 +256,7 @@ if isinstance(x, list):
 [out]
 
 [case testForwardRefToTypeVar]
+# flags: --disable-error-code=used-before-def
 
 from typing import TypeVar, List
 reveal_type(a)  # N: Revealed type is "builtins.list[builtins.int]"
@@ -444,7 +447,7 @@ A = Union[None]
 [case testAliasToClassMethod]
 from typing import TypeVar, Generic, Union, Type
 
-T = TypeVar('T', bound=C)
+T = TypeVar('T', bound='C')
 
 MYPY = False
 if MYPY:
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index d277fa441b1e7..e426b8a7630b1 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -1494,7 +1494,7 @@ class G(Generic[T]):
 
 yb: G[int] # E: Type argument "int" of "G" must be a subtype of "M"
 yg: G[M]
-z: int = G[M]().x['x']
+z: int = G[M]().x['x']  # type: ignore[used-before-def]
 
 class M(TypedDict):
     x: int
@@ -2279,7 +2279,7 @@ reveal_type(foo['baz'])  # N: Revealed type is "builtins.list[Any]"
 from mypy_extensions import TypedDict
 from typing import Any, List
 
-Foo = TypedDict('Foo', {'bar': Bar, 'baz': Bar})
+Foo = TypedDict('Foo', {'bar': 'Bar', 'baz': 'Bar'})
 
 Bar = List[Any]
 
diff --git a/test-data/unit/check-varargs.test b/test-data/unit/check-varargs.test
index 00ac7df320d28..d598fe13b7e96 100644
--- a/test-data/unit/check-varargs.test
+++ b/test-data/unit/check-varargs.test
@@ -38,6 +38,13 @@ def test(*t: type) -> None:
 
 
 [case testCallingVarArgsFunction]
+def f( *a: 'A') -> None: pass
+
+def g() -> None: pass
+
+class A: pass
+class B(A): pass
+class C: pass
 
 a = None # type: A
 b = None # type: B
@@ -51,17 +58,14 @@ f()
 f(a)
 f(b)
 f(a, b, a, b)
+[builtins fixtures/list.pyi]
 
-def f( *a: 'A') -> None: pass
-
-def g() -> None: pass
+[case testCallingVarArgsFunctionWithAlsoNormalArgs]
+def f(a: 'C', *b: 'A') -> None: pass
 
 class A: pass
 class B(A): pass
 class C: pass
-[builtins fixtures/list.pyi]
-
-[case testCallingVarArgsFunctionWithAlsoNormalArgs]
 
 a = None # type: A
 b = None # type: B
@@ -73,16 +77,16 @@ f(c, a, b, c)  # E: Argument 4 to "f" has incompatible type "C"; expected "A"
 f(c)
 f(c, a)
 f(c, b, b, a, b)
+[builtins fixtures/list.pyi]
 
-def f(a: 'C', *b: 'A') -> None: pass
+[case testCallingVarArgsFunctionWithDefaultArgs]
+# flags: --implicit-optional --no-strict-optional
+def f(a: 'C' = None, *b: 'A') -> None:
+    pass
 
 class A: pass
 class B(A): pass
 class C: pass
-[builtins fixtures/list.pyi]
-
-[case testCallingVarArgsFunctionWithDefaultArgs]
-# flags: --implicit-optional --no-strict-optional
 
 a = None # type: A
 b = None # type: B
@@ -95,13 +99,6 @@ f()
 f(c)
 f(c, a)
 f(c, b, b, a, b)
-
-def f(a: 'C' = None, *b: 'A') -> None:
-    pass
-
-class A: pass
-class B(A): pass
-class C: pass
 [builtins fixtures/list.pyi]
 
 [case testCallVarargsFunctionWithIterable]
@@ -156,6 +153,14 @@ f(*it1, '') # E: Argument 2 to "f" has incompatible type "str"; expected "int"
 [case testTypeInferenceWithCalleeVarArgs]
 from typing import TypeVar
 T = TypeVar('T')
+
+def f( *a: T) -> T:
+    pass
+
+class A: pass
+class B(A): pass
+class C: pass
+
 a = None # type: A
 b = None # type: B
 c = None # type: C
@@ -180,13 +185,6 @@ if int():
     o = f(a, b, o)
 if int():
     c = f(c)
-
-def f( *a: T) -> T:
-    pass
-
-class A: pass
-class B(A): pass
-class C: pass
 [builtins fixtures/list.pyi]
 
 [case testTypeInferenceWithCalleeVarArgsAndDefaultArgs]
@@ -195,6 +193,11 @@ T = TypeVar('T')
 a = None # type: A
 o = None # type: object
 
+def f(a: T, b: T = None, *c: T) -> T:
+    pass
+
+class A: pass
+
 if int():
     a = f(o) # E: Incompatible types in assignment (expression has type "object", variable has type "A")
 if int():
@@ -210,11 +213,6 @@ if int():
     a = f(a, a)
 if int():
     a = f(a, a, a)
-
-def f(a: T, b: T = None, *c: T) -> T:
-    pass
-
-class A: pass
 [builtins fixtures/list.pyi]
 
 
@@ -224,27 +222,31 @@ class A: pass
 
 [case testCallingWithListVarArgs]
 from typing import List, Any, cast
+
+def f(a: 'A', b: 'B') -> None:
+    pass
+
+class A: pass
+class B: pass
+
 aa = None # type: List[A]
 ab = None # type: List[B]
 a = None # type: A
 b = None # type: B
 
-f(*aa)    # Fail
+f(*aa)  # E: Argument 1 to "f" has incompatible type "*List[A]"; expected "B"
 f(a, *ab) # Ok
 f(a, b)
 (cast(Any, f))(*aa)     # IDEA: Move to check-dynamic?
 (cast(Any, f))(a, *ab)  # IDEA: Move to check-dynamic?
-
-def f(a: 'A', b: 'B') -> None:
-    pass
+[builtins fixtures/list.pyi]
+[case testCallingWithTupleVarArgs]
+def f(a: 'A', b: 'B', c: 'C') -> None: pass
 
 class A: pass
 class B: pass
-[builtins fixtures/list.pyi]
-[out]
-main:7: error: Argument 1 to "f" has incompatible type "*List[A]"; expected "B"
-
-[case testCallingWithTupleVarArgs]
+class C: pass
+class CC(C): pass
 
 a = None # type: A
 b = None # type: B
@@ -262,27 +264,20 @@ f(*(a, b, c))
 f(a, *(b, c))
 f(a, b, *(c,))
 f(a, *(b, cc))
-
-def f(a: 'A', b: 'B', c: 'C') -> None: pass
-
-class A: pass
-class B: pass
-class C: pass
-class CC(C): pass
 [builtins fixtures/tuple.pyi]
 
 [case testInvalidVarArg]
 
+def f(a: 'A') -> None:
+    pass
+
+class A: pass
+
 a = None # type: A
 
 f(*None)
 f(*a)    # E: List or tuple expected as variadic arguments
 f(*(a,))
-
-def f(a: 'A') -> None:
-    pass
-
-class A: pass
 [builtins fixtures/tuple.pyi]
 
 
@@ -292,34 +287,33 @@ class A: pass
 
 [case testCallingVarArgsFunctionWithListVarArgs]
 from typing import List
+
+def f(a: 'A', *b: 'B') -> None: pass
+def g(a: 'A', *b: 'A') -> None: pass
+class A: pass
+class B: pass
+
 aa, ab, a, b = None, None, None, None # type: (List[A], List[B], A, B)
-f(*aa)           # Fail
-f(a, *aa)        # Fail
-f(b, *ab)        # Fail
-f(a, a, *ab)     # Fail
-f(a, b, *aa)     # Fail
-f(b, b, *ab)     # Fail
-g(*ab)           # Fail
+f(*aa)           # E: Argument 1 to "f" has incompatible type "*List[A]"; expected "B"
+f(a, *aa)        # E: Argument 2 to "f" has incompatible type "*List[A]"; expected "B"
+f(b, *ab)        # E: Argument 1 to "f" has incompatible type "B"; expected "A"
+f(a, a, *ab)     # E: Argument 2 to "f" has incompatible type "A"; expected "B"
+f(a, b, *aa)     # E: Argument 3 to "f" has incompatible type "*List[A]"; expected "B"
+f(b, b, *ab)     # E: Argument 1 to "f" has incompatible type "B"; expected "A"
+g(*ab)           # E: Argument 1 to "g" has incompatible type "*List[B]"; expected "A"
 f(a, *ab)
 f(a, b, *ab)
 f(a, b, b, *ab)
 g(*aa)
+[builtins fixtures/list.pyi]
+[case testCallingVarArgsFunctionWithTupleVarArgs]
+def f(a: 'A', *b: 'B') -> None:
+    pass
 
-def f(a: 'A', *b: 'B') -> None: pass
-def g(a: 'A', *b: 'A') -> None: pass
 class A: pass
 class B: pass
-[builtins fixtures/list.pyi]
-[out]
-main:3: error: Argument 1 to "f" has incompatible type "*List[A]"; expected "B"
-main:4: error: Argument 2 to "f" has incompatible type "*List[A]"; expected "B"
-main:5: error: Argument 1 to "f" has incompatible type "B"; expected "A"
-main:6: error: Argument 2 to "f" has incompatible type "A"; expected "B"
-main:7: error: Argument 3 to "f" has incompatible type "*List[A]"; expected "B"
-main:8: error: Argument 1 to "f" has incompatible type "B"; expected "A"
-main:9: error: Argument 1 to "g" has incompatible type "*List[B]"; expected "A"
-
-[case testCallingVarArgsFunctionWithTupleVarArgs]
+class C: pass
+class CC(C): pass
 
 a, b, c, cc = None, None, None, None # type: (A, B, C, CC)
 
@@ -335,14 +329,6 @@ f(*())          # E: Too few arguments for "f"
 f(*(a, b, b))
 f(a, *(b, b))
 f(a, b, *(b,))
-
-def f(a: 'A', *b: 'B') -> None:
-    pass
-
-class A: pass
-class B: pass
-class C: pass
-class CC(C): pass
 [builtins fixtures/list.pyi]
 
 
@@ -352,32 +338,21 @@ class CC(C): pass
 
 [case testDynamicVarArg]
 from typing import Any
+def f(a: 'A') -> None: pass
+def g(a: 'A', *b: 'A') -> None: pass
+class A: pass
+
 d, a = None, None # type: (Any, A)
-f(a, a, *d) # Fail
+f(a, a, *d) # E: Too many arguments for "f"
 f(a, *d)    # Ok
 f(*d)       # Ok
 
 g(*d)
 g(a, *d)
 g(a, a, *d)
-
-def f(a: 'A') -> None: pass
-def g(a: 'A', *b: 'A') -> None: pass
-class A: pass
 [builtins fixtures/list.pyi]
-[out]
-main:3: error: Too many arguments for "f"
-
 [case testListVarArgsAndSubtyping]
 from typing import List
-aa = None # type: List[A]
-ab = None # type: List[B]
-
-g(*aa) # E: Argument 1 to "g" has incompatible type "*List[A]"; expected "B"
-f(*aa)
-f(*ab)
-g(*ab)
-
 def f( *a: 'A') -> None:
     pass
 
@@ -386,11 +361,25 @@ def g( *a: 'B') -> None:
 
 class A: pass
 class B(A): pass
+
+aa = None # type: List[A]
+ab = None # type: List[B]
+
+g(*aa) # E: Argument 1 to "g" has incompatible type "*List[A]"; expected "B"
+f(*aa)
+f(*ab)
+g(*ab)
 [builtins fixtures/list.pyi]
 
 [case testCallerVarArgsAndDefaultArgs]
 # flags: --implicit-optional --no-strict-optional
 
+def f(a: 'A', b: 'B' = None, *c: 'B') -> None:
+    pass
+
+class A: pass
+class B: pass
+
 a, b = None, None # type: (A, B)
 f(*())        # E: Too few arguments for "f"
 f(a, *[a])    # E: Argument 2 to "f" has incompatible type "*List[A]"; expected "Optional[B]" \
@@ -403,12 +392,6 @@ f(*(a, b, b, b))
 f(a, *[])
 f(a, *[b])
 f(a, *[b, b])
-
-def f(a: 'A', b: 'B' = None, *c: 'B') -> None:
-    pass
-
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testVarArgsAfterKeywordArgInCall1]
@@ -528,6 +511,13 @@ def f(a: B, *b: B) -> B: pass
 from typing import List, TypeVar, Tuple
 S = TypeVar('S')
 T = TypeVar('T')
+
+def f(a: S, *b: T) -> Tuple[S, T]:
+    pass
+
+class A: pass
+class B: pass
+
 a, b, aa = None, None, None # type: (A, B, List[A])
 
 if int():
@@ -551,18 +541,18 @@ if int():
     b, a = f(b, *aa)
 if int():
     b, a = f(b, a, *aa)
-
-def f(a: S, *b: T) -> Tuple[S, T]:
-    pass
-
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testCallerVarArgsTupleWithTypeInference]
 from typing import TypeVar, Tuple
 S = TypeVar('S')
 T = TypeVar('T')
+
+def f(a: S, b: T) -> Tuple[S, T]: pass
+
+class A: pass
+class B: pass
+
 a, b = None, None # type: (A, B)
 
 if int():
@@ -579,11 +569,6 @@ if int():
     a, b = f(*(a, b))
 if int():
     a, b = f(a, *(b,))
-
-def f(a: S, b: T) -> Tuple[S, T]: pass
-
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testCallerVarargsAndComplexTypeInference]
@@ -595,6 +580,13 @@ ao = None # type: List[object]
 aa = None # type: List[A]
 ab = None # type: List[B]
 
+class G(Generic[T]):
+    def f(self, *a: S) -> Tuple[List[S], List[T]]:
+        pass
+
+class A: pass
+class B: pass
+
 if int():
     a, aa = G().f(*[a]) \
       # E: Incompatible types in assignment (expression has type "List[A]", variable has type "A") \
@@ -621,13 +613,6 @@ if int():
       # E: Incompatible types in assignment (expression has type "List[<nothing>]", variable has type "List[A]") \
       # N: "List" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance \
       # N: Consider using "Sequence" instead, which is covariant
-
-class G(Generic[T]):
-    def f(self, *a: S) -> Tuple[List[S], List[T]]:
-        pass
-
-class A: pass
-class B: pass
 [builtins fixtures/list.pyi]
 
 [case testCallerTupleVarArgsAndGenericCalleeVarArg]
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index 5a7f21d48c20a..d4b2d34698711 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -5525,11 +5525,13 @@ a.py:5: error: Argument 1 to "f" has incompatible type "C"; expected "int"
 
 import a
 from typing import Generic
-Alias = C[C[a.T]]
 
 class C(Generic[a.T]):
     def meth(self, x: a.T) -> None:
         pass
+
+Alias = C[C[a.T]]
+
 def outer() -> None:
     def func(x: a.T) -> Alias[a.T]:
         pass
@@ -5542,25 +5544,27 @@ def T() -> None:
     pass
 [out]
 ==
-main:4: error: "C" expects no type arguments, but 1 given
-main:4: error: Function "a.T" is not valid as a type
-main:4: note: Perhaps you need "Callable[...]" or a callback protocol?
-main:6: error: Free type variable expected in Generic[...]
-main:7: error: Function "a.T" is not valid as a type
-main:7: note: Perhaps you need "Callable[...]" or a callback protocol?
-main:10: error: Function "a.T" is not valid as a type
-main:10: note: Perhaps you need "Callable[...]" or a callback protocol?
-main:10: error: Bad number of arguments for type alias, expected: 0, given: 1
+main:5: error: Free type variable expected in Generic[...]
+main:6: error: Function "a.T" is not valid as a type
+main:6: note: Perhaps you need "Callable[...]" or a callback protocol?
+main:9: error: "C" expects no type arguments, but 1 given
+main:9: error: Function "a.T" is not valid as a type
+main:9: note: Perhaps you need "Callable[...]" or a callback protocol?
+main:12: error: Function "a.T" is not valid as a type
+main:12: note: Perhaps you need "Callable[...]" or a callback protocol?
+main:12: error: Bad number of arguments for type alias, expected: 0, given: 1
 
 [case testChangeTypeVarToModule]
 
 import a
 from typing import Generic
-Alias = C[C[a.T]]
 
 class C(Generic[a.T]):
     def meth(self, x: a.T) -> None:
         pass
+
+Alias = C[C[a.T]]
+
 def outer() -> None:
     def func(x: a.T) -> Alias[a.T]:
         pass
@@ -5574,15 +5578,15 @@ import T
 [out]
 ==
 ==
-main:4: error: "C" expects no type arguments, but 1 given
-main:4: error: Module "T" is not valid as a type
-main:4: note: Perhaps you meant to use a protocol matching the module structure?
-main:6: error: Free type variable expected in Generic[...]
-main:7: error: Module "T" is not valid as a type
-main:7: note: Perhaps you meant to use a protocol matching the module structure?
-main:10: error: Module "T" is not valid as a type
-main:10: note: Perhaps you meant to use a protocol matching the module structure?
-main:10: error: Bad number of arguments for type alias, expected: 0, given: 1
+main:5: error: Free type variable expected in Generic[...]
+main:6: error: Module "T" is not valid as a type
+main:6: note: Perhaps you meant to use a protocol matching the module structure?
+main:9: error: "C" expects no type arguments, but 1 given
+main:9: error: Module "T" is not valid as a type
+main:9: note: Perhaps you meant to use a protocol matching the module structure?
+main:12: error: Module "T" is not valid as a type
+main:12: note: Perhaps you meant to use a protocol matching the module structure?
+main:12: error: Bad number of arguments for type alias, expected: 0, given: 1
 
 [case testChangeClassToModule]
 
@@ -5614,11 +5618,13 @@ main:8: note: Perhaps you meant to use a protocol matching the module structure?
 
 import a
 from typing import Generic
-Alias = C[C[a.T]]
 
 class C(Generic[a.T]):
     def meth(self, x: a.T) -> None:
         pass
+
+Alias = C[C[a.T]]
+
 def outer() -> None:
     def func(x: a.T) -> Alias[a.T]:
         pass
@@ -5630,9 +5636,9 @@ from typing import TypeVar
 T = int
 [out]
 ==
-main:4: error: "C" expects no type arguments, but 1 given
-main:6: error: Free type variable expected in Generic[...]
-main:10: error: Bad number of arguments for type alias, expected: 0, given: 1
+main:5: error: Free type variable expected in Generic[...]
+main:9: error: "C" expects no type arguments, but 1 given
+main:12: error: Bad number of arguments for type alias, expected: 0, given: 1
 
 [case testChangeTypeAliasToModule]
 
@@ -8201,6 +8207,7 @@ x = 1
 ==
 
 [case testIdLikeDecoForwardCrashAlias]
+# flags: --disable-error-code used-before-def
 import b
 [file b.py]
 from typing import Callable, Any, TypeVar
diff --git a/test-data/unit/semanal-basic.test b/test-data/unit/semanal-basic.test
index 870c686807c30..20443517e03ec 100644
--- a/test-data/unit/semanal-basic.test
+++ b/test-data/unit/semanal-basic.test
@@ -50,26 +50,27 @@ MypyFile:1(
       Args())))
 
 [case testAccessingGlobalNameBeforeDefinition]
+# flags: --disable-error-code used-before-def
 x
 f()
 x = 1
 def f(): pass
 [out]
 MypyFile:1(
-  ExpressionStmt:1(
-    NameExpr(x [__main__.x]))
   ExpressionStmt:2(
-    CallExpr:2(
+    NameExpr(x [__main__.x]))
+  ExpressionStmt:3(
+    CallExpr:3(
       NameExpr(f [__main__.f])
       Args()))
-  AssignmentStmt:3(
+  AssignmentStmt:4(
     NameExpr(x [__main__.x])
     IntExpr(1)
     builtins.int)
-  FuncDef:4(
+  FuncDef:5(
     f
-    Block:4(
-      PassStmt:4())))
+    Block:5(
+      PassStmt:5())))
 
 [case testFunctionArgs]
 def f(x, y):
diff --git a/test-data/unit/semanal-statements.test b/test-data/unit/semanal-statements.test
index 27ff101c04d01..013452068cf1c 100644
--- a/test-data/unit/semanal-statements.test
+++ b/test-data/unit/semanal-statements.test
@@ -789,6 +789,7 @@ MypyFile:1(
           Args())))))
 
 [case testTryExceptWithMultipleHandlers]
+class Err(BaseException): pass
 try:
     pass
 except BaseException as e:
@@ -796,36 +797,34 @@ except BaseException as e:
 except Err as f:
     f = BaseException() # Fail
     f = Err()
-class Err(BaseException): pass
 [builtins fixtures/exception.pyi]
 [out]
 MypyFile:1(
-  TryStmt:1(
-    Block:1(
-      PassStmt:2())
+  ClassDef:1(
+    Err
+    BaseType(
+      builtins.BaseException)
+    PassStmt:1())
+  TryStmt:2(
+    Block:2(
+      PassStmt:3())
     NameExpr(BaseException [builtins.BaseException])
     NameExpr(e* [__main__.e])
-    Block:3(
-      PassStmt:4())
+    Block:4(
+      PassStmt:5())
     NameExpr(Err [__main__.Err])
     NameExpr(f* [__main__.f])
-    Block:5(
-      AssignmentStmt:6(
+    Block:6(
+      AssignmentStmt:7(
         NameExpr(f [__main__.f])
-        CallExpr:6(
+        CallExpr:7(
           NameExpr(BaseException [builtins.BaseException])
           Args()))
-      AssignmentStmt:7(
+      AssignmentStmt:8(
         NameExpr(f [__main__.f])
-        CallExpr:7(
+        CallExpr:8(
           NameExpr(Err [__main__.Err])
-          Args()))))
-  ClassDef:8(
-    Err
-    BaseType(
-      builtins.BaseException)
-    PassStmt:8()))
-
+          Args())))))
 [case testMultipleAssignmentWithPartialNewDef]
 # flags: --allow-redefinition
 o = None
diff --git a/test-data/unit/typexport-basic.test b/test-data/unit/typexport-basic.test
index 5cbdf38d1b4f2..26caef0d6ddee 100644
--- a/test-data/unit/typexport-basic.test
+++ b/test-data/unit/typexport-basic.test
@@ -21,15 +21,15 @@
 
 [case testConstructorCall]
 import typing
-A()
-B()
 class A: pass
 class B: pass
+A()
+B()
 [out]
-CallExpr(2) : A
-NameExpr(2) : def () -> A
-CallExpr(3) : B
-NameExpr(3) : def () -> B
+CallExpr(4) : A
+NameExpr(4) : def () -> A
+CallExpr(5) : B
+NameExpr(5) : def () -> B
 
 [case testLiterals]
 import typing
@@ -202,17 +202,17 @@ UnaryExpr(6) : builtins.bool
 [case testFunctionCall]
 ## CallExpr
 from typing import Tuple
-f(
-  A(),
-  B())
 class A: pass
 class B: pass
 def f(a: A, b: B) -> Tuple[A, B]: pass
+f(
+  A(),
+  B())
 [builtins fixtures/tuple-simple.pyi]
 [out]
-CallExpr(3) : Tuple[A, B]
-CallExpr(4) : A
-CallExpr(5) : B
+CallExpr(6) : Tuple[A, B]
+CallExpr(7) : A
+CallExpr(8) : B
 
 
 -- Statements
@@ -602,28 +602,26 @@ NameExpr(4) : def [t] (x: t`-1) -> t`-1
 ## CallExpr
 from typing import TypeVar, Generic
 T = TypeVar('T')
-f(g())
-f(h(b))
-f(h(c))
-
-b = None # type: B
-c = None # type: C
-
+class A(Generic[T]): pass
+class B: pass
+class C(B): pass
 def f(a: 'A[B]') -> None: pass
-
 def g() -> 'A[T]': pass
 def h(a: T) -> 'A[T]': pass
 
-class A(Generic[T]): pass
-class B: pass
-class C(B): pass
+b = None # type: B
+c = None # type: C
+
+f(g())
+f(h(b))
+f(h(c))
 [out]
-CallExpr(4) : None
-CallExpr(4) : A[B]
-CallExpr(5) : None
-CallExpr(5) : A[B]
-CallExpr(6) : None
-CallExpr(6) : A[B]
+CallExpr(14) : None
+CallExpr(14) : A[B]
+CallExpr(15) : None
+CallExpr(15) : A[B]
+CallExpr(16) : None
+CallExpr(16) : A[B]
 
 [case testInferGenericTypeForLocalVariable]
 from typing import TypeVar, Generic
@@ -697,21 +695,21 @@ ListExpr(2) : builtins.list[Any]
 from typing import TypeVar, Callable, List
 t = TypeVar('t')
 s = TypeVar('s')
-map(
-    f,
-    [A()])
 def map(f: Callable[[t], s], a: List[t]) -> List[s]: pass
 class A: pass
 class B: pass
 def f(a: A) -> B: pass
+map(
+    f,
+    [A()])
 [builtins fixtures/list.pyi]
 [out]
-CallExpr(4) : builtins.list[B]
-NameExpr(4) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
-NameExpr(5) : def (a: A) -> B
-CallExpr(6) : A
-ListExpr(6) : builtins.list[A]
-NameExpr(6) : def () -> A
+CallExpr(8) : builtins.list[B]
+NameExpr(8) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
+NameExpr(9) : def (a: A) -> B
+CallExpr(10) : A
+ListExpr(10) : builtins.list[A]
+NameExpr(10) : def () -> A
 
 
 -- Lambdas
@@ -761,106 +759,106 @@ ListExpr(2) : builtins.list[A]
 from typing import TypeVar, Callable, List
 t = TypeVar('t')
 s = TypeVar('s')
-l = None # type: List[A]
-map(
-  lambda x: f(x), l)
 def map(f: Callable[[t], s], a: List[t]) -> List[s]: pass
 class A: pass
 class B: pass
 def f(a: A) -> B: pass
+l = None # type: List[A]
+map(
+  lambda x: f(x), l)
 [builtins fixtures/list.pyi]
 [out]
-CallExpr(5) : builtins.list[B]
-NameExpr(5) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
-CallExpr(6) : B
-LambdaExpr(6) : def (A) -> B
-NameExpr(6) : def (a: A) -> B
-NameExpr(6) : builtins.list[A]
-NameExpr(6) : A
+CallExpr(9) : builtins.list[B]
+NameExpr(9) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
+CallExpr(10) : B
+LambdaExpr(10) : def (A) -> B
+NameExpr(10) : def (a: A) -> B
+NameExpr(10) : builtins.list[A]
+NameExpr(10) : A
 
 [case testLambdaAndHigherOrderFunction2]
 ## LambdaExpr|NameExpr|ListExpr
 from typing import TypeVar, List, Callable
 t = TypeVar('t')
 s = TypeVar('s')
-l = None # type: List[A]
-map(
-  lambda x: [f(x)], l)
 def map(f: Callable[[t], List[s]], a: List[t]) -> List[s]: pass
 class A: pass
 class B: pass
 def f(a: A) -> B: pass
+l = None # type: List[A]
+map(
+  lambda x: [f(x)], l)
 [builtins fixtures/list.pyi]
 [out]
-NameExpr(6) : def (f: def (A) -> builtins.list[B], a: builtins.list[A]) -> builtins.list[B]
-LambdaExpr(7) : def (A) -> builtins.list[B]
-ListExpr(7) : builtins.list[B]
-NameExpr(7) : def (a: A) -> B
-NameExpr(7) : builtins.list[A]
-NameExpr(7) : A
+NameExpr(10) : def (f: def (A) -> builtins.list[B], a: builtins.list[A]) -> builtins.list[B]
+LambdaExpr(11) : def (A) -> builtins.list[B]
+ListExpr(11) : builtins.list[B]
+NameExpr(11) : def (a: A) -> B
+NameExpr(11) : builtins.list[A]
+NameExpr(11) : A
 
 [case testLambdaInListAndHigherOrderFunction]
 from typing import TypeVar, Callable, List
 t = TypeVar('t')
 s = TypeVar('s')
+def map(f: List[Callable[[t], s]], a: List[t]) -> List[s]: pass
+class A: pass
 l = None # type: List[A]
 map(
   [lambda x: x],
   l)
-def map(f: List[Callable[[t], s]], a: List[t]) -> List[s]: pass
-class A: pass
 [builtins fixtures/list.pyi]
 [out]
 -- TODO We probably should not silently infer 'Any' types in statically typed
 --      context. Perhaps just fail instead?
-CallExpr(5) : builtins.list[Any]
-NameExpr(5) : def (f: builtins.list[def (A) -> Any], a: builtins.list[A]) -> builtins.list[Any]
-LambdaExpr(6) : def (A) -> A
-ListExpr(6) : builtins.list[def (A) -> Any]
-NameExpr(6) : A
-NameExpr(7) : builtins.list[A]
+CallExpr(7) : builtins.list[Any]
+NameExpr(7) : def (f: builtins.list[def (A) -> Any], a: builtins.list[A]) -> builtins.list[Any]
+LambdaExpr(8) : def (A) -> A
+ListExpr(8) : builtins.list[def (A) -> Any]
+NameExpr(8) : A
+NameExpr(9) : builtins.list[A]
 
 [case testLambdaAndHigherOrderFunction3]
 from typing import TypeVar, Callable, List
 t = TypeVar('t')
 s = TypeVar('s')
-l = None # type: List[A]
-map(
-  lambda x: x.b,
-  l)
 def map(f: Callable[[t], s], a: List[t]) -> List[s]: pass
 class A:
   b = None # type: B
 class B: pass
+l = None # type: List[A]
+map(
+  lambda x: x.b,
+  l)
 [builtins fixtures/list.pyi]
 [out]
-CallExpr(5) : builtins.list[B]
-NameExpr(5) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
-LambdaExpr(6) : def (A) -> B
-MemberExpr(6) : B
-NameExpr(6) : A
-NameExpr(7) : builtins.list[A]
+CallExpr(9) : builtins.list[B]
+NameExpr(9) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
+LambdaExpr(10) : def (A) -> B
+MemberExpr(10) : B
+NameExpr(10) : A
+NameExpr(11) : builtins.list[A]
 
 [case testLambdaAndHigherOrderFunctionAndKeywordArgs]
 from typing import TypeVar, Callable, List
 t = TypeVar('t')
 s = TypeVar('s')
+def map(f: Callable[[t], s], a: List[t]) -> List[s]: pass
+class A:
+    b = None # type: B
+class B: pass
 l = None # type: List[A]
 map(
   a=l,
   f=lambda x: x.b)
-def map(f: Callable[[t], s], a: List[t]) -> List[s]: pass
-class A:
-  b = None # type: B
-class B: pass
 [builtins fixtures/list.pyi]
 [out]
-CallExpr(5) : builtins.list[B]
-NameExpr(5) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
-NameExpr(6) : builtins.list[A]
-LambdaExpr(7) : def (A) -> B
-MemberExpr(7) : B
-NameExpr(7) : A
+CallExpr(9) : builtins.list[B]
+NameExpr(9) : def (f: def (A) -> B, a: builtins.list[A]) -> builtins.list[B]
+NameExpr(10) : builtins.list[A]
+LambdaExpr(11) : def (A) -> B
+MemberExpr(11) : B
+NameExpr(11) : A
 
 
 -- Boolean operations

From 9a8c171ed81c0c9510386f7a0451682167021d02 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Fri, 20 Jan 2023 16:54:22 +0000
Subject: [PATCH 189/231] Fix false positive on generic base class with six
 (#14478)

Fixes #14475

The fix is straightforward. We need to use the "guarded accept" at this
stage, similar to e.g. `clean_up_bases_and_infer_type_variables()`.
---
 mypy/semanal.py                   |  2 +-
 test-data/unit/check-classes.test | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index acc485a609e0c..176a9e4053a81 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -2181,7 +2181,7 @@ def infer_metaclass_and_bases_from_compat_helpers(self, defn: ClassDef) -> None:
         if len(defn.base_type_exprs) == 1:
             base_expr = defn.base_type_exprs[0]
             if isinstance(base_expr, CallExpr) and isinstance(base_expr.callee, RefExpr):
-                base_expr.accept(self)
+                self.analyze_type_expr(base_expr)
                 if (
                     base_expr.callee.fullname
                     in {
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index fce1aa1768f91..9a38d8f344f71 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -5293,6 +5293,19 @@ class F(six.with_metaclass(t.M)): pass
 class G: pass
 [builtins fixtures/tuple.pyi]
 
+[case testSixMetaclassGenericBase]
+import six
+import abc
+from typing import TypeVar, Generic
+
+T = TypeVar("T")
+
+class C(six.with_metaclass(abc.ABCMeta, Generic[T])):
+    pass
+class D(six.with_metaclass(abc.ABCMeta, C[T])):
+    pass
+[builtins fixtures/tuple.pyi]
+
 -- Special support for future.utils
 -- --------------------------------
 

From 8f4da0e6f07a15a1d4acae98a588796c8ad81fb6 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Fri, 20 Jan 2023 14:12:49 -0800
Subject: [PATCH 190/231] Fix incorrect join in the presence of Any fallback
 (#14404)

Fixes #11925

This avoids mypy from guessing subtype relationships because of the any
fallback over here:

https://github.com/python/mypy/blob/e1bfb75ed2187db76d51ed875ce953da3ba4d02c/mypy/subtypes.py#L438
---
 mypy/join.py                        |  5 ++++-
 mypy/subtypes.py                    |  6 +-----
 test-data/unit/check-inference.test | 12 ++++++++++++
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/mypy/join.py b/mypy/join.py
index 84aa03f8eeba8..62d256f4440f9 100644
--- a/mypy/join.py
+++ b/mypy/join.py
@@ -9,6 +9,7 @@
 from mypy.nodes import CONTRAVARIANT, COVARIANT, INVARIANT
 from mypy.state import state
 from mypy.subtypes import (
+    SubtypeContext,
     find_member,
     is_equivalent,
     is_proper_subtype,
@@ -101,7 +102,9 @@ def join_instances(self, t: Instance, s: Instance) -> ProperType:
                 assert new_type is not None
                 args.append(new_type)
             result: ProperType = Instance(t.type, args)
-        elif t.type.bases and is_subtype(t, s, ignore_type_params=True):
+        elif t.type.bases and is_proper_subtype(
+            t, s, subtype_context=SubtypeContext(ignore_type_params=True)
+        ):
             result = self.join_instances_via_supertype(t, s)
         else:
             # Now t is not a subtype of s, and t != s. Now s could be a subtype
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 83cb22d48fabf..0214e7ae308ac 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -103,11 +103,7 @@ def check_context(self, proper_subtype: bool) -> None:
         # Historically proper and non-proper subtypes were defined using different helpers
         # and different visitors. Check if flag values are such that we definitely support.
         if proper_subtype:
-            assert (
-                not self.ignore_type_params
-                and not self.ignore_pos_arg_names
-                and not self.ignore_declared_variance
-            )
+            assert not self.ignore_pos_arg_names and not self.ignore_declared_variance
         else:
             assert not self.erase_instances and not self.keep_erased_types
 
diff --git a/test-data/unit/check-inference.test b/test-data/unit/check-inference.test
index 41fe942b83397..331b110fded67 100644
--- a/test-data/unit/check-inference.test
+++ b/test-data/unit/check-inference.test
@@ -3380,3 +3380,15 @@ class A:
 T = TypeVar("T")
 def type_or_callable(value: T, tp: Union[Type[T], Callable[[int], T]]) -> T: ...
 reveal_type(type_or_callable(A("test"), A))  # N: Revealed type is "__main__.A"
+
+[case testJoinWithAnyFallback]
+from unknown import X  # type: ignore[import]
+
+class A: ...
+class B(X, A): ...
+class C(B): ...
+class D(C): ...
+class E(D): ...
+
+reveal_type([E(), D()])  # N: Revealed type is "builtins.list[__main__.D]"
+reveal_type([D(), E()])  # N: Revealed type is "builtins.list[__main__.D]"

From 272c8fd4948fcae9ae91430fbb5623d341e87ddd Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sat, 21 Jan 2023 14:06:48 +0000
Subject: [PATCH 191/231] Fix recursive TypedDicts/NamedTuples defined with
 call syntax (#14488)

Fixes #14460

Recursive TypedDicts/NamedTuples defined with call syntax that have item
types that look like type applications suffer the same chicken-and-egg
problem that recursive type aliases. Fortunately, there is a very simple
way to distinguish them without fully analyzing rvalues, this is what
this PR does.
---
 mypy/semanal.py                           | 17 ++++++++++-------
 test-data/unit/check-recursive-types.test | 17 +++++++++++++++++
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 176a9e4053a81..d7bf60501b36c 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -2648,7 +2648,7 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
         # But we can't use a full visit because it may emit extra incomplete refs (namely
         # when analysing any type applications there) thus preventing the further analysis.
         # To break the tie, we first analyse rvalue partially, if it can be a type alias.
-        if self.can_possibly_be_index_alias(s):
+        if self.can_possibly_be_type_form(s):
             old_basic_type_applications = self.basic_type_applications
             self.basic_type_applications = True
             with self.allow_unbound_tvars_set():
@@ -2664,7 +2664,7 @@ def visit_assignment_stmt(self, s: AssignmentStmt) -> None:
             for expr in names_modified_by_assignment(s):
                 self.mark_incomplete(expr.name, expr)
             return
-        if self.can_possibly_be_index_alias(s):
+        if self.can_possibly_be_type_form(s):
             # Now re-visit those rvalues that were we skipped type applications above.
             # This should be safe as generally semantic analyzer is idempotent.
             with self.allow_unbound_tvars_set():
@@ -2807,16 +2807,19 @@ def can_be_type_alias(self, rv: Expression, allow_none: bool = False) -> bool:
                 return True
         return False
 
-    def can_possibly_be_index_alias(self, s: AssignmentStmt) -> bool:
-        """Like can_be_type_alias(), but simpler and doesn't require analyzed rvalue.
+    def can_possibly_be_type_form(self, s: AssignmentStmt) -> bool:
+        """Like can_be_type_alias(), but simpler and doesn't require fully analyzed rvalue.
 
-        Instead, use lvalues/annotations structure to figure out whether this can
-        potentially be a type alias definition. Another difference from above function
-        is that we are only interested IndexExpr and OpExpr rvalues, since only those
+        Instead, use lvalues/annotations structure to figure out whether this can potentially be
+        a type alias definition, NamedTuple, or TypedDict. Another difference from above function
+        is that we are only interested IndexExpr, CallExpr and OpExpr rvalues, since only those
         can be potentially recursive (things like `A = A` are never valid).
         """
         if len(s.lvalues) > 1:
             return False
+        if isinstance(s.rvalue, CallExpr) and isinstance(s.rvalue.callee, RefExpr):
+            ref = s.rvalue.callee.fullname
+            return ref in TPDICT_NAMES or ref in TYPED_NAMEDTUPLE_NAMES
         if not isinstance(s.lvalues[0], NameExpr):
             return False
         if s.unanalyzed_type is not None and not self.is_pep_613(s):
diff --git a/test-data/unit/check-recursive-types.test b/test-data/unit/check-recursive-types.test
index 53811521f4422..b7b4372ecc12f 100644
--- a/test-data/unit/check-recursive-types.test
+++ b/test-data/unit/check-recursive-types.test
@@ -880,3 +880,20 @@ class InListRecurse(Generic[T], List[InList[T]]): ...
 def list_thing(transforming: InList[T]) -> T:
     ...
 reveal_type(list_thing([5]))  # N: Revealed type is "builtins.list[builtins.int]"
+
+[case testRecursiveTypedDictWithList]
+from typing import List
+from typing_extensions import TypedDict
+
+Example = TypedDict("Example", {"rec": List["Example"]})
+e: Example
+reveal_type(e)  # N: Revealed type is "TypedDict('__main__.Example', {'rec': builtins.list[...]})"
+[builtins fixtures/dict.pyi]
+
+[case testRecursiveNamedTupleWithList]
+from typing import List, NamedTuple
+
+Example = NamedTuple("Example", [("rec", List["Example"])])
+e: Example
+reveal_type(e)  # N: Revealed type is "Tuple[builtins.list[...], fallback=__main__.Example]"
+[builtins fixtures/tuple.pyi]

From eea917ee5c060569fdc9326b30eb0a38ea6f977a Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sat, 21 Jan 2023 14:35:32 +0000
Subject: [PATCH 192/231] Fix crash in await inside comprehension outside
 function (#14486)

Fixes #14345

I also decided to make this error a blocker, since it is essentially a
syntax error. (And also a similar error for `yield` is a blocker).
---
 mypy/semanal.py                       |  7 ++++---
 test-data/unit/check-async-await.test | 12 ++++++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index d7bf60501b36c..f42eee28517e6 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -5166,10 +5166,11 @@ def visit_yield_expr(self, e: YieldExpr) -> None:
             e.expr.accept(self)
 
     def visit_await_expr(self, expr: AwaitExpr) -> None:
-        if not self.is_func_scope():
-            self.fail('"await" outside function', expr)
+        if not self.is_func_scope() or not self.function_stack:
+            # We check both because is_function_scope() returns True inside comprehensions.
+            self.fail('"await" outside function', expr, serious=True, blocker=True)
         elif not self.function_stack[-1].is_coroutine:
-            self.fail('"await" outside coroutine ("async def")', expr)
+            self.fail('"await" outside coroutine ("async def")', expr, serious=True, blocker=True)
         expr.expr.accept(self)
 
     #
diff --git a/test-data/unit/check-async-await.test b/test-data/unit/check-async-await.test
index d53cba2fc642b..40efe2d2cece4 100644
--- a/test-data/unit/check-async-await.test
+++ b/test-data/unit/check-async-await.test
@@ -943,3 +943,15 @@ async def bar(x: Union[A, B]) -> None:
 
 [builtins fixtures/async_await.pyi]
 [typing fixtures/typing-async.pyi]
+
+[case testInvalidComprehensionNoCrash]
+async def foo(x: int) -> int: ...
+
+crasher = [await foo(x) for x in [1, 2, 3]]  # E: "await" outside function
+
+def bad() -> None:
+    y = [await foo(x) for x in [1, 2, 3]]  # E: "await" outside coroutine ("async def")
+async def good() -> None:
+    y = [await foo(x) for x in [1, 2, 3]]  # OK
+[builtins fixtures/async_await.pyi]
+[typing fixtures/typing-async.pyi]

From af895641ff395c7e78d012f0a9b995b8ed016c17 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Sat, 21 Jan 2023 16:04:48 +0000
Subject: [PATCH 193/231] [mypyc] Add irbuild test case for cast(i64, ...)
 (#14493)

This tests already supported functionality to detect regressions.
---
 mypyc/test-data/irbuild-i64.test | 41 ++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/mypyc/test-data/irbuild-i64.test b/mypyc/test-data/irbuild-i64.test
index c6b62996bc808..2c4052fa4796c 100644
--- a/mypyc/test-data/irbuild-i64.test
+++ b/mypyc/test-data/irbuild-i64.test
@@ -1730,3 +1730,44 @@ L0:
 def f5():
 L0:
     return 4
+
+[case testI64Cast]
+from typing import cast
+from mypy_extensions import i64
+
+def cast_object(o: object) -> i64:
+    return cast(i64, o)
+
+def cast_int(x: int) -> i64:
+    return cast(i64, x)
+[out]
+def cast_object(o):
+    o :: object
+    r0 :: int64
+L0:
+    r0 = unbox(int64, o)
+    return r0
+def cast_int(x):
+    x :: int
+    r0 :: native_int
+    r1 :: bit
+    r2, r3 :: int64
+    r4 :: ptr
+    r5 :: c_ptr
+    r6 :: int64
+L0:
+    r0 = x & 1
+    r1 = r0 == 0
+    if r1 goto L1 else goto L2 :: bool
+L1:
+    r2 = x >> 1
+    r3 = r2
+    goto L3
+L2:
+    r4 = x ^ 1
+    r5 = r4
+    r6 = CPyLong_AsInt64(r5)
+    r3 = r6
+    keep_alive x
+L3:
+    return r3

From cc1bcc9c35ed018d59596f6d75a70a5d8b8c1805 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sat, 21 Jan 2023 16:19:03 +0000
Subject: [PATCH 194/231] Properly expand type in generic class with Self and
 TypeVar with values (#14491)

Fixes #14374

It looks like we need to special-case `Self` in `expand_type()` to
support it in generics over `TypeVar` with values, since `Self` is the
only type variable that can legitimately have other type variables in
its upper bound.
---
 mypy/expandtype.py                 |  4 ++++
 test-data/unit/check-selftype.test | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/mypy/expandtype.py b/mypy/expandtype.py
index 203c71b4e8243..7933283b24d6a 100644
--- a/mypy/expandtype.py
+++ b/mypy/expandtype.py
@@ -222,6 +222,10 @@ def visit_instance(self, t: Instance) -> Type:
             return args
 
     def visit_type_var(self, t: TypeVarType) -> Type:
+        # Normally upper bounds can't contain other type variables, the only exception is
+        # special type variable Self`0 <: C[T, S], where C is the class where Self is used.
+        if t.id.raw_id == 0:
+            t = t.copy_modified(upper_bound=t.upper_bound.accept(self))
         repl = self.variables.get(t.id, t)
         if isinstance(repl, ProperType) and isinstance(repl, Instance):
             # TODO: do we really need to do this?
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index dd177e143aaa0..2d45d28764a05 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -1785,3 +1785,23 @@ class C(B, Generic[T]):
         inst = super().copy()
         reveal_type(inst)  # N: Revealed type is "Self`0"
         return inst
+
+[case testTypingSelfWithValuesExpansion]
+from typing import Self, Generic, TypeVar
+
+class A: pass
+class B: pass
+T = TypeVar("T", A, B)
+
+class C(Generic[T]):
+    val: T
+    def foo(self, x: T) -> None: ...
+    def bar(self, x: T) -> Self:
+        reveal_type(self.foo)  # N: Revealed type is "def (x: __main__.A)" \
+                               # N: Revealed type is "def (x: __main__.B)"
+        self.foo(x)
+        return self
+    def baz(self: Self, x: T) -> None:
+        reveal_type(self.val)  # N: Revealed type is "__main__.A" \
+                               # N: Revealed type is "__main__.B"
+        self.val = x

From e8c844b613ff95a41aeba63096aecbde80b78d99 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sun, 22 Jan 2023 11:18:05 +0000
Subject: [PATCH 195/231] Fix crash on Any metaclass in incremental mode
 (#14495)

Fixes #14254

This essentially re-implements https://github.com/python/mypy/pull/13605
in a simpler way that also works in incremental mode. Also I decided to
set `meta_fallback_to_any` in case of errors, to match how we do this
for base classes.
---
 mypy/checkmember.py                   |  2 +-
 mypy/nodes.py                         |  7 +++++
 mypy/semanal.py                       | 40 ++++++++++++++++-----------
 mypy/server/astdiff.py                |  1 +
 mypy/subtypes.py                      |  2 +-
 test-data/unit/check-classes.test     | 10 +++++--
 test-data/unit/check-incremental.test | 11 ++++++++
 test-data/unit/fine-grained.test      |  2 --
 8 files changed, 52 insertions(+), 23 deletions(-)

diff --git a/mypy/checkmember.py b/mypy/checkmember.py
index 918ce7520454e..f90a4f706a874 100644
--- a/mypy/checkmember.py
+++ b/mypy/checkmember.py
@@ -901,7 +901,7 @@ def analyze_class_attribute_access(
             # For modules use direct symbol table lookup.
             if not itype.extra_attrs.mod_name:
                 return itype.extra_attrs.attrs[name]
-        if info.fallback_to_any:
+        if info.fallback_to_any or info.meta_fallback_to_any:
             return apply_class_attr_hook(mx, hook, AnyType(TypeOfAny.special_form))
         return None
 
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 4a4de9d4503db..38639d553b3d7 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -2800,6 +2800,7 @@ class is generic then it will be a type constructor of higher kind.
         "inferring",
         "is_enum",
         "fallback_to_any",
+        "meta_fallback_to_any",
         "type_vars",
         "has_param_spec_type",
         "bases",
@@ -2894,6 +2895,10 @@ class is generic then it will be a type constructor of higher kind.
     # (and __setattr__), but without the __getattr__ method.
     fallback_to_any: bool
 
+    # Same as above but for cases where metaclass has type Any. This will suppress
+    # all attribute errors only for *class object* access.
+    meta_fallback_to_any: bool
+
     # Information related to type annotations.
 
     # Generic type variable names (full names)
@@ -2963,6 +2968,7 @@ class is generic then it will be a type constructor of higher kind.
         "is_abstract",
         "is_enum",
         "fallback_to_any",
+        "meta_fallback_to_any",
         "is_named_tuple",
         "is_newtype",
         "is_protocol",
@@ -3002,6 +3008,7 @@ def __init__(self, names: SymbolTable, defn: ClassDef, module_name: str) -> None
         self.is_final = False
         self.is_enum = False
         self.fallback_to_any = False
+        self.meta_fallback_to_any = False
         self._promote = []
         self.alt_promote = None
         self.tuple_type = None
diff --git a/mypy/semanal.py b/mypy/semanal.py
index f42eee28517e6..5653aa4547c46 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1579,7 +1579,9 @@ def analyze_class(self, defn: ClassDef) -> None:
             self.mark_incomplete(defn.name, defn)
             return
 
-        declared_metaclass, should_defer = self.get_declared_metaclass(defn.name, defn.metaclass)
+        declared_metaclass, should_defer, any_meta = self.get_declared_metaclass(
+            defn.name, defn.metaclass
+        )
         if should_defer or self.found_incomplete_ref(tag):
             # Metaclass was not ready. Defer current target.
             self.mark_incomplete(defn.name, defn)
@@ -1599,6 +1601,8 @@ def analyze_class(self, defn: ClassDef) -> None:
         self.setup_type_vars(defn, tvar_defs)
         if base_error:
             defn.info.fallback_to_any = True
+        if any_meta:
+            defn.info.meta_fallback_to_any = True
 
         with self.scope.class_scope(defn.info):
             self.configure_base_classes(defn, base_types)
@@ -2247,8 +2251,17 @@ def is_base_class(self, t: TypeInfo, s: TypeInfo) -> bool:
 
     def get_declared_metaclass(
         self, name: str, metaclass_expr: Expression | None
-    ) -> tuple[Instance | None, bool]:
-        """Returns either metaclass instance or boolean whether we should defer."""
+    ) -> tuple[Instance | None, bool, bool]:
+        """Get declared metaclass from metaclass expression.
+
+        Returns a tuple of three values:
+          * A metaclass instance or None
+          * A boolean indicating whether we should defer
+          * A boolean indicating whether we should set metaclass Any fallback
+            (either for Any metaclass or invalid/dynamic metaclass).
+
+        The two boolean flags can only be True if instance is None.
+        """
         declared_metaclass = None
         if metaclass_expr:
             metaclass_name = None
@@ -2258,25 +2271,20 @@ def get_declared_metaclass(
                 metaclass_name = get_member_expr_fullname(metaclass_expr)
             if metaclass_name is None:
                 self.fail(f'Dynamic metaclass not supported for "{name}"', metaclass_expr)
-                return None, False
+                return None, False, True
             sym = self.lookup_qualified(metaclass_name, metaclass_expr)
             if sym is None:
                 # Probably a name error - it is already handled elsewhere
-                return None, False
+                return None, False, True
             if isinstance(sym.node, Var) and isinstance(get_proper_type(sym.node.type), AnyType):
-                # Create a fake TypeInfo that fallbacks to `Any`, basically allowing
-                # all the attributes. Same thing as we do for `Any` base class.
-                any_info = self.make_empty_type_info(ClassDef(sym.node.name, Block([])))
-                any_info.fallback_to_any = True
-                any_info._fullname = sym.node.fullname
                 if self.options.disallow_subclassing_any:
                     self.fail(
-                        f'Class cannot use "{any_info.fullname}" as a metaclass (has type "Any")',
+                        f'Class cannot use "{sym.node.name}" as a metaclass (has type "Any")',
                         metaclass_expr,
                     )
-                return Instance(any_info, []), False
+                return None, False, True
             if isinstance(sym.node, PlaceholderNode):
-                return None, True  # defer later in the caller
+                return None, True, False  # defer later in the caller
 
             # Support type aliases, like `_Meta: TypeAlias = type`
             if (
@@ -2291,16 +2299,16 @@ def get_declared_metaclass(
 
             if not isinstance(metaclass_info, TypeInfo) or metaclass_info.tuple_type is not None:
                 self.fail(f'Invalid metaclass "{metaclass_name}"', metaclass_expr)
-                return None, False
+                return None, False, False
             if not metaclass_info.is_metaclass():
                 self.fail(
                     'Metaclasses not inheriting from "type" are not supported', metaclass_expr
                 )
-                return None, False
+                return None, False, False
             inst = fill_typevars(metaclass_info)
             assert isinstance(inst, Instance)
             declared_metaclass = inst
-        return declared_metaclass, False
+        return declared_metaclass, False, False
 
     def recalculate_metaclass(self, defn: ClassDef, declared_metaclass: Instance | None) -> None:
         defn.info.declared_metaclass = declared_metaclass
diff --git a/mypy/server/astdiff.py b/mypy/server/astdiff.py
index 97f811384d370..012d395e632f2 100644
--- a/mypy/server/astdiff.py
+++ b/mypy/server/astdiff.py
@@ -255,6 +255,7 @@ def snapshot_definition(node: SymbolNode | None, common: tuple[object, ...]) ->
             node.is_enum,
             node.is_protocol,
             node.fallback_to_any,
+            node.meta_fallback_to_any,
             node.is_named_tuple,
             node.is_newtype,
             # We need this to e.g. trigger metaclass calculation in subclasses.
diff --git a/mypy/subtypes.py b/mypy/subtypes.py
index 0214e7ae308ac..4bf3672af7405 100644
--- a/mypy/subtypes.py
+++ b/mypy/subtypes.py
@@ -1167,7 +1167,7 @@ def find_member(
                     if isinstance(getattr_type, CallableType):
                         return getattr_type.ret_type
                     return getattr_type
-        if itype.type.fallback_to_any:
+        if itype.type.fallback_to_any or class_obj and itype.type.meta_fallback_to_any:
             return AnyType(TypeOfAny.special_form)
         if isinstance(v, TypeInfo):
             # PEP 544 doesn't specify anything about such use cases. So we just try
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
index 9a38d8f344f71..f1af13923fd79 100644
--- a/test-data/unit/check-classes.test
+++ b/test-data/unit/check-classes.test
@@ -4439,7 +4439,7 @@ def f(TB: Type[B]):
     reveal_type(TB.x)  # N: Revealed type is "builtins.int"
 
 [case testMetaclassAsAny]
-from typing import Any, ClassVar
+from typing import Any, ClassVar, Type
 
 MyAny: Any
 class WithMeta(metaclass=MyAny):
@@ -4451,13 +4451,15 @@ reveal_type(WithMeta.x)   # N: Revealed type is "builtins.int"
 reveal_type(WithMeta().x) # N: Revealed type is "builtins.int"
 WithMeta().m              # E: "WithMeta" has no attribute "m"
 WithMeta().a              # E: "WithMeta" has no attribute "a"
+t: Type[WithMeta]
+t.unknown  # OK
 
 [case testMetaclassAsAnyWithAFlag]
 # flags: --disallow-subclassing-any
-from typing import Any, ClassVar
+from typing import Any, ClassVar, Type
 
 MyAny: Any
-class WithMeta(metaclass=MyAny):  # E: Class cannot use "__main__.MyAny" as a metaclass (has type "Any")
+class WithMeta(metaclass=MyAny):  # E: Class cannot use "MyAny" as a metaclass (has type "Any")
     x: ClassVar[int]
 
 reveal_type(WithMeta.a)   # N: Revealed type is "Any"
@@ -4466,6 +4468,8 @@ reveal_type(WithMeta.x)   # N: Revealed type is "builtins.int"
 reveal_type(WithMeta().x) # N: Revealed type is "builtins.int"
 WithMeta().m              # E: "WithMeta" has no attribute "m"
 WithMeta().a              # E: "WithMeta" has no attribute "a"
+t: Type[WithMeta]
+t.unknown  # OK
 
 [case testMetaclassIterable]
 from typing import Iterable, Iterator
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index 60917db041a1f..1aff1ba2862f8 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -6348,3 +6348,14 @@ class C(B):
         self.x = self.foo()
 [out]
 [out2]
+
+[case testNoCrashIncrementalMetaAny]
+import a
+[file a.py]
+from m import Foo
+[file a.py.2]
+from m import Foo
+# touch
+[file m.py]
+from missing_module import Meta  # type: ignore[import]
+class Foo(metaclass=Meta): ...
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index d4b2d34698711..ed33776af438d 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -3124,7 +3124,6 @@ whatever: int
 [out]
 ==
 b.py:2: error: Name "c.M" is not defined
-a.py:3: error: "Type[B]" has no attribute "x"
 
 [case testFixMissingMetaclass]
 import a
@@ -3143,7 +3142,6 @@ class M(type):
     x: int
 [out]
 b.py:2: error: Name "c.M" is not defined
-a.py:3: error: "Type[B]" has no attribute "x"
 ==
 
 [case testGoodMetaclassSpoiled]

From a08388cf6de053f659a9d663387f8f71e68664d8 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Sun, 22 Jan 2023 11:22:06 +0000
Subject: [PATCH 196/231] Fix crash in astdiff and clean it up (#14497)

Ref #14329

This fixes one of the crashes reported in the issue. In fact, using
recursive type caught this crash statically, plus another subtle crash
in `snapshot_optional_type()`, _without a single false positive_ (I was
able to cleanly type also symbol table snapshots, but decided it is not
worth the churn since we only ever compare them with `==`, supported by
~every Python object). I feel triumphant :-)
---
 mypy/server/astdiff.py           | 30 ++++++++++++++++++------------
 mypy/server/update.py            | 10 +++++++---
 test-data/unit/fine-grained.test | 28 ++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 15 deletions(-)

diff --git a/mypy/server/astdiff.py b/mypy/server/astdiff.py
index 012d395e632f2..40b60f1a69d80 100644
--- a/mypy/server/astdiff.py
+++ b/mypy/server/astdiff.py
@@ -52,7 +52,7 @@ class level -- these are handled at attribute level (say, 'mod.Cls.method'
 
 from __future__ import annotations
 
-from typing import Sequence, Tuple, cast
+from typing import Sequence, Tuple, Union, cast
 from typing_extensions import TypeAlias as _TypeAlias
 
 from mypy.expandtype import expand_type
@@ -109,11 +109,17 @@ class level -- these are handled at attribute level (say, 'mod.Cls.method'
 # snapshots are immutable).
 #
 # For example, the snapshot of the 'int' type is ('Instance', 'builtins.int', ()).
-SnapshotItem: _TypeAlias = Tuple[object, ...]
+
+# Type snapshots are strict, they must be hashable and ordered (e.g. for Unions).
+Primitive: _TypeAlias = Union[str, float, int, bool]  # float is for Literal[3.14] support.
+SnapshotItem: _TypeAlias = Tuple[Union[Primitive, "SnapshotItem"], ...]
+
+# Symbol snapshots can be more lenient.
+SymbolSnapshot: _TypeAlias = Tuple[object, ...]
 
 
 def compare_symbol_table_snapshots(
-    name_prefix: str, snapshot1: dict[str, SnapshotItem], snapshot2: dict[str, SnapshotItem]
+    name_prefix: str, snapshot1: dict[str, SymbolSnapshot], snapshot2: dict[str, SymbolSnapshot]
 ) -> set[str]:
     """Return names that are different in two snapshots of a symbol table.
 
@@ -155,7 +161,7 @@ def compare_symbol_table_snapshots(
     return triggers
 
 
-def snapshot_symbol_table(name_prefix: str, table: SymbolTable) -> dict[str, SnapshotItem]:
+def snapshot_symbol_table(name_prefix: str, table: SymbolTable) -> dict[str, SymbolSnapshot]:
     """Create a snapshot description that represents the state of a symbol table.
 
     The snapshot has a representation based on nested tuples and dicts
@@ -165,7 +171,7 @@ def snapshot_symbol_table(name_prefix: str, table: SymbolTable) -> dict[str, Sna
     things defined in other modules are represented just by the names of
     the targets.
     """
-    result: dict[str, SnapshotItem] = {}
+    result: dict[str, SymbolSnapshot] = {}
     for name, symbol in table.items():
         node = symbol.node
         # TODO: cross_ref?
@@ -206,7 +212,7 @@ def snapshot_symbol_table(name_prefix: str, table: SymbolTable) -> dict[str, Sna
     return result
 
 
-def snapshot_definition(node: SymbolNode | None, common: tuple[object, ...]) -> tuple[object, ...]:
+def snapshot_definition(node: SymbolNode | None, common: SymbolSnapshot) -> SymbolSnapshot:
     """Create a snapshot description of a symbol table node.
 
     The representation is nested tuples and dicts. Only externally
@@ -290,11 +296,11 @@ def snapshot_type(typ: Type) -> SnapshotItem:
     return typ.accept(SnapshotTypeVisitor())
 
 
-def snapshot_optional_type(typ: Type | None) -> SnapshotItem | None:
+def snapshot_optional_type(typ: Type | None) -> SnapshotItem:
     if typ:
         return snapshot_type(typ)
     else:
-        return None
+        return ("<not set>",)
 
 
 def snapshot_types(types: Sequence[Type]) -> SnapshotItem:
@@ -396,7 +402,7 @@ def visit_parameters(self, typ: Parameters) -> SnapshotItem:
             "Parameters",
             snapshot_types(typ.arg_types),
             tuple(encode_optional_str(name) for name in typ.arg_names),
-            tuple(typ.arg_kinds),
+            tuple(k.value for k in typ.arg_kinds),
         )
 
     def visit_callable_type(self, typ: CallableType) -> SnapshotItem:
@@ -407,7 +413,7 @@ def visit_callable_type(self, typ: CallableType) -> SnapshotItem:
             snapshot_types(typ.arg_types),
             snapshot_type(typ.ret_type),
             tuple(encode_optional_str(name) for name in typ.arg_names),
-            tuple(typ.arg_kinds),
+            tuple(k.value for k in typ.arg_kinds),
             typ.is_type_obj(),
             typ.is_ellipsis_args,
             snapshot_types(typ.variables),
@@ -464,7 +470,7 @@ def visit_type_alias_type(self, typ: TypeAliasType) -> SnapshotItem:
         return ("TypeAliasType", typ.alias.fullname, snapshot_types(typ.args))
 
 
-def snapshot_untyped_signature(func: OverloadedFuncDef | FuncItem) -> tuple[object, ...]:
+def snapshot_untyped_signature(func: OverloadedFuncDef | FuncItem) -> SymbolSnapshot:
     """Create a snapshot of the signature of a function that has no explicit signature.
 
     If the arguments to a function without signature change, it must be
@@ -476,7 +482,7 @@ def snapshot_untyped_signature(func: OverloadedFuncDef | FuncItem) -> tuple[obje
     if isinstance(func, FuncItem):
         return (tuple(func.arg_names), tuple(func.arg_kinds))
     else:
-        result = []
+        result: list[SymbolSnapshot] = []
         for item in func.items:
             if isinstance(item, Decorator):
                 if item.var.type:
diff --git a/mypy/server/update.py b/mypy/server/update.py
index 83cce22873a12..00b823c99dfd0 100644
--- a/mypy/server/update.py
+++ b/mypy/server/update.py
@@ -151,7 +151,11 @@
     semantic_analysis_for_scc,
     semantic_analysis_for_targets,
 )
-from mypy.server.astdiff import SnapshotItem, compare_symbol_table_snapshots, snapshot_symbol_table
+from mypy.server.astdiff import (
+    SymbolSnapshot,
+    compare_symbol_table_snapshots,
+    snapshot_symbol_table,
+)
 from mypy.server.astmerge import merge_asts
 from mypy.server.aststrip import SavedAttributes, strip_target
 from mypy.server.deps import get_dependencies_of_target, merge_dependencies
@@ -417,7 +421,7 @@ def update_module(
 
         t0 = time.time()
         # Record symbol table snapshot of old version the changed module.
-        old_snapshots: dict[str, dict[str, SnapshotItem]] = {}
+        old_snapshots: dict[str, dict[str, SymbolSnapshot]] = {}
         if module in manager.modules:
             snapshot = snapshot_symbol_table(module, manager.modules[module].names)
             old_snapshots[module] = snapshot
@@ -751,7 +755,7 @@ def get_sources(
 
 def calculate_active_triggers(
     manager: BuildManager,
-    old_snapshots: dict[str, dict[str, SnapshotItem]],
+    old_snapshots: dict[str, dict[str, SymbolSnapshot]],
     new_modules: dict[str, MypyFile | None],
 ) -> set[str]:
     """Determine activated triggers by comparing old and new symbol tables.
diff --git a/test-data/unit/fine-grained.test b/test-data/unit/fine-grained.test
index ed33776af438d..d47c21283c919 100644
--- a/test-data/unit/fine-grained.test
+++ b/test-data/unit/fine-grained.test
@@ -10313,3 +10313,31 @@ a.py:3: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#varia
 a.py:4: note: Revealed type is "A?"
 ==
 a.py:4: note: Revealed type is "Union[builtins.str, builtins.int]"
+
+[case testUnionOfSimilarCallablesCrash]
+import b
+
+[file b.py]
+from a import x
+
+[file m.py]
+from typing import Union, TypeVar
+
+T = TypeVar("T")
+S = TypeVar("S")
+def foo(x: T, y: S) -> Union[T, S]: ...
+def f(x: int) -> int: ...
+def g(*x: int) -> int: ...
+
+[file a.py]
+from m import f, g, foo
+x = foo(f, g)
+
+[file a.py.2]
+from m import f, g, foo
+x = foo(f, g)
+reveal_type(x)
+[builtins fixtures/tuple.pyi]
+[out]
+==
+a.py:3: note: Revealed type is "Union[def (x: builtins.int) -> builtins.int, def (*x: builtins.int) -> builtins.int]"

From cb14d6f0cf8e434928557d0f0c73c8a9c7e18c52 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sun, 22 Jan 2023 05:36:59 -0800
Subject: [PATCH 197/231] stubgen: treat dlls as c modules (#14503)

Fixes #14028
---
 mypy/moduleinspect.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/moduleinspect.py b/mypy/moduleinspect.py
index feca1f43abf26..b383fc9dc1454 100644
--- a/mypy/moduleinspect.py
+++ b/mypy/moduleinspect.py
@@ -36,7 +36,7 @@ def is_c_module(module: ModuleType) -> bool:
         # Could be a namespace package. These must be handled through
         # introspection, since there is no source file.
         return True
-    return os.path.splitext(module.__dict__["__file__"])[-1] in [".so", ".pyd"]
+    return os.path.splitext(module.__dict__["__file__"])[-1] in [".so", ".pyd", ".dll"]
 
 
 class InspectError(Exception):

From d8418599f3a7d9af9b40a15b6a5c5d73fe51ac85 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 23 Jan 2023 10:25:34 +0000
Subject: [PATCH 198/231] Properly support union of TypedDicts as dict literal
 context (#14505)

Fixes #14481 (regression)
Fixes #13274
Fixes #8533

Most notably, if literal matches multiple items in union, it is not an
error, it is only an error if it matches none of them, so I adjust the
error message accordingly.

An import caveat is that an unrelated error like `{"key": 42 + "no"}`
can cause no item to match (an hence an extra error), but I think it is
fine, since we still show the actual error, and avoiding this would
require some dirty hacks.

Also note there was an (obvious) bug in one of the fixtures, that caused
one of repros not repro in tests, fixing it required tweaking an
unrelated test.
---
 mypy/checkexpr.py                   | 56 ++++++++++-------
 mypy/messages.py                    |  4 +-
 test-data/unit/check-typeddict.test | 96 +++++++++++++++++++++++++++--
 test-data/unit/check-unions.test    |  6 +-
 test-data/unit/fixtures/dict.pyi    |  2 +-
 5 files changed, 131 insertions(+), 33 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 1c25b8ea7a12b..c2cf226ef210c 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -4188,6 +4188,17 @@ def fast_dict_type(self, e: DictExpr) -> Type | None:
         self.resolved_type[e] = dt
         return dt
 
+    def check_typeddict_literal_in_context(
+        self, e: DictExpr, typeddict_context: TypedDictType
+    ) -> Type:
+        orig_ret_type = self.check_typeddict_call_with_dict(
+            callee=typeddict_context, kwargs=e, context=e, orig_callee=None
+        )
+        ret_type = get_proper_type(orig_ret_type)
+        if isinstance(ret_type, TypedDictType):
+            return ret_type.copy_modified()
+        return typeddict_context.copy_modified()
+
     def visit_dict_expr(self, e: DictExpr) -> Type:
         """Type check a dict expression.
 
@@ -4197,15 +4208,20 @@ def visit_dict_expr(self, e: DictExpr) -> Type:
         # an error, but returns the TypedDict type that matches the literal it found
         # that would cause a second error when that TypedDict type is returned upstream
         # to avoid the second error, we always return TypedDict type that was requested
-        typeddict_context = self.find_typeddict_context(self.type_context[-1], e)
-        if typeddict_context:
-            orig_ret_type = self.check_typeddict_call_with_dict(
-                callee=typeddict_context, kwargs=e, context=e, orig_callee=None
-            )
-            ret_type = get_proper_type(orig_ret_type)
-            if isinstance(ret_type, TypedDictType):
-                return ret_type.copy_modified()
-            return typeddict_context.copy_modified()
+        typeddict_contexts = self.find_typeddict_context(self.type_context[-1], e)
+        if typeddict_contexts:
+            if len(typeddict_contexts) == 1:
+                return self.check_typeddict_literal_in_context(e, typeddict_contexts[0])
+            # Multiple items union, check if at least one of them matches cleanly.
+            for typeddict_context in typeddict_contexts:
+                with self.msg.filter_errors() as err, self.chk.local_type_map() as tmap:
+                    ret_type = self.check_typeddict_literal_in_context(e, typeddict_context)
+                if err.has_new_errors():
+                    continue
+                self.chk.store_types(tmap)
+                return ret_type
+            # No item matched without an error, so we can't unambiguously choose the item.
+            self.msg.typeddict_context_ambiguous(typeddict_contexts, e)
 
         # fast path attempt
         dt = self.fast_dict_type(e)
@@ -4271,26 +4287,20 @@ def visit_dict_expr(self, e: DictExpr) -> Type:
 
     def find_typeddict_context(
         self, context: Type | None, dict_expr: DictExpr
-    ) -> TypedDictType | None:
+    ) -> list[TypedDictType]:
         context = get_proper_type(context)
         if isinstance(context, TypedDictType):
-            return context
+            return [context]
         elif isinstance(context, UnionType):
             items = []
             for item in context.items:
-                item_context = self.find_typeddict_context(item, dict_expr)
-                if item_context is not None and self.match_typeddict_call_with_dict(
-                    item_context, dict_expr, dict_expr
-                ):
-                    items.append(item_context)
-            if len(items) == 1:
-                # Only one union item is valid TypedDict for the given dict_expr, so use the
-                # context as it's unambiguous.
-                return items[0]
-            if len(items) > 1:
-                self.msg.typeddict_context_ambiguous(items, dict_expr)
+                item_contexts = self.find_typeddict_context(item, dict_expr)
+                for item_context in item_contexts:
+                    if self.match_typeddict_call_with_dict(item_context, dict_expr, dict_expr):
+                        items.append(item_context)
+            return items
         # No TypedDict type in context.
-        return None
+        return []
 
     def visit_lambda_expr(self, e: LambdaExpr) -> Type:
         """Type check lambda expression."""
diff --git a/mypy/messages.py b/mypy/messages.py
index 5d8bf79ec8a32..94a97f696b6c3 100644
--- a/mypy/messages.py
+++ b/mypy/messages.py
@@ -1705,7 +1705,9 @@ def typeddict_key_not_found(
 
     def typeddict_context_ambiguous(self, types: list[TypedDictType], context: Context) -> None:
         formatted_types = ", ".join(list(format_type_distinctly(*types)))
-        self.fail(f"Type of TypedDict is ambiguous, could be any of ({formatted_types})", context)
+        self.fail(
+            f"Type of TypedDict is ambiguous, none of ({formatted_types}) matches cleanly", context
+        )
 
     def typeddict_key_cannot_be_deleted(
         self, typ: TypedDictType, item_name: str, context: Context
diff --git a/test-data/unit/check-typeddict.test b/test-data/unit/check-typeddict.test
index e426b8a7630b1..70ff6a4a67595 100644
--- a/test-data/unit/check-typeddict.test
+++ b/test-data/unit/check-typeddict.test
@@ -895,15 +895,25 @@ c: Union[A, B] = {'@type': 'a-type', 'a': 'Test'}
 reveal_type(c) # N: Revealed type is "Union[TypedDict('__main__.A', {'@type': Literal['a-type'], 'a': builtins.str}), TypedDict('__main__.B', {'@type': Literal['b-type'], 'b': builtins.int})]"
 [builtins fixtures/dict.pyi]
 
-[case testTypedDictUnionAmbiguousCase]
+[case testTypedDictUnionAmbiguousCaseBothMatch]
 from typing import Union, Mapping, Any, cast
 from typing_extensions import TypedDict, Literal
 
-A = TypedDict('A', {'@type': Literal['a-type'], 'a': str})
-B = TypedDict('B', {'@type': Literal['a-type'], 'a': str})
+A = TypedDict('A', {'@type': Literal['a-type'], 'value': str})
+B = TypedDict('B', {'@type': Literal['b-type'], 'value': str})
+
+c: Union[A, B] = {'@type': 'a-type', 'value': 'Test'}
+[builtins fixtures/dict.pyi]
+
+[case testTypedDictUnionAmbiguousCaseNoMatch]
+from typing import Union, Mapping, Any, cast
+from typing_extensions import TypedDict, Literal
 
-c: Union[A, B] = {'@type': 'a-type', 'a': 'Test'} # E: Type of TypedDict is ambiguous, could be any of ("A", "B") \
-                                                  # E: Incompatible types in assignment (expression has type "Dict[str, str]", variable has type "Union[A, B]")
+A = TypedDict('A', {'@type': Literal['a-type'], 'value': int})
+B = TypedDict('B', {'@type': Literal['b-type'], 'value': int})
+
+c: Union[A, B] = {'@type': 'a-type', 'value': 'Test'}  # E: Type of TypedDict is ambiguous, none of ("A", "B") matches cleanly \
+                                                       # E: Incompatible types in assignment (expression has type "Dict[str, str]", variable has type "Union[A, B]")
 [builtins fixtures/dict.pyi]
 
 -- Use dict literals
@@ -2786,3 +2796,79 @@ TDC = TypedDict("TDC", {"val": int, "next": Optional[Self]})  # E: Self type can
 
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
+
+[case testUnionOfEquivalentTypedDictsInferred]
+from typing import TypedDict, Dict
+
+D = TypedDict("D", {"foo": int}, total=False)
+
+def f(d: Dict[str, D]) -> None:
+    args = d["a"]
+    args.update(d.get("b", {}))  # OK
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testUnionOfEquivalentTypedDictsDeclared]
+from typing import TypedDict, Union
+
+class A(TypedDict, total=False):
+    name: str
+class B(TypedDict, total=False):
+    name: str
+
+def foo(data: Union[A, B]) -> None: ...
+foo({"name": "Robert"})  # OK
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testUnionOfEquivalentTypedDictsEmpty]
+from typing import TypedDict, Union
+
+class Foo(TypedDict, total=False):
+    foo: str
+class Bar(TypedDict, total=False):
+    bar: str
+
+def foo(body: Union[Foo, Bar] = {}) -> None:  # OK
+    ...
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testUnionOfEquivalentTypedDictsDistinct]
+from typing import TypedDict, Union, Literal
+
+class A(TypedDict):
+    type: Literal['a']
+    value: bool
+class B(TypedDict):
+    type: Literal['b']
+    value: str
+
+Response = Union[A, B]
+def method(message: Response) -> None: ...
+
+method({'type': 'a', 'value': True})  # OK
+method({'type': 'b', 'value': 'abc'})  # OK
+method({'type': 'a', 'value': 'abc'})  # E: Type of TypedDict is ambiguous, none of ("A", "B") matches cleanly \
+                                       # E: Argument 1 to "method" has incompatible type "Dict[str, str]"; expected "Union[A, B]"
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
+
+[case testUnionOfEquivalentTypedDictsNested]
+from typing import TypedDict, Union
+
+class A(TypedDict, total=False):
+    foo: C
+class B(TypedDict, total=False):
+    foo: D
+class C(TypedDict, total=False):
+    c: str
+class D(TypedDict, total=False):
+    d: str
+
+def foo(data: Union[A, B]) -> None: ...
+foo({"foo": {"c": "foo"}})  # OK
+foo({"foo": {"e": "foo"}})  # E: Type of TypedDict is ambiguous, none of ("A", "B") matches cleanly \
+                            # E: Argument 1 to "foo" has incompatible type "Dict[str, Dict[str, str]]"; expected "Union[A, B]"
+[builtins fixtures/dict.pyi]
+[typing fixtures/typing-typeddict.pyi]
diff --git a/test-data/unit/check-unions.test b/test-data/unit/check-unions.test
index 4c4fbc32ec3fb..cabc28e786b2c 100644
--- a/test-data/unit/check-unions.test
+++ b/test-data/unit/check-unions.test
@@ -971,14 +971,14 @@ if x:
 [builtins fixtures/dict.pyi]
 [out]
 
-[case testUnpackUnionNoCrashOnPartialNoneList]
+[case testUnpackUnionNoCrashOnPartialList]
 # flags: --strict-optional
 from typing import Dict, Tuple, List, Any
 
 a: Any
 d: Dict[str, Tuple[List[Tuple[str, str]], str]]
-x, _ = d.get(a, ([], []))
-reveal_type(x) # N: Revealed type is "Union[builtins.list[Tuple[builtins.str, builtins.str]], builtins.list[<nothing>]]"
+x, _ = d.get(a, ([], ""))
+reveal_type(x) # N: Revealed type is "builtins.list[Tuple[builtins.str, builtins.str]]"
 
 for y in x: pass
 [builtins fixtures/dict.pyi]
diff --git a/test-data/unit/fixtures/dict.pyi b/test-data/unit/fixtures/dict.pyi
index f4ec15e4fa9af..856b8b7266c11 100644
--- a/test-data/unit/fixtures/dict.pyi
+++ b/test-data/unit/fixtures/dict.pyi
@@ -29,7 +29,7 @@ class dict(Mapping[KT, VT]):
     @overload
     def get(self, k: KT) -> Optional[VT]: pass
     @overload
-    def get(self, k: KT, default: Union[KT, T]) -> Union[VT, T]: pass
+    def get(self, k: KT, default: Union[VT, T]) -> Union[VT, T]: pass
     def __len__(self) -> int: ...
 
 class int: # for convenience

From 9bbb93cf69f81ea1fc33f223ff03cf2a1b604bc5 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 23 Jan 2023 10:30:54 +0000
Subject: [PATCH 199/231] Typeshed cherry-pick: Add __eq__ to
 types.MappingProxyType (#9580) (#14507)

This fixes a false positive when using `--strict-equality`.

See
https://github.com/python/typeshed/commit/d5b88c552cd7530b598b6369fef66bda745de93d
for context.
---
 mypy/typeshed/stdlib/types.pyi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mypy/typeshed/stdlib/types.pyi b/mypy/typeshed/stdlib/types.pyi
index 6928032f92b16..e3e6418347b14 100644
--- a/mypy/typeshed/stdlib/types.pyi
+++ b/mypy/typeshed/stdlib/types.pyi
@@ -310,6 +310,7 @@ class MappingProxyType(Mapping[_KT, _VT_co], Generic[_KT, _VT_co]):
     def __getitem__(self, __key: _KT) -> _VT_co: ...
     def __iter__(self) -> Iterator[_KT]: ...
     def __len__(self) -> int: ...
+    def __eq__(self, other: object) -> bool: ...
     def copy(self) -> dict[_KT, _VT_co]: ...
     def keys(self) -> KeysView[_KT]: ...
     def values(self) -> ValuesView[_VT_co]: ...

From dcf910e05fdcff00b1fb9a8b9ca85f9a6667b946 Mon Sep 17 00:00:00 2001
From: Ivan Levkivskyi <levkivskyi@gmail.com>
Date: Mon, 23 Jan 2023 11:45:03 +0000
Subject: [PATCH 200/231] Fix crash in daemon mode on new import cycle (#14508)

Fixes #14329

This fixes the second crash reported in the issue (other one is already
fixed). This one is tricky, it looks like it happens only when we bring
in a new import cycle in an incremental update with
`--follow-import=normal`. To explain the reason, a little reminder of
how semantic analyzer passes work:

* Originally, we recorded progress automatically when some new symbol
was resolved and added to symbol tables.
* With implementation of recursive types, this mechanism was
insufficient, as recursive types require modifying some symbols _in
place_, this is why `force_progress` flag was added to `defer()`.
* I was only careful with this flag for recursive type aliases (that
were implemented first), for other things (like recursive TypedDicts,
etc) I just always passed `force_progress=True` (without checking if we
actually resolved some placeholder types).
* The reasoning for that is if we ever add `becomes_typeinfo=True`,
there is no way this symbol will later be unresolved (otherwise how
would we know this is something that is a type).
* It turns out this reasoning doesn't work in some edge cases in daemon
mode, we do put some placeholders with `becomes_typeinfo=True` for
symbols imported from modules that were not yet processed, thus causing
a crash (see test cases).
* There were two options to fix this: one is to stop creating
placeholders with `becomes_typeinfo=True` for unimported symbols in
daemon mode, other one is to always carefully check if in-place update
of a symbol actually resulted in progress.
* Ultimately I decided that the first way is too fragile (and I don't
understand how import following works for daemon anyway), and the second
way is something that is technically correct anyway, so here is this PR

I didn't add test cases for each of the crash scenarios, since they are
all very similar. I only added two that I encountered "in the wild",
upper bound and tuple base caused actual crash in `trio` stubs, plus
also randomly a test for a TypedDict crash.

_EDIT:_ and one more thing, the "cannot resolve name" error should never
appear in normal mode, only in daemon update (see reasoning above), so I
don't make those error messages detailed, just add some minimal info if
we will need to debug them.
---
 mypy/semanal.py                               | 28 +++++--
 mypy/semanal_namedtuple.py                    |  4 +-
 mypy/semanal_newtype.py                       | 10 ++-
 mypy/semanal_shared.py                        |  6 ++
 mypy/semanal_typeddict.py                     |  4 +-
 mypy/types.py                                 |  8 ++
 .../unit/fine-grained-follow-imports.test     | 77 +++++++++++++++++++
 7 files changed, 126 insertions(+), 11 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 5653aa4547c46..34cb45194d19d 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -1049,7 +1049,12 @@ def setup_self_type(self) -> None:
         if info.self_type is not None:
             if has_placeholder(info.self_type.upper_bound):
                 # Similar to regular (user defined) type variables.
-                self.defer(force_progress=True)
+                self.process_placeholder(
+                    None,
+                    "Self upper bound",
+                    info,
+                    force_progress=info.self_type.upper_bound != fill_typevars(info),
+                )
             else:
                 return
         info.self_type = TypeVarType("Self", f"{info.fullname}.Self", 0, [], fill_typevars(info))
@@ -2132,7 +2137,9 @@ def configure_tuple_base_class(self, defn: ClassDef, base: TupleType) -> Instanc
             self.fail("Class has two incompatible bases derived from tuple", defn)
             defn.has_incompatible_baseclass = True
         if info.special_alias and has_placeholder(info.special_alias.target):
-            self.defer(force_progress=True)
+            self.process_placeholder(
+                None, "tuple base", defn, force_progress=base != info.tuple_type
+            )
         info.update_tuple_type(base)
         self.setup_alias_type_vars(defn)
 
@@ -3913,12 +3920,16 @@ def process_typevar_declaration(self, s: AssignmentStmt) -> bool:
             type_var = TypeVarExpr(name, self.qualified_name(name), values, upper_bound, variance)
             type_var.line = call.line
             call.analyzed = type_var
+            updated = True
         else:
             assert isinstance(call.analyzed, TypeVarExpr)
+            updated = values != call.analyzed.values or upper_bound != call.analyzed.upper_bound
             call.analyzed.upper_bound = upper_bound
             call.analyzed.values = values
         if any(has_placeholder(v) for v in values) or has_placeholder(upper_bound):
-            self.defer(force_progress=True)
+            self.process_placeholder(
+                None, f"TypeVar {'values' if values else 'upper bound'}", s, force_progress=updated
+            )
 
         self.add_symbol(name, call.analyzed, s)
         return True
@@ -5931,7 +5942,9 @@ def is_incomplete_namespace(self, fullname: str) -> bool:
         """
         return fullname in self.incomplete_namespaces
 
-    def process_placeholder(self, name: str, kind: str, ctx: Context) -> None:
+    def process_placeholder(
+        self, name: str | None, kind: str, ctx: Context, force_progress: bool = False
+    ) -> None:
         """Process a reference targeting placeholder node.
 
         If this is not a final iteration, defer current node,
@@ -5943,10 +5956,11 @@ def process_placeholder(self, name: str, kind: str, ctx: Context) -> None:
         if self.final_iteration:
             self.cannot_resolve_name(name, kind, ctx)
         else:
-            self.defer(ctx)
+            self.defer(ctx, force_progress=force_progress)
 
-    def cannot_resolve_name(self, name: str, kind: str, ctx: Context) -> None:
-        self.fail(f'Cannot resolve {kind} "{name}" (possible cyclic definition)', ctx)
+    def cannot_resolve_name(self, name: str | None, kind: str, ctx: Context) -> None:
+        name_format = f' "{name}"' if name else ""
+        self.fail(f"Cannot resolve {kind}{name_format} (possible cyclic definition)", ctx)
         if not self.options.disable_recursive_aliases and self.is_func_scope():
             self.note("Recursive types are not allowed at function scope", ctx)
 
diff --git a/mypy/semanal_namedtuple.py b/mypy/semanal_namedtuple.py
index ec5f13d0fce09..226c2e50326bc 100644
--- a/mypy/semanal_namedtuple.py
+++ b/mypy/semanal_namedtuple.py
@@ -501,7 +501,9 @@ def build_namedtuple_typeinfo(
         info.is_named_tuple = True
         tuple_base = TupleType(types, fallback)
         if info.special_alias and has_placeholder(info.special_alias.target):
-            self.api.defer(force_progress=True)
+            self.api.process_placeholder(
+                None, "NamedTuple item", info, force_progress=tuple_base != info.tuple_type
+            )
         info.update_tuple_type(tuple_base)
         info.line = line
         # For use by mypyc.
diff --git a/mypy/semanal_newtype.py b/mypy/semanal_newtype.py
index b6fb64532e6ea..cb1055a621862 100644
--- a/mypy/semanal_newtype.py
+++ b/mypy/semanal_newtype.py
@@ -249,10 +249,16 @@ def build_newtype_typeinfo(
         init_func = FuncDef("__init__", args, Block([]), typ=signature)
         init_func.info = info
         init_func._fullname = info.fullname + ".__init__"
+        if not existing_info:
+            updated = True
+        else:
+            previous_sym = info.names["__init__"].node
+            assert isinstance(previous_sym, FuncDef)
+            updated = old_type != previous_sym.arguments[1].variable.type
         info.names["__init__"] = SymbolTableNode(MDEF, init_func)
 
-        if has_placeholder(old_type) or info.tuple_type and has_placeholder(info.tuple_type):
-            self.api.defer(force_progress=True)
+        if has_placeholder(old_type):
+            self.api.process_placeholder(None, "NewType base", info, force_progress=updated)
         return info
 
     # Helpers
diff --git a/mypy/semanal_shared.py b/mypy/semanal_shared.py
index e5be4aa55cd31..f4bc173b52d59 100644
--- a/mypy/semanal_shared.py
+++ b/mypy/semanal_shared.py
@@ -232,6 +232,12 @@ def qualified_name(self, n: str) -> str:
     def is_typeshed_stub_file(self) -> bool:
         raise NotImplementedError
 
+    @abstractmethod
+    def process_placeholder(
+        self, name: str | None, kind: str, ctx: Context, force_progress: bool = False
+    ) -> None:
+        raise NotImplementedError
+
 
 def set_callable_name(sig: Type, fdef: FuncDef) -> ProperType:
     sig = get_proper_type(sig)
diff --git a/mypy/semanal_typeddict.py b/mypy/semanal_typeddict.py
index cd3d02bc6bb8b..55618318c1e8d 100644
--- a/mypy/semanal_typeddict.py
+++ b/mypy/semanal_typeddict.py
@@ -535,7 +535,9 @@ def build_typeddict_typeinfo(
         info = existing_info or self.api.basic_new_typeinfo(name, fallback, line)
         typeddict_type = TypedDictType(dict(zip(items, types)), required_keys, fallback)
         if info.special_alias and has_placeholder(info.special_alias.target):
-            self.api.defer(force_progress=True)
+            self.api.process_placeholder(
+                None, "TypedDict item", info, force_progress=typeddict_type != info.typeddict_type
+            )
         info.update_typeddict_type(typeddict_type)
         return info
 
diff --git a/mypy/types.py b/mypy/types.py
index 7af83b6c11d39..bf610a01b63b9 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -2857,6 +2857,14 @@ def accept(self, visitor: TypeVisitor[T]) -> T:
         assert isinstance(visitor, SyntheticTypeVisitor)
         return cast(T, visitor.visit_placeholder_type(self))
 
+    def __hash__(self) -> int:
+        return hash((self.fullname, tuple(self.args)))
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, PlaceholderType):
+            return NotImplemented
+        return self.fullname == other.fullname and self.args == other.args
+
     def serialize(self) -> str:
         # We should never get here since all placeholders should be replaced
         # during semantic analysis.
diff --git a/test-data/unit/fine-grained-follow-imports.test b/test-data/unit/fine-grained-follow-imports.test
index ebe8b86b37ab3..22f2a7895cf96 100644
--- a/test-data/unit/fine-grained-follow-imports.test
+++ b/test-data/unit/fine-grained-follow-imports.test
@@ -769,3 +769,80 @@ from . import mod3
 ==
 main.py:1: error: Cannot find implementation or library stub for module named "pkg"
 main.py:1: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
+
+[case testNewImportCycleTypeVarBound]
+# flags: --follow-imports=normal
+# cmd: mypy main.py
+# cmd2: mypy other.py
+
+[file main.py]
+# empty
+
+[file other.py.2]
+import trio
+
+[file trio/__init__.py.2]
+from typing import TypeVar
+import trio
+from . import abc as abc
+
+T = TypeVar("T", bound=trio.abc.A)
+
+[file trio/abc.py.2]
+import trio
+class A: ...
+[out]
+==
+
+[case testNewImportCycleTupleBase]
+# flags: --follow-imports=normal
+# cmd: mypy main.py
+# cmd2: mypy other.py
+
+[file main.py]
+# empty
+
+[file other.py.2]
+import trio
+
+[file trio/__init__.py.2]
+from typing import TypeVar, Tuple
+import trio
+from . import abc as abc
+
+class C(Tuple[trio.abc.A, trio.abc.A]): ...
+
+[file trio/abc.py.2]
+import trio
+class A: ...
+[builtins fixtures/tuple.pyi]
+[out]
+==
+
+[case testNewImportCycleTypedDict]
+# flags: --follow-imports=normal
+# cmd: mypy main.py
+# cmd2: mypy other.py
+
+[file main.py]
+# empty
+
+[file other.py.2]
+import trio
+
+[file trio/__init__.py.2]
+from typing import TypeVar
+from typing_extensions import TypedDict
+import trio
+from . import abc as abc
+
+class C(TypedDict):
+    x: trio.abc.A
+    y: trio.abc.A
+
+[file trio/abc.py.2]
+import trio
+class A: ...
+[builtins fixtures/dict.pyi]
+[out]
+==

From 77f872568998bf54a24f497fef72893a60d84633 Mon Sep 17 00:00:00 2001
From: Alessio Izzo <alessio.izzo86@gmail.com>
Date: Mon, 23 Jan 2023 14:37:52 +0100
Subject: [PATCH 201/231] Fix missing self check dependency on 3.11 (#14492)

Fixes #14487
---
 test-requirements.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test-requirements.txt b/test-requirements.txt
index ac965f4abc520..aec11e87e96f6 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -17,3 +17,4 @@ pytest-cov>=2.10.0
 py>=1.5.2
 setuptools>=65.5.1
 six
+tomli>=1.1.0

From db440ab063c3f01819a29d45e3e2288562f39891 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 23 Jan 2023 14:34:19 +0000
Subject: [PATCH 202/231] Don't consider 'object' always truthy (#14510)

There are two reasons I'm proposing this change. First, we know that
many subclasses of 'object' can be falsy. Second, mypy sometimes
simplifies `object | Any` into just `object`. The latter was considered
always truthy, while the prior one wasn't. Now both of them are treated
consistently. An alternative fix would be to not simplify unions like
`object | Any`, but this seems a bit ad hoc.

This only has an effect when the `truthy-bool` error code is explicitly
enabled.

Fixes #14480. This doesn't just fix the regression but fixes a more
general issue.
---
 mypy/checker.py                      |  1 +
 test-data/unit/check-errorcodes.test | 26 ++++++++++++++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/mypy/checker.py b/mypy/checker.py
index 61104756b2979..46200f5813cc1 100644
--- a/mypy/checker.py
+++ b/mypy/checker.py
@@ -5151,6 +5151,7 @@ def _is_truthy_type(self, t: ProperType) -> bool:
                 and bool(t.type)
                 and not t.type.has_readable_member("__bool__")
                 and not t.type.has_readable_member("__len__")
+                and t.type.fullname != "builtins.object"
             )
             or isinstance(t, FunctionLike)
             or (
diff --git a/test-data/unit/check-errorcodes.test b/test-data/unit/check-errorcodes.test
index d966eb44b6e39..19ce56057ff5a 100644
--- a/test-data/unit/check-errorcodes.test
+++ b/test-data/unit/check-errorcodes.test
@@ -803,12 +803,15 @@ from typing_extensions import TypedDict
 
 Foo = TypedDict("Bar", {})  # E: First argument "Bar" to TypedDict() does not match variable name "Foo"  [name-match]
 [builtins fixtures/dict.pyi]
+
 [case testTruthyBool]
 # flags: --enable-error-code truthy-bool
-from typing import List, Union
+from typing import List, Union, Any
 
 class Foo:
     pass
+class Bar:
+    pass
 
 foo = Foo()
 if foo:  # E: "__main__.foo" has type "Foo" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
@@ -836,15 +839,30 @@ if good_union:
 if not good_union:
     pass
 
-bad_union: Union[Foo, object] = Foo()
-if bad_union:  # E: "__main__.bad_union" has type "Union[Foo, object]" of which no members implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
+bad_union: Union[Foo, Bar] = Foo()
+if bad_union:  # E: "__main__.bad_union" has type "Union[Foo, Bar]" of which no members implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
+    pass
+if not bad_union:  # E: "__main__.bad_union" has type "Union[Foo, Bar]" of which no members implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
+    pass
+
+# 'object' is special and is treated as potentially falsy
+obj: object = Foo()
+if obj:
     pass
-if not bad_union:  # E: "__main__.bad_union" has type "object" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
+if not obj:
     pass
 
 lst: List[int] = []
 if lst:
     pass
+
+a: Any
+if a:
+    pass
+
+any_or_object: Union[object, Any]
+if any_or_object:
+    pass
 [builtins fixtures/list.pyi]
 
 [case testTruthyFunctions]

From 4de3f5d771fd159b69010e547a664a52ae41ce79 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 23 Jan 2023 18:01:18 +0000
Subject: [PATCH 203/231] [mypyc] Make explicit conversions i64(x) and i32(x)
 faster (#14504)

These behave the same as `int(x)` and we want them to be no slower than
the corresponding `int` conversions. Optimize them for bool, float, str
and RInstance arguments.

Work on mypyc/mypyc#837.
---
 mypyc/irbuild/specialize.py                 | 12 +++-
 mypyc/primitives/int_ops.py                 | 66 +++++++++++----------
 mypyc/test-data/irbuild-i32.test            | 52 ++++++++++++++++
 mypyc/test-data/irbuild-i64.test            | 63 ++++++++++++++++++++
 mypyc/test-data/run-i32.test                | 16 +++++
 mypyc/test-data/run-i64.test                | 62 +++++++++++++++++++
 test-data/unit/lib-stub/mypy_extensions.pyi |  9 ++-
 7 files changed, 243 insertions(+), 37 deletions(-)

diff --git a/mypyc/irbuild/specialize.py b/mypyc/irbuild/specialize.py
index e62350778f548..8cb24c5b47dac 100644
--- a/mypyc/irbuild/specialize.py
+++ b/mypyc/irbuild/specialize.py
@@ -160,6 +160,8 @@ def translate_globals(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Va
 @specialize_function("builtins.int")
 @specialize_function("builtins.float")
 @specialize_function("builtins.complex")
+@specialize_function("mypy_extensions.i64")
+@specialize_function("mypy_extensions.i32")
 def translate_builtins_with_unary_dunder(
     builder: IRBuilder, expr: CallExpr, callee: RefExpr
 ) -> Value | None:
@@ -167,7 +169,11 @@ def translate_builtins_with_unary_dunder(
     if len(expr.args) == 1 and expr.arg_kinds == [ARG_POS] and isinstance(callee, NameExpr):
         arg = expr.args[0]
         arg_typ = builder.node_type(arg)
-        method = f"__{callee.name}__"
+        shortname = callee.fullname.split(".")[1]
+        if shortname in ("i64", "i32"):
+            method = "__int__"
+        else:
+            method = f"__{shortname}__"
         if isinstance(arg_typ, RInstance) and arg_typ.class_ir.has_method(method):
             obj = builder.accept(arg)
             return builder.gen_method_call(obj, method, [], None, expr.line)
@@ -676,7 +682,7 @@ def translate_i64(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value
     elif is_int32_rprimitive(arg_type):
         val = builder.accept(arg)
         return builder.add(Extend(val, int64_rprimitive, signed=True, line=expr.line))
-    elif is_int_rprimitive(arg_type):
+    elif is_int_rprimitive(arg_type) or is_bool_rprimitive(arg_type):
         val = builder.accept(arg)
         return builder.coerce(val, int64_rprimitive, expr.line)
     return None
@@ -693,7 +699,7 @@ def translate_i32(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value
     elif is_int64_rprimitive(arg_type):
         val = builder.accept(arg)
         return builder.add(Truncate(val, int32_rprimitive, line=expr.line))
-    elif is_int_rprimitive(arg_type):
+    elif is_int_rprimitive(arg_type) or is_bool_rprimitive(arg_type):
         val = builder.accept(arg)
         return builder.coerce(val, int32_rprimitive, expr.line)
     return None
diff --git a/mypyc/primitives/int_ops.py b/mypyc/primitives/int_ops.py
index 382bceb217f47..7eda9bab7e3c6 100644
--- a/mypyc/primitives/int_ops.py
+++ b/mypyc/primitives/int_ops.py
@@ -35,39 +35,43 @@
     unary_op,
 )
 
-# These int constructors produce object_rprimitives that then need to be unboxed
-# I guess unboxing ourselves would save a check and branch though?
-
-# Get the type object for 'builtins.int'.
-# For ordinary calls to int() we use a load_address to the type
-load_address_op(name="builtins.int", type=object_rprimitive, src="PyLong_Type")
-
-# int(float). We could do a bit better directly.
-function_op(
-    name="builtins.int",
-    arg_types=[float_rprimitive],
-    return_type=object_rprimitive,
-    c_function_name="CPyLong_FromFloat",
-    error_kind=ERR_MAGIC,
-)
+# Constructors for builtins.int and native int types have the same behavior. In
+# interpreted mode, native int types are just aliases to 'int'.
+for int_name in ("builtins.int", "mypy_extensions.i64", "mypy_extensions.i32"):
+    # These int constructors produce object_rprimitives that then need to be unboxed
+    # I guess unboxing ourselves would save a check and branch though?
+
+    # Get the type object for 'builtins.int' or a native int type.
+    # For ordinary calls to int() we use a load_address to the type.
+    # Native ints don't have a separate type object -- we just use 'builtins.int'.
+    load_address_op(name=int_name, type=object_rprimitive, src="PyLong_Type")
+
+    # int(float). We could do a bit better directly.
+    function_op(
+        name=int_name,
+        arg_types=[float_rprimitive],
+        return_type=object_rprimitive,
+        c_function_name="CPyLong_FromFloat",
+        error_kind=ERR_MAGIC,
+    )
 
-# int(string)
-function_op(
-    name="builtins.int",
-    arg_types=[str_rprimitive],
-    return_type=object_rprimitive,
-    c_function_name="CPyLong_FromStr",
-    error_kind=ERR_MAGIC,
-)
+    # int(string)
+    function_op(
+        name=int_name,
+        arg_types=[str_rprimitive],
+        return_type=object_rprimitive,
+        c_function_name="CPyLong_FromStr",
+        error_kind=ERR_MAGIC,
+    )
 
-# int(string, base)
-function_op(
-    name="builtins.int",
-    arg_types=[str_rprimitive, int_rprimitive],
-    return_type=object_rprimitive,
-    c_function_name="CPyLong_FromStrWithBase",
-    error_kind=ERR_MAGIC,
-)
+    # int(string, base)
+    function_op(
+        name=int_name,
+        arg_types=[str_rprimitive, int_rprimitive],
+        return_type=object_rprimitive,
+        c_function_name="CPyLong_FromStrWithBase",
+        error_kind=ERR_MAGIC,
+    )
 
 # str(int)
 int_to_str_op = function_op(
diff --git a/mypyc/test-data/irbuild-i32.test b/mypyc/test-data/irbuild-i32.test
index 818c3138e4e35..7ea3c08647285 100644
--- a/mypyc/test-data/irbuild-i32.test
+++ b/mypyc/test-data/irbuild-i32.test
@@ -480,3 +480,55 @@ L0:
     y = 11
     z = -3
     return 1
+
+[case testI32ExplicitConversionFromVariousTypes]
+from mypy_extensions import i32
+
+def bool_to_i32(b: bool) -> i32:
+    return i32(b)
+
+def str_to_i32(s: str) -> i32:
+    return i32(s)
+
+class C:
+    def __int__(self) -> i32:
+        return 5
+
+def instance_to_i32(c: C) -> i32:
+    return i32(c)
+
+def float_to_i32(x: float) -> i32:
+    return i32(x)
+[out]
+def bool_to_i32(b):
+    b :: bool
+    r0 :: int32
+L0:
+    r0 = extend b: builtins.bool to int32
+    return r0
+def str_to_i32(s):
+    s :: str
+    r0 :: object
+    r1 :: int32
+L0:
+    r0 = CPyLong_FromStr(s)
+    r1 = unbox(int32, r0)
+    return r1
+def C.__int__(self):
+    self :: __main__.C
+L0:
+    return 5
+def instance_to_i32(c):
+    c :: __main__.C
+    r0 :: int32
+L0:
+    r0 = c.__int__()
+    return r0
+def float_to_i32(x):
+    x :: float
+    r0 :: object
+    r1 :: int32
+L0:
+    r0 = CPyLong_FromFloat(x)
+    r1 = unbox(int32, r0)
+    return r1
diff --git a/mypyc/test-data/irbuild-i64.test b/mypyc/test-data/irbuild-i64.test
index 2c4052fa4796c..47802d8e0c978 100644
--- a/mypyc/test-data/irbuild-i64.test
+++ b/mypyc/test-data/irbuild-i64.test
@@ -1771,3 +1771,66 @@ L2:
     keep_alive x
 L3:
     return r3
+
+[case testI64ExplicitConversionFromVariousTypes]
+from mypy_extensions import i64
+
+def bool_to_i64(b: bool) -> i64:
+    return i64(b)
+
+def str_to_i64(s: str) -> i64:
+    return i64(s)
+
+def str_to_i64_with_base(s: str) -> i64:
+    return i64(s, 2)
+
+class C:
+    def __int__(self) -> i64:
+        return 5
+
+def instance_to_i64(c: C) -> i64:
+    return i64(c)
+
+def float_to_i64(x: float) -> i64:
+    return i64(x)
+[out]
+def bool_to_i64(b):
+    b :: bool
+    r0 :: int64
+L0:
+    r0 = extend b: builtins.bool to int64
+    return r0
+def str_to_i64(s):
+    s :: str
+    r0 :: object
+    r1 :: int64
+L0:
+    r0 = CPyLong_FromStr(s)
+    r1 = unbox(int64, r0)
+    return r1
+def str_to_i64_with_base(s):
+    s :: str
+    r0 :: object
+    r1 :: int64
+L0:
+    r0 = CPyLong_FromStrWithBase(s, 4)
+    r1 = unbox(int64, r0)
+    return r1
+def C.__int__(self):
+    self :: __main__.C
+L0:
+    return 5
+def instance_to_i64(c):
+    c :: __main__.C
+    r0 :: int64
+L0:
+    r0 = c.__int__()
+    return r0
+def float_to_i64(x):
+    x :: float
+    r0 :: object
+    r1 :: int64
+L0:
+    r0 = CPyLong_FromFloat(x)
+    r1 = unbox(int64, r0)
+    return r1
diff --git a/mypyc/test-data/run-i32.test b/mypyc/test-data/run-i32.test
index 3d2f3e59e83c7..384e6bd4f02c8 100644
--- a/mypyc/test-data/run-i32.test
+++ b/mypyc/test-data/run-i32.test
@@ -306,6 +306,22 @@ def test_i32_truncate_from_i64() -> None:
     x = i32(small2)
     assert x == 2**31 - 1
 
+def from_float(x: float) -> i32:
+    return i32(x)
+
+def test_explicit_conversion_from_float() -> None:
+    assert from_float(0.0) == 0
+    assert from_float(1.456) == 1
+    assert from_float(-1234.567) == -1234
+    assert from_float(2**31 - 1) == 2**31 - 1
+    assert from_float(-2**31) == -2**31
+    # The error message could be better, but this is acceptable
+    with assertRaises(OverflowError, "int too large to convert to i32"):
+        assert from_float(float(2**31))
+    with assertRaises(OverflowError, "int too large to convert to i32"):
+        # One ulp below the lowest valid i64 value
+        from_float(float(-2**31 - 2048))
+
 def test_tuple_i32() -> None:
     a: i32 = 1
     b: i32 = 2
diff --git a/mypyc/test-data/run-i64.test b/mypyc/test-data/run-i64.test
index c2a218156e663..0fc4b91330d49 100644
--- a/mypyc/test-data/run-i64.test
+++ b/mypyc/test-data/run-i64.test
@@ -310,6 +310,68 @@ def test_i64_from_large_small_literal() -> None:
     x = i64(-2**63)
     assert x == -2**63
 
+def from_float(x: float) -> i64:
+    return i64(x)
+
+def test_explicit_conversion_from_float() -> None:
+    assert from_float(0.0) == 0
+    assert from_float(1.456) == 1
+    assert from_float(-1234.567) == -1234
+    assert from_float(2**63 - 1) == 2**63 - 1
+    assert from_float(-2**63) == -2**63
+    # The error message could be better, but this is acceptable
+    with assertRaises(OverflowError, "int too large to convert to i64"):
+        assert from_float(float(2**63))
+    with assertRaises(OverflowError, "int too large to convert to i64"):
+        # One ulp below the lowest valid i64 value
+        from_float(float(-2**63 - 2048))
+
+def from_str(s: str) -> i64:
+    return i64(s)
+
+def test_explicit_conversion_from_str() -> None:
+    assert from_str("0") == 0
+    assert from_str("1") == 1
+    assert from_str("-1234") == -1234
+    with assertRaises(ValueError):
+        from_str("1.2")
+
+def from_str_with_base(s: str, base: int) -> i64:
+    return i64(s, base)
+
+def test_explicit_conversion_from_str_with_base() -> None:
+    assert from_str_with_base("101", 2) == 5
+    assert from_str_with_base("109", 10) == 109
+    assert from_str_with_base("-f0A", 16) == -3850
+    assert from_str_with_base("0x1a", 16) == 26
+    assert from_str_with_base("0X1A", 16) == 26
+    with assertRaises(ValueError):
+        from_str_with_base("1.2", 16)
+
+def from_bool(b: bool) -> i64:
+    return i64(b)
+
+def test_explicit_conversion_from_bool() -> None:
+    assert from_bool(True) == 1
+    assert from_bool(False) == 0
+
+class IntConv:
+    def __init__(self, x: i64) -> None:
+        self.x = x
+
+    def __int__(self) -> i64:
+        return self.x + 1
+
+def test_explicit_conversion_from_instance() -> None:
+    assert i64(IntConv(0)) == 1
+    assert i64(IntConv(12345)) == 12346
+    assert i64(IntConv(-23)) == -22
+
+def test_explicit_conversion_from_any() -> None:
+    # This can't be specialized
+    a: Any = "101"
+    assert i64(a, base=2) == 5
+
 def test_tuple_i64() -> None:
     a: i64 = 1
     b: i64 = 2
diff --git a/test-data/unit/lib-stub/mypy_extensions.pyi b/test-data/unit/lib-stub/mypy_extensions.pyi
index 6274163c497dc..d79be8719417c 100644
--- a/test-data/unit/lib-stub/mypy_extensions.pyi
+++ b/test-data/unit/lib-stub/mypy_extensions.pyi
@@ -1,7 +1,7 @@
 # NOTE: Requires fixtures/dict.pyi
 from typing import (
     Any, Dict, Type, TypeVar, Optional, Any, Generic, Mapping, NoReturn as NoReturn, Iterator,
-    Union
+    Union, Protocol
 )
 import sys
 
@@ -51,10 +51,13 @@ mypyc_attr: Any
 class FlexibleAlias(Generic[_T, _U]): ...
 
 if sys.version_info >= (3, 0):
+    class __SupportsInt(Protocol[T_co]):
+        def __int__(self) -> int: pass
+
     _Int = Union[int, i32, i64]
 
     class i32:
-        def __init__(self, x: _Int) -> None: ...
+        def __init__(self, x: Union[_Int, str, bytes, SupportsInt], base: int = 10) -> None: ...
         def __add__(self, x: i32) -> i32: ...
         def __radd__(self, x: i32) -> i32: ...
         def __sub__(self, x: i32) -> i32: ...
@@ -84,7 +87,7 @@ if sys.version_info >= (3, 0):
         def __gt__(self, x: i32) -> bool: ...
 
     class i64:
-        def __init__(self, x: _Int) -> None: ...
+        def __init__(self, x: Union[_Int, str, bytes, SupportsInt], base: int = 10) -> None: ...
         def __add__(self, x: i64) -> i64: ...
         def __radd__(self, x: i64) -> i64: ...
         def __sub__(self, x: i64) -> i64: ...

From 9ca303501ecbb2f235b75961d3711c6fce657c0f Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Mon, 23 Jan 2023 19:19:08 +0000
Subject: [PATCH 204/231] Fix strict equality check if operand item type has
 custom __eq__ (#14513)

Don't complain about comparing lists, variable-length tuples or sets if
one of the operands has an item type with a custom `__eq__` method.

Fix #14511.
---
 mypy/checkexpr.py                     | 38 +++++++++++++++------------
 test-data/unit/check-expressions.test | 18 +++++++++++++
 test-data/unit/fixtures/bool.pyi      |  2 +-
 test-data/unit/fixtures/set.pyi       |  1 +
 4 files changed, 41 insertions(+), 18 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index c2cf226ef210c..8dea7d0e85512 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -2988,20 +2988,14 @@ def visit_comparison_expr(self, e: ComparisonExpr) -> Type:
                 # testCustomEqCheckStrictEquality for an example.
                 if not w.has_new_errors() and operator in ("==", "!="):
                     right_type = self.accept(right)
-                    # We suppress the error if there is a custom __eq__() method on either
-                    # side. User defined (or even standard library) classes can define this
-                    # to return True for comparisons between non-overlapping types.
-                    if not custom_special_method(
-                        left_type, "__eq__"
-                    ) and not custom_special_method(right_type, "__eq__"):
-                        # Also flag non-overlapping literals in situations like:
-                        #    x: Literal['a', 'b']
-                        #    if x == 'c':
-                        #        ...
-                        left_type = try_getting_literal(left_type)
-                        right_type = try_getting_literal(right_type)
-                        if self.dangerous_comparison(left_type, right_type):
-                            self.msg.dangerous_comparison(left_type, right_type, "equality", e)
+                    # Also flag non-overlapping literals in situations like:
+                    #    x: Literal['a', 'b']
+                    #    if x == 'c':
+                    #        ...
+                    left_type = try_getting_literal(left_type)
+                    right_type = try_getting_literal(right_type)
+                    if self.dangerous_comparison(left_type, right_type):
+                        self.msg.dangerous_comparison(left_type, right_type, "equality", e)
 
             elif operator == "is" or operator == "is not":
                 right_type = self.accept(right)  # validate the right operand
@@ -3064,6 +3058,12 @@ def dangerous_comparison(
 
         left, right = get_proper_types((left, right))
 
+        # We suppress the error if there is a custom __eq__() method on either
+        # side. User defined (or even standard library) classes can define this
+        # to return True for comparisons between non-overlapping types.
+        if custom_special_method(left, "__eq__") or custom_special_method(right, "__eq__"):
+            return False
+
         if self.chk.binder.is_unreachable_warning_suppressed():
             # We are inside a function that contains type variables with value restrictions in
             # its signature. In this case we just suppress all strict-equality checks to avoid
@@ -3094,14 +3094,18 @@ def dangerous_comparison(
             return False
         if isinstance(left, Instance) and isinstance(right, Instance):
             # Special case some builtin implementations of AbstractSet.
+            left_name = left.type.fullname
+            right_name = right.type.fullname
             if (
-                left.type.fullname in OVERLAPPING_TYPES_ALLOWLIST
-                and right.type.fullname in OVERLAPPING_TYPES_ALLOWLIST
+                left_name in OVERLAPPING_TYPES_ALLOWLIST
+                and right_name in OVERLAPPING_TYPES_ALLOWLIST
             ):
                 abstract_set = self.chk.lookup_typeinfo("typing.AbstractSet")
                 left = map_instance_to_supertype(left, abstract_set)
                 right = map_instance_to_supertype(right, abstract_set)
-                return not is_overlapping_types(left.args[0], right.args[0])
+                return self.dangerous_comparison(left.args[0], right.args[0])
+            elif left_name in ("builtins.list", "builtins.tuple") and right_name == left_name:
+                return self.dangerous_comparison(left.args[0], right.args[0])
         if isinstance(left, LiteralType) and isinstance(right, LiteralType):
             if isinstance(left.value, bool) and isinstance(right.value, bool):
                 # Comparing different booleans is not dangerous.
diff --git a/test-data/unit/check-expressions.test b/test-data/unit/check-expressions.test
index 78ef78e9ad980..20ccbb17d5d5e 100644
--- a/test-data/unit/check-expressions.test
+++ b/test-data/unit/check-expressions.test
@@ -1985,6 +1985,24 @@ class B:
 A() == B()  # E: Unsupported operand types for == ("A" and "B")
 [builtins fixtures/bool.pyi]
 
+[case testStrictEqualitySequenceAndCustomEq]
+# flags: --strict-equality
+from typing import Tuple
+
+class C: pass
+class D:
+    def __eq__(self, other): return True
+
+a = [C()]
+b = [D()]
+a == b
+b == a
+t1: Tuple[C, ...]
+t2: Tuple[D, ...]
+t1 == t2
+t2 == t1
+[builtins fixtures/bool.pyi]
+
 [case testCustomEqCheckStrictEqualityOKInstance]
 # flags: --strict-equality
 class A:
diff --git a/test-data/unit/fixtures/bool.pyi b/test-data/unit/fixtures/bool.pyi
index 245526d789072..c48efcbd72692 100644
--- a/test-data/unit/fixtures/bool.pyi
+++ b/test-data/unit/fixtures/bool.pyi
@@ -16,5 +16,5 @@ class float: pass
 class str: pass
 class unicode: pass
 class ellipsis: pass
-class list: pass
+class list(Generic[T]): pass
 class property: pass
diff --git a/test-data/unit/fixtures/set.pyi b/test-data/unit/fixtures/set.pyi
index 9852bbc9fcc62..d397d4f54af2b 100644
--- a/test-data/unit/fixtures/set.pyi
+++ b/test-data/unit/fixtures/set.pyi
@@ -6,6 +6,7 @@ T = TypeVar('T')
 
 class object:
     def __init__(self) -> None: pass
+    def __eq__(self, other): pass
 
 class type: pass
 class tuple(Generic[T]): pass

From eee3a2a9fdfa1cce7f031ef362570ab3ba5d9790 Mon Sep 17 00:00:00 2001
From: Lakshay Bisht <lakshaybisht.777@gmail.com>
Date: Tue, 24 Jan 2023 18:51:16 +0530
Subject: [PATCH 205/231] Remove references to unicode under test-data/unit
 (#14515)

Fixes #14512.
---
 test-data/unit/fixtures/attr.pyi         | 1 -
 test-data/unit/fixtures/bool.pyi         | 1 -
 test-data/unit/fixtures/dict.pyi         | 1 -
 test-data/unit/fixtures/exception.pyi    | 1 -
 test-data/unit/fixtures/ops.pyi          | 2 --
 test-data/unit/fixtures/staticmethod.pyi | 1 -
 test-data/unit/fixtures/tuple.pyi        | 1 -
 test-data/unit/fixtures/type.pyi         | 1 -
 test-data/unit/lib-stub/__builtin__.pyi  | 1 -
 9 files changed, 10 deletions(-)

diff --git a/test-data/unit/fixtures/attr.pyi b/test-data/unit/fixtures/attr.pyi
index c209abfef0d97..3ac535c211082 100644
--- a/test-data/unit/fixtures/attr.pyi
+++ b/test-data/unit/fixtures/attr.pyi
@@ -23,6 +23,5 @@ class complex:
     def __init__(self, real: str = ...) -> None: ...
 
 class str: pass
-class unicode: pass
 class ellipsis: pass
 class tuple: pass
diff --git a/test-data/unit/fixtures/bool.pyi b/test-data/unit/fixtures/bool.pyi
index c48efcbd72692..0f6e1a174c7bd 100644
--- a/test-data/unit/fixtures/bool.pyi
+++ b/test-data/unit/fixtures/bool.pyi
@@ -14,7 +14,6 @@ class int: pass
 class bool(int): pass
 class float: pass
 class str: pass
-class unicode: pass
 class ellipsis: pass
 class list(Generic[T]): pass
 class property: pass
diff --git a/test-data/unit/fixtures/dict.pyi b/test-data/unit/fixtures/dict.pyi
index 856b8b7266c11..153832411f50c 100644
--- a/test-data/unit/fixtures/dict.pyi
+++ b/test-data/unit/fixtures/dict.pyi
@@ -41,7 +41,6 @@ class int: # for convenience
     imag: int
 
 class str: pass # for keyword argument key type
-class unicode: pass # needed for py2 docstrings
 class bytes: pass
 
 class list(Sequence[T]): # needed by some test cases
diff --git a/test-data/unit/fixtures/exception.pyi b/test-data/unit/fixtures/exception.pyi
index 1c88723e71918..70e3b19c4149f 100644
--- a/test-data/unit/fixtures/exception.pyi
+++ b/test-data/unit/fixtures/exception.pyi
@@ -11,7 +11,6 @@ class tuple(Generic[T]):
 class function: pass
 class int: pass
 class str: pass
-class unicode: pass
 class bool: pass
 class ellipsis: pass
 
diff --git a/test-data/unit/fixtures/ops.pyi b/test-data/unit/fixtures/ops.pyi
index d5845aba43c63..2b29414448cf4 100644
--- a/test-data/unit/fixtures/ops.pyi
+++ b/test-data/unit/fixtures/ops.pyi
@@ -33,8 +33,6 @@ class str:
     def startswith(self, x: 'str') -> bool: pass
     def strip(self) -> 'str': pass
 
-class unicode: pass
-
 class int:
     def __add__(self, x: 'int') -> 'int': pass
     def __radd__(self, x: 'int') -> 'int': pass
diff --git a/test-data/unit/fixtures/staticmethod.pyi b/test-data/unit/fixtures/staticmethod.pyi
index 7d5d98634e480..08fbda8ccf8ff 100644
--- a/test-data/unit/fixtures/staticmethod.pyi
+++ b/test-data/unit/fixtures/staticmethod.pyi
@@ -16,6 +16,5 @@ class int:
     def from_bytes(bytes: bytes, byteorder: str) -> int: pass
 
 class str: pass
-class unicode: pass
 class bytes: pass
 class ellipsis: pass
diff --git a/test-data/unit/fixtures/tuple.pyi b/test-data/unit/fixtures/tuple.pyi
index 14e6683751755..60e47dd022201 100644
--- a/test-data/unit/fixtures/tuple.pyi
+++ b/test-data/unit/fixtures/tuple.pyi
@@ -37,7 +37,6 @@ class bool(int): pass
 class str: pass # For convenience
 class bytes: pass
 class bytearray: pass
-class unicode: pass
 
 class list(Sequence[T], Generic[T]):
     @overload
diff --git a/test-data/unit/fixtures/type.pyi b/test-data/unit/fixtures/type.pyi
index 33dfb5475efa4..39357a693638b 100644
--- a/test-data/unit/fixtures/type.pyi
+++ b/test-data/unit/fixtures/type.pyi
@@ -24,5 +24,4 @@ class function: pass
 class bool: pass
 class int: pass
 class str: pass
-class unicode: pass
 class ellipsis: pass
diff --git a/test-data/unit/lib-stub/__builtin__.pyi b/test-data/unit/lib-stub/__builtin__.pyi
index e7109a179aacc..f9ee7b74011dd 100644
--- a/test-data/unit/lib-stub/__builtin__.pyi
+++ b/test-data/unit/lib-stub/__builtin__.pyi
@@ -18,7 +18,6 @@ class int: pass
 class float: pass
 
 class str: pass
-class unicode: pass
 
 class tuple(Generic[_T]): pass
 class function: pass

From 8b309132188ebbcb889300f9f2fc9bc47df3a3bd Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Tue, 24 Jan 2023 07:27:57 -0800
Subject: [PATCH 206/231] [used before def] rework builtin handling (#14483)

When doing multiple passes, in the example below, `range` will refer to
current's module range. When doing a single pass, `range` will refer to
`builtins.range`:
```python
_range = range
_C = C  # error: Name "C" is used before definition
class range: pass
class C: pass
```

Instead of looking at the output of semanal to check if a variable is
resolving to a `builtins` package, we can just check if it's part of
builtins module.

Fixes #14476.
---
 mypy/build.py                                |  5 ++++-
 mypy/partially_defined.py                    | 20 +++++++++++++-------
 test-data/unit/check-possibly-undefined.test | 10 ++++++++++
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/mypy/build.py b/mypy/build.py
index 1747c4518c632..a4817d1866c7e 100644
--- a/mypy/build.py
+++ b/mypy/build.py
@@ -2359,7 +2359,10 @@ def detect_possibly_undefined_vars(self) -> None:
         ) or manager.errors.is_error_code_enabled(codes.USED_BEFORE_DEF):
             self.tree.accept(
                 PossiblyUndefinedVariableVisitor(
-                    MessageBuilder(manager.errors, manager.modules), self.type_map(), self.options
+                    MessageBuilder(manager.errors, manager.modules),
+                    self.type_map(),
+                    self.options,
+                    self.tree.names,
                 )
             )
 
diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index 9a58df04371f8..af09493c9cae2 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -27,12 +27,13 @@
     ListExpr,
     Lvalue,
     MatchStmt,
+    MypyFile,
     NameExpr,
     NonlocalDecl,
     RaiseStmt,
-    RefExpr,
     ReturnStmt,
     StarExpr,
+    SymbolTable,
     TryStmt,
     TupleExpr,
     WhileStmt,
@@ -286,10 +287,6 @@ def is_undefined(self, name: str) -> bool:
         return self._scope().branch_stmts[-1].is_undefined(name)
 
 
-def refers_to_builtin(o: RefExpr) -> bool:
-    return o.fullname.startswith("builtins.")
-
-
 class Loop:
     def __init__(self) -> None:
         self.has_break = False
@@ -314,11 +311,20 @@ class PossiblyUndefinedVariableVisitor(ExtendedTraverserVisitor):
     """
 
     def __init__(
-        self, msg: MessageBuilder, type_map: dict[Expression, Type], options: Options
+        self,
+        msg: MessageBuilder,
+        type_map: dict[Expression, Type],
+        options: Options,
+        names: SymbolTable,
     ) -> None:
         self.msg = msg
         self.type_map = type_map
         self.options = options
+        self.builtins = SymbolTable()
+        builtins_mod = names.get("__builtins__", None)
+        if builtins_mod:
+            assert isinstance(builtins_mod.node, MypyFile)
+            self.builtins = builtins_mod.node.names
         self.loops: list[Loop] = []
         self.try_depth = 0
         self.tracker = DefinedVariableTracker()
@@ -597,7 +603,7 @@ def visit_starred_pattern(self, o: StarredPattern) -> None:
         super().visit_starred_pattern(o)
 
     def visit_name_expr(self, o: NameExpr) -> None:
-        if refers_to_builtin(o):
+        if o.name in self.builtins:
             return
         if self.tracker.is_possibly_undefined(o.name):
             # A variable is only defined in some branches.
diff --git a/test-data/unit/check-possibly-undefined.test b/test-data/unit/check-possibly-undefined.test
index 802635c30b35a..29c4868e97aff 100644
--- a/test-data/unit/check-possibly-undefined.test
+++ b/test-data/unit/check-possibly-undefined.test
@@ -909,6 +909,16 @@ def f0() -> None:
     type = "abc"
     a = type
 
+[case testUsedBeforeDefBuiltinsMultipass]
+# flags: --enable-error-code used-before-def
+
+# When doing multiple passes, mypy resolves references slightly differently.
+# In this case, it would refer the earlier `type` call to the range class defined below.
+_type = type  # No error
+_C = C  # E: Name "C" is used before definition
+class type: pass
+class C: pass
+
 [case testUsedBeforeDefImplicitModuleAttrs]
 # flags: --enable-error-code used-before-def
 a = __name__  # No error.

From 757e0d4894d68b43810d5723ad496c268a850468 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 24 Jan 2023 16:40:24 +0000
Subject: [PATCH 207/231] [mypyc] Support inheriting native int attributes from
 traits (#14490)

Regular trait attributes are accessed via looking up the field offset
from a vtable. This doesn't work with native ints, since they may also
require access to a defined attributes bitmap, and also looking that up
from a vtable would be too complicated.

Work around this may always accessing trait native int attributes using
accessor methods. These can raise an exception if an attribute is
undefined.

Add empty accessor methods in traits for each attribute with overlapping
error values. Also synthesize real accessors in each concrete subclass.

When accessing the attribute using a concrete subclass, still prefer
direct field and bitmap access. Only attribute access through a trait
type requires accessors to be used.

Work on mypyc/mypyc#837.
---
 mypyc/analysis/attrdefined.py |  9 +++++
 mypyc/codegen/emitfunc.py     |  3 +-
 mypyc/ir/class_ir.py          |  7 ++--
 mypyc/irbuild/classdef.py     |  6 ++--
 mypyc/irbuild/function.py     | 18 +++++++---
 mypyc/irbuild/prepare.py      | 23 ++++++++++++-
 mypyc/irbuild/vtable.py       |  4 +--
 mypyc/test-data/run-i64.test  | 62 +++++++++++++++++++++++++++++++++++
 8 files changed, 119 insertions(+), 13 deletions(-)

diff --git a/mypyc/analysis/attrdefined.py b/mypyc/analysis/attrdefined.py
index 1368b7f5315fc..02e02a82a4f99 100644
--- a/mypyc/analysis/attrdefined.py
+++ b/mypyc/analysis/attrdefined.py
@@ -415,6 +415,9 @@ def update_always_defined_attrs_using_subclasses(cl: ClassIR, seen: set[ClassIR]
 
 
 def detect_undefined_bitmap(cl: ClassIR, seen: Set[ClassIR]) -> None:
+    if cl.is_trait:
+        return
+
     if cl in seen:
         return
     seen.add(cl)
@@ -426,3 +429,9 @@ def detect_undefined_bitmap(cl: ClassIR, seen: Set[ClassIR]) -> None:
     for n, t in cl.attributes.items():
         if t.error_overlap and not cl.is_always_defined(n):
             cl.bitmap_attrs.append(n)
+
+    for base in cl.mro[1:]:
+        if base.is_trait:
+            for n, t in base.attributes.items():
+                if t.error_overlap and not cl.is_always_defined(n) and n not in cl.bitmap_attrs:
+                    cl.bitmap_attrs.append(n)
diff --git a/mypyc/codegen/emitfunc.py b/mypyc/codegen/emitfunc.py
index 534c4d1f20eaf..56a22447eeac2 100644
--- a/mypyc/codegen/emitfunc.py
+++ b/mypyc/codegen/emitfunc.py
@@ -330,7 +330,8 @@ def visit_get_attr(self, op: GetAttr) -> None:
         rtype = op.class_type
         cl = rtype.class_ir
         attr_rtype, decl_cl = cl.attr_details(op.attr)
-        if cl.get_method(op.attr):
+        prefer_method = cl.is_trait and attr_rtype.error_overlap
+        if cl.get_method(op.attr, prefer_method=prefer_method):
             # Properties are essentially methods, so use vtable access for them.
             version = "_TRAIT" if cl.is_trait else ""
             self.emit_line(
diff --git a/mypyc/ir/class_ir.py b/mypyc/ir/class_ir.py
index 9b73eea3f8e6f..a1534780b79ba 100644
--- a/mypyc/ir/class_ir.py
+++ b/mypyc/ir/class_ir.py
@@ -294,10 +294,13 @@ def get_method_and_class(
 
         return None
 
-    def get_method(self, name: str) -> FuncIR | None:
-        res = self.get_method_and_class(name)
+    def get_method(self, name: str, *, prefer_method: bool = False) -> FuncIR | None:
+        res = self.get_method_and_class(name, prefer_method=prefer_method)
         return res[0] if res else None
 
+    def has_method_decl(self, name: str) -> bool:
+        return any(name in ir.method_decls for ir in self.mro)
+
     def subclasses(self) -> set[ClassIR] | None:
         """Return all subclasses of this class, both direct and indirect.
 
diff --git a/mypyc/irbuild/classdef.py b/mypyc/irbuild/classdef.py
index 4e4263458b3e1..59b1c05a0ddbd 100644
--- a/mypyc/irbuild/classdef.py
+++ b/mypyc/irbuild/classdef.py
@@ -161,14 +161,16 @@ def transform_class_def(builder: IRBuilder, cdef: ClassDef) -> None:
     # Generate implicit property setters/getters
     for name, decl in ir.method_decls.items():
         if decl.implicit and decl.is_prop_getter:
-            getter_ir = gen_property_getter_ir(builder, decl, cdef)
+            getter_ir = gen_property_getter_ir(builder, decl, cdef, ir.is_trait)
             builder.functions.append(getter_ir)
             ir.methods[getter_ir.decl.name] = getter_ir
 
             setter_ir = None
             setter_name = PROPSET_PREFIX + name
             if setter_name in ir.method_decls:
-                setter_ir = gen_property_setter_ir(builder, ir.method_decls[setter_name], cdef)
+                setter_ir = gen_property_setter_ir(
+                    builder, ir.method_decls[setter_name], cdef, ir.is_trait
+                )
                 builder.functions.append(setter_ir)
                 ir.methods[setter_name] = setter_ir
 
diff --git a/mypyc/irbuild/function.py b/mypyc/irbuild/function.py
index 523f8c299c2fd..5262b74e2853c 100644
--- a/mypyc/irbuild/function.py
+++ b/mypyc/irbuild/function.py
@@ -1028,7 +1028,9 @@ def get_native_impl_ids(builder: IRBuilder, singledispatch_func: FuncDef) -> dic
     return {impl: i for i, (typ, impl) in enumerate(impls) if not is_decorated(builder, impl)}
 
 
-def gen_property_getter_ir(builder: IRBuilder, func_decl: FuncDecl, cdef: ClassDef) -> FuncIR:
+def gen_property_getter_ir(
+    builder: IRBuilder, func_decl: FuncDecl, cdef: ClassDef, is_trait: bool
+) -> FuncIR:
     """Generate an implicit trivial property getter for an attribute.
 
     These are used if an attribute can also be accessed as a property.
@@ -1036,13 +1038,18 @@ def gen_property_getter_ir(builder: IRBuilder, func_decl: FuncDecl, cdef: ClassD
     name = func_decl.name
     builder.enter(name)
     self_reg = builder.add_argument("self", func_decl.sig.args[0].type)
-    value = builder.builder.get_attr(self_reg, name, func_decl.sig.ret_type, -1)
-    builder.add(Return(value))
+    if not is_trait:
+        value = builder.builder.get_attr(self_reg, name, func_decl.sig.ret_type, -1)
+        builder.add(Return(value))
+    else:
+        builder.add(Unreachable())
     args, _, blocks, ret_type, fn_info = builder.leave()
     return FuncIR(func_decl, args, blocks)
 
 
-def gen_property_setter_ir(builder: IRBuilder, func_decl: FuncDecl, cdef: ClassDef) -> FuncIR:
+def gen_property_setter_ir(
+    builder: IRBuilder, func_decl: FuncDecl, cdef: ClassDef, is_trait: bool
+) -> FuncIR:
     """Generate an implicit trivial property setter for an attribute.
 
     These are used if an attribute can also be accessed as a property.
@@ -1053,7 +1060,8 @@ def gen_property_setter_ir(builder: IRBuilder, func_decl: FuncDecl, cdef: ClassD
     value_reg = builder.add_argument("value", func_decl.sig.args[1].type)
     assert name.startswith(PROPSET_PREFIX)
     attr_name = name[len(PROPSET_PREFIX) :]
-    builder.add(SetAttr(self_reg, attr_name, value_reg, -1))
+    if not is_trait:
+        builder.add(SetAttr(self_reg, attr_name, value_reg, -1))
     builder.add(Return(builder.none()))
     args, _, blocks, ret_type, fn_info = builder.leave()
     return FuncIR(func_decl, args, blocks)
diff --git a/mypyc/irbuild/prepare.py b/mypyc/irbuild/prepare.py
index eb8288b848182..3c519c3d1c33d 100644
--- a/mypyc/irbuild/prepare.py
+++ b/mypyc/irbuild/prepare.py
@@ -305,7 +305,15 @@ def prepare_methods_and_attributes(
         if isinstance(node.node, Var):
             assert node.node.type, "Class member %s missing type" % name
             if not node.node.is_classvar and name not in ("__slots__", "__deletable__"):
-                ir.attributes[name] = mapper.type_to_rtype(node.node.type)
+                attr_rtype = mapper.type_to_rtype(node.node.type)
+                if ir.is_trait and attr_rtype.error_overlap:
+                    # Traits don't have attribute definedness bitmaps, so use
+                    # property accessor methods to access attributes that need them.
+                    # We will generate accessor implementations that use the class bitmap
+                    # for any concrete subclasses.
+                    add_getter_declaration(ir, name, attr_rtype, module_name)
+                    add_setter_declaration(ir, name, attr_rtype, module_name)
+                ir.attributes[name] = attr_rtype
         elif isinstance(node.node, (FuncDef, Decorator)):
             prepare_method_def(ir, module_name, cdef, mapper, node.node)
         elif isinstance(node.node, OverloadedFuncDef):
@@ -329,11 +337,20 @@ def prepare_methods_and_attributes(
 def prepare_implicit_property_accessors(
     info: TypeInfo, ir: ClassIR, module_name: str, mapper: Mapper
 ) -> None:
+    concrete_attributes = set()
     for base in ir.base_mro:
         for name, attr_rtype in base.attributes.items():
+            concrete_attributes.add(name)
             add_property_methods_for_attribute_if_needed(
                 info, ir, name, attr_rtype, module_name, mapper
             )
+    for base in ir.mro[1:]:
+        if base.is_trait:
+            for name, attr_rtype in base.attributes.items():
+                if name not in concrete_attributes:
+                    add_property_methods_for_attribute_if_needed(
+                        info, ir, name, attr_rtype, module_name, mapper
+                    )
 
 
 def add_property_methods_for_attribute_if_needed(
@@ -350,6 +367,7 @@ def add_property_methods_for_attribute_if_needed(
     """
     for base in info.mro[1:]:
         if base in mapper.type_to_ir:
+            base_ir = mapper.type_to_ir[base]
             n = base.names.get(attr_name)
             if n is None:
                 continue
@@ -361,6 +379,9 @@ def add_property_methods_for_attribute_if_needed(
                 # Defined as a read-write property in base class/trait
                 add_getter_declaration(ir, attr_name, attr_rtype, module_name)
                 add_setter_declaration(ir, attr_name, attr_rtype, module_name)
+            elif base_ir.is_trait and attr_rtype.error_overlap:
+                add_getter_declaration(ir, attr_name, attr_rtype, module_name)
+                add_setter_declaration(ir, attr_name, attr_rtype, module_name)
 
 
 def add_getter_declaration(
diff --git a/mypyc/irbuild/vtable.py b/mypyc/irbuild/vtable.py
index 13bc4d46e15df..2d4f7261e4ca6 100644
--- a/mypyc/irbuild/vtable.py
+++ b/mypyc/irbuild/vtable.py
@@ -40,7 +40,7 @@ def compute_vtable(cls: ClassIR) -> None:
     for t in [cls] + cls.traits:
         for fn in itertools.chain(t.methods.values()):
             # TODO: don't generate a new entry when we overload without changing the type
-            if fn == cls.get_method(fn.name):
+            if fn == cls.get_method(fn.name, prefer_method=True):
                 cls.vtable[fn.name] = len(entries)
                 # If the class contains a glue method referring to itself, that is a
                 # shadow glue method to support interpreted subclasses.
@@ -60,7 +60,7 @@ def specialize_parent_vtable(cls: ClassIR, parent: ClassIR) -> VTableEntries:
     for entry in parent.vtable_entries:
         # Find the original method corresponding to this vtable entry.
         # (This may not be the method in the entry, if it was overridden.)
-        orig_parent_method = entry.cls.get_method(entry.name)
+        orig_parent_method = entry.cls.get_method(entry.name, prefer_method=True)
         assert orig_parent_method
         method_cls = cls.get_method_and_class(entry.name, prefer_method=True)
         if method_cls:
diff --git a/mypyc/test-data/run-i64.test b/mypyc/test-data/run-i64.test
index 0fc4b91330d49..d0f0fed4aabed 100644
--- a/mypyc/test-data/run-i64.test
+++ b/mypyc/test-data/run-i64.test
@@ -1433,3 +1433,65 @@ def test_read_only_property_in_trait_implemented_as_property() -> None:
     assert t.x == 6
     with assertRaises(TypeError):
         t.y
+
+@trait
+class T2:
+    x: i64
+    y: i64
+
+class C2(T2):
+    pass
+
+def test_inherit_trait_attribute() -> None:
+    c = C2()
+    c.x = 5
+    assert c.x == 5
+    c.x = MAGIC
+    assert c.x == MAGIC
+    with assertRaises(AttributeError):
+        c.y
+    c.y = 6
+    assert c.y == 6
+    t: T2 = C2()
+    with assertRaises(AttributeError):
+        t.y
+    t = c
+    assert t.x == MAGIC
+    c.x = 55
+    assert t.x == 55
+    assert t.y == 6
+    a: Any = c
+    assert a.x == 55
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8
+
+class D2(T2):
+    x: i64
+    y: i64 = 4
+
+def test_implement_trait_attribute() -> None:
+    d = D2()
+    d.x = 5
+    assert d.x == 5
+    d.x = MAGIC
+    assert d.x == MAGIC
+    assert d.y == 4
+    d.y = 6
+    assert d.y == 6
+    t: T2 = D2()
+    assert t.y == 4
+    t = d
+    assert t.x == MAGIC
+    d.x = 55
+    assert t.x == 55
+    assert t.y == 6
+    a: Any = d
+    assert a.x == 55
+    assert a.y == 6
+    a.x = 7
+    a.y = 8
+    assert a.x == 7
+    assert a.y == 8

From 0665ce924290dad3f30010b3bb93310a71c8db81 Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Tue, 24 Jan 2023 17:46:17 +0000
Subject: [PATCH 208/231] Fix strict equality with enum type with custom __eq__
 (#14518)

Fixes regression introduced in #14513.
---
 mypy/checkexpr.py                     | 31 ++++++++++++++++++---------
 test-data/unit/check-expressions.test | 26 ++++++++++++++++++++++
 2 files changed, 47 insertions(+), 10 deletions(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index 8dea7d0e85512..e19d48f4f5e74 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -2970,7 +2970,7 @@ def visit_comparison_expr(self, e: ComparisonExpr) -> Type:
                     not local_errors.has_new_errors()
                     and cont_type
                     and self.dangerous_comparison(
-                        left_type, cont_type, original_container=right_type
+                        left_type, cont_type, original_container=right_type, prefer_literal=False
                     )
                 ):
                     self.msg.dangerous_comparison(left_type, cont_type, "container", e)
@@ -2988,21 +2988,19 @@ def visit_comparison_expr(self, e: ComparisonExpr) -> Type:
                 # testCustomEqCheckStrictEquality for an example.
                 if not w.has_new_errors() and operator in ("==", "!="):
                     right_type = self.accept(right)
-                    # Also flag non-overlapping literals in situations like:
-                    #    x: Literal['a', 'b']
-                    #    if x == 'c':
-                    #        ...
-                    left_type = try_getting_literal(left_type)
-                    right_type = try_getting_literal(right_type)
                     if self.dangerous_comparison(left_type, right_type):
+                        # Show the most specific literal types possible
+                        left_type = try_getting_literal(left_type)
+                        right_type = try_getting_literal(right_type)
                         self.msg.dangerous_comparison(left_type, right_type, "equality", e)
 
             elif operator == "is" or operator == "is not":
                 right_type = self.accept(right)  # validate the right operand
                 sub_result = self.bool_type()
-                left_type = try_getting_literal(left_type)
-                right_type = try_getting_literal(right_type)
                 if self.dangerous_comparison(left_type, right_type):
+                    # Show the most specific literal types possible
+                    left_type = try_getting_literal(left_type)
+                    right_type = try_getting_literal(right_type)
                     self.msg.dangerous_comparison(left_type, right_type, "identity", e)
                 method_type = None
             else:
@@ -3036,7 +3034,12 @@ def find_partial_type_ref_fast_path(self, expr: Expression) -> Type | None:
         return None
 
     def dangerous_comparison(
-        self, left: Type, right: Type, original_container: Type | None = None
+        self,
+        left: Type,
+        right: Type,
+        original_container: Type | None = None,
+        *,
+        prefer_literal: bool = True,
     ) -> bool:
         """Check for dangerous non-overlapping comparisons like 42 == 'no'.
 
@@ -3064,6 +3067,14 @@ def dangerous_comparison(
         if custom_special_method(left, "__eq__") or custom_special_method(right, "__eq__"):
             return False
 
+        if prefer_literal:
+            # Also flag non-overlapping literals in situations like:
+            #    x: Literal['a', 'b']
+            #    if x == 'c':
+            #        ...
+            left = try_getting_literal(left)
+            right = try_getting_literal(right)
+
         if self.chk.binder.is_unreachable_warning_suppressed():
             # We are inside a function that contains type variables with value restrictions in
             # its signature. In this case we just suppress all strict-equality checks to avoid
diff --git a/test-data/unit/check-expressions.test b/test-data/unit/check-expressions.test
index 20ccbb17d5d5e..49a3f0d4aaa7b 100644
--- a/test-data/unit/check-expressions.test
+++ b/test-data/unit/check-expressions.test
@@ -2221,6 +2221,32 @@ int == y
 y == int
 [builtins fixtures/bool.pyi]
 
+[case testStrictEqualityAndEnumWithCustomEq]
+# flags: --strict-equality
+from enum import Enum
+
+class E1(Enum):
+    X = 0
+    Y = 1
+
+class E2(Enum):
+    X = 0
+    Y = 1
+
+    def __eq__(self, other: object) -> bool:
+        return bool()
+
+E1.X == E1.Y  # E: Non-overlapping equality check (left operand type: "Literal[E1.X]", right operand type: "Literal[E1.Y]")
+E2.X == E2.Y
+[builtins fixtures/bool.pyi]
+
+[case testStrictEqualityWithBytesContains]
+# flags: --strict-equality
+data = b"xy"
+b"x" in data
+[builtins fixtures/primitives.pyi]
+[typing fixtures/typing-full.pyi]
+
 [case testUnimportedHintAny]
 def f(x: Any) -> None:  # E: Name "Any" is not defined \
                         # N: Did you forget to import it from "typing"? (Suggestion: "from typing import Any")

From 425fb0b4cfaa78cd0bf23fd165e4d6a1170670fe Mon Sep 17 00:00:00 2001
From: Alex Waygood <Alex.Waygood@Gmail.com>
Date: Fri, 27 Jan 2023 09:54:05 +0000
Subject: [PATCH 209/231] [1.0 backport] Adjust SCC setup to enable earlier
 collections.abc import in typeshed (#14531)

A backport of #14088 to the `release-1.0` branch.

Co-authored-by: Michael Lee <michael.lee.0x2a@gmail.com>
---
 mypy/semanal.py      | 9 ++++++---
 mypy/semanal_main.py | 9 ++++++++-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/mypy/semanal.py b/mypy/semanal.py
index 34cb45194d19d..45cfb5b13847e 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -615,9 +615,12 @@ def refresh_top_level(self, file_node: MypyFile) -> None:
 
     def add_implicit_module_attrs(self, file_node: MypyFile) -> None:
         """Manually add implicit definitions of module '__name__' etc."""
+        str_type: Type | None = self.named_type_or_none("builtins.str")
+        if str_type is None:
+            str_type = UnboundType("builtins.str")
         for name, t in implicit_module_attrs.items():
             if name == "__doc__":
-                typ: Type = UnboundType("__builtins__.str")
+                typ: Type = str_type
             elif name == "__path__":
                 if not file_node.is_package_init_file():
                     continue
@@ -630,7 +633,7 @@ def add_implicit_module_attrs(self, file_node: MypyFile) -> None:
                 if not isinstance(node, TypeInfo):
                     self.defer(node)
                     return
-                typ = Instance(node, [self.str_type()])
+                typ = Instance(node, [str_type])
             elif name == "__annotations__":
                 sym = self.lookup_qualified("__builtins__.dict", Context(), suppress_errors=True)
                 if not sym:
@@ -639,7 +642,7 @@ def add_implicit_module_attrs(self, file_node: MypyFile) -> None:
                 if not isinstance(node, TypeInfo):
                     self.defer(node)
                     return
-                typ = Instance(node, [self.str_type(), AnyType(TypeOfAny.special_form)])
+                typ = Instance(node, [str_type, AnyType(TypeOfAny.special_form)])
             else:
                 assert t is not None, f"type should be specified for {name}"
                 typ = UnboundType(t)
diff --git a/mypy/semanal_main.py b/mypy/semanal_main.py
index 9e3aeaa7fa4bc..31bcdc2b703d0 100644
--- a/mypy/semanal_main.py
+++ b/mypy/semanal_main.py
@@ -66,7 +66,14 @@
 
 # Number of passes over core modules before going on to the rest of the builtin SCC.
 CORE_WARMUP: Final = 2
-core_modules: Final = ["typing", "builtins", "abc", "collections"]
+core_modules: Final = [
+    "typing",
+    "_collections_abc",
+    "builtins",
+    "abc",
+    "collections",
+    "collections.abc",
+]
 
 
 def semantic_analysis_for_scc(graph: Graph, scc: list[str], errors: Errors) -> None:

From b7c850cdaf8dbd46abaf00df07e9421ed140aed5 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sun, 29 Jan 2023 12:03:31 -0800
Subject: [PATCH 210/231] [1.0 backport] minimal implementation of
 dataclass_transform (#14523) (#14532)

This is a very simple first step to implementing [PEP
0681](https://peps.python.org/pep-0681/#decorator-function-example),
which will allow MyPy to recognize user-defined types that behave
similarly to dataclasses.

This initial implementation is very limited: we only support
decorator-style use of `typing.dataclass_transform` and do not support
passing additional options to the transform (such as `freeze` or
`init`).

Within MyPy, we add a new `is_dataclass_transform` field to `FuncBase`
which is populated during semantic analysis. When we check for plugin
hooks later, we add new special cases to use the existing dataclasses
plugin if a class decorator is marked with `is_dataclass_transform`.
Ideally we would use a proper plugin API; the hacky special case here
can be replaced in subsequent iterations.

Co-authored-by: Wesley Collin Wright <deinlebenandern@gmail.com>
Co-authored-by: Wesley Wright <wesleyw@dropbox.com>
---
 mypy/nodes.py                                 | 10 +++-
 mypy/plugins/common.py                        |  2 +-
 mypy/semanal.py                               | 23 ++++++++--
 mypy/semanal_main.py                          | 14 +++++-
 mypy/semanal_shared.py                        |  5 ++
 mypy/types.py                                 |  5 ++
 test-data/unit/check-dataclass-transform.test | 46 +++++++++++++++++++
 test-data/unit/fixtures/dataclasses.pyi       |  6 ++-
 test-data/unit/fixtures/typing-medium.pyi     |  2 +
 test-data/unit/lib-stub/typing_extensions.pyi |  2 +
 10 files changed, 106 insertions(+), 9 deletions(-)
 create mode 100644 test-data/unit/check-dataclass-transform.test

diff --git a/mypy/nodes.py b/mypy/nodes.py
index 38639d553b3d7..98976f4fe56a6 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -480,7 +480,13 @@ def accept(self, visitor: StatementVisitor[T]) -> T:
         return visitor.visit_import_all(self)
 
 
-FUNCBASE_FLAGS: Final = ["is_property", "is_class", "is_static", "is_final"]
+FUNCBASE_FLAGS: Final = [
+    "is_property",
+    "is_class",
+    "is_static",
+    "is_final",
+    "is_dataclass_transform",
+]
 
 
 class FuncBase(Node):
@@ -506,6 +512,7 @@ class FuncBase(Node):
         "is_static",  # Uses "@staticmethod"
         "is_final",  # Uses "@final"
         "_fullname",
+        "is_dataclass_transform",  # Is decorated with "@typing.dataclass_transform" or similar
     )
 
     def __init__(self) -> None:
@@ -524,6 +531,7 @@ def __init__(self) -> None:
         self.is_final = False
         # Name with module prefix
         self._fullname = ""
+        self.is_dataclass_transform = False
 
     @property
     @abstractmethod
diff --git a/mypy/plugins/common.py b/mypy/plugins/common.py
index 07cd5dc7de7fd..a2a38f256da33 100644
--- a/mypy/plugins/common.py
+++ b/mypy/plugins/common.py
@@ -19,7 +19,7 @@
     Var,
 )
 from mypy.plugin import CheckerPluginInterface, ClassDefContext, SemanticAnalyzerPluginInterface
-from mypy.semanal import ALLOW_INCOMPATIBLE_OVERRIDE, set_callable_name
+from mypy.semanal_shared import ALLOW_INCOMPATIBLE_OVERRIDE, set_callable_name
 from mypy.typeops import (  # noqa: F401  # Part of public API
     try_getting_str_literals as try_getting_str_literals,
 )
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 45cfb5b13847e..15566c9396c64 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -194,6 +194,7 @@
     Plugin,
     SemanticAnalyzerPluginInterface,
 )
+from mypy.plugins import dataclasses as dataclasses_plugin
 from mypy.reachability import (
     ALWAYS_FALSE,
     ALWAYS_TRUE,
@@ -208,6 +209,7 @@
 from mypy.semanal_namedtuple import NamedTupleAnalyzer
 from mypy.semanal_newtype import NewTypeAnalyzer
 from mypy.semanal_shared import (
+    ALLOW_INCOMPATIBLE_OVERRIDE,
     PRIORITY_FALLBACKS,
     SemanticAnalyzerInterface,
     calculate_tuple_fallback,
@@ -234,6 +236,7 @@
 from mypy.typeops import function_type, get_type_vars
 from mypy.types import (
     ASSERT_TYPE_NAMES,
+    DATACLASS_TRANSFORM_NAMES,
     FINAL_DECORATOR_NAMES,
     FINAL_TYPE_NAMES,
     NEVER_NAMES,
@@ -304,10 +307,6 @@
 # available very early on.
 CORE_BUILTIN_CLASSES: Final = ["object", "bool", "function"]
 
-# Subclasses can override these Var attributes with incompatible types. This can also be
-# set for individual attributes using 'allow_incompatible_override' of Var.
-ALLOW_INCOMPATIBLE_OVERRIDE: Final = ("__slots__", "__deletable__", "__match_args__")
-
 
 # Used for tracking incomplete references
 Tag: _TypeAlias = int
@@ -1508,6 +1507,10 @@ def visit_decorator(self, dec: Decorator) -> None:
                     removed.append(i)
                 else:
                     self.fail("@final cannot be used with non-method functions", d)
+            elif isinstance(d, CallExpr) and refers_to_fullname(
+                d.callee, DATACLASS_TRANSFORM_NAMES
+            ):
+                dec.func.is_dataclass_transform = True
             elif not dec.var.is_property:
                 # We have seen a "non-trivial" decorator before seeing @property, if
                 # we will see a @property later, give an error, as we don't support this.
@@ -1709,6 +1712,11 @@ def apply_class_plugin_hooks(self, defn: ClassDef) -> None:
             decorator_name = self.get_fullname_for_hook(decorator)
             if decorator_name:
                 hook = self.plugin.get_class_decorator_hook(decorator_name)
+                # Special case: if the decorator is itself decorated with
+                # typing.dataclass_transform, apply the hook for the dataclasses plugin
+                # TODO: remove special casing here
+                if hook is None and is_dataclass_transform_decorator(decorator):
+                    hook = dataclasses_plugin.dataclass_tag_callback
                 if hook:
                     hook(ClassDefContext(defn, decorator, self))
 
@@ -6599,3 +6607,10 @@ def halt(self, reason: str = ...) -> NoReturn:
     return isinstance(stmt, PassStmt) or (
         isinstance(stmt, ExpressionStmt) and isinstance(stmt.expr, EllipsisExpr)
     )
+
+
+def is_dataclass_transform_decorator(node: Node | None) -> bool:
+    if isinstance(node, RefExpr):
+        return is_dataclass_transform_decorator(node.node)
+
+    return isinstance(node, Decorator) and node.func.is_dataclass_transform
diff --git a/mypy/semanal_main.py b/mypy/semanal_main.py
index 31bcdc2b703d0..d2dd0e32398d3 100644
--- a/mypy/semanal_main.py
+++ b/mypy/semanal_main.py
@@ -37,9 +37,11 @@
 from mypy.nodes import Decorator, FuncDef, MypyFile, OverloadedFuncDef, TypeInfo, Var
 from mypy.options import Options
 from mypy.plugin import ClassDefContext
+from mypy.plugins import dataclasses as dataclasses_plugin
 from mypy.semanal import (
     SemanticAnalyzer,
     apply_semantic_analyzer_patches,
+    is_dataclass_transform_decorator,
     remove_imported_names_from_symtable,
 )
 from mypy.semanal_classprop import (
@@ -457,11 +459,19 @@ def apply_hooks_to_class(
     ok = True
     for decorator in defn.decorators:
         with self.file_context(file_node, options, info):
+            hook = None
+
             decorator_name = self.get_fullname_for_hook(decorator)
             if decorator_name:
                 hook = self.plugin.get_class_decorator_hook_2(decorator_name)
-                if hook:
-                    ok = ok and hook(ClassDefContext(defn, decorator, self))
+            # Special case: if the decorator is itself decorated with
+            # typing.dataclass_transform, apply the hook for the dataclasses plugin
+            # TODO: remove special casing here
+            if hook is None and is_dataclass_transform_decorator(decorator):
+                hook = dataclasses_plugin.dataclass_class_maker_callback
+
+            if hook:
+                ok = ok and hook(ClassDefContext(defn, decorator, self))
     return ok
 
 
diff --git a/mypy/semanal_shared.py b/mypy/semanal_shared.py
index f4bc173b52d59..11c4af314a3b0 100644
--- a/mypy/semanal_shared.py
+++ b/mypy/semanal_shared.py
@@ -38,6 +38,11 @@
     get_proper_type,
 )
 
+# Subclasses can override these Var attributes with incompatible types. This can also be
+# set for individual attributes using 'allow_incompatible_override' of Var.
+ALLOW_INCOMPATIBLE_OVERRIDE: Final = ("__slots__", "__deletable__", "__match_args__")
+
+
 # Priorities for ordering of patches within the "patch" phase of semantic analysis
 # (after the main pass):
 
diff --git a/mypy/types.py b/mypy/types.py
index bf610a01b63b9..74656cc270f3d 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -150,6 +150,11 @@
     "typing_extensions.Never",
 )
 
+DATACLASS_TRANSFORM_NAMES: Final = (
+    "typing.dataclass_transform",
+    "typing_extensions.dataclass_transform",
+)
+
 # A placeholder used for Bogus[...] parameters
 _dummy: Final[Any] = object()
 
diff --git a/test-data/unit/check-dataclass-transform.test b/test-data/unit/check-dataclass-transform.test
new file mode 100644
index 0000000000000..4f907e3186b68
--- /dev/null
+++ b/test-data/unit/check-dataclass-transform.test
@@ -0,0 +1,46 @@
+[case testDataclassTransformReusesDataclassLogic]
+# flags: --python-version 3.7
+from typing import dataclass_transform, Type
+
+@dataclass_transform()
+def my_dataclass(cls: Type) -> Type:
+    return cls
+
+@my_dataclass
+class Person:
+    name: str
+    age: int
+
+    def summary(self):
+        return "%s is %d years old." % (self.name, self.age)
+
+reveal_type(Person)  # N: Revealed type is "def (name: builtins.str, age: builtins.int) -> __main__.Person"
+Person('John', 32)
+Person('Jonh', 21, None)  # E: Too many arguments for "Person"
+
+[typing fixtures/typing-medium.pyi]
+[builtins fixtures/dataclasses.pyi]
+
+[case testDataclassTransformIsFoundInTypingExtensions]
+# flags: --python-version 3.7
+from typing import Type
+from typing_extensions import dataclass_transform
+
+@dataclass_transform()
+def my_dataclass(cls: Type) -> Type:
+    return cls
+
+@my_dataclass
+class Person:
+    name: str
+    age: int
+
+    def summary(self):
+        return "%s is %d years old." % (self.name, self.age)
+
+reveal_type(Person)  # N: Revealed type is "def (name: builtins.str, age: builtins.int) -> __main__.Person"
+Person('John', 32)
+Person('Jonh', 21, None)  # E: Too many arguments for "Person"
+
+[typing fixtures/typing-full.pyi]
+[builtins fixtures/dataclasses.pyi]
diff --git a/test-data/unit/fixtures/dataclasses.pyi b/test-data/unit/fixtures/dataclasses.pyi
index 206843a88b244..7de40af9cfe78 100644
--- a/test-data/unit/fixtures/dataclasses.pyi
+++ b/test-data/unit/fixtures/dataclasses.pyi
@@ -37,7 +37,11 @@ class dict(Mapping[KT, VT]):
     def get(self, k: KT, default: Union[KT, _T]) -> Union[VT, _T]: pass
     def __len__(self) -> int: ...
 
-class list(Generic[_T], Sequence[_T]): pass
+class list(Generic[_T], Sequence[_T]):
+    def __contains__(self, item: object) -> int: pass
+    def __getitem__(self, key: int) -> _T: pass
+    def __iter__(self) -> Iterator[_T]: pass
+
 class function: pass
 class classmethod: pass
 property = object()
diff --git a/test-data/unit/fixtures/typing-medium.pyi b/test-data/unit/fixtures/typing-medium.pyi
index 863b0703989d0..0d0e13468013a 100644
--- a/test-data/unit/fixtures/typing-medium.pyi
+++ b/test-data/unit/fixtures/typing-medium.pyi
@@ -71,3 +71,5 @@ class ContextManager(Generic[T]):
 class _SpecialForm: pass
 
 TYPE_CHECKING = 1
+
+def dataclass_transform() -> Callable[[T], T]: ...
diff --git a/test-data/unit/lib-stub/typing_extensions.pyi b/test-data/unit/lib-stub/typing_extensions.pyi
index cbf692fc71111..89f7108fe83ce 100644
--- a/test-data/unit/lib-stub/typing_extensions.pyi
+++ b/test-data/unit/lib-stub/typing_extensions.pyi
@@ -57,3 +57,5 @@ class _TypedDict(Mapping[str, object]):
 def TypedDict(typename: str, fields: Dict[str, Type[_T]], *, total: Any = ...) -> Type[dict]: ...
 
 def reveal_type(__obj: T) -> T: pass
+
+def dataclass_transform() -> Callable[[T], T]: ...

From 332616cd9d210148a025ae56d1b6b18c321a4fed Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sun, 29 Jan 2023 12:29:34 -0800
Subject: [PATCH 211/231] [1.0 backport] Fix internal crash when resolve same
 partial type twice (#14552) (#14553)

Fixes: #14548

Fixed case when untyped list item type resolving can lead to an internal
crash.

Code to reproduce this issue:
```py
arr = []
arr.append(arr.append(1))
```

Basically, the issue is that after the first resolving of `arr.append`
method, `var` is deleted from `partial_types`, and as war as
`arr.append` is a nested call we try to delete the same `var` that was
already deleted.

Co-authored-by: Yurii Karabas <1998uriyyo@gmail.com>
---
 mypy/checkexpr.py                   | 3 ++-
 test-data/unit/check-inference.test | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
index e19d48f4f5e74..35371de155d76 100644
--- a/mypy/checkexpr.py
+++ b/mypy/checkexpr.py
@@ -895,7 +895,8 @@ def try_infer_partial_type(self, e: CallExpr) -> None:
                 return
             var, partial_types = ret
             typ = self.try_infer_partial_value_type_from_call(e, callee.name, var)
-            if typ is not None:
+            # Var may be deleted from partial_types in try_infer_partial_value_type_from_call
+            if typ is not None and var in partial_types:
                 var.type = typ
                 del partial_types[var]
         elif isinstance(callee.expr, IndexExpr) and isinstance(callee.expr.base, RefExpr):
diff --git a/test-data/unit/check-inference.test b/test-data/unit/check-inference.test
index 331b110fded67..fc8113766f1a9 100644
--- a/test-data/unit/check-inference.test
+++ b/test-data/unit/check-inference.test
@@ -1951,6 +1951,13 @@ class A:
 [out]
 main:4: error: "None" has no attribute "__iter__" (not iterable)
 
+[case testPartialTypeErrorSpecialCase4]
+# This used to crash.
+arr = []
+arr.append(arr.append(1))
+[builtins fixtures/list.pyi]
+[out]
+main:3: error: "append" of "list" does not return a value
 
 -- Multipass
 -- ---------

From 61d6cadf2f104a8100ec05c44d8fccb0636aacf8 Mon Sep 17 00:00:00 2001
From: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Date: Mon, 30 Jan 2023 20:05:13 +0100
Subject: [PATCH 212/231] [1.0 backport] Fix `AttrsInstance` protocol check
 with cache (#14551) (#14558)

---
 mypy/plugins/attrs.py                 |  2 +-
 test-data/unit/fine-grained-attr.test | 34 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/mypy/plugins/attrs.py b/mypy/plugins/attrs.py
index 16e8891e5f575..50d2955d25844 100644
--- a/mypy/plugins/attrs.py
+++ b/mypy/plugins/attrs.py
@@ -828,7 +828,7 @@ def _add_attrs_magic_attribute(
         ctx.cls,
         MAGIC_ATTR_NAME,
         TupleType(attributes_types, fallback=attributes_type),
-        fullname=f"{ctx.cls.fullname}.{attr_name}",
+        fullname=f"{ctx.cls.fullname}.{MAGIC_ATTR_NAME}",
         override_allow_incompatible=True,
         is_classvar=True,
     )
diff --git a/test-data/unit/fine-grained-attr.test b/test-data/unit/fine-grained-attr.test
index fd7c97da06623..3fd40b774c7b4 100644
--- a/test-data/unit/fine-grained-attr.test
+++ b/test-data/unit/fine-grained-attr.test
@@ -46,3 +46,37 @@ A.__attrs_attrs__.b
 
 [out]
 ==
+
+[case magicAttributeConsistency2-only_when_cache]
+[file c.py]
+import attr
+
+@attr.s
+class Entry:
+    var: int = attr.ib()
+[builtins fixtures/attr.pyi]
+
+[file m.py]
+from typing import Any, ClassVar, Protocol
+from c import Entry
+
+class AttrsInstance(Protocol):
+    __attrs_attrs__: ClassVar[Any]
+
+def func(e: AttrsInstance) -> None: ...
+func(Entry(2))
+
+[file m.py.2]
+from typing import Any, ClassVar, Protocol
+from c import Entry
+
+class AttrsInstance(Protocol):
+    __attrs_attrs__: ClassVar[Any]
+
+def func(e: AttrsInstance) -> int:
+    return 2  # Change return type to force reanalysis
+
+func(Entry(2))
+
+[out]
+==

From 319980b24eeb5c7d21a6cfc88b4c6319aed8cfec Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Wed, 1 Feb 2023 22:18:54 -0800
Subject: [PATCH 213/231] [1.0 backport] Fix crash on prefixed paramspec with
 deferral (#14569) (#14586)

Fixes #14565

The fix looks simple, looks like an obvious omission.

Co-authored-by: Ivan Levkivskyi <levkivskyi@gmail.com>
---
 mypy/types.py                                     |  4 ++--
 test-data/unit/check-parameter-specification.test | 15 +++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index 74656cc270f3d..b4710a95164ce 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -713,13 +713,13 @@ def name_with_suffix(self) -> str:
         return n
 
     def __hash__(self) -> int:
-        return hash((self.id, self.flavor))
+        return hash((self.id, self.flavor, self.prefix))
 
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, ParamSpecType):
             return NotImplemented
         # Upper bound can be ignored, since it's determined by flavor.
-        return self.id == other.id and self.flavor == other.flavor
+        return self.id == other.id and self.flavor == other.flavor and self.prefix == other.prefix
 
     def serialize(self) -> JsonDict:
         assert not self.id.is_meta_var()
diff --git a/test-data/unit/check-parameter-specification.test b/test-data/unit/check-parameter-specification.test
index 463ba3e654662..56fc3b6faa14e 100644
--- a/test-data/unit/check-parameter-specification.test
+++ b/test-data/unit/check-parameter-specification.test
@@ -1456,3 +1456,18 @@ class C(Generic[T]): ...
 C[Callable[P, int]]()  # E: The first argument to Callable must be a list of types, parameter specification, or "..." \
                        # N: See https://mypy.readthedocs.io/en/stable/kinds_of_types.html#callable-types-and-lambdas
 [builtins fixtures/paramspec.pyi]
+
+[case testConcatDeferralNoCrash]
+from typing import Callable, TypeVar
+from typing_extensions import Concatenate, ParamSpec
+
+P = ParamSpec("P")
+T = TypeVar("T", bound="Defer")
+
+Alias = Callable[P, bool]
+Concat = Alias[Concatenate[T, P]]
+
+def test(f: Concat[T, ...]) -> None: ...
+
+class Defer: ...
+[builtins fixtures/paramspec.pyi]

From d6a460303441f84358484d3ca2d7ab1ad832a948 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Wed, 1 Feb 2023 11:02:34 -0800
Subject: [PATCH 214/231] More improvements to getting started docs (#14572)

For the most part, this shortens the Getting Started page, which was
getting a little too long to read comfortably and had caveats that
aren't super important.

The cheat sheet does a really great job of "show, don't tell", so
recommend that even more aggressively for beginners. The BankAccount
example was nice, and the cheat sheet was missing a discussion on
inheritance, so move a version of that over there.

Finally, most users of mypy don't need to know the details of typeshed
and stub files, especially not when getting started. So reframe as a
more generic section about types for third party libraries.

Linking #13681
---
 docs/source/cheat_sheet_py3.rst |  67 ++++++---
 docs/source/getting_started.rst | 237 ++++++++------------------------
 docs/source/index.rst           |   2 +-
 docs/source/running_mypy.rst    |   5 +-
 docs/source/stubs.rst           |   7 +-
 5 files changed, 111 insertions(+), 207 deletions(-)

diff --git a/docs/source/cheat_sheet_py3.rst b/docs/source/cheat_sheet_py3.rst
index 7179318e31b84..5aa1770512b85 100644
--- a/docs/source/cheat_sheet_py3.rst
+++ b/docs/source/cheat_sheet_py3.rst
@@ -34,7 +34,9 @@ Useful built-in types
 
 .. code-block:: python
 
-   # For most types, just use the name of the type
+   # For most types, just use the name of the type.
+   # Note that mypy can usually infer the type of a variable from its value,
+   # so technically these annotations are redundant
    x: int = 1
    x: float = 1.0
    x: bool = True
@@ -100,12 +102,18 @@ Functions
    def show(value: str, excitement: int = 10) -> None:
        print(value + "!" * excitement)
 
+    # Note that arguments without a type are dynamically typed (treated as Any)
+    # and that functions without any annotations not checked
+    def untyped(x):
+        x.anything() + 1 + "string"  # no errors
+
    # This is how you annotate a callable (function) value
    x: Callable[[int, float], float] = f
+   def register(callback: Callable[[str], int]) -> None: ...
 
    # A generator function that yields ints is secretly just a function that
    # returns an iterator of ints, so that's how we annotate it
-   def g(n: int) -> Iterator[int]:
+   def gen(n: int) -> Iterator[int]:
        i = 0
        while i < n:
            yield i
@@ -143,28 +151,49 @@ Classes
 
 .. code-block:: python
 
-   class MyClass:
-       # You can optionally declare instance variables in the class body
-       attr: int
-       # This is an instance variable with a default value
-       charge_percent: int = 100
-
+   class BankAccount:
        # The "__init__" method doesn't return anything, so it gets return
        # type "None" just like any other method that doesn't return anything
-       def __init__(self) -> None:
-           ...
+       def __init__(self, account_name: str, initial_balance: int = 0) -> None:
+           # mypy will infer the correct types for these instance variables
+           # based on the types of the parameters.
+           self.account_name = account_name
+           self.balance = initial_balance
 
        # For instance methods, omit type for "self"
-       def my_method(self, num: int, str1: str) -> str:
-           return num * str1
+       def deposit(self, amount: int) -> None:
+           self.balance += amount
+
+       def withdraw(self, amount: int) -> None:
+           self.balance -= amount
 
    # User-defined classes are valid as types in annotations
-   x: MyClass = MyClass()
+   account: BankAccount = BankAccount("Alice", 400)
+   def transfer(src: BankAccount, dst: BankAccount, amount: int) -> None:
+       src.withdraw(amount)
+       dst.deposit(amount)
+
+   # Functions that accept BankAccount also accept any subclass of BankAccount!
+   class AuditedBankAccount(BankAccount):
+       # You can optionally declare instance variables in the class body
+       audit_log: list[str]
+       # This is an instance variable with a default value
+       auditor_name: str = "The Spanish Inquisition"
+
+       def __init__(self, account_name: str, initial_balance: int = 0) -> None:
+           super().__init__(account_name, initial_balance)
+           self.audit_log: list[str] = []
+
+       def deposit(self, amount: int) -> None:
+           self.audit_log.append(f"Deposited {amount}")
+           self.balance += amount
+
+       def withdraw(self, amount: int) -> None:
+           self.audit_log.append(f"Withdrew {amount}")
+           self.balance -= amount
 
-   # You can also declare the type of an attribute in "__init__"
-   class Box:
-       def __init__(self) -> None:
-           self.items: list[str] = []
+   audited = AuditedBankAccount("Bob", 300)
+   transfer(audited, account, 100)  # type checks!
 
    # You can use the ClassVar annotation to declare a class variable
    class Car:
@@ -172,9 +201,7 @@ Classes
        passengers: ClassVar[list[str]]
 
    # If you want dynamic attributes on your class, have it
-   # override "__setattr__" or "__getattr__":
-   # - "__getattr__" allows for dynamic access to names
-   # - "__setattr__" allows for dynamic assignment to names
+   # override "__setattr__" or "__getattr__"
    class A:
        # This will allow assignment to any A.x, if x is the same type as "value"
        # (use "value: Any" to allow arbitrary types)
diff --git a/docs/source/getting_started.rst b/docs/source/getting_started.rst
index db7c18d5e242c..bbe2d25d3b039 100644
--- a/docs/source/getting_started.rst
+++ b/docs/source/getting_started.rst
@@ -132,8 +132,8 @@ may be useful. See :ref:`getting-to-strict` for how to build up to ``--strict``.
 See :ref:`command-line` and :ref:`config-file` for a complete reference on
 configuration options.
 
-Additional types, and the typing module
-***************************************
+More complex types
+******************
 
 So far, we've added type hints that use only basic concrete types like
 ``str`` and ``float``. What if we want to express more complex types,
@@ -159,28 +159,11 @@ accept one or more *type parameters*. In this case, we *parameterized* :py:class
 by writing ``list[str]``. This lets mypy know that ``greet_all`` accepts specifically
 lists containing strings, and not lists containing ints or any other type.
 
-In Python 3.8 and earlier, you can instead import the
-:py:class:`~typing.List` type from the :py:mod:`typing` module:
-
-.. code-block:: python
-
-   from typing import List  # Python 3.8 and earlier
-
-   def greet_all(names: List[str]) -> None:
-       for name in names:
-           print('Hello ' + name)
-
-   ...
-
-You can find many of these more complex static types in the :py:mod:`typing` module.
-
 In the above examples, the type signature is perhaps a little too rigid.
 After all, there's no reason why this function must accept *specifically* a list --
 it would run just fine if you were to pass in a tuple, a set, or any other custom iterable.
 
-You can express this idea using the
-:py:class:`collections.abc.Iterable` (or :py:class:`typing.Iterable` in Python
-3.8 and earlier) type instead of :py:class:`list` :
+You can express this idea using :py:class:`collections.abc.Iterable`:
 
 .. code-block:: python
 
@@ -190,8 +173,19 @@ You can express this idea using the
        for name in names:
            print('Hello ' + name)
 
+This behavior is actually a fundamental aspect of the PEP 484 type system: when
+we annotate some variable with a type ``T``, we are actually telling mypy that
+variable can be assigned an instance of ``T``, or an instance of a *subtype* of ``T``.
+That is, ``list[str]`` is a subtype of ``Iterable[str]``.
+
+This also applies to inheritance, so if you have a class ``Child`` that inherits from
+``Parent``, then a value of type ``Child`` can be assigned to a variable of type ``Parent``.
+For example, a ``RuntimeError`` instance can be passed to a function that is annotated
+as taking an ``Exception``.
+
 As another example, suppose you want to write a function that can accept *either*
-ints or strings, but no other types. You can express this using the :py:data:`~typing.Union` type:
+ints or strings, but no other types. You can express this using the
+:py:data:`~typing.Union` type. For example, ``int`` is a subtype of ``Union[int, str]``:
 
 .. code-block:: python
 
@@ -203,26 +197,12 @@ ints or strings, but no other types. You can express this using the :py:data:`~t
        else:
            return user_id
 
-Similarly, suppose that you want the function to accept only strings or ``None``. You can
-again use :py:data:`~typing.Union` and use ``Union[str, None]`` -- or alternatively, use the type
-``Optional[str]``. These two types are identical and interchangeable: ``Optional[str]``
-is just a shorthand or *alias* for ``Union[str, None]``. It exists mostly as a convenience
-to help function signatures look a little cleaner:
+The :py:mod:`typing` module contains many other useful types.
 
-.. code-block:: python
+For a quick overview, look through the :ref:`mypy cheatsheet <cheat-sheet-py3>`.
 
-   from typing import Optional
-
-   def greeting(name: Optional[str] = None) -> str:
-       # Optional[str] means the same thing as Union[str, None]
-       if name is None:
-           name = 'stranger'
-       return 'Hello, ' + name
-
-The :py:mod:`typing` module contains many other useful types. You can find a
-quick overview by looking through the :ref:`mypy cheatsheet <cheat-sheet-py3>`
-and a more detailed overview (including information on how to make your own
-generic types or your own type aliases) by looking through the
+For a detailed overview (including information on how to make your own
+generic types or your own type aliases), look through the
 :ref:`type system reference <overview-type-system-reference>`.
 
 .. note::
@@ -250,10 +230,7 @@ mypy will try and *infer* as many details as possible.
 
 We saw an example of this in the ``normalize_id`` function above -- mypy understands
 basic :py:func:`isinstance <isinstance>` checks and so can infer that the ``user_id`` variable was of
-type ``int`` in the if-branch and of type ``str`` in the else-branch. Similarly, mypy
-was able to understand that ``name`` could not possibly be ``None`` in the ``greeting``
-function above, based both on the ``name is None`` check and the variable assignment
-in that if statement.
+type ``int`` in the if-branch and of type ``str`` in the else-branch.
 
 As another example, consider the following function. Mypy can type check this function
 without a problem: it will use the available context and deduce that ``output`` must be
@@ -268,114 +245,16 @@ of type ``list[float]`` and that ``num`` must be of type ``float``:
                output.append(num)
        return output
 
-Mypy will warn you if it is unable to determine the type of some variable --
-for example, when assigning an empty dictionary to some global value:
-
-.. code-block:: python
-
-    my_global_dict = {}  # Error: Need type annotation for "my_global_dict"
-
-You can teach mypy what type ``my_global_dict`` is meant to have by giving it
-a type hint. For example, if you knew this variable is supposed to be a dict
-of ints to floats, you could annotate it using either variable annotations
-(introduced in Python 3.6 by :pep:`526`) or using a comment-based
-syntax like so:
-
-.. code-block:: python
-
-   # If you're using Python 3.9+
-   my_global_dict: dict[int, float] = {}
-
-   # If you're using Python 3.6+
-   my_global_dict: Dict[int, float] = {}
-
-
-Types and classes
-*****************
-
-So far, we've only seen examples of pre-existing types like the ``int``
-or ``float`` builtins, or generic types from ``collections.abc`` and
-``typing``, such as ``Iterable``. However, these aren't the only types you can
-use: in fact, you can use any Python class as a type!
-
-For example, suppose you've defined a custom class representing a bank account:
-
-.. code-block:: python
-
-    class BankAccount:
-        # Note: It is ok to omit type hints for the "self" parameter.
-        # Mypy will infer the correct type.
-
-        def __init__(self, account_name: str, initial_balance: int = 0) -> None:
-            # Note: Mypy will infer the correct types of your fields
-            # based on the types of the parameters.
-            self.account_name = account_name
-            self.balance = initial_balance
-
-        def deposit(self, amount: int) -> None:
-            self.balance += amount
-
-        def withdraw(self, amount: int) -> None:
-            self.balance -= amount
-
-        def overdrawn(self) -> bool:
-            return self.balance < 0
+For more details, see :ref:`type-inference-and-annotations`.
 
-You can declare that a function will accept any instance of your class
-by simply annotating the parameters with ``BankAccount``:
-
-.. code-block:: python
-
-    def transfer(src: BankAccount, dst: BankAccount, amount: int) -> None:
-        src.withdraw(amount)
-        dst.deposit(amount)
-
-    account_1 = BankAccount('Alice', 400)
-    account_2 = BankAccount('Bob', 200)
-    transfer(account_1, account_2, 50)
-
-In fact, the ``transfer`` function we wrote above can accept more then just
-instances of ``BankAccount``: it can also accept any instance of a *subclass*
-of ``BankAccount``. For example, suppose you write a new class that looks like this:
-
-.. code-block:: python
-
-    class AuditedBankAccount(BankAccount):
-        def __init__(self, account_name: str, initial_balance: int = 0) -> None:
-            super().__init__(account_name, initial_balance)
-            self.audit_log: list[str] = []
-
-        def deposit(self, amount: int) -> None:
-            self.audit_log.append(f"Deposited {amount}")
-            self.balance += amount
-
-        def withdraw(self, amount: int) -> None:
-            self.audit_log.append(f"Withdrew {amount}")
-            self.balance -= amount
-
-Since ``AuditedBankAccount`` is a subclass of ``BankAccount``, we can directly pass
-in instances of it into our ``transfer`` function:
-
-.. code-block:: python
-
-    audited = AuditedBankAccount('Charlie', 300)
-    transfer(account_1, audited, 100)   # Type checks!
-
-This behavior is actually a fundamental aspect of the PEP 484 type system: when
-we annotate some variable with a type ``T``, we are actually telling mypy that
-variable can be assigned an instance of ``T``, or an instance of a *subclass* of ``T``.
-The same rule applies to type hints on parameters or fields.
-
-See :ref:`class-basics` to learn more about how to work with code involving classes.
-
-
-.. _stubs-intro:
+Types from libraries
+********************
 
-Stubs files and typeshed
-************************
+Mypy can also understand how to work with types from libraries that you use.
 
-Mypy also understands how to work with classes found in the standard library.
-For example, here is a function which uses the ``Path`` object from the
+For instance, mypy comes out of the box with an intimate knowledge of the
+Python standard library. For example, here is a function which uses the
+``Path`` object from the
 `pathlib standard library module <https://docs.python.org/3/library/pathlib.html>`_:
 
 .. code-block:: python
@@ -383,52 +262,43 @@ For example, here is a function which uses the ``Path`` object from the
     from pathlib import Path
 
     def load_template(template_path: Path, name: str) -> str:
-        # Mypy understands that 'file_path.read_text()' returns a str...
+        # Mypy knows that `file_path` has a `read_text` method that returns a str
         template = template_path.read_text()
-
-        # ...so understands this line type checks.
+        # ...so it understands this line type checks
         return template.replace('USERNAME', name)
 
-This behavior may surprise you if you're familiar with how
-Python internally works. The standard library does not use type hints
-anywhere, so how did mypy know that ``Path.read_text()`` returns a ``str``,
-or that ``str.replace(...)`` accepts exactly two ``str`` arguments?
+If a third party library you use :ref:`declares support for type checking <installed-packages>`,
+mypy will type check your use of that library based on the type hints
+it contains.
 
-The answer is that mypy comes bundled with *stub files* from the
-the `typeshed <https://github.com/python/typeshed>`_ project, which
-contains stub files for the Python builtins, the standard library,
-and selected third-party packages.
+However, if the third party library does not have type hints, mypy will
+complain about missing type information.
 
-A *stub file* is a file containing a skeleton of the public interface
-of that Python module, including classes, variables, functions -- and
-most importantly, their types.
+.. code-block:: text
 
-Mypy complains if it can't find a stub (or a real module) for a
-library module that you import. Some modules ship with stubs or inline
-annotations that mypy can automatically find, or you can install
-additional stubs using pip (see :ref:`fix-missing-imports` and
-:ref:`installed-packages` for the details). For example, you can install
-the stubs for the ``requests`` package like this:
+  prog.py:1: error: Library stubs not installed for "yaml"
+  prog.py:1: note: Hint: "python3 -m pip install types-PyYAML"
+  prog.py:2: error: Library stubs not installed for "requests"
+  prog.py:2: note: Hint: "python3 -m pip install types-requests"
+  ...
 
-.. code-block:: shell
+In this case, you can provide mypy a different source of type information,
+by installing a *stub* package. A stub package is a package that contains
+type hints for another library, but no actual code.
 
-  $ python3 -m pip install types-requests
+.. code-block:: shell
 
-The stubs are usually packaged in a distribution named
-``types-<distribution>``.  Note that the distribution name may be
-different from the name of the package that you import. For example,
-``types-PyYAML`` contains stubs for the ``yaml`` package. Mypy can
-often suggest the name of the stub distribution:
+  $ python3 -m pip install types-PyYAML types-requests
 
-.. code-block:: text
+Stubs packages for a distribution are often named ``types-<distribution>``.
+Note that a distribution name may be different from the name of the package that
+you import. For example, ``types-PyYAML`` contains stubs for the ``yaml``
+package.
 
-  prog.py:1: error: Library stubs not installed for "yaml"
-  prog.py:1: note: Hint: "python3 -m pip install types-PyYAML"
-  ...
+For more discussion on strategies for handling errors about libraries without
+type information, refer to :ref:`fix-missing-imports`.
 
-You can also :ref:`create
-stubs <stub-files>` easily. We discuss strategies for handling errors
-about missing stubs in :ref:`ignore-missing-imports`.
+For more information about stubs, see :ref:`stub-files`.
 
 Next steps
 **********
@@ -463,5 +333,8 @@ resources:
   `mypy issue tracker <https://github.com/python/mypy/issues>`_ and
   typing `Gitter chat <https://gitter.im/python/typing>`_.
 
+* For general questions about Python typing, try posting at
+  `typing discussions <https://github.com/python/typing/discussions>`_.
+
 You can also continue reading this document and skip sections that
 aren't relevant for you. You don't need to read sections in order.
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 27b3a078af6c7..3546e1f4efa5c 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -52,8 +52,8 @@ Contents
    :caption: First steps
 
    getting_started
-   existing_code
    cheat_sheet_py3
+   existing_code
 
 .. _overview-type-system-reference:
 
diff --git a/docs/source/running_mypy.rst b/docs/source/running_mypy.rst
index 4a7b5dcf40930..ffc04e6ea14c4 100644
--- a/docs/source/running_mypy.rst
+++ b/docs/source/running_mypy.rst
@@ -281,8 +281,9 @@ will continue to be of type ``Any``.
     line containing the import.
 
 2.  To suppress *all* missing import errors from a single library, add
-    a section to your :ref:`mypy config file <config-file>` for that library setting
-    :confval:`ignore_missing_imports` to True. For example, suppose your codebase
+    a per-module section to your :ref:`mypy config file <config-file>` setting
+    :confval:`ignore_missing_imports` to True for that library. For example,
+    suppose your codebase
     makes heavy use of an (untyped) library named ``foobar``. You can silence
     all import errors associated with that library and that library alone by
     adding the following section to your config file::
diff --git a/docs/source/stubs.rst b/docs/source/stubs.rst
index af47a0e2afdd1..7c84a9718b3eb 100644
--- a/docs/source/stubs.rst
+++ b/docs/source/stubs.rst
@@ -3,12 +3,15 @@
 Stub files
 ==========
 
+A *stub file* is a file containing a skeleton of the public interface
+of that Python module, including classes, variables, functions -- and
+most importantly, their types.
+
 Mypy uses stub files stored in the
 `typeshed <https://github.com/python/typeshed>`_ repository to determine
 the types of standard library and third-party library functions, classes,
 and other definitions. You can also create your own stubs that will be
-used to type check your code. The basic properties of stubs were introduced
-back in :ref:`stubs-intro`.
+used to type check your code.
 
 Creating a stub
 ***************

From eb2e02df60e7881a36759c02d2eec9b8efd8be7d Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Wed, 1 Feb 2023 12:19:41 -0800
Subject: [PATCH 215/231] Fix passenv for tox 4 (#14578)

Fixes #14522
---
 tox.ini | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tox.ini b/tox.ini
index a155ec7263869..df7784f0731f5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,7 +13,11 @@ isolated_build = true
 
 [testenv]
 description = run the test driver with {basepython}
-passenv = PYTEST_XDIST_WORKER_COUNT PROGRAMDATA PROGRAMFILES(X86) PYTEST_ADDOPTS
+passenv =
+    PYTEST_XDIST_WORKER_COUNT
+    PROGRAMDATA
+    PROGRAMFILES(X86)
+    PYTEST_ADDOPTS
 deps = -rtest-requirements.txt
 commands = python -m pytest {posargs}
 

From a6dce8408f2a958333f6bebf17df9e9e0b23ef62 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Wed, 1 Feb 2023 14:03:57 -0800
Subject: [PATCH 216/231] Upgrade to tox v4 (#14579)

---
 .github/workflows/docs.yml    |  6 +++---
 .github/workflows/test.yml    | 12 ++++++------
 CONTRIBUTING.md               |  6 +++---
 docs/source/existing_code.rst |  2 +-
 tox.ini                       |  7 +++++--
 5 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 9f984e3a346ba..a3294c08a79ca 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -26,8 +26,8 @@ jobs:
         with:
           python-version: '3.7'
       - name: Install tox
-        run: pip install --upgrade 'setuptools!=50' tox==3.24.5
+        run: pip install --upgrade 'setuptools!=50' tox==4.4.4
       - name: Setup tox environment
-        run: tox -e ${{ env.TOXENV }} --notest
+        run: tox run -e ${{ env.TOXENV }} --notest
       - name: Test
-        run: tox -e ${{ env.TOXENV }} --skip-pkg-install
+        run: tox run -e ${{ env.TOXENV }} --skip-pkg-install
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a02378cc01ab0..e7072f5369c2a 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -127,16 +127,16 @@ jobs:
         ./misc/build-debug-python.sh $PYTHONVERSION $PYTHONDIR $VENV
         source $VENV/bin/activate
     - name: Install tox
-      run: pip install --upgrade 'setuptools!=50' tox==3.24.5
+      run: pip install --upgrade 'setuptools!=50' tox==4.4.4
     - name: Compiled with mypyc
       if: ${{ matrix.test_mypyc }}
       run: |
         pip install -r test-requirements.txt
         CC=clang MYPYC_OPT_LEVEL=0 MYPY_USE_MYPYC=1 pip install -e .
     - name: Setup tox environment
-      run: tox -e ${{ matrix.toxenv }} --notest
+      run: tox run -e ${{ matrix.toxenv }} --notest
     - name: Test
-      run: tox -e ${{ matrix.toxenv }} --skip-pkg-install -- ${{ matrix.tox_extra_args }}
+      run: tox run -e ${{ matrix.toxenv }} --skip-pkg-install -- ${{ matrix.tox_extra_args }}
 
   python-nightly:
     runs-on: ubuntu-latest
@@ -147,11 +147,11 @@ jobs:
         with:
           python-version: '3.12-dev'
       - name: Install tox
-        run: pip install --upgrade 'setuptools!=50' tox==3.24.5
+        run: pip install --upgrade 'setuptools!=50' tox==4.4.4
       - name: Setup tox environment
-        run: tox -e py --notest
+        run: tox run -e py --notest
       - name: Test
-        run: tox -e py --skip-pkg-install -- "-n 2"
+        run: tox run -e py --skip-pkg-install -- "-n 2"
         continue-on-error: true
       - name: Mark as a success
         run: exit 0
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 193c9f27c85b2..2b2e6cdb9734c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -53,13 +53,13 @@ python3 runtests.py
 
 You can also use `tox` to run tests (`tox` handles setting up the test environment for you):
 ```
-tox -e py
+tox run -e py
 
 # Or some specific python version:
-tox -e py39
+tox run -e py39
 
 # Or some specific command:
-tox -e lint
+tox run -e lint
 ```
 
 Some useful commands for running specific tests include:
diff --git a/docs/source/existing_code.rst b/docs/source/existing_code.rst
index 5b1fda40f2d65..410d7af0c3509 100644
--- a/docs/source/existing_code.rst
+++ b/docs/source/existing_code.rst
@@ -51,7 +51,7 @@ A simple CI script could look something like this:
     python3 -m pip install mypy==0.971
     # Run your standardised mypy invocation, e.g.
     mypy my_project
-    # This could also look like `scripts/run_mypy.sh`, `tox -e mypy`, `make mypy`, etc
+    # This could also look like `scripts/run_mypy.sh`, `tox run -e mypy`, `make mypy`, etc
 
 Ignoring errors from certain modules
 ------------------------------------
diff --git a/tox.ini b/tox.ini
index df7784f0731f5..443f05dc8bcfa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.8.0
+minversion = 4.4.4
 skip_missing_interpreters = {env:TOX_SKIP_MISSING_INTERPRETERS:True}
 envlist =
     py37,
@@ -30,7 +30,10 @@ commands =
 
 [testenv:type]
 description = type check ourselves
-passenv = TERM MYPY_FORCE_COLOR MYPY_FORCE_TERMINAL_WIDTH
+passenv =
+    TERM
+    MYPY_FORCE_COLOR
+    MYPY_FORCE_TERMINAL_WIDTH
 commands =
     python -m mypy --config-file mypy_self_check.ini -p mypy -p mypyc
     python -m mypy --config-file mypy_self_check.ini misc --exclude misc/fix_annotate.py --exclude misc/async_matrix.py --exclude misc/sync-typeshed.py

From dd2c9a6c15527b773c192b924cbdc88e8ba020b5 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 2 Feb 2023 05:39:08 -0800
Subject: [PATCH 217/231] Improve some dynamic typing docs (#14576)

Linking #13681
---
 docs/source/dynamic_typing.rst                | 80 +++++++++++++++----
 docs/source/getting_started.rst               |  2 +
 docs/source/running_mypy.rst                  | 17 ++--
 .../source/type_inference_and_annotations.rst | 42 +++++++++-
 4 files changed, 119 insertions(+), 22 deletions(-)

diff --git a/docs/source/dynamic_typing.rst b/docs/source/dynamic_typing.rst
index 390bc52d9e2ca..d3476de2ca641 100644
--- a/docs/source/dynamic_typing.rst
+++ b/docs/source/dynamic_typing.rst
@@ -4,27 +4,39 @@
 Dynamically typed code
 ======================
 
-As mentioned earlier, bodies of functions that don't have any explicit
-types in their function annotation are dynamically typed (operations
-are checked at runtime). Code outside functions is statically typed by
-default, and types of variables are inferred. This does usually the
-right thing, but you can also make any variable dynamically typed by
-defining it explicitly with the type ``Any``:
+In :ref:`getting-started-dynamic-vs-static`, we discussed how bodies of functions
+that don't have any explicit type annotations in their function are "dynamically typed"
+and that mypy will not check them. In this section, we'll talk a little bit more
+about what that means and how you can enable dynamic typing on a more fine grained basis.
+
+In cases where your code is too magical for mypy to understand, you can make a
+variable or parameter dynamically typed by explicitly giving it the type
+``Any``. Mypy will let you do basically anything with a value of type ``Any``,
+including assigning a value of type ``Any`` to a variable of any type (or vice
+versa).
 
 .. code-block:: python
 
    from typing import Any
 
-   s = 1         # Statically typed (type int)
-   d: Any = 1    # Dynamically typed (type Any)
-   s = 'x'       # Type check error
-   d = 'x'       # OK
+   num = 1         # Statically typed (inferred to be int)
+   num = 'x'       # error: Incompatible types in assignment (expression has type "str", variable has type "int")
+
+   dyn: Any = 1    # Dynamically typed (type Any)
+   dyn = 'x'       # OK
+
+   num = dyn       # No error, mypy will let you assign a value of type Any to any variable
+   num += 1        # Oops, mypy still thinks num is an int
+
+You can think of ``Any`` as a way to locally disable type checking.
+See :ref:`silencing-type-errors` for other ways you can shut up
+the type checker.
 
 Operations on Any values
 ------------------------
 
-You can do anything using a value with type ``Any``, and type checker
-does not complain:
+You can do anything using a value with type ``Any``, and the type checker
+will not complain:
 
 .. code-block:: python
 
@@ -37,7 +49,7 @@ does not complain:
         open(x).read()
         return x
 
-Values derived from an ``Any`` value also often have the type ``Any``
+Values derived from an ``Any`` value also usually have the type ``Any``
 implicitly, as mypy can't infer a more precise result type. For
 example, if you get the attribute of an ``Any`` value or call a
 ``Any`` value the result is ``Any``:
@@ -45,12 +57,45 @@ example, if you get the attribute of an ``Any`` value or call a
 .. code-block:: python
 
     def f(x: Any) -> None:
-        y = x.foo()  # y has type Any
-        y.bar()      # Okay as well!
+        y = x.foo()
+        reveal_type(y)  # Revealed type is "Any"
+        z = y.bar("mypy will let you do anything to y")
+        reveal_type(z)  # Revealed type is "Any"
 
 ``Any`` types may propagate through your program, making type checking
 less effective, unless you are careful.
 
+Function parameters without annotations are also implicitly ``Any``:
+
+.. code-block:: python
+
+    def f(x) -> None:
+        reveal_type(x)  # Revealed type is "Any"
+        x.can.do["anything", x]("wants", 2)
+
+You can make mypy warn you about untyped function parameters using the
+:option:`--disallow-untyped-defs <mypy --disallow-untyped-defs>` flag.
+
+Generic types missing type parameters will have those parameters implicitly
+treated as ``Any``:
+
+.. code-block:: python
+
+    from typing import List
+
+    def f(x: List) -> None:
+        reveal_type(x)        # Revealed type is "builtins.list[Any]"
+        reveal_type(x[0])     # Revealed type is "Any"
+        x[0].anything_goes()  # OK
+
+You can make mypy warn you about untyped function parameters using the
+:option:`--disallow-any-generics <mypy --disallow-any-generics>` flag.
+
+Finally, another major source of ``Any`` types leaking into your program is from
+third party libraries that mypy does not know about. This is particularly the case
+when using the :option:`--ignore-missing-imports <mypy --ignore-missing-imports>`
+flag. See :ref:`fix-missing-imports` for more information about this.
+
 Any vs. object
 --------------
 
@@ -80,6 +125,11 @@ operations:
         n: int = 1
         n = o         # Error!
 
+
+If you're not sure whether you need to use :py:class:`object` or ``Any``, use
+:py:class:`object` -- only switch to using ``Any`` if you get a type checker
+complaint.
+
 You can use different :ref:`type narrowing <type-narrowing>`
 techniques to narrow :py:class:`object` to a more specific
 type (subtype) such as ``int``. Type narrowing is not needed with
diff --git a/docs/source/getting_started.rst b/docs/source/getting_started.rst
index bbe2d25d3b039..9b927097cfd20 100644
--- a/docs/source/getting_started.rst
+++ b/docs/source/getting_started.rst
@@ -44,6 +44,8 @@ easy to adopt mypy incrementally.
 In order to get useful diagnostics from mypy, you must add *type annotations*
 to your code. See the section below for details.
 
+.. _getting-started-dynamic-vs-static:
+
 Dynamic vs static typing
 ************************
 
diff --git a/docs/source/running_mypy.rst b/docs/source/running_mypy.rst
index ffc04e6ea14c4..c5222d9d5f477 100644
--- a/docs/source/running_mypy.rst
+++ b/docs/source/running_mypy.rst
@@ -228,6 +228,11 @@ attribute of the module will automatically succeed:
     # But this type checks, and x will have type 'Any'
     x = does_not_exist.foobar()
 
+This can result in mypy failing to warn you about errors in your code. Since
+operations on ``Any`` result in ``Any``, these dynamic types can propagate
+through your code, making type checking less effective. See
+:ref:`dynamic-typing` for more information.
+
 The next sections describe what each of these errors means and recommended next steps; scroll to
 the section that matches your error.
 
@@ -245,7 +250,7 @@ unless they either have declared themselves to be
 themselves on `typeshed <https://github.com/python/typeshed>`_, the repository
 of types for the standard library and some 3rd party libraries.
 
-If you are getting this error, try:
+If you are getting this error, try to obtain type hints for the library you're using:
 
 1.  Upgrading the version of the library you're using, in case a newer version
     has started to include type hints.
@@ -264,7 +269,7 @@ If you are getting this error, try:
     adding the location to the ``MYPYPATH`` environment variable.
 
     These stub files do not need to be complete! A good strategy is to use
-    stubgen, a program that comes bundled with mypy, to generate a first
+    :ref:`stubgen <stubgen>`, a program that comes bundled with mypy, to generate a first
     rough draft of the stubs. You can then iterate on just the parts of the
     library you need.
 
@@ -273,9 +278,11 @@ If you are getting this error, try:
     :ref:`PEP 561 compliant packages <installed-packages>`.
 
 If you are unable to find any existing type hints nor have time to write your
-own, you can instead *suppress* the errors. All this will do is make mypy stop
-reporting an error on the line containing the import: the imported module
-will continue to be of type ``Any``.
+own, you can instead *suppress* the errors.
+
+All this will do is make mypy stop reporting an error on the line containing the
+import: the imported module will continue to be of type ``Any``, and mypy may
+not catch errors in its use.
 
 1.  To suppress a *single* missing import error, add a ``# type: ignore`` at the end of the
     line containing the import.
diff --git a/docs/source/type_inference_and_annotations.rst b/docs/source/type_inference_and_annotations.rst
index 5c58d56d85a13..6adb4e6512242 100644
--- a/docs/source/type_inference_and_annotations.rst
+++ b/docs/source/type_inference_and_annotations.rst
@@ -185,6 +185,8 @@ Working around the issue is easy by adding a type annotation:
     a: list[int] = []  # OK
     foo(a)
 
+.. _silencing-type-errors:
+
 Silencing type errors
 *********************
 
@@ -228,6 +230,8 @@ short explanation of the bug. To do that, use this format:
     # Starting app on http://localhost:8000
     app.run(8000)  # type: ignore  # `run()` in v2.0 accepts an `int`, as a port
 
+Type ignore error codes
+-----------------------
 
 By default, mypy displays an error code for each error:
 
@@ -240,7 +244,21 @@ It is possible to add a specific error-code in your ignore comment (e.g.
 ``# type: ignore[attr-defined]``) to clarify what's being silenced. You can
 find more information about error codes :ref:`here <silence-error-codes>`.
 
-Similarly, you can also ignore all mypy errors in a file, by adding a
+Other ways to silence errors
+----------------------------
+
+You can get mypy to silence errors about a specific variable by dynamically
+typing it with ``Any``. See :ref:`dynamic-typing` for more information.
+
+.. code-block:: python
+
+    from typing import Any
+
+    def f(x: Any, y: str) -> None:
+        x = 'hello'
+        x += 1  # OK
+
+You can ignore all mypy errors in a file by adding a
 ``# mypy: ignore-errors`` at the top of the file:
 
 .. code-block:: python
@@ -250,8 +268,28 @@ Similarly, you can also ignore all mypy errors in a file, by adding a
     import unittest
     ...
 
+You can also specify per-module configuration options in your :ref:`config-file`.
+For example:
+
+.. code-block:: ini
+
+    # Don't report errors in the 'package_to_fix_later' package
+    [mypy-package_to_fix_later.*]
+    ignore_errors = True
+
+    # Disable specific error codes in the 'tests' package
+    # Also don't require type annotations
+    [mypy-tests.*]
+    disable_error_code = var-annotated, has-type
+    allow_untyped_defs = True
+
+    # Silence import errors from the 'library_missing_types' package
+    [mypy-library_missing_types.*]
+    ignore_missing_imports = True
+
 Finally, adding a ``@typing.no_type_check`` decorator to a class, method or
-function has the effect of ignoring that class, method or function.
+function causes mypy to avoid type checking that class, method or function
+and to treat it as not having any type annotations.
 
 .. code-block:: python
 

From 7cf13919330a49059c3ae5b87ad5d2f9d25f99e2 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 2 Feb 2023 11:54:59 -0800
Subject: [PATCH 218/231] Make a top-level TypedDict page (#14584)

This just moves content around (with minimal editing to make the moves
make sense).

TypedDict has been the target for several features, including some that
are not yet documented. There was another PEP drafted today that was
TypedDict themed. It's also pretty popular with users.

Linking https://github.com/python/mypy/issues/13681
---
 docs/source/index.rst      |   1 +
 docs/source/more_types.rst | 254 +------------------------------------
 docs/source/typed_dict.rst | 250 ++++++++++++++++++++++++++++++++++++
 3 files changed, 252 insertions(+), 253 deletions(-)
 create mode 100644 docs/source/typed_dict.rst

diff --git a/docs/source/index.rst b/docs/source/index.rst
index 3546e1f4efa5c..067f37cdc58c9 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -74,6 +74,7 @@ Contents
    generics
    more_types
    literal_types
+   typed_dict
    final_attrs
    metaclasses
 
diff --git a/docs/source/more_types.rst b/docs/source/more_types.rst
index 722909a038b5a..ff5e8d3843516 100644
--- a/docs/source/more_types.rst
+++ b/docs/source/more_types.rst
@@ -2,7 +2,7 @@ More types
 ==========
 
 This section introduces a few additional kinds of types, including :py:data:`~typing.NoReturn`,
-:py:func:`NewType <typing.NewType>`, ``TypedDict``, and types for async code. It also discusses
+:py:func:`NewType <typing.NewType>`, and types for async code. It also discusses
 how to give functions more precise types using overloads. All of these are only
 situationally useful, so feel free to skip this section and come back when you
 have a need for some of them.
@@ -20,9 +20,6 @@ Here's a quick summary of what's covered here:
   signatures. This is useful if you need to encode a relationship between the
   arguments and the return type that would be difficult to express normally.
 
-* ``TypedDict`` lets you give precise types for dictionaries that represent
-  objects with a fixed schema, such as ``{'id': 1, 'items': ['x']}``.
-
 * Async types let you type check programs using ``async`` and ``await``.
 
 .. _noreturn:
@@ -949,252 +946,3 @@ generator type as the return type:
    loop = asyncio.get_event_loop()
    loop.run_until_complete(countdown_2("USS Enterprise", 5))
    loop.close()
-
-
-.. _typeddict:
-
-TypedDict
-*********
-
-Python programs often use dictionaries with string keys to represent objects.
-Here is a typical example:
-
-.. code-block:: python
-
-   movie = {'name': 'Blade Runner', 'year': 1982}
-
-Only a fixed set of string keys is expected (``'name'`` and
-``'year'`` above), and each key has an independent value type (``str``
-for ``'name'`` and ``int`` for ``'year'`` above). We've previously
-seen the ``dict[K, V]`` type, which lets you declare uniform
-dictionary types, where every value has the same type, and arbitrary keys
-are supported. This is clearly not a good fit for
-``movie`` above. Instead, you can use a ``TypedDict`` to give a precise
-type for objects like ``movie``, where the type of each
-dictionary value depends on the key:
-
-.. code-block:: python
-
-   from typing_extensions import TypedDict
-
-   Movie = TypedDict('Movie', {'name': str, 'year': int})
-
-   movie: Movie = {'name': 'Blade Runner', 'year': 1982}
-
-``Movie`` is a ``TypedDict`` type with two items: ``'name'`` (with type ``str``)
-and ``'year'`` (with type ``int``). Note that we used an explicit type
-annotation for the ``movie`` variable. This type annotation is
-important -- without it, mypy will try to infer a regular, uniform
-:py:class:`dict` type for ``movie``, which is not what we want here.
-
-.. note::
-
-   If you pass a ``TypedDict`` object as an argument to a function, no
-   type annotation is usually necessary since mypy can infer the
-   desired type based on the declared argument type. Also, if an
-   assignment target has been previously defined, and it has a
-   ``TypedDict`` type, mypy will treat the assigned value as a ``TypedDict``,
-   not :py:class:`dict`.
-
-Now mypy will recognize these as valid:
-
-.. code-block:: python
-
-   name = movie['name']  # Okay; type of name is str
-   year = movie['year']  # Okay; type of year is int
-
-Mypy will detect an invalid key as an error:
-
-.. code-block:: python
-
-   director = movie['director']  # Error: 'director' is not a valid key
-
-Mypy will also reject a runtime-computed expression as a key, as
-it can't verify that it's a valid key. You can only use string
-literals as ``TypedDict`` keys.
-
-The ``TypedDict`` type object can also act as a constructor. It
-returns a normal :py:class:`dict` object at runtime -- a ``TypedDict`` does
-not define a new runtime type:
-
-.. code-block:: python
-
-   toy_story = Movie(name='Toy Story', year=1995)
-
-This is equivalent to just constructing a dictionary directly using
-``{ ... }`` or ``dict(key=value, ...)``. The constructor form is
-sometimes convenient, since it can be used without a type annotation,
-and it also makes the type of the object explicit.
-
-Like all types, ``TypedDict``\s can be used as components to build
-arbitrarily complex types. For example, you can define nested
-``TypedDict``\s and containers with ``TypedDict`` items.
-Unlike most other types, mypy uses structural compatibility checking
-(or structural subtyping) with ``TypedDict``\s. A ``TypedDict`` object with
-extra items is compatible with (a subtype of) a narrower
-``TypedDict``, assuming item types are compatible (*totality* also affects
-subtyping, as discussed below).
-
-A ``TypedDict`` object is not a subtype of the regular ``dict[...]``
-type (and vice versa), since :py:class:`dict` allows arbitrary keys to be
-added and removed, unlike ``TypedDict``. However, any ``TypedDict`` object is
-a subtype of (that is, compatible with) ``Mapping[str, object]``, since
-:py:class:`~typing.Mapping` only provides read-only access to the dictionary items:
-
-.. code-block:: python
-
-   def print_typed_dict(obj: Mapping[str, object]) -> None:
-       for key, value in obj.items():
-           print(f'{key}: {value}')
-
-   print_typed_dict(Movie(name='Toy Story', year=1995))  # OK
-
-.. note::
-
-   Unless you are on Python 3.8 or newer (where ``TypedDict`` is available in
-   standard library :py:mod:`typing` module) you need to install ``typing_extensions``
-   using pip to use ``TypedDict``:
-
-   .. code-block:: text
-
-      python3 -m pip install --upgrade typing-extensions
-
-Totality
---------
-
-By default mypy ensures that a ``TypedDict`` object has all the specified
-keys. This will be flagged as an error:
-
-.. code-block:: python
-
-   # Error: 'year' missing
-   toy_story: Movie = {'name': 'Toy Story'}
-
-Sometimes you want to allow keys to be left out when creating a
-``TypedDict`` object. You can provide the ``total=False`` argument to
-``TypedDict(...)`` to achieve this:
-
-.. code-block:: python
-
-   GuiOptions = TypedDict(
-       'GuiOptions', {'language': str, 'color': str}, total=False)
-   options: GuiOptions = {}  # Okay
-   options['language'] = 'en'
-
-You may need to use :py:meth:`~dict.get` to access items of a partial (non-total)
-``TypedDict``, since indexing using ``[]`` could fail at runtime.
-However, mypy still lets use ``[]`` with a partial ``TypedDict`` -- you
-just need to be careful with it, as it could result in a :py:exc:`KeyError`.
-Requiring :py:meth:`~dict.get` everywhere would be too cumbersome. (Note that you
-are free to use :py:meth:`~dict.get` with total ``TypedDict``\s as well.)
-
-Keys that aren't required are shown with a ``?`` in error messages:
-
-.. code-block:: python
-
-   # Revealed type is "TypedDict('GuiOptions', {'language'?: builtins.str,
-   #                                            'color'?: builtins.str})"
-   reveal_type(options)
-
-Totality also affects structural compatibility. You can't use a partial
-``TypedDict`` when a total one is expected. Also, a total ``TypedDict`` is not
-valid when a partial one is expected.
-
-Supported operations
---------------------
-
-``TypedDict`` objects support a subset of dictionary operations and methods.
-You must use string literals as keys when calling most of the methods,
-as otherwise mypy won't be able to check that the key is valid. List
-of supported operations:
-
-* Anything included in :py:class:`~typing.Mapping`:
-
-  * ``d[key]``
-  * ``key in d``
-  * ``len(d)``
-  * ``for key in d`` (iteration)
-  * :py:meth:`d.get(key[, default]) <dict.get>`
-  * :py:meth:`d.keys() <dict.keys>`
-  * :py:meth:`d.values() <dict.values>`
-  * :py:meth:`d.items() <dict.items>`
-
-* :py:meth:`d.copy() <dict.copy>`
-* :py:meth:`d.setdefault(key, default) <dict.setdefault>`
-* :py:meth:`d1.update(d2) <dict.update>`
-* :py:meth:`d.pop(key[, default]) <dict.pop>` (partial ``TypedDict``\s only)
-* ``del d[key]`` (partial ``TypedDict``\s only)
-
-.. note::
-
-   :py:meth:`~dict.clear` and :py:meth:`~dict.popitem` are not supported since they are unsafe
-   -- they could delete required ``TypedDict`` items that are not visible to
-   mypy because of structural subtyping.
-
-Class-based syntax
-------------------
-
-An alternative, class-based syntax to define a ``TypedDict`` is supported
-in Python 3.6 and later:
-
-.. code-block:: python
-
-   from typing_extensions import TypedDict
-
-   class Movie(TypedDict):
-       name: str
-       year: int
-
-The above definition is equivalent to the original ``Movie``
-definition. It doesn't actually define a real class. This syntax also
-supports a form of inheritance -- subclasses can define additional
-items. However, this is primarily a notational shortcut. Since mypy
-uses structural compatibility with ``TypedDict``\s, inheritance is not
-required for compatibility. Here is an example of inheritance:
-
-.. code-block:: python
-
-   class Movie(TypedDict):
-       name: str
-       year: int
-
-   class BookBasedMovie(Movie):
-       based_on: str
-
-Now ``BookBasedMovie`` has keys ``name``, ``year`` and ``based_on``.
-
-Mixing required and non-required items
---------------------------------------
-
-In addition to allowing reuse across ``TypedDict`` types, inheritance also allows
-you to mix required and non-required (using ``total=False``) items
-in a single ``TypedDict``. Example:
-
-.. code-block:: python
-
-   class MovieBase(TypedDict):
-       name: str
-       year: int
-
-   class Movie(MovieBase, total=False):
-       based_on: str
-
-Now ``Movie`` has required keys ``name`` and ``year``, while ``based_on``
-can be left out when constructing an object. A ``TypedDict`` with a mix of required
-and non-required keys, such as ``Movie`` above, will only be compatible with
-another ``TypedDict`` if all required keys in the other ``TypedDict`` are required keys in the
-first ``TypedDict``, and all non-required keys of the other ``TypedDict`` are also non-required keys
-in the first ``TypedDict``.
-
-Unions of TypedDicts
---------------------
-
-Since TypedDicts are really just regular dicts at runtime, it is not possible to
-use ``isinstance`` checks to distinguish between different variants of a Union of
-TypedDict in the same way you can with regular objects.
-
-Instead, you can use the :ref:`tagged union pattern <tagged_unions>`. The referenced
-section of the docs has a full description with an example, but in short, you will
-need to give each TypedDict the same key where each value has a unique
-:ref:`Literal type <literal_types>`. Then, check that key to distinguish
-between your TypedDicts.
diff --git a/docs/source/typed_dict.rst b/docs/source/typed_dict.rst
new file mode 100644
index 0000000000000..19a717d7feb70
--- /dev/null
+++ b/docs/source/typed_dict.rst
@@ -0,0 +1,250 @@
+.. _typeddict:
+
+TypedDict
+*********
+
+Python programs often use dictionaries with string keys to represent objects.
+``TypedDict`` lets you give precise types for dictionaries that represent
+objects with a fixed schema, such as ``{'id': 1, 'items': ['x']}``.
+
+Here is a typical example:
+
+.. code-block:: python
+
+   movie = {'name': 'Blade Runner', 'year': 1982}
+
+Only a fixed set of string keys is expected (``'name'`` and
+``'year'`` above), and each key has an independent value type (``str``
+for ``'name'`` and ``int`` for ``'year'`` above). We've previously
+seen the ``dict[K, V]`` type, which lets you declare uniform
+dictionary types, where every value has the same type, and arbitrary keys
+are supported. This is clearly not a good fit for
+``movie`` above. Instead, you can use a ``TypedDict`` to give a precise
+type for objects like ``movie``, where the type of each
+dictionary value depends on the key:
+
+.. code-block:: python
+
+   from typing_extensions import TypedDict
+
+   Movie = TypedDict('Movie', {'name': str, 'year': int})
+
+   movie: Movie = {'name': 'Blade Runner', 'year': 1982}
+
+``Movie`` is a ``TypedDict`` type with two items: ``'name'`` (with type ``str``)
+and ``'year'`` (with type ``int``). Note that we used an explicit type
+annotation for the ``movie`` variable. This type annotation is
+important -- without it, mypy will try to infer a regular, uniform
+:py:class:`dict` type for ``movie``, which is not what we want here.
+
+.. note::
+
+   If you pass a ``TypedDict`` object as an argument to a function, no
+   type annotation is usually necessary since mypy can infer the
+   desired type based on the declared argument type. Also, if an
+   assignment target has been previously defined, and it has a
+   ``TypedDict`` type, mypy will treat the assigned value as a ``TypedDict``,
+   not :py:class:`dict`.
+
+Now mypy will recognize these as valid:
+
+.. code-block:: python
+
+   name = movie['name']  # Okay; type of name is str
+   year = movie['year']  # Okay; type of year is int
+
+Mypy will detect an invalid key as an error:
+
+.. code-block:: python
+
+   director = movie['director']  # Error: 'director' is not a valid key
+
+Mypy will also reject a runtime-computed expression as a key, as
+it can't verify that it's a valid key. You can only use string
+literals as ``TypedDict`` keys.
+
+The ``TypedDict`` type object can also act as a constructor. It
+returns a normal :py:class:`dict` object at runtime -- a ``TypedDict`` does
+not define a new runtime type:
+
+.. code-block:: python
+
+   toy_story = Movie(name='Toy Story', year=1995)
+
+This is equivalent to just constructing a dictionary directly using
+``{ ... }`` or ``dict(key=value, ...)``. The constructor form is
+sometimes convenient, since it can be used without a type annotation,
+and it also makes the type of the object explicit.
+
+Like all types, ``TypedDict``\s can be used as components to build
+arbitrarily complex types. For example, you can define nested
+``TypedDict``\s and containers with ``TypedDict`` items.
+Unlike most other types, mypy uses structural compatibility checking
+(or structural subtyping) with ``TypedDict``\s. A ``TypedDict`` object with
+extra items is compatible with (a subtype of) a narrower
+``TypedDict``, assuming item types are compatible (*totality* also affects
+subtyping, as discussed below).
+
+A ``TypedDict`` object is not a subtype of the regular ``dict[...]``
+type (and vice versa), since :py:class:`dict` allows arbitrary keys to be
+added and removed, unlike ``TypedDict``. However, any ``TypedDict`` object is
+a subtype of (that is, compatible with) ``Mapping[str, object]``, since
+:py:class:`~typing.Mapping` only provides read-only access to the dictionary items:
+
+.. code-block:: python
+
+   def print_typed_dict(obj: Mapping[str, object]) -> None:
+       for key, value in obj.items():
+           print(f'{key}: {value}')
+
+   print_typed_dict(Movie(name='Toy Story', year=1995))  # OK
+
+.. note::
+
+   Unless you are on Python 3.8 or newer (where ``TypedDict`` is available in
+   standard library :py:mod:`typing` module) you need to install ``typing_extensions``
+   using pip to use ``TypedDict``:
+
+   .. code-block:: text
+
+      python3 -m pip install --upgrade typing-extensions
+
+Totality
+--------
+
+By default mypy ensures that a ``TypedDict`` object has all the specified
+keys. This will be flagged as an error:
+
+.. code-block:: python
+
+   # Error: 'year' missing
+   toy_story: Movie = {'name': 'Toy Story'}
+
+Sometimes you want to allow keys to be left out when creating a
+``TypedDict`` object. You can provide the ``total=False`` argument to
+``TypedDict(...)`` to achieve this:
+
+.. code-block:: python
+
+   GuiOptions = TypedDict(
+       'GuiOptions', {'language': str, 'color': str}, total=False)
+   options: GuiOptions = {}  # Okay
+   options['language'] = 'en'
+
+You may need to use :py:meth:`~dict.get` to access items of a partial (non-total)
+``TypedDict``, since indexing using ``[]`` could fail at runtime.
+However, mypy still lets use ``[]`` with a partial ``TypedDict`` -- you
+just need to be careful with it, as it could result in a :py:exc:`KeyError`.
+Requiring :py:meth:`~dict.get` everywhere would be too cumbersome. (Note that you
+are free to use :py:meth:`~dict.get` with total ``TypedDict``\s as well.)
+
+Keys that aren't required are shown with a ``?`` in error messages:
+
+.. code-block:: python
+
+   # Revealed type is "TypedDict('GuiOptions', {'language'?: builtins.str,
+   #                                            'color'?: builtins.str})"
+   reveal_type(options)
+
+Totality also affects structural compatibility. You can't use a partial
+``TypedDict`` when a total one is expected. Also, a total ``TypedDict`` is not
+valid when a partial one is expected.
+
+Supported operations
+--------------------
+
+``TypedDict`` objects support a subset of dictionary operations and methods.
+You must use string literals as keys when calling most of the methods,
+as otherwise mypy won't be able to check that the key is valid. List
+of supported operations:
+
+* Anything included in :py:class:`~typing.Mapping`:
+
+  * ``d[key]``
+  * ``key in d``
+  * ``len(d)``
+  * ``for key in d`` (iteration)
+  * :py:meth:`d.get(key[, default]) <dict.get>`
+  * :py:meth:`d.keys() <dict.keys>`
+  * :py:meth:`d.values() <dict.values>`
+  * :py:meth:`d.items() <dict.items>`
+
+* :py:meth:`d.copy() <dict.copy>`
+* :py:meth:`d.setdefault(key, default) <dict.setdefault>`
+* :py:meth:`d1.update(d2) <dict.update>`
+* :py:meth:`d.pop(key[, default]) <dict.pop>` (partial ``TypedDict``\s only)
+* ``del d[key]`` (partial ``TypedDict``\s only)
+
+.. note::
+
+   :py:meth:`~dict.clear` and :py:meth:`~dict.popitem` are not supported since they are unsafe
+   -- they could delete required ``TypedDict`` items that are not visible to
+   mypy because of structural subtyping.
+
+Class-based syntax
+------------------
+
+An alternative, class-based syntax to define a ``TypedDict`` is supported
+in Python 3.6 and later:
+
+.. code-block:: python
+
+   from typing_extensions import TypedDict
+
+   class Movie(TypedDict):
+       name: str
+       year: int
+
+The above definition is equivalent to the original ``Movie``
+definition. It doesn't actually define a real class. This syntax also
+supports a form of inheritance -- subclasses can define additional
+items. However, this is primarily a notational shortcut. Since mypy
+uses structural compatibility with ``TypedDict``\s, inheritance is not
+required for compatibility. Here is an example of inheritance:
+
+.. code-block:: python
+
+   class Movie(TypedDict):
+       name: str
+       year: int
+
+   class BookBasedMovie(Movie):
+       based_on: str
+
+Now ``BookBasedMovie`` has keys ``name``, ``year`` and ``based_on``.
+
+Mixing required and non-required items
+--------------------------------------
+
+In addition to allowing reuse across ``TypedDict`` types, inheritance also allows
+you to mix required and non-required (using ``total=False``) items
+in a single ``TypedDict``. Example:
+
+.. code-block:: python
+
+   class MovieBase(TypedDict):
+       name: str
+       year: int
+
+   class Movie(MovieBase, total=False):
+       based_on: str
+
+Now ``Movie`` has required keys ``name`` and ``year``, while ``based_on``
+can be left out when constructing an object. A ``TypedDict`` with a mix of required
+and non-required keys, such as ``Movie`` above, will only be compatible with
+another ``TypedDict`` if all required keys in the other ``TypedDict`` are required keys in the
+first ``TypedDict``, and all non-required keys of the other ``TypedDict`` are also non-required keys
+in the first ``TypedDict``.
+
+Unions of TypedDicts
+--------------------
+
+Since TypedDicts are really just regular dicts at runtime, it is not possible to
+use ``isinstance`` checks to distinguish between different variants of a Union of
+TypedDict in the same way you can with regular objects.
+
+Instead, you can use the :ref:`tagged union pattern <tagged_unions>`. The referenced
+section of the docs has a full description with an example, but in short, you will
+need to give each TypedDict the same key where each value has a unique
+:ref:`Literal type <literal_types>`. Then, check that key to distinguish
+between your TypedDicts.

From 2cfc46c3dcd14e6b84dcd22ae17b015d3ee4e3b9 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 2 Feb 2023 12:08:21 -0800
Subject: [PATCH 219/231] Improve the Common Issues page (#14581)

Linking #13681
---
 docs/source/common_issues.rst | 149 ++++++++++++++++------------------
 docs/source/running_mypy.rst  |   8 ++
 2 files changed, 80 insertions(+), 77 deletions(-)

diff --git a/docs/source/common_issues.rst b/docs/source/common_issues.rst
index 465035307d5de..afb8e7d3ffe18 100644
--- a/docs/source/common_issues.rst
+++ b/docs/source/common_issues.rst
@@ -9,15 +9,6 @@ doesn't work as expected. Statically typed code is often identical to
 normal Python code (except for type annotations), but sometimes you need
 to do things slightly differently.
 
-Can't install mypy using pip
-----------------------------
-
-If installation fails, you've probably hit one of these issues:
-
-* Mypy needs Python 3.6 or later to run.
-* You may have to run pip like this:
-  ``python3 -m pip install mypy``.
-
 .. _annotations_needed:
 
 No errors reported for obviously wrong code
@@ -26,7 +17,9 @@ No errors reported for obviously wrong code
 There are several common reasons why obviously wrong code is not
 flagged as an error.
 
-**The function containing the error is not annotated.** Functions that
+**The function containing the error is not annotated.**
+
+Functions that
 do not have any annotations (neither for any argument nor for the
 return type) are not type-checked, and even the most blatant type
 errors (e.g. ``2 + 'a'``) pass silently.  The solution is to add
@@ -52,7 +45,9 @@ once you add annotations:
 
 If you don't know what types to add, you can use ``Any``, but beware:
 
-**One of the values involved has type 'Any'.** Extending the above
+**One of the values involved has type 'Any'.**
+
+Extending the above
 example, if we were to leave out the annotation for ``a``, we'd get
 no error:
 
@@ -68,49 +63,52 @@ The reason is that if the type of ``a`` is unknown, the type of
 If you're having trouble debugging such situations,
 :ref:`reveal_type() <reveal-type>` might come in handy.
 
-Note that sometimes library stubs have imprecise type information,
-e.g. the :py:func:`pow` builtin returns ``Any`` (see `typeshed issue 285
-<https://github.com/python/typeshed/issues/285>`_ for the reason).
+Note that sometimes library stubs with imprecise type information
+can be a source of ``Any`` values.
 
 :py:meth:`__init__ <object.__init__>` **method has no annotated
-arguments or return type annotation.** :py:meth:`__init__ <object.__init__>`
-is considered fully-annotated **if at least one argument is annotated**,
-while mypy will infer the return type as ``None``.
-The implication is that, for a :py:meth:`__init__ <object.__init__>` method
-that has no argument, you'll have to explicitly annotate the return type
-as ``None`` to type-check this :py:meth:`__init__ <object.__init__>` method:
+arguments and no return type annotation.**
+
+This is basically a combination of the two cases above, in that ``__init__``
+without annotations can cause ``Any`` types leak into instance variables:
 
 .. code-block:: python
 
-    def foo(s: str) -> str:
-        return s
+    class Bad:
+        def __init__(self):
+            self.value = "asdf"
+            1 + "asdf"  # No error!
+
+    bad = Bad()
+    bad.value + 1           # No error!
+    reveal_type(bad)        # Revealed type is "__main__.Bad"
+    reveal_type(bad.value)  # Revealed type is "Any"
 
-    class A():
-        def __init__(self, value: str): # Return type inferred as None, considered as typed method
+    class Good:
+        def __init__(self) -> None:  # Explicitly return None
             self.value = value
-            foo(1) # error: Argument 1 to "foo" has incompatible type "int"; expected "str"
-
-    class B():
-        def __init__(self):  # No argument is annotated, considered as untyped method
-            foo(1)  # No error!
-
-    class C():
-        def __init__(self) -> None:  # Must specify return type to type-check
-            foo(1) # error: Argument 1 to "foo" has incompatible type "int"; expected "str"
-
-**Some imports may be silently ignored**.  Another source of
-unexpected ``Any`` values are the :option:`--ignore-missing-imports
-<mypy --ignore-missing-imports>` and :option:`--follow-imports=skip
-<mypy --follow-imports>` flags.  When you use :option:`--ignore-missing-imports <mypy --ignore-missing-imports>`,
-any imported module that cannot be found is silently replaced with
-``Any``.  When using :option:`--follow-imports=skip <mypy --follow-imports>` the same is true for
-modules for which a ``.py`` file is found but that are not specified
-on the command line.  (If a ``.pyi`` stub is found it is always
-processed normally, regardless of the value of
-:option:`--follow-imports <mypy --follow-imports>`.)  To help debug the former situation (no
-module found at all) leave out :option:`--ignore-missing-imports <mypy --ignore-missing-imports>`; to get
-clarity about the latter use :option:`--follow-imports=error <mypy --follow-imports>`.  You can
-read up about these and other useful flags in :ref:`command-line`.
+
+
+**Some imports may be silently ignored**.
+
+A common source of unexpected ``Any`` values is the
+:option:`--ignore-missing-imports <mypy --ignore-missing-imports>` flag.
+
+When you use :option:`--ignore-missing-imports <mypy --ignore-missing-imports>`,
+any imported module that cannot be found is silently replaced with ``Any``.
+
+To help debug this, simply leave out
+:option:`--ignore-missing-imports <mypy --ignore-missing-imports>`.
+As mentioned in :ref:`fix-missing-imports`, setting ``ignore_missing_imports=True``
+on a per-module basis will make bad surprises less likely and is highly encouraged.
+
+Use of the :option:`--follow-imports=skip <mypy --follow-imports>` flags can also
+cause problems. Use of these flags is strongly discouraged and only required in
+relatively niche situations. See :ref:`follow-imports` for more information.
+
+**mypy considers some of your code unreachable**.
+
+See :ref:`unreachable` for more information.
 
 **A function annotated as returning a non-optional type returns 'None'
 and mypy doesn't complain**.
@@ -186,25 +184,17 @@ over ``.py`` files.
 Ignoring a whole file
 ---------------------
 
-A ``# type: ignore`` comment at the top of a module (before any statements,
+* To only ignore errors, use a top-level ``# mypy: ignore-errors`` comment instead.
+* To only ignore errors with a specific error code, use a top-level
+  ``# mypy: disable-error-code=...`` comment.
+* To replace the contents of a module with ``Any``, use a per-module ``follow_imports = skip``.
+  See :ref:`Following imports <follow-imports>` for details.
+
+Note that a ``# type: ignore`` comment at the top of a module (before any statements,
 including imports or docstrings) has the effect of ignoring the entire contents of the module.
 This behaviour can be surprising and result in
 "Module ... has no attribute ... [attr-defined]" errors.
 
-To only ignore errors, use a top-level ``# mypy: ignore-errors`` comment instead.
-To only ignore errors with a specific error code, use a top-level
-``# mypy: disable-error-code=...`` comment.
-To replace the contents of the module with ``Any``, use a per-module ``follow_imports = skip``.
-See :ref:`Following imports <follow-imports>` for details.
-
-.. code-block:: python
-
-    # type: ignore
-
-    import foo
-
-    foo.bar()
-
 Issues with code at runtime
 ---------------------------
 
@@ -262,20 +252,20 @@ Redefinitions with incompatible types
 
 Each name within a function only has a single 'declared' type. You can
 reuse for loop indices etc., but if you want to use a variable with
-multiple types within a single function, you may need to declare it
-with the ``Any`` type.
+multiple types within a single function, you may need to instead use
+multiple variables (or maybe declare the variable with an ``Any`` type).
 
 .. code-block:: python
 
    def f() -> None:
        n = 1
        ...
-       n = 'x'        # Type error: n has type int
+       n = 'x'  # error: Incompatible types in assignment (expression has type "str", variable has type "int")
 
 .. note::
 
-   This limitation could be lifted in a future mypy
-   release.
+   Using the :option:`--allow-redefinition <mypy --allow-redefinition>`
+   flag can suppress this error in several cases.
 
 Note that you can redefine a variable with a more *precise* or a more
 concrete type. For example, you can redefine a sequence (which does
@@ -289,6 +279,8 @@ not support ``sort()``) as a list and sort it in-place:
         # Type of x is List[int] here.
         x.sort()  # Okay!
 
+See :ref:`type-narrowing` for more information.
+
 .. _variance:
 
 Invariance vs covariance
@@ -340,24 +332,24 @@ Declaring a supertype as variable type
 
 Sometimes the inferred type is a subtype (subclass) of the desired
 type. The type inference uses the first assignment to infer the type
-of a name (assume here that ``Shape`` is the base class of both
-``Circle`` and ``Triangle``):
+of a name:
 
 .. code-block:: python
 
-   shape = Circle()    # Infer shape to be Circle
-   ...
-   shape = Triangle()  # Type error: Triangle is not a Circle
+   class Shape: ...
+   class Circle(Shape): ...
+   class Triangle(Shape): ...
+
+   shape = Circle()    # mypy infers the type of shape to be Circle
+   shape = Triangle()  # error: Incompatible types in assignment (expression has type "Triangle", variable has type "Circle")
 
 You can just give an explicit type for the variable in cases such the
 above example:
 
 .. code-block:: python
 
-   shape = Circle() # type: Shape   # The variable s can be any Shape,
-                                    # not just Circle
-   ...
-   shape = Triangle()               # OK
+   shape: Shape = Circle()  # The variable s can be any Shape, not just Circle
+   shape = Triangle()       # OK
 
 Complex type tests
 ------------------
@@ -622,7 +614,10 @@ You can install the latest development version of mypy from source. Clone the
 
     git clone https://github.com/python/mypy.git
     cd mypy
-    sudo python3 -m pip install --upgrade .
+    python3 -m pip install --upgrade .
+
+To install a development version of mypy that is mypyc-compiled, see the
+instructions at the `mypyc wheels repo <https://github.com/mypyc/mypy_mypyc-wheels>`_.
 
 Variables vs type aliases
 -------------------------
diff --git a/docs/source/running_mypy.rst b/docs/source/running_mypy.rst
index c5222d9d5f477..b0cefec9dafa2 100644
--- a/docs/source/running_mypy.rst
+++ b/docs/source/running_mypy.rst
@@ -357,6 +357,9 @@ other than the one mypy is running in, you can use :option:`--python-executable
 <mypy --python-executable>` flag to point to the Python executable for that
 environment, and mypy will find packages installed for that Python executable.
 
+If you've installed the relevant stub packages and are still getting this error,
+see the :ref:`section below <missing-type-hints-for-third-party-library>`.
+
 .. _missing-type-hints-for-third-party-library:
 
 Cannot find implementation or library stub
@@ -379,6 +382,11 @@ this error, try:
     line flag to point the Python interpreter containing your installed
     third party packages.
 
+    You can confirm that you are running mypy from the environment you expect
+    by running it like ``python -m mypy ...``. You can confirm that you are
+    installing into the environment you expect by running pip like
+    ``python -m pip ...``.
+
 2.  Reading the :ref:`finding-imports` section below to make sure you
     understand how exactly mypy searches for and finds modules and modify
     how you're invoking mypy accordingly.

From cb2ec3d08b0db4b1cda22e32aa461ad62c1cd243 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 2 Feb 2023 12:40:28 -0800
Subject: [PATCH 220/231] Improve protocols documentation (#14577)

Linking #13681
---
 docs/source/protocols.rst | 89 +++++++++++++++++++++++++++++++++------
 1 file changed, 76 insertions(+), 13 deletions(-)

diff --git a/docs/source/protocols.rst b/docs/source/protocols.rst
index 603c9fd0dcc80..cb51809a66d50 100644
--- a/docs/source/protocols.rst
+++ b/docs/source/protocols.rst
@@ -4,14 +4,17 @@ Protocols and structural subtyping
 ==================================
 
 Mypy supports two ways of deciding whether two classes are compatible
-as types: nominal subtyping and structural subtyping. *Nominal*
-subtyping is strictly based on the class hierarchy. If class ``D``
+as types: nominal subtyping and structural subtyping.
+
+*Nominal* subtyping is strictly based on the class hierarchy. If class ``D``
 inherits class ``C``, it's also a subtype of ``C``, and instances of
 ``D`` can be used when ``C`` instances are expected. This form of
 subtyping is used by default in mypy, since it's easy to understand
 and produces clear and concise error messages, and since it matches
 how the native :py:func:`isinstance <isinstance>` check works -- based on class
-hierarchy. *Structural* subtyping can also be useful. Class ``D`` is
+hierarchy.
+
+*Structural* subtyping is based on the operations that can be performed with an object. Class ``D`` is
 a structural subtype of class ``C`` if the former has all attributes
 and methods of the latter, and with compatible types.
 
@@ -72,15 +75,16 @@ class:
    from typing_extensions import Protocol
 
    class SupportsClose(Protocol):
-       def close(self) -> None:
-          ...  # Empty method body (explicit '...')
+       # Empty method body (explicit '...')
+       def close(self) -> None: ...
 
    class Resource:  # No SupportsClose base class!
-       # ... some methods ...
 
        def close(self) -> None:
           self.resource.release()
 
+       # ... other methods ...
+
    def close_all(items: Iterable[SupportsClose]) -> None:
        for item in items:
            item.close()
@@ -146,7 +150,9 @@ present if you are defining a protocol:
 
 You can also include default implementations of methods in
 protocols. If you explicitly subclass these protocols you can inherit
-these default implementations. Explicitly including a protocol as a
+these default implementations.
+
+Explicitly including a protocol as a
 base class is also a way of documenting that your class implements a
 particular protocol, and it forces mypy to verify that your class
 implementation is actually compatible with the protocol. In particular,
@@ -157,12 +163,62 @@ abstract:
 
    class SomeProto(Protocol):
        attr: int  # Note, no right hand side
-       def method(self) -> str: ...  # Literal ... here
+       def method(self) -> str: ...  # Literally just ... here
+
    class ExplicitSubclass(SomeProto):
        pass
+
    ExplicitSubclass()  # error: Cannot instantiate abstract class 'ExplicitSubclass'
                        # with abstract attributes 'attr' and 'method'
 
+Invariance of protocol attributes
+*********************************
+
+A common issue with protocols is that protocol attributes are invariant.
+For example:
+
+.. code-block:: python
+
+   class Box(Protocol):
+         content: object
+
+   class IntBox:
+         content: int
+
+   def takes_box(box: Box) -> None: ...
+
+   takes_box(IntBox())  # error: Argument 1 to "takes_box" has incompatible type "IntBox"; expected "Box"
+                        # note:  Following member(s) of "IntBox" have conflicts:
+                        # note:      content: expected "object", got "int"
+
+This is because ``Box`` defines ``content`` as a mutable attribute.
+Here's why this is problematic:
+
+.. code-block:: python
+
+   def takes_box_evil(box: Box) -> None:
+       box.content = "asdf"  # This is bad, since box.content is supposed to be an object
+
+   my_int_box = IntBox()
+   takes_box_evil(my_int_box)
+   my_int_box.content + 1  # Oops, TypeError!
+
+This can be fixed by declaring ``content`` to be read-only in the ``Box``
+protocol using ``@property``:
+
+.. code-block:: python
+
+   class Box(Protocol):
+       @property
+       def content(self) -> object: ...
+
+   class IntBox:
+       content: int
+
+   def takes_box(box: Box) -> None: ...
+
+   takes_box(IntBox(42))  # OK
+
 Recursive protocols
 *******************
 
@@ -197,7 +253,7 @@ Using isinstance() with protocols
 
 You can use a protocol class with :py:func:`isinstance` if you decorate it
 with the ``@runtime_checkable`` class decorator. The decorator adds
-support for basic runtime structural checks:
+rudimentary support for runtime structural checks:
 
 .. code-block:: python
 
@@ -214,16 +270,23 @@ support for basic runtime structural checks:
    def use(handles: int) -> None: ...
 
    mug = Mug()
-   if isinstance(mug, Portable):
-      use(mug.handles)  # Works statically and at runtime
+   if isinstance(mug, Portable):  # Works at runtime!
+      use(mug.handles)
 
 :py:func:`isinstance` also works with the :ref:`predefined protocols <predefined_protocols>`
 in :py:mod:`typing` such as :py:class:`~typing.Iterable`.
 
-.. note::
+.. warning::
    :py:func:`isinstance` with protocols is not completely safe at runtime.
    For example, signatures of methods are not checked. The runtime
-   implementation only checks that all protocol members are defined.
+   implementation only checks that all protocol members exist,
+   not that they have the correct type. :py:func:`issubclass` with protocols
+   will only check for the existence of methods.
+
+.. note::
+   :py:func:`isinstance` with protocols can also be surprisingly slow.
+   In many cases, you're better served by using :py:func:`hasattr` to
+   check for the presence of attributes.
 
 .. _callback_protocols:
 

From 9aa1776fe43109c4393f052dc149b258ae6f6694 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 2 Feb 2023 12:43:02 -0800
Subject: [PATCH 221/231] Improve Generics docs page (#14587)

Linking https://github.com/python/mypy/issues/13681
---
 docs/source/generics.rst | 474 ++++++++++++++++++++++-----------------
 1 file changed, 262 insertions(+), 212 deletions(-)

diff --git a/docs/source/generics.rst b/docs/source/generics.rst
index a867bc863c839..d0541d52aebf4 100644
--- a/docs/source/generics.rst
+++ b/docs/source/generics.rst
@@ -50,17 +50,9 @@ Using ``Stack`` is similar to built-in container types:
    stack = Stack[int]()
    stack.push(2)
    stack.pop()
-   stack.push('x')        # Type error
+   stack.push('x')  # error: Argument 1 to "push" of "Stack" has incompatible type "str"; expected "int"
 
-Type inference works for user-defined generic types as well:
-
-.. code-block:: python
-
-   def process(stack: Stack[int]) -> None: ...
-
-   process(Stack())   # Argument has inferred type Stack[int]
-
-Construction of instances of generic types is also type checked:
+Construction of instances of generic types is type checked:
 
 .. code-block:: python
 
@@ -68,77 +60,17 @@ Construction of instances of generic types is also type checked:
        def __init__(self, content: T) -> None:
            self.content = content
 
-   Box(1)  # OK, inferred type is Box[int]
+   Box(1)       # OK, inferred type is Box[int]
    Box[int](1)  # Also OK
-   s = 'some string'
-   Box[int](s)  # Type error
-
-Generic class internals
-***********************
-
-You may wonder what happens at runtime when you index
-``Stack``. Indexing ``Stack`` returns a *generic alias*
-to ``Stack`` that returns instances of the original class on
-instantiation:
-
-.. code-block:: python
-
-   >>> print(Stack)
-   __main__.Stack
-   >>> print(Stack[int])
-   __main__.Stack[int]
-   >>> print(Stack[int]().__class__)
-   __main__.Stack
-
-Generic aliases can be instantiated or subclassed, similar to real
-classes, but the above examples illustrate that type variables are
-erased at runtime. Generic ``Stack`` instances are just ordinary
-Python objects, and they have no extra runtime overhead or magic due
-to being generic, other than a metaclass that overloads the indexing
-operator.
-
-Note that in Python 3.8 and lower, the built-in types
-:py:class:`list`, :py:class:`dict` and others do not support indexing.
-This is why we have the aliases :py:class:`~typing.List`,
-:py:class:`~typing.Dict` and so on in the :py:mod:`typing`
-module. Indexing these aliases gives you a generic alias that
-resembles generic aliases constructed by directly indexing the target
-class in more recent versions of Python:
-
-.. code-block:: python
-
-   >>> # Only relevant for Python 3.8 and below
-   >>> # For Python 3.9 onwards, prefer `list[int]` syntax
-   >>> from typing import List
-   >>> List[int]
-   typing.List[int]
-
-Note that the generic aliases in ``typing`` don't support constructing
-instances:
-
-.. code-block:: python
-
-   >>> from typing import List
-   >>> List[int]()
-   Traceback (most recent call last):
-   ...
-   TypeError: Type List cannot be instantiated; use list() instead
-
-.. note::
-
-   In Python 3.6 indexing generic types or type aliases results in actual
-   type objects. This means that generic types in type annotations can
-   have a significant runtime cost. This was changed in Python 3.7, and
-   indexing generic types became a cheap operation.
+   Box[int]('some string')  # error: Argument 1 to "Box" has incompatible type "str"; expected "int"
 
 .. _generic-subclasses:
 
-Defining sub-classes of generic classes
-***************************************
+Defining subclasses of generic classes
+**************************************
 
 User-defined generic classes and generic classes defined in :py:mod:`typing`
-can be used as base classes for another classes, both generic and
-non-generic. For example:
+can be used as a base class for another class (generic or non-generic). For example:
 
 .. code-block:: python
 
@@ -147,29 +79,29 @@ non-generic. For example:
    KT = TypeVar('KT')
    VT = TypeVar('VT')
 
-   class MyMap(Mapping[KT, VT]):  # This is a generic subclass of Mapping
-       def __getitem__(self, k: KT) -> VT:
-           ...  # Implementations omitted
-       def __iter__(self) -> Iterator[KT]:
-           ...
-       def __len__(self) -> int:
-           ...
+   # This is a generic subclass of Mapping
+   class MyMap(Mapping[KT, VT]):
+       def __getitem__(self, k: KT) -> VT: ...
+       def __iter__(self) -> Iterator[KT]: ...
+       def __len__(self) -> int: ...
 
-   items: MyMap[str, int]  # Okay
+   items: MyMap[str, int]  # OK
 
-   class StrDict(dict[str, str]):  # This is a non-generic subclass of dict
+   # This is a non-generic subclass of dict
+   class StrDict(dict[str, str]):
        def __str__(self) -> str:
            return f'StrDict({super().__str__()})'
 
+
    data: StrDict[int, int]  # Error! StrDict is not generic
    data2: StrDict  # OK
 
+   # This is a user-defined generic class
    class Receiver(Generic[T]):
-       def accept(self, value: T) -> None:
-           ...
+       def accept(self, value: T) -> None: ...
 
-   class AdvancedReceiver(Receiver[T]):
-       ...
+   # This is a generic subclass of Receiver
+   class AdvancedReceiver(Receiver[T]): ...
 
 .. note::
 
@@ -215,15 +147,16 @@ For example:
 Generic functions
 *****************
 
-Generic type variables can also be used to define generic functions:
+Type variables can be used to define generic functions:
 
 .. code-block:: python
 
    from typing import TypeVar, Sequence
 
-   T = TypeVar('T')      # Declare type variable
+   T = TypeVar('T')
 
-   def first(seq: Sequence[T]) -> T:   # Generic function
+   # A generic function!
+   def first(seq: Sequence[T]) -> T:
        return seq[0]
 
 As with generic classes, the type variable can be replaced with any
@@ -232,10 +165,8 @@ return type is derived from the sequence item type. For example:
 
 .. code-block:: python
 
-   # Assume first defined as above.
-
-   s = first('foo')      # s has type str.
-   n = first([1, 2, 3])  # n has type int.
+   reveal_type(first([1, 2, 3]))   # Revealed type is "builtins.int"
+   reveal_type(first(['a', 'b']))  # Revealed type is "builtins.str"
 
 Note also that a single definition of a type variable (such as ``T``
 above) can be used in multiple generic functions or classes. In this
@@ -399,51 +330,84 @@ relations between them: invariant, covariant, and contravariant.
 Assuming that we have a pair of types ``A`` and ``B``, and ``B`` is
 a subtype of ``A``, these are defined as follows:
 
-* A generic class ``MyCovGen[T, ...]`` is called covariant in type variable
-  ``T`` if ``MyCovGen[B, ...]`` is always a subtype of ``MyCovGen[A, ...]``.
-* A generic class ``MyContraGen[T, ...]`` is called contravariant in type
-  variable ``T`` if ``MyContraGen[A, ...]`` is always a subtype of
-  ``MyContraGen[B, ...]``.
-* A generic class ``MyInvGen[T, ...]`` is called invariant in ``T`` if neither
+* A generic class ``MyCovGen[T]`` is called covariant in type variable
+  ``T`` if ``MyCovGen[B]`` is always a subtype of ``MyCovGen[A]``.
+* A generic class ``MyContraGen[T]`` is called contravariant in type
+  variable ``T`` if ``MyContraGen[A]`` is always a subtype of
+  ``MyContraGen[B]``.
+* A generic class ``MyInvGen[T]`` is called invariant in ``T`` if neither
   of the above is true.
 
 Let us illustrate this by few simple examples:
 
-* :py:data:`~typing.Union` is covariant in all variables: ``Union[Cat, int]`` is a subtype
-  of ``Union[Animal, int]``,
-  ``Union[Dog, int]`` is also a subtype of ``Union[Animal, int]``, etc.
-  Most immutable containers such as :py:class:`~typing.Sequence` and :py:class:`~typing.FrozenSet` are also
-  covariant.
-* :py:data:`~typing.Callable` is an example of type that behaves contravariant in types of
-  arguments, namely ``Callable[[Employee], int]`` is a subtype of
-  ``Callable[[Manager], int]``. To understand this, consider a function:
+.. code-block:: python
+
+    # We'll use these classes in the examples below
+    class Shape: ...
+    class Triangle(Shape): ...
+    class Square(Shape): ...
+
+* Most immutable containers, such as :py:class:`~typing.Sequence` and
+  :py:class:`~typing.FrozenSet` are covariant. :py:data:`~typing.Union` is
+  also covariant in all variables: ``Union[Triangle, int]`` is
+  a subtype of ``Union[Shape, int]``.
 
   .. code-block:: python
 
-     def salaries(staff: list[Manager],
-                  accountant: Callable[[Manager], int]) -> list[int]: ...
+    def count_lines(shapes: Sequence[Shape]) -> int:
+        return sum(shape.num_sides for shape in shapes)
 
-  This function needs a callable that can calculate a salary for managers, and
-  if we give it a callable that can calculate a salary for an arbitrary
-  employee, it's still safe.
-* :py:class:`~typing.List` is an invariant generic type. Naively, one would think
-  that it is covariant, but let us consider this code:
+    triangles: Sequence[Triangle]
+    count_lines(triangles)  # OK
+
+    def foo(triangle: Triangle, num: int):
+        shape_or_number: Union[Shape, int]
+        # a Triangle is a Shape, and a Shape is a valid Union[Shape, int]
+        shape_or_number = triangle
+
+  Covariance should feel relatively intuitive, but contravariance and invariance
+  can be harder to reason about.
+
+* :py:data:`~typing.Callable` is an example of type that behaves contravariant
+  in types of arguments. That is, ``Callable[[Shape], int]`` is a subtype of
+  ``Callable[[Triangle], int]``, despite ``Shape`` being a supertype of
+  ``Triangle``. To understand this, consider:
 
   .. code-block:: python
 
-     class Shape:
-         pass
+    def cost_of_paint_required(
+        triangle: Triangle,
+        area_calculator: Callable[[Triangle], float]
+    ) -> float:
+        return area_calculator(triangle) * DOLLAR_PER_SQ_FT
+
+    # This straightforwardly works
+    def area_of_triangle(triangle: Triangle) -> float: ...
+    cost_of_paint_required(triangle, area_of_triangle)  # OK
+
+    # But this works as well!
+    def area_of_any_shape(shape: Shape) -> float: ...
+    cost_of_paint_required(triangle, area_of_any_shape)  # OK
+
+  ``cost_of_paint_required`` needs a callable that can calculate the area of a
+  triangle. If we give it a callable that can calculate the area of an
+  arbitrary shape (not just triangles), everything still works.
+
+* :py:class:`~typing.List` is an invariant generic type. Naively, one would think
+  that it is covariant, like :py:class:`~typing.Sequence` above, but consider this code:
+
+  .. code-block:: python
 
      class Circle(Shape):
-         def rotate(self):
-             ...
+         # The rotate method is only defined on Circle, not on Shape
+         def rotate(self): ...
 
      def add_one(things: list[Shape]) -> None:
          things.append(Shape())
 
-     my_things: list[Circle] = []
-     add_one(my_things)     # This may appear safe, but...
-     my_things[0].rotate()  # ...this will fail
+     my_circles: list[Circle] = []
+     add_one(my_circles)     # This may appear safe, but...
+     my_circles[-1].rotate()  # ...this will fail, since my_circles[0] is now a Shape, not a Circle
 
   Another example of invariant type is :py:class:`~typing.Dict`. Most mutable containers
   are invariant.
@@ -471,6 +435,45 @@ type variables defined with special keyword arguments ``covariant`` or
    my_box = Box(Cat())
    look_into(my_box)  # OK, but mypy would complain here for an invariant type
 
+.. _type-variable-upper-bound:
+
+Type variables with upper bounds
+********************************
+
+A type variable can also be restricted to having values that are
+subtypes of a specific type. This type is called the upper bound of
+the type variable, and is specified with the ``bound=...`` keyword
+argument to :py:class:`~typing.TypeVar`.
+
+.. code-block:: python
+
+   from typing import TypeVar, SupportsAbs
+
+   T = TypeVar('T', bound=SupportsAbs[float])
+
+In the definition of a generic function that uses such a type variable
+``T``, the type represented by ``T`` is assumed to be a subtype of
+its upper bound, so the function can use methods of the upper bound on
+values of type ``T``.
+
+.. code-block:: python
+
+   def largest_in_absolute_value(*xs: T) -> T:
+       return max(xs, key=abs)  # Okay, because T is a subtype of SupportsAbs[float].
+
+In a call to such a function, the type ``T`` must be replaced by a
+type that is a subtype of its upper bound. Continuing the example
+above:
+
+.. code-block:: python
+
+   largest_in_absolute_value(-3.5, 2)   # Okay, has type float.
+   largest_in_absolute_value(5+6j, 7)   # Okay, has type complex.
+   largest_in_absolute_value('a', 'b')  # Error: 'str' is not a subtype of SupportsAbs[float].
+
+Type parameters of generic classes may also have upper bounds, which
+restrict the valid values for the type parameter in the same way.
+
 .. _type-variable-value-restriction:
 
 Type variables with value restriction
@@ -505,7 +508,7 @@ argument types:
    concat(b'a', b'b')  # Okay
    concat(1, 2)        # Error!
 
-Note that this is different from a union type, since combinations
+Importantly, this is different from a union type, since combinations
 of ``str`` and ``bytes`` are not accepted:
 
 .. code-block:: python
@@ -513,8 +516,8 @@ of ``str`` and ``bytes`` are not accepted:
    concat('string', b'bytes')   # Error!
 
 In this case, this is exactly what we want, since it's not possible
-to concatenate a string and a bytes object! The type checker
-will reject this function:
+to concatenate a string and a bytes object! If we tried to use
+``Union``, the type checker would complain about this possibility:
 
 .. code-block:: python
 
@@ -529,10 +532,13 @@ subtype of ``str``:
     class S(str): pass
 
     ss = concat(S('foo'), S('bar'))
+    reveal_type(ss)  # Revealed type is "builtins.str"
 
 You may expect that the type of ``ss`` is ``S``, but the type is
 actually ``str``: a subtype gets promoted to one of the valid values
-for the type variable, which in this case is ``str``. This is thus
+for the type variable, which in this case is ``str``.
+
+This is thus
 subtly different from *bounded quantification* in languages such as
 Java, where the return type would be ``S``. The way mypy implements
 this is correct for ``concat``, since ``concat`` actually returns a
@@ -548,66 +554,25 @@ values when defining a generic class. For example, mypy uses the type
 :py:class:`Pattern[AnyStr] <typing.Pattern>` for the return value of :py:func:`re.compile`,
 since regular expressions can be based on a string or a bytes pattern.
 
-.. _type-variable-upper-bound:
-
-Type variables with upper bounds
-********************************
-
-A type variable can also be restricted to having values that are
-subtypes of a specific type. This type is called the upper bound of
-the type variable, and is specified with the ``bound=...`` keyword
-argument to :py:class:`~typing.TypeVar`.
-
-.. code-block:: python
-
-   from typing import TypeVar, SupportsAbs
-
-   T = TypeVar('T', bound=SupportsAbs[float])
-
-In the definition of a generic function that uses such a type variable
-``T``, the type represented by ``T`` is assumed to be a subtype of
-its upper bound, so the function can use methods of the upper bound on
-values of type ``T``.
-
-.. code-block:: python
-
-   def largest_in_absolute_value(*xs: T) -> T:
-       return max(xs, key=abs)  # Okay, because T is a subtype of SupportsAbs[float].
-
-In a call to such a function, the type ``T`` must be replaced by a
-type that is a subtype of its upper bound. Continuing the example
-above,
-
-.. code-block:: python
-
-   largest_in_absolute_value(-3.5, 2)   # Okay, has type float.
-   largest_in_absolute_value(5+6j, 7)   # Okay, has type complex.
-   largest_in_absolute_value('a', 'b')  # Error: 'str' is not a subtype of SupportsAbs[float].
-
-Type parameters of generic classes may also have upper bounds, which
-restrict the valid values for the type parameter in the same way.
-
 A type variable may not have both a value restriction (see
-:ref:`type-variable-value-restriction`) and an upper bound.
+:ref:`type-variable-upper-bound`) and an upper bound.
 
 .. _declaring-decorators:
 
 Declaring decorators
 ********************
 
-One common application of type variables along with parameter specifications
-is in declaring a decorator that preserves the signature of the function it decorates.
-
-Note that class decorators are handled differently than function decorators in
-mypy: decorating a class does not erase its type, even if the decorator has
-incomplete type annotations.
+Decorators are typically functions that take a function as an argument and
+return another function. Describing this behaviour in terms of types can
+be a little tricky; we'll show how you can use ``TypeVar`` and a special
+kind of type variable called a *parameter specification* to do so.
 
 Suppose we have the following decorator, not type annotated yet,
 that preserves the original function's signature and merely prints the decorated function's name:
 
 .. code-block:: python
 
-   def my_decorator(func):
+   def printing_decorator(func):
        def wrapper(*args, **kwds):
            print("Calling", func)
            return func(*args, **kwds)
@@ -618,20 +583,28 @@ and we use it to decorate function ``add_forty_two``:
 .. code-block:: python
 
    # A decorated function.
-   @my_decorator
+   @printing_decorator
    def add_forty_two(value: int) -> int:
        return value + 42
 
    a = add_forty_two(3)
 
-Since ``my_decorator`` is not type-annotated, the following won't get type-checked:
+Since ``printing_decorator`` is not type-annotated, the following won't get type checked:
 
 .. code-block:: python
 
-   reveal_type(a)  # revealed type: Any
-   add_forty_two('foo')  # no type-checker error :(
+   reveal_type(a)        # Revealed type is "Any"
+   add_forty_two('foo')  # No type checker error :(
+
+This is a sorry state of affairs! If you run with ``--strict``, mypy will
+even alert you to this fact:
+``Untyped decorator makes function "add_forty_two" untyped``
+
+Note that class decorators are handled differently than function decorators in
+mypy: decorating a class does not erase its type, even if the decorator has
+incomplete type annotations.
 
-Before parameter specifications, here's how one might have annotated the decorator:
+Here's how one could annotate the decorator:
 
 .. code-block:: python
 
@@ -640,50 +613,58 @@ Before parameter specifications, here's how one might have annotated the decorat
    F = TypeVar('F', bound=Callable[..., Any])
 
    # A decorator that preserves the signature.
-   def my_decorator(func: F) -> F:
+   def printing_decorator(func: F) -> F:
        def wrapper(*args, **kwds):
            print("Calling", func)
            return func(*args, **kwds)
        return cast(F, wrapper)
 
-and that would enable the following type checks:
-
-.. code-block:: python
+   @printing_decorator
+   def add_forty_two(value: int) -> int:
+       return value + 42
 
-   reveal_type(a)  # Revealed type is "builtins.int"
+   a = add_forty_two(3)
+   reveal_type(a)      # Revealed type is "builtins.int"
    add_forty_two('x')  # Argument 1 to "add_forty_two" has incompatible type "str"; expected "int"
 
+This still has some shortcomings. First, we need to use the unsafe
+:py:func:`~typing.cast` to convince mypy that ``wrapper()`` has the same
+signature as ``func``. See :ref:`casts <casts>`.
 
-Note that the ``wrapper()`` function is not type-checked. Wrapper
-functions are typically small enough that this is not a big
+Second, the ``wrapper()`` function is not tightly type checked, although
+wrapper functions are typically small enough that this is not a big
 problem. This is also the reason for the :py:func:`~typing.cast` call in the
-``return`` statement in ``my_decorator()``. See :ref:`casts <casts>`.  However,
-with the introduction of parameter specifications in mypy 0.940, we can now
-have a more faithful type annotation:
+``return`` statement in ``printing_decorator()``.
+
+However, we can use a parameter specification (:py:class:`~typing.ParamSpec`),
+for a more faithful type annotation:
 
 .. code-block:: python
 
-   from typing import Callable, ParamSpec, TypeVar
+   from typing import Callable, TypeVar
+   from typing_extensions import ParamSpec
 
    P = ParamSpec('P')
    T = TypeVar('T')
 
-   def my_decorator(func: Callable[P, T]) -> Callable[P, T]:
+   def printing_decorator(func: Callable[P, T]) -> Callable[P, T]:
        def wrapper(*args: P.args, **kwds: P.kwargs) -> T:
            print("Calling", func)
            return func(*args, **kwds)
        return wrapper
 
-When the decorator alters the signature, parameter specifications truly show their potential:
+Parameter specifications also allow you to describe decorators that
+alter the signature of the input function:
 
 .. code-block:: python
 
-   from typing import Callable, ParamSpec, TypeVar
+   from typing import Callable, TypeVar
+   from typing_extensions import ParamSpec
 
    P = ParamSpec('P')
    T = TypeVar('T')
 
-    # Note: We reuse 'P' in the return type, but replace 'T' with 'str'
+    # We reuse 'P' in the return type, but replace 'T' with 'str'
    def stringify(func: Callable[P, T]) -> Callable[P, str]:
        def wrapper(*args: P.args, **kwds: P.kwargs) -> str:
            return str(func(*args, **kwds))
@@ -694,9 +675,30 @@ When the decorator alters the signature, parameter specifications truly show the
         return value + 42
 
     a = add_forty_two(3)
-    reveal_type(a)  # str
-    foo('x')    # Type check error: incompatible type "str"; expected "int"
+    reveal_type(a)      # Revealed type is "builtins.str"
+    add_forty_two('x')  # error: Argument 1 to "add_forty_two" has incompatible type "str"; expected "int"
 
+Or insert an argument:
+
+.. code-block:: python
+
+    from typing import Callable, TypeVar
+    from typing_extensions import Concatenate, ParamSpec
+
+    P = ParamSpec('P')
+    T = TypeVar('T')
+
+    def printing_decorator(func: Callable[P, T]) -> Callable[Concatenate[str, P], T]:
+        def wrapper(msg: str, /, *args: P.args, **kwds: P.kwargs) -> T:
+            print("Calling", func, "with", msg)
+            return func(*args, **kwds)
+        return wrapper
+
+    @printing_decorator
+    def add_forty_two(value: int) -> int:
+        return value + 42
+
+    a = add_forty_two('three', 3)
 
 .. _decorator-factories:
 
@@ -786,9 +788,8 @@ protocols mostly follow the normal rules for generic classes. Example:
    y: Box[int] = ...
    x = y  # Error -- Box is invariant
 
-Per :pep:`PEP 544: Generic protocols <544#generic-protocols>`, ``class
-ClassName(Protocol[T])`` is allowed as a shorthand for ``class
-ClassName(Protocol, Generic[T])``.
+Note that ``class ClassName(Protocol[T])`` is allowed as a shorthand for
+``class ClassName(Protocol, Generic[T])``, as per :pep:`PEP 544: Generic protocols <544#generic-protocols>`,
 
 The main difference between generic protocols and ordinary generic
 classes is that mypy checks that the declared variances of generic
@@ -799,20 +800,18 @@ variable is invariant:
 
 .. code-block:: python
 
-   from typing import TypeVar
-   from typing_extensions import Protocol
+   from typing import Protocol, TypeVar
 
    T = TypeVar('T')
 
-   class ReadOnlyBox(Protocol[T]):  # Error: covariant type variable expected
+   class ReadOnlyBox(Protocol[T]):  # error: Invariant type variable "T" used in protocol where covariant one is expected
        def content(self) -> T: ...
 
 This example correctly uses a covariant type variable:
 
 .. code-block:: python
 
-   from typing import TypeVar
-   from typing_extensions import Protocol
+   from typing import Protocol, TypeVar
 
    T_co = TypeVar('T_co', covariant=True)
 
@@ -837,16 +836,12 @@ Generic protocols can also be recursive. Example:
 
    class L:
        val: int
+       def next(self) -> 'L': ...
 
-       ...  # details omitted
-
-       def next(self) -> 'L':
-           ...  # details omitted
-
-   def last(seq: Linked[T]) -> T:
-       ...  # implementation omitted
+   def last(seq: Linked[T]) -> T: ...
 
-   result = last(L())  # Inferred type of 'result' is 'int'
+   result = last(L())
+   reveal_type(result)  # Revealed type is "builtins.int"
 
 .. _generic-type-aliases:
 
@@ -918,3 +913,58 @@ defeating the purpose of using aliases.  Example:
 
 Using type variable bounds or values in generic aliases, has the same effect
 as in generic classes/functions.
+
+
+Generic class internals
+***********************
+
+You may wonder what happens at runtime when you index a generic class.
+Indexing returns a *generic alias* to the original class that returns instances
+of the original class on instantiation:
+
+.. code-block:: python
+
+   >>> from typing import TypeVar, Generic
+   >>> T = TypeVar('T')
+   >>> class Stack(Generic[T]): ...
+   >>> Stack
+   __main__.Stack
+   >>> Stack[int]
+   __main__.Stack[int]
+   >>> instance = Stack[int]()
+   >>> instance.__class__
+   __main__.Stack
+
+Generic aliases can be instantiated or subclassed, similar to real
+classes, but the above examples illustrate that type variables are
+erased at runtime. Generic ``Stack`` instances are just ordinary
+Python objects, and they have no extra runtime overhead or magic due
+to being generic, other than a metaclass that overloads the indexing
+operator.
+
+Note that in Python 3.8 and lower, the built-in types
+:py:class:`list`, :py:class:`dict` and others do not support indexing.
+This is why we have the aliases :py:class:`~typing.List`,
+:py:class:`~typing.Dict` and so on in the :py:mod:`typing`
+module. Indexing these aliases gives you a generic alias that
+resembles generic aliases constructed by directly indexing the target
+class in more recent versions of Python:
+
+.. code-block:: python
+
+   >>> # Only relevant for Python 3.8 and below
+   >>> # For Python 3.9 onwards, prefer `list[int]` syntax
+   >>> from typing import List
+   >>> List[int]
+   typing.List[int]
+
+Note that the generic aliases in ``typing`` don't support constructing
+instances:
+
+.. code-block:: python
+
+   >>> from typing import List
+   >>> List[int]()
+   Traceback (most recent call last):
+   ...
+   TypeError: Type List cannot be instantiated; use list() instead

From 8ef98cc7cdc884cd078c9867608cc8a89a68df1b Mon Sep 17 00:00:00 2001
From: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
Date: Wed, 1 Feb 2023 23:28:15 +0000
Subject: [PATCH 222/231] Various documentation and error message tweaks
 (#14574)

I looked at `git diff v0.991 master -- docs` and did some editing. There
no major changes to content. Also updated one error message.
---
 docs/source/error_code_list2.rst   | 42 +++++++++++++++---------
 docs/source/generics.rst           | 51 +++++++++++++++++-------------
 docs/source/index.rst              |  2 +-
 mypy/semanal.py                    |  2 +-
 test-data/unit/check-selftype.test |  4 +--
 5 files changed, 60 insertions(+), 41 deletions(-)

diff --git a/docs/source/error_code_list2.rst b/docs/source/error_code_list2.rst
index 85ab76da5cee7..f160515f0a9e1 100644
--- a/docs/source/error_code_list2.rst
+++ b/docs/source/error_code_list2.rst
@@ -85,8 +85,11 @@ Example:
 Check that methods do not have redundant Self annotations [redundant-self]
 --------------------------------------------------------------------------
 
-Such annotations are allowed by :pep:`673` but are redundant, so if you want
-warnings about them, enable this error code.
+If a method uses the ``Self`` type in the return type or the type of a
+non-self argument, there is no need to annotate the ``self`` argument
+explicitly. Such annotations are allowed by :pep:`673` but are
+redundant. If you enable this error code, mypy will generate an error if
+there is a redundant ``Self`` type.
 
 Example:
 
@@ -97,7 +100,7 @@ Example:
    from typing import Self
 
    class C:
-       # Error: Redundant Self annotation on method first argument
+       # Error: Redundant "Self" annotation for the first method argument
        def copy(self: Self) -> Self:
            return type(self)()
 
@@ -236,29 +239,34 @@ mypy generates an error if it thinks that an expression is redundant.
 Check that expression is not implicitly true in boolean context [truthy-bool]
 -----------------------------------------------------------------------------
 
-Warn when an expression whose type does not implement ``__bool__`` or ``__len__`` is used in boolean context,
-since unless implemented by a sub-type, the expression will always evaluate to true.
+Warn when the type of an expression in a boolean context does not
+implement ``__bool__`` or ``__len__``. Unless one of these is
+implemented by a subtype, the expression will always be considered
+true, and there may be a bug in the condition.
+
+As an exception, the ``object`` type is allowed in a boolean context.
+Using an iterable value in a boolean context has a separate error code
+(see below).
 
 .. code-block:: python
 
     # Use "mypy --enable-error-code truthy-bool ..."
 
     class Foo:
-      pass
+        pass
     foo = Foo()
     # Error: "foo" has type "Foo" which does not implement __bool__ or __len__ so it could always be true in boolean context
     if foo:
-       ...
-
-The check is similar in concept to ensuring that an expression's type implements an expected interface (e.g. ``Sized``),
-except that attempting to invoke an undefined method (e.g. ``__len__``) results in an error,
-while attempting to evaluate an object in boolean context without a concrete implementation results in a truthy value.
+         ...
 
 
 Check that iterable is not implicitly true in boolean context [truthy-iterable]
 -------------------------------------------------------------------------------
 
-``Iterable`` does not implement ``__len__`` and so this code will be flagged:
+Generate an error if a value of type ``Iterable`` is used as a boolean
+condition, since ``Iterable`` does not implement ``__len__`` or ``__bool__``.
+
+Example:
 
 .. code-block:: python
 
@@ -270,9 +278,13 @@ Check that iterable is not implicitly true in boolean context [truthy-iterable]
             return [42]
         return [x + 1 for x in items]
 
-If called with a ``Generator`` like ``int(x) for x in []``, this function would not return ``[42]`` unlike
-what the author might have intended. Of course it's possible that ``transform`` is only passed ``list`` objects,
-and so there is no error in practice. In such case, it is recommended to annotate ``items: Collection[int]``.
+If ``transform`` is called with a ``Generator`` argument, such as
+``int(x) for x in []``, this function would not return ``[42]`` unlike
+what might be intended. Of course, it's possible that ``transform`` is
+only called with ``list`` or other container objects, and the ``if not
+items`` check is actually valid. If that is the case, it is
+recommended to annotate ``items`` as ``Collection[int]`` instead of
+``Iterable[int]``.
 
 
 .. _ignore-without-code:
diff --git a/docs/source/generics.rst b/docs/source/generics.rst
index d0541d52aebf4..9ac79f90121de 100644
--- a/docs/source/generics.rst
+++ b/docs/source/generics.rst
@@ -193,10 +193,11 @@ Generic methods and generic self
 ********************************
 
 You can also define generic methods — just use a type variable in the
-method signature that is different from class type variables. In particular,
-``self`` may also be generic, allowing a method to return the most precise
-type known at the point of access. In this way, for example, you can typecheck
-chaining of setter methods:
+method signature that is different from class type variables. In
+particular, the ``self`` argument may also be generic, allowing a
+method to return the most precise type known at the point of access.
+In this way, for example, you can type check a chain of setter
+methods:
 
 .. code-block:: python
 
@@ -222,7 +223,9 @@ chaining of setter methods:
    circle: Circle = Circle().set_scale(0.5).set_radius(2.7)
    square: Square = Square().set_scale(0.5).set_width(3.2)
 
-Without using generic ``self``, the last two lines could not be type-checked properly.
+Without using generic ``self``, the last two lines could not be type
+checked properly, since the return type of ``set_scale`` would be
+``Shape``, which doesn't define ``set_radius`` or ``set_width``.
 
 Other uses are factory methods, such as copy and deserialization.
 For class methods, you can also define generic ``cls``, using :py:class:`Type[T] <typing.Type>`:
@@ -255,16 +258,18 @@ In the latter case, you must implement this method in all future subclasses.
 Note also that mypy cannot always verify that the implementation of a copy
 or a deserialization method returns the actual type of self. Therefore
 you may need to silence mypy inside these methods (but not at the call site),
-possibly by making use of the ``Any`` type.
+possibly by making use of the ``Any`` type or a ``# type: ignore`` comment.
 
-Note that this feature may accept some unsafe code for the purpose of
-*practicality*. For example:
+Note that mypy lets you use generic self types in certain unsafe ways
+in order to support common idioms. For example, using a generic
+self type in an argument type is accepted even though it's unsafe:
 
 .. code-block:: python
 
    from typing import TypeVar
 
    T = TypeVar("T")
+
    class Base:
        def compare(self: T, other: T) -> bool:
            return False
@@ -273,25 +278,27 @@ Note that this feature may accept some unsafe code for the purpose of
        def __init__(self, x: int) -> None:
            self.x = x
 
-       # This is unsafe (see below), but allowed because it is
-       # a common pattern, and rarely causes issues in practice.
+       # This is unsafe (see below) but allowed because it's
+       # a common pattern and rarely causes issues in practice.
        def compare(self, other: Sub) -> bool:
            return self.x > other.x
 
    b: Base = Sub(42)
    b.compare(Base())  # Runtime error here: 'Base' object has no attribute 'x'
 
-For some advanced uses of self-types see :ref:`additional examples <advanced_self>`.
+For some advanced uses of self types, see :ref:`additional examples <advanced_self>`.
 
 Automatic self types using typing.Self
 **************************************
 
-The patterns described above are quite common, so there is a syntactic sugar
-for them introduced in :pep:`673`. Instead of defining a type variable and
-using an explicit ``self`` annotation, you can import a magic type ``typing.Self``
-that is automatically transformed into a type variable with an upper bound of
-current class, and you don't need an annotation for ``self`` (or ``cls`` for
-class methods). The above example can thus be rewritten as:
+Since the patterns described above are quite common, mypy supports a
+simpler syntax, introduced in :pep:`673`, to make them easier to use.
+Instead of defining a type variable and using an explicit annotation
+for ``self``, you can import the special type ``typing.Self`` that is
+automatically transformed into a type variable with the current class
+as the upper bound, and you don't need an annotation for ``self`` (or
+``cls`` in class methods). The example from the previous section can
+be made simpler by using ``Self``:
 
 .. code-block:: python
 
@@ -312,13 +319,13 @@ class methods). The above example can thus be rewritten as:
 
    a, b = SuperFriend.make_pair()
 
-This is more compact than using explicit type variables, plus additionally
-you can use ``Self`` in attribute annotations, not just in methods.
+This is more compact than using explicit type variables. Also, you can
+use ``Self`` in attribute annotations in addition to methods.
 
 .. note::
 
-   To use this feature on versions of Python before 3.11, you will need to
-   import ``Self`` from ``typing_extensions`` version 4.0 or newer.
+   To use this feature on Python versions earlier than 3.11, you will need to
+   import ``Self`` from ``typing_extensions`` (version 4.0 or newer).
 
 .. _variance-of-generics:
 
@@ -911,7 +918,7 @@ defeating the purpose of using aliases.  Example:
 
     OIntVec = Optional[Vec[int]]
 
-Using type variable bounds or values in generic aliases, has the same effect
+Using type variable bounds or values in generic aliases has the same effect
 as in generic classes/functions.
 
 
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 067f37cdc58c9..7ab3edebad397 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -39,7 +39,7 @@ understand, debug, and maintain.
 
 .. note::
 
-   Although mypy is production ready, there will be occasional changes
+   Although mypy is production ready, there may be occasional changes
    that break backward compatibility. The mypy development team tries to
    minimize the impact of changes to user code. In case of a major breaking
    change, mypy's major version will be bumped.
diff --git a/mypy/semanal.py b/mypy/semanal.py
index 15566c9396c64..203f9b3d153e8 100644
--- a/mypy/semanal.py
+++ b/mypy/semanal.py
@@ -972,7 +972,7 @@ def prepare_method_signature(self, func: FuncDef, info: TypeInfo, has_self_type:
                             # This error is off by default, since it is explicitly allowed
                             # by the PEP 673.
                             self.fail(
-                                "Redundant Self annotation on method first argument",
+                                'Redundant "Self" annotation for the first method argument',
                                 func,
                                 code=codes.REDUNDANT_SELF_TYPE,
                             )
diff --git a/test-data/unit/check-selftype.test b/test-data/unit/check-selftype.test
index 2d45d28764a05..555cef3641f8e 100644
--- a/test-data/unit/check-selftype.test
+++ b/test-data/unit/check-selftype.test
@@ -1627,13 +1627,13 @@ class C:
 from typing import Self, Type
 
 class C:
-    def copy(self: Self) -> Self:  # E: Redundant Self annotation on method first argument
+    def copy(self: Self) -> Self:  # E: Redundant "Self" annotation for the first method argument
         d: Defer
         class Defer: ...
         return self
 
     @classmethod
-    def g(cls: Type[Self]) -> Self:  # E: Redundant Self annotation on method first argument
+    def g(cls: Type[Self]) -> Self:  # E: Redundant "Self" annotation for the first method argument
         d: DeferAgain
         class DeferAgain: ...
         return cls()

From c2876bf6806137579d11a74abe524c99fc226326 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Fri, 3 Feb 2023 10:22:20 -0800
Subject: [PATCH 223/231] [1.0 backport] [used before def] add documentation
 (#14592) (#14597)

Adding documentation for used-before-def check.
---
 docs/source/error_code_list.rst | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/docs/source/error_code_list.rst b/docs/source/error_code_list.rst
index 1a39bf8feb6cb..efafb4d01f967 100644
--- a/docs/source/error_code_list.rst
+++ b/docs/source/error_code_list.rst
@@ -89,6 +89,23 @@ This example accidentally calls ``sort()`` instead of :py:func:`sorted`:
 
     x = sort([3, 2, 4])  # Error: Name "sort" is not defined  [name-defined]
 
+
+Check that a variable is not used before it's defined [used-before-def]
+-----------------------------------------------------------------------
+
+Mypy will generate an error if a name is used before it's defined.
+While the name-defined check will catch issues with names that are undefined,
+it will not flag if a variable is used and then defined later in the scope.
+used-before-def check will catch such cases.
+
+Example:
+
+.. code-block:: python
+
+    print(x)  # Error: Name "x" is used before definition [used-before-def]
+    x = 123
+
+
 Check arguments in calls [call-arg]
 -----------------------------------
 

From bc18017c19eb81bf5c11756f4e7dede4791e2823 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Mon, 6 Feb 2023 09:49:10 -0800
Subject: [PATCH 224/231] Promote 1.0.0+dev to 1.0.0 (#14594)

In the release branch!
---
 mypy/version.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/version.py b/mypy/version.py
index b125385f9b433..e0c07b82c7f5e 100644
--- a/mypy/version.py
+++ b/mypy/version.py
@@ -8,7 +8,7 @@
 # - Release versions have the form "1.2.3".
 # - Dev versions have the form "1.2.3+dev" (PLUS sign to conform to PEP 440).
 # - Before 1.0 we had the form "0.NNN".
-__version__ = "1.0.0+dev"
+__version__ = "1.0.0"
 base_version = __version__
 
 mypy_dir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))

From b562f53110cf112eaa6f9642e9bae11a46f84e17 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Thu, 9 Feb 2023 09:13:09 -0800
Subject: [PATCH 225/231] bump version to 1.0.1+dev

---
 mypy/version.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/version.py b/mypy/version.py
index e0c07b82c7f5e..ac0237fad5d85 100644
--- a/mypy/version.py
+++ b/mypy/version.py
@@ -8,7 +8,7 @@
 # - Release versions have the form "1.2.3".
 # - Dev versions have the form "1.2.3+dev" (PLUS sign to conform to PEP 440).
 # - Before 1.0 we had the form "0.NNN".
-__version__ = "1.0.0"
+__version__ = "1.0.1+dev"
 base_version = __version__
 
 mypy_dir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))

From 0c9958583cf7c2b9ba568b19853aa63aa9d6e670 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Thu, 9 Feb 2023 09:15:17 -0800
Subject: [PATCH 226/231] [backport] Fix crash on deferred value constrained
 TypeVar (#14642) (#14655)

Fixes #14631

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
---
 mypy/types.py                            | 8 ++++++--
 test-data/unit/check-typevar-values.test | 9 +++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/mypy/types.py b/mypy/types.py
index b4710a95164ce..60145cf44527b 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -587,12 +587,16 @@ def accept(self, visitor: TypeVisitor[T]) -> T:
         return visitor.visit_type_var(self)
 
     def __hash__(self) -> int:
-        return hash((self.id, self.upper_bound))
+        return hash((self.id, self.upper_bound, tuple(self.values)))
 
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, TypeVarType):
             return NotImplemented
-        return self.id == other.id and self.upper_bound == other.upper_bound
+        return (
+            self.id == other.id
+            and self.upper_bound == other.upper_bound
+            and self.values == other.values
+        )
 
     def serialize(self) -> JsonDict:
         assert not self.id.is_meta_var()
diff --git a/test-data/unit/check-typevar-values.test b/test-data/unit/check-typevar-values.test
index d5a94f96fae7b..a4a4d68bd9fe0 100644
--- a/test-data/unit/check-typevar-values.test
+++ b/test-data/unit/check-typevar-values.test
@@ -702,3 +702,12 @@ class Indexable:
 
 [builtins fixtures/tuple.pyi]
 [builtins fixtures/classmethod.pyi]
+
+[case testTypeVarWithValueDeferral]
+from typing import TypeVar, Callable
+
+T = TypeVar("T", "A", "B")
+Func = Callable[[], T]
+
+class A: ...
+class B: ...

From c090ca2a55ef2343cc39222ffb6e503432cfe9f4 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Thu, 9 Feb 2023 09:16:08 -0800
Subject: [PATCH 227/231] [backport] [used before def] correctly handle walrus
 operator (#14646) (#14654)

Fixes #14626.

I believe changing the way that we analyze call expression makes sense
(first, we analyze the callee, then we analyze the arguments).
---
 mypy/traverser.py                  | 2 +-
 test-data/unit/check-python38.test | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/mypy/traverser.py b/mypy/traverser.py
index 378d44c67f47a..038d948522f0d 100644
--- a/mypy/traverser.py
+++ b/mypy/traverser.py
@@ -253,9 +253,9 @@ def visit_yield_expr(self, o: YieldExpr) -> None:
             o.expr.accept(self)
 
     def visit_call_expr(self, o: CallExpr) -> None:
+        o.callee.accept(self)
         for a in o.args:
             a.accept(self)
-        o.callee.accept(self)
         if o.analyzed:
             o.analyzed.accept(self)
 
diff --git a/test-data/unit/check-python38.test b/test-data/unit/check-python38.test
index c8fb1eb5aac87..bb88fcc3cff72 100644
--- a/test-data/unit/check-python38.test
+++ b/test-data/unit/check-python38.test
@@ -573,6 +573,14 @@ def foo() -> None:
     [x := x + y for y in [1, 2, 3]]
 [builtins fixtures/dict.pyi]
 
+[case testWalrusUsedBeforeDef]
+# flags: --python-version 3.8
+class C:
+    def f(self, c: 'C') -> None: pass
+
+(x := C()).f(y)  # E: Cannot determine type of "y"  # E: Name "y" is used before definition
+(y := C()).f(y)
+
 [case testOverloadWithPositionalOnlySelf]
 # flags: --python-version 3.8
 from typing import overload, Optional

From 83db0856e2680fcdd84841a5e3ddb66508f533f8 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Mon, 13 Feb 2023 07:26:05 -0800
Subject: [PATCH 228/231] [backport] [used before def] handle walrus
 declaration in match subject correctly (#14672)

Backport of #14665.
---
 mypy/partially_defined.py           |  2 +-
 test-data/unit/check-python310.test | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/mypy/partially_defined.py b/mypy/partially_defined.py
index af09493c9cae2..9b8238eff83f7 100644
--- a/mypy/partially_defined.py
+++ b/mypy/partially_defined.py
@@ -396,8 +396,8 @@ def visit_if_stmt(self, o: IfStmt) -> None:
         self.tracker.end_branch_statement()
 
     def visit_match_stmt(self, o: MatchStmt) -> None:
-        self.tracker.start_branch_statement()
         o.subject.accept(self)
+        self.tracker.start_branch_statement()
         for i in range(len(o.patterns)):
             pattern = o.patterns[i]
             pattern.accept(self)
diff --git a/test-data/unit/check-python310.test b/test-data/unit/check-python310.test
index 12fd2b43c80a9..7a934348aaf2f 100644
--- a/test-data/unit/check-python310.test
+++ b/test-data/unit/check-python310.test
@@ -1813,6 +1813,19 @@ def f1(x: int) -> int:
 
 [typing fixtures/typing-medium.pyi]
 
+[case testUsedBeforeDefMatchWalrus]
+# flags: --enable-error-code used-before-def
+import typing
+
+def f0(x: int) -> None:
+    a = y  # E: Cannot determine type of "y"  # E: Name "y" is used before definition
+    match y := x:
+        case 1:
+            b = y
+        case 2:
+            c = y
+    d = y
+
 [case testTypeAliasWithNewUnionSyntaxAndNoneLeftOperand]
 from typing import overload
 class C:

From a9051d26711905a01382587b1ab3ee7acdae090e Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Wed, 15 Feb 2023 03:41:04 -0800
Subject: [PATCH 229/231] [backport] [mypyc] Fix test case testI64Cast on
 32-bit architectures (#14700)

Backport of #14691.

Co-authored-by: Jukka Lehtosalo <jukka.lehtosalo@iki.fi>
---
 mypyc/test-data/irbuild-i64.test | 35 +++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/mypyc/test-data/irbuild-i64.test b/mypyc/test-data/irbuild-i64.test
index 47802d8e0c978..8257cfd1dbae8 100644
--- a/mypyc/test-data/irbuild-i64.test
+++ b/mypyc/test-data/irbuild-i64.test
@@ -1731,7 +1731,7 @@ def f5():
 L0:
     return 4
 
-[case testI64Cast]
+[case testI64Cast_64bit]
 from typing import cast
 from mypy_extensions import i64
 
@@ -1772,6 +1772,39 @@ L2:
 L3:
     return r3
 
+[case testI64Cast_32bit]
+from typing import cast
+from mypy_extensions import i64
+
+def cast_int(x: int) -> i64:
+    return cast(i64, x)
+[out]
+def cast_int(x):
+    x :: int
+    r0 :: native_int
+    r1 :: bit
+    r2, r3, r4 :: int64
+    r5 :: ptr
+    r6 :: c_ptr
+    r7 :: int64
+L0:
+    r0 = x & 1
+    r1 = r0 == 0
+    if r1 goto L1 else goto L2 :: bool
+L1:
+    r2 = extend signed x: builtins.int to int64
+    r3 = r2 >> 1
+    r4 = r3
+    goto L3
+L2:
+    r5 = x ^ 1
+    r6 = r5
+    r7 = CPyLong_AsInt64(r6)
+    r4 = r7
+    keep_alive x
+L3:
+    return r4
+
 [case testI64ExplicitConversionFromVariousTypes]
 from mypy_extensions import i64
 

From 18c46938e77a3ab01e6e38b57c0b3f1286966109 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <ilinskiy.sv@gmail.com>
Date: Wed, 15 Feb 2023 08:41:49 -0800
Subject: [PATCH 230/231] [Backport] Fix generic TypedDict/NamedTuple fixup
 (#14701)

Backport of  #14675.

---------

Co-authored-by: Ivan Levkivskyi <levkivskyi@gmail.com>
---
 mypy/fixup.py                         |  4 ++++
 mypy/nodes.py                         | 14 ++++++++++--
 test-data/unit/check-incremental.test | 31 +++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/mypy/fixup.py b/mypy/fixup.py
index 3593e4faa184e..af6d3f3d7b07c 100644
--- a/mypy/fixup.py
+++ b/mypy/fixup.py
@@ -80,9 +80,13 @@ def visit_type_info(self, info: TypeInfo) -> None:
             if info.tuple_type:
                 info.tuple_type.accept(self.type_fixer)
                 info.update_tuple_type(info.tuple_type)
+                if info.special_alias:
+                    info.special_alias.alias_tvars = list(info.defn.type_vars)
             if info.typeddict_type:
                 info.typeddict_type.accept(self.type_fixer)
                 info.update_typeddict_type(info.typeddict_type)
+                if info.special_alias:
+                    info.special_alias.alias_tvars = list(info.defn.type_vars)
             if info.declared_metaclass:
                 info.declared_metaclass.accept(self.type_fixer)
             if info.metaclass_type:
diff --git a/mypy/nodes.py b/mypy/nodes.py
index 98976f4fe56a6..b1c12cde99815 100644
--- a/mypy/nodes.py
+++ b/mypy/nodes.py
@@ -3473,8 +3473,13 @@ def __init__(
 
     @classmethod
     def from_tuple_type(cls, info: TypeInfo) -> TypeAlias:
-        """Generate an alias to the tuple type described by a given TypeInfo."""
+        """Generate an alias to the tuple type described by a given TypeInfo.
+
+        NOTE: this doesn't set type alias type variables (for generic tuple types),
+        they must be set by the caller (when fully analyzed).
+        """
         assert info.tuple_type
+        # TODO: is it possible to refactor this to set the correct type vars here?
         return TypeAlias(
             info.tuple_type.copy_modified(fallback=mypy.types.Instance(info, info.defn.type_vars)),
             info.fullname,
@@ -3484,8 +3489,13 @@ def from_tuple_type(cls, info: TypeInfo) -> TypeAlias:
 
     @classmethod
     def from_typeddict_type(cls, info: TypeInfo) -> TypeAlias:
-        """Generate an alias to the TypedDict type described by a given TypeInfo."""
+        """Generate an alias to the TypedDict type described by a given TypeInfo.
+
+        NOTE: this doesn't set type alias type variables (for generic TypedDicts),
+        they must be set by the caller (when fully analyzed).
+        """
         assert info.typeddict_type
+        # TODO: is it possible to refactor this to set the correct type vars here?
         return TypeAlias(
             info.typeddict_type.copy_modified(
                 fallback=mypy.types.Instance(info, info.defn.type_vars)
diff --git a/test-data/unit/check-incremental.test b/test-data/unit/check-incremental.test
index 1aff1ba2862f8..2897e895a3943 100644
--- a/test-data/unit/check-incremental.test
+++ b/test-data/unit/check-incremental.test
@@ -6359,3 +6359,34 @@ from m import Foo
 [file m.py]
 from missing_module import Meta  # type: ignore[import]
 class Foo(metaclass=Meta): ...
+
+[case testGenericTypedDictWithError]
+import b
+[file a.py]
+from typing import Generic, TypeVar
+from typing_extensions import TypedDict
+
+TValue = TypeVar("TValue")
+class Dict(TypedDict, Generic[TValue]):
+    value: TValue
+
+[file b.py]
+from a import Dict, TValue
+
+def f(d: Dict[TValue]) -> TValue:
+    return d["value"]
+def g(d: Dict[TValue]) -> TValue:
+    return d["x"]
+
+[file b.py.2]
+from a import Dict, TValue
+
+def f(d: Dict[TValue]) -> TValue:
+    return d["value"]
+def g(d: Dict[TValue]) -> TValue:
+    return d["y"]
+[builtins fixtures/dict.pyi]
+[out]
+tmp/b.py:6: error: TypedDict "a.Dict[TValue]" has no key "x"
+[out2]
+tmp/b.py:6: error: TypedDict "a.Dict[TValue]" has no key "y"

From ecf05e6388eb5c3c0c5d7ea963817c0f81b65618 Mon Sep 17 00:00:00 2001
From: Stas Ilinskiy <stas@dropbox.com>
Date: Thu, 16 Feb 2023 21:16:59 -0800
Subject: [PATCH 231/231] bump version to 1.0.1

---
 mypy/version.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/version.py b/mypy/version.py
index ac0237fad5d85..2f519543cd440 100644
--- a/mypy/version.py
+++ b/mypy/version.py
@@ -8,7 +8,7 @@
 # - Release versions have the form "1.2.3".
 # - Dev versions have the form "1.2.3+dev" (PLUS sign to conform to PEP 440).
 # - Before 1.0 we had the form "0.NNN".
-__version__ = "1.0.1+dev"
+__version__ = "1.0.1"
 base_version = __version__
 
 mypy_dir = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))