diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index acad35d18d5f35..609fd338b7a77d 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -4693,6 +4693,11 @@ def test_no_isinstance(self): with self.assertRaises(TypeError): isinstance(42, TypeAlias) + def test_stringized_usage(self): + class A: + a: "TypeAlias" + self.assertEqual(get_type_hints(A), {'a': TypeAlias}) + def test_no_issubclass(self): with self.assertRaises(TypeError): issubclass(Employee, TypeAlias) diff --git a/Lib/typing.py b/Lib/typing.py index 25225470afbac2..368c4c82f83e71 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -165,7 +165,7 @@ def _type_check(arg, msg, is_argument=True, module=None, *, is_class=False): if (isinstance(arg, _GenericAlias) and arg.__origin__ in invalid_generic_forms): raise TypeError(f"{arg} is not valid as type argument") - if arg in (Any, NoReturn, Final): + if arg in (Any, NoReturn, Final, TypeAlias): return arg if isinstance(arg, _SpecialForm) or arg in (Generic, Protocol): raise TypeError(f"Plain {arg} is not valid as type argument") diff --git a/Misc/NEWS.d/next/Library/2022-02-06-08-54-03.bpo-46655.DiLzYv.rst b/Misc/NEWS.d/next/Library/2022-02-06-08-54-03.bpo-46655.DiLzYv.rst new file mode 100644 index 00000000000000..4f0de9519a00e4 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-02-06-08-54-03.bpo-46655.DiLzYv.rst @@ -0,0 +1 @@ +In :func:`typing.get_type_hints`, support evaluating bare stringified ``TypeAlias`` annotations. Patch by Gregory Beauregard. \ No newline at end of file