Merge branch 'master' into refactor-typing-generic-alias

python · serhiy-storchaka · May 7, 2020 · Apr 26, 2020 · Apr 26, 2020 · May 2, 2020
commit e626caf9f3274e659945b15630aa41494478be2b
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
@@ -3007,6 +3007,8 @@ class C(Generic[T]): pass
         self.assertIs(get_origin(List[Tuple[T, T]][int]), list)
         self.assertIs(get_origin(Annotated[T, 'thing']), Annotated)
         self.assertIs(get_origin(List), list)
+        self.assertIs(get_origin(list[int]), list)
+        self.assertIs(get_origin(list), None)
 
     def test_get_args(self):
         T = TypeVar('T')
@@ -3029,6 +3031,8 @@ class C(Generic[T]): pass
         self.assertEqual(get_args(Tuple[()]), ((),))
         self.assertEqual(get_args(Annotated[T, 'one', 2, ['three']]), (T, 'one', 2, ['three']))
         self.assertEqual(get_args(List), (typing.T,))
+        self.assertEqual(get_args(list[int]), (int,))
+        self.assertEqual(get_args(list), ())
 
 
 class CollectionsAbcTests(BaseTestCase):

diff --git a/Lib/typing.py b/Lib/typing.py
@@ -190,7 +190,7 @@ def _subs_tvars(tp, tvars, subs):
     """Substitute type variables 'tvars' with substitutions 'subs'.
     These two must have the same length.
     """
-    if not isinstance(tp, _BaseGenericAlias):
+    if not isinstance(tp, (_BaseGenericAlias, GenericAlias)):
         return tp
     new_args = list(tp.__args__)
     for a, arg in enumerate(tp.__args__):
@@ -278,6 +278,11 @@ def _eval_type(t, globalns, localns):
         if ev_args == t.__args__:
             return t
         return t.copy_with(ev_args)
+    if isinstance(t, GenericAlias):
+        ev_args = tuple(_eval_type(a, globalns, localns) for a in t.__args__)
+        if ev_args == t.__args__:
+            return t
+        return GenericAlias(t.__origin__, ev_args)
     return t
 
 
@@ -1372,6 +1377,11 @@ def _strip_annotations(t):
         if stripped_args == t.__args__:
             return t
         return t.copy_with(stripped_args)
+    if isinstance(t, GenericAlias):
+        stripped_args = tuple(_strip_annotations(a) for a in t.__args__)
+        if stripped_args == t.__args__:
+            return t
+        return GenericAlias(t.__origin__, stripped_args)
     return t
 
 
@@ -1391,7 +1401,7 @@ def get_origin(tp):
     """
     if isinstance(tp, _AnnotatedAlias):
         return Annotated
-    if isinstance(tp, _BaseGenericAlias):
+    if isinstance(tp, (_BaseGenericAlias, GenericAlias)):
         return tp.__origin__
     if tp is Generic:
         return Generic
@@ -1411,7 +1421,7 @@ def get_args(tp):
     """
     if isinstance(tp, _AnnotatedAlias):
         return (tp.__origin__,) + tp.__metadata__
-    if isinstance(tp, _BaseGenericAlias):
+    if isinstance(tp, (_BaseGenericAlias, GenericAlias)):
         res = tp.__args__
         if tp.__origin__ is collections.abc.Callable and res[0] is not Ellipsis:
             res = (list(res[:-1]), res[-1])