diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 1bf216a0e0c..91ccf6fdbbe 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -86,6 +86,7 @@ env:
     test_math
     test_operator
     test_ordered_dict
+    test_pep646_syntax
     test_pow
     test_raise
     test_richcmp
diff --git a/Lib/test/test_pep646_syntax.py b/Lib/test/test_pep646_syntax.py
new file mode 100644
index 00000000000..d9a0aa9a90e
--- /dev/null
+++ b/Lib/test/test_pep646_syntax.py
@@ -0,0 +1,338 @@
+import doctest
+import unittest
+
+doctests = """
+
+Setup
+
+    >>> class AClass:
+    ...    def __init__(self):
+    ...        self._setitem_name = None
+    ...        self._setitem_val = None
+    ...        self._delitem_name = None
+    ...    def __setitem__(self, name, val):
+    ...        self._delitem_name = None
+    ...        self._setitem_name = name
+    ...        self._setitem_val = val
+    ...    def __repr__(self):
+    ...        if self._setitem_name is not None:
+    ...            return f"A[{self._setitem_name}]={self._setitem_val}"
+    ...        elif self._delitem_name is not None:
+    ...            return f"delA[{self._delitem_name}]"
+    ...    def __getitem__(self, name):
+    ...        return ParameterisedA(name)
+    ...    def __delitem__(self, name):
+    ...        self._setitem_name = None
+    ...        self._delitem_name = name
+    ...
+    >>> class ParameterisedA:
+    ...    def __init__(self, name):
+    ...        self._name = name
+    ...    def __repr__(self):
+    ...        return f"A[{self._name}]"
+    ...    def __iter__(self):
+    ...        for p in self._name:
+    ...            yield p
+    >>> class B:
+    ...    def __iter__(self):
+    ...        yield StarredB()
+    ...    def __repr__(self):
+    ...        return "B"
+    >>> class StarredB:
+    ...    def __repr__(self):
+    ...        return "StarredB"
+    >>> A = AClass()
+    >>> b = B()
+
+Slices that are supposed to work, starring our custom B class
+
+    >>> A[*b]
+    A[(StarredB,)]
+    >>> A[*b] = 1; A
+    A[(StarredB,)]=1
+    >>> del A[*b]; A
+    delA[(StarredB,)]
+
+    >>> A[*b, *b]
+    A[(StarredB, StarredB)]
+    >>> A[*b, *b] = 1; A
+    A[(StarredB, StarredB)]=1
+    >>> del A[*b, *b]; A
+    delA[(StarredB, StarredB)]
+
+    >>> A[b, *b]
+    A[(B, StarredB)]
+    >>> A[b, *b] = 1; A
+    A[(B, StarredB)]=1
+    >>> del A[b, *b]; A
+    delA[(B, StarredB)]
+
+    >>> A[*b, b]
+    A[(StarredB, B)]
+    >>> A[*b, b] = 1; A
+    A[(StarredB, B)]=1
+    >>> del A[*b, b]; A
+    delA[(StarredB, B)]
+
+    >>> A[b, b, *b]
+    A[(B, B, StarredB)]
+    >>> A[b, b, *b] = 1; A
+    A[(B, B, StarredB)]=1
+    >>> del A[b, b, *b]; A
+    delA[(B, B, StarredB)]
+
+    >>> A[*b, b, b]
+    A[(StarredB, B, B)]
+    >>> A[*b, b, b] = 1; A
+    A[(StarredB, B, B)]=1
+    >>> del A[*b, b, b]; A
+    delA[(StarredB, B, B)]
+
+    >>> A[b, *b, b]
+    A[(B, StarredB, B)]
+    >>> A[b, *b, b] = 1; A
+    A[(B, StarredB, B)]=1
+    >>> del A[b, *b, b]; A
+    delA[(B, StarredB, B)]
+
+    >>> A[b, b, *b, b]
+    A[(B, B, StarredB, B)]
+    >>> A[b, b, *b, b] = 1; A
+    A[(B, B, StarredB, B)]=1
+    >>> del A[b, b, *b, b]; A
+    delA[(B, B, StarredB, B)]
+
+    >>> A[b, *b, b, b]
+    A[(B, StarredB, B, B)]
+    >>> A[b, *b, b, b] = 1; A
+    A[(B, StarredB, B, B)]=1
+    >>> del A[b, *b, b, b]; A
+    delA[(B, StarredB, B, B)]
+
+    >>> A[A[b, *b, b]]
+    A[A[(B, StarredB, B)]]
+    >>> A[A[b, *b, b]] = 1; A
+    A[A[(B, StarredB, B)]]=1
+    >>> del A[A[b, *b, b]]; A
+    delA[A[(B, StarredB, B)]]
+
+    >>> A[*A[b, *b, b]]
+    A[(B, StarredB, B)]
+    >>> A[*A[b, *b, b]] = 1; A
+    A[(B, StarredB, B)]=1
+    >>> del A[*A[b, *b, b]]; A
+    delA[(B, StarredB, B)]
+
+    >>> A[b, ...]
+    A[(B, Ellipsis)]
+    >>> A[b, ...] = 1; A
+    A[(B, Ellipsis)]=1
+    >>> del A[b, ...]; A
+    delA[(B, Ellipsis)]
+
+    >>> A[*A[b, ...]]
+    A[(B, Ellipsis)]
+    >>> A[*A[b, ...]] = 1; A
+    A[(B, Ellipsis)]=1
+    >>> del A[*A[b, ...]]; A
+    delA[(B, Ellipsis)]
+
+Slices that are supposed to work, starring a list
+
+    >>> l = [1, 2, 3]
+
+    >>> A[*l]
+    A[(1, 2, 3)]
+    >>> A[*l] = 1; A
+    A[(1, 2, 3)]=1
+    >>> del A[*l]; A
+    delA[(1, 2, 3)]
+
+    >>> A[*l, 4]
+    A[(1, 2, 3, 4)]
+    >>> A[*l, 4] = 1; A
+    A[(1, 2, 3, 4)]=1
+    >>> del A[*l, 4]; A
+    delA[(1, 2, 3, 4)]
+
+    >>> A[0, *l]
+    A[(0, 1, 2, 3)]
+    >>> A[0, *l] = 1; A
+    A[(0, 1, 2, 3)]=1
+    >>> del A[0, *l]; A
+    delA[(0, 1, 2, 3)]
+
+    >>> A[1:2, *l]
+    A[(slice(1, 2, None), 1, 2, 3)]
+    >>> A[1:2, *l] = 1; A
+    A[(slice(1, 2, None), 1, 2, 3)]=1
+    >>> del A[1:2, *l]; A
+    delA[(slice(1, 2, None), 1, 2, 3)]
+
+    >>> repr(A[1:2, *l]) == repr(A[1:2, 1, 2, 3])
+    True
+
+Slices that are supposed to work, starring a tuple
+
+    >>> t = (1, 2, 3)
+
+    >>> A[*t]
+    A[(1, 2, 3)]
+    >>> A[*t] = 1; A
+    A[(1, 2, 3)]=1
+    >>> del A[*t]; A
+    delA[(1, 2, 3)]
+
+    >>> A[*t, 4]
+    A[(1, 2, 3, 4)]
+    >>> A[*t, 4] = 1; A
+    A[(1, 2, 3, 4)]=1
+    >>> del A[*t, 4]; A
+    delA[(1, 2, 3, 4)]
+
+    >>> A[0, *t]
+    A[(0, 1, 2, 3)]
+    >>> A[0, *t] = 1; A
+    A[(0, 1, 2, 3)]=1
+    >>> del A[0, *t]; A
+    delA[(0, 1, 2, 3)]
+
+    >>> A[1:2, *t]
+    A[(slice(1, 2, None), 1, 2, 3)]
+    >>> A[1:2, *t] = 1; A
+    A[(slice(1, 2, None), 1, 2, 3)]=1
+    >>> del A[1:2, *t]; A
+    delA[(slice(1, 2, None), 1, 2, 3)]
+
+    >>> repr(A[1:2, *t]) == repr(A[1:2, 1, 2, 3])
+    True
+
+Starring an expression (rather than a name) in a slice
+
+    >>> def returns_list():
+    ...     return [1, 2, 3]
+
+    >>> A[returns_list()]
+    A[[1, 2, 3]]
+    >>> A[returns_list()] = 1; A
+    A[[1, 2, 3]]=1
+    >>> del A[returns_list()]; A
+    delA[[1, 2, 3]]
+
+    >>> A[returns_list(), 4]
+    A[([1, 2, 3], 4)]
+    >>> A[returns_list(), 4] = 1; A
+    A[([1, 2, 3], 4)]=1
+    >>> del A[returns_list(), 4]; A
+    delA[([1, 2, 3], 4)]
+
+    >>> A[*returns_list()]
+    A[(1, 2, 3)]
+    >>> A[*returns_list()] = 1; A
+    A[(1, 2, 3)]=1
+    >>> del A[*returns_list()]; A
+    delA[(1, 2, 3)]
+
+    >>> A[*returns_list(), 4]
+    A[(1, 2, 3, 4)]
+    >>> A[*returns_list(), 4] = 1; A
+    A[(1, 2, 3, 4)]=1
+    >>> del A[*returns_list(), 4]; A
+    delA[(1, 2, 3, 4)]
+
+    >>> A[0, *returns_list()]
+    A[(0, 1, 2, 3)]
+    >>> A[0, *returns_list()] = 1; A
+    A[(0, 1, 2, 3)]=1
+    >>> del A[0, *returns_list()]; A
+    delA[(0, 1, 2, 3)]
+
+    >>> A[*returns_list(), *returns_list()]
+    A[(1, 2, 3, 1, 2, 3)]
+    >>> A[*returns_list(), *returns_list()] = 1; A
+    A[(1, 2, 3, 1, 2, 3)]=1
+    >>> del A[*returns_list(), *returns_list()]; A
+    delA[(1, 2, 3, 1, 2, 3)]
+
+Using both a starred object and a start:stop in a slice
+(See also tests in test_syntax confirming that starring *inside* a start:stop
+is *not* valid syntax.)
+
+    >>> A[1:2, *b]
+    A[(slice(1, 2, None), StarredB)]
+    >>> A[*b, 1:2]
+    A[(StarredB, slice(1, 2, None))]
+    >>> A[1:2, *b, 1:2]
+    A[(slice(1, 2, None), StarredB, slice(1, 2, None))]
+    >>> A[*b, 1:2, *b]
+    A[(StarredB, slice(1, 2, None), StarredB)]
+
+    >>> A[1:, *b]
+    A[(slice(1, None, None), StarredB)]
+    >>> A[*b, 1:]
+    A[(StarredB, slice(1, None, None))]
+    >>> A[1:, *b, 1:]
+    A[(slice(1, None, None), StarredB, slice(1, None, None))]
+    >>> A[*b, 1:, *b]
+    A[(StarredB, slice(1, None, None), StarredB)]
+
+    >>> A[:1, *b]
+    A[(slice(None, 1, None), StarredB)]
+    >>> A[*b, :1]
+    A[(StarredB, slice(None, 1, None))]
+    >>> A[:1, *b, :1]
+    A[(slice(None, 1, None), StarredB, slice(None, 1, None))]
+    >>> A[*b, :1, *b]
+    A[(StarredB, slice(None, 1, None), StarredB)]
+
+    >>> A[:, *b]
+    A[(slice(None, None, None), StarredB)]
+    >>> A[*b, :]
+    A[(StarredB, slice(None, None, None))]
+    >>> A[:, *b, :]
+    A[(slice(None, None, None), StarredB, slice(None, None, None))]
+    >>> A[*b, :, *b]
+    A[(StarredB, slice(None, None, None), StarredB)]
+
+*args annotated as starred expression
+
+    >>> def f1(*args: *b): pass
+    >>> f1.__annotations__
+    {'args': StarredB}
+
+    >>> def f2(*args: *b, arg1): pass
+    >>> f2.__annotations__
+    {'args': StarredB}
+
+    >>> def f3(*args: *b, arg1: int): pass
+    >>> f3.__annotations__ # TODO: RUSTPYTHON # doctest: +EXPECTED_FAILURE
+    {'args': StarredB, 'arg1': <class 'int'>}
+
+    >>> def f4(*args: *b, arg1: int = 2): pass
+    >>> f4.__annotations__ # TODO: RUSTPYTHON # doctest: +EXPECTED_FAILURE
+    {'args': StarredB, 'arg1': <class 'int'>}
+
+    >>> def f5(*args: *b = (1,)): pass # TODO: RUSTPYTHON # doctest: +EXPECTED_FAILURE
+    Traceback (most recent call last):
+        ...
+    SyntaxError: invalid syntax
+"""
+
+__test__ = {'doctests' : doctests}
+
+EXPECTED_FAILURE = doctest.register_optionflag('EXPECTED_FAILURE') # TODO: RUSTPYTHON
+class CustomOutputChecker(doctest.OutputChecker): # TODO: RUSTPYTHON
+    def check_output(self, want, got, optionflags): # TODO: RUSTPYTHON
+        if optionflags & EXPECTED_FAILURE: # TODO: RUSTPYTHON
+            if want == got: # TODO: RUSTPYTHON
+                return False # TODO: RUSTPYTHON
+            return True # TODO: RUSTPYTHON
+        return super().check_output(want, got, optionflags) # TODO: RUSTPYTHON
+
+def load_tests(loader, tests, pattern):
+    tests.addTest(doctest.DocTestSuite(checker=CustomOutputChecker())) # TODO: RUSTPYTHON
+    return tests
+
+
+if __name__ == "__main__":
+    unittest.main()