https://github.com/python/cpython/commit/75177358a62afeabd1d3aa0e9f395c2b9d4... commit: 75177358a62afeabd1d3aa0e9f395c2b9d4495ca branch: main author: Nikita Sobolev <mail@sobolevn.me> committer: serhiy-storchaka <storchaka@gmail.com> date: 2022-08-30T10:34:55+03:00 summary: gh-96385: Correctly raise error on `[*T, *V]` substitution (GH-96386) files: A Misc/NEWS.d/next/Library/2022-08-29-15-28-39.gh-issue-96385.uLRTsf.rst M Lib/test/test_typing.py M Lib/typing.py diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index ca7bd8e083c4..7eea01909ec8 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -596,6 +596,7 @@ class GenericAliasSubstitutionTests(BaseTestCase): def test_one_parameter(self): T = TypeVar('T') Ts = TypeVarTuple('Ts') + Ts2 = TypeVarTuple('Ts2') class C(Generic[T]): pass @@ -621,6 +622,8 @@ class C(Generic[T]): pass # Should definitely raise TypeError: list only takes one argument. ('list[T, *tuple_type[int, ...]]', '[int]', 'list[int, *tuple_type[int, ...]]'), ('List[T, *tuple_type[int, ...]]', '[int]', 'TypeError'), + # Should raise, because more than one `TypeVarTuple` is not supported. + ('generic[*Ts, *Ts2]', '[int]', 'TypeError'), ] for alias_template, args_template, expected_template in tests: diff --git a/Lib/typing.py b/Lib/typing.py index 43ef07e50cfe..596744ed1322 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1074,7 +1074,7 @@ def __typing_subst__(self, arg): def __typing_prepare_subst__(self, alias, args): params = alias.__parameters__ typevartuple_index = params.index(self) - for param in enumerate(params[typevartuple_index + 1:]): + for param in params[typevartuple_index + 1:]: if isinstance(param, TypeVarTuple): raise TypeError(f"More than one TypeVarTuple parameter in {alias}") diff --git a/Misc/NEWS.d/next/Library/2022-08-29-15-28-39.gh-issue-96385.uLRTsf.rst b/Misc/NEWS.d/next/Library/2022-08-29-15-28-39.gh-issue-96385.uLRTsf.rst new file mode 100644 index 000000000000..57354826f349 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-08-29-15-28-39.gh-issue-96385.uLRTsf.rst @@ -0,0 +1,3 @@ +Fix ``TypeVarTuple.__typing_prepare_subst__``. ``TypeError`` was not raised +when using more than one ``TypeVarTuple``, like ``[*T, *V]`` in type alias +substitutions.