ParamSpec appears to get lost with mock.patch()

[Dreamsorcerer]

Bug Report

It appears that ParamSpec is used in typeshed (python/typeshed#10325), but when using --disallow-any-decorated it seems to be complaining that the parameters are gone.

To Reproduce

from unittest import mock

@mock.patch("aiohttp.connector.ClientRequest")
def test_connect(foo: int) -> None:
    ...

Actual Behavior

error: Type of decorated function contains type "Any"
("Callable[..., None]")  [misc]
    def test_connect(foo: int) -> None:

Your Environment

• Mypy version used: 1.14.1
• Mypy command-line flags: --disallow-any-decorated
• Python version used: 3.9

[sterliakov]

For reference, the patch signature without new= argument does not use ParamSpec. However, this error should likely be improved indeed, as there's nothing end users can do about it...

Resolution site:

mypy/mypy/typeshed/stdlib/unittest/mock.pyi

Lines 314 to 325 in 237933a

	@overload
	def __call__(
	self,
	target: str,
	*,
	spec: Any | None = ...,
	create: bool = ...,
	spec_set: Any | None = ...,
	autospec: Any | None = ...,
	new_callable: Any | None = ...,
	**kwargs: Any,
	) -> _patch_default_new: ...

Definition site with explanatory comment:

mypy/mypy/typeshed/stdlib/unittest/mock.pyi

Lines 270 to 276 in 237933a

	class _patch_default_new(_patch[MagicMock | AsyncMock]):
	@overload
	def __call__(self, func: _TT) -> _TT: ...
	# Can't use the following as ParamSpec is only allowed as last parameter:
	# def __call__(self, func: Callable[_P, _R]) -> Callable[Concatenate[_P, MagicMock], _R]: ...
	@overload
	def __call__(self, func: Callable[..., _R]) -> Callable[..., _R]: ...

[Dreamsorcerer]

Ah, I see. Not going to work then.