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@overload doesn't work with @asynccontextmanager #17340

@alenzo-arch

Description

@alenzo-arch

Bug Report

When trying to annotate overloads for an asynccontextmanager, I think mypy incorrectly reports an invalid return type.

To Reproduce

from contextlib import asynccontextmanager, contextmanager from typing import AsyncIterator, Iterator, overload @overload @asynccontextmanager async def test_async() -> AsyncIterator[int]: ... @overload @asynccontextmanager async def test_async(val: int = ...) -> AsyncIterator[int]: ... @asynccontextmanager async def test_async(val: int = 1) -> AsyncIterator[int]: yield val @overload @contextmanager def test_sync() -> Iterator[int]: ... @overload @contextmanager def test_sync(val: int = ...) -> Iterator[int]: ... @contextmanager def test_sync(val: int = 1) -> Iterator[int]: yield val

This gives an error of "Argument 1 to "asynccontextmanager" has incompatible type "Callable[[int], Coroutine[Any, Any, AsyncIterator[int]]]"; expected "Callable[[int], AsyncIterator[Never]]"

Where the synchronous version checks fine.

Expected Behavior

I expect the async version to work the same as the sync version

Actual Behavior

Mypy reports and error

mypy test.py test.py:5: error: Argument 1 to "asynccontextmanager" has incompatible type "Callable[[], Coroutine[Any, Any, AsyncIterator[int]]]"; expected "Callable[[], AsyncIterator[Never]]" [arg-type] test.py:10: error: Argument 1 to "asynccontextmanager" has incompatible type "Callable[[int], Coroutine[Any, Any, AsyncIterator[int]]]"; expected "Callable[[int], AsyncIterator[Never]]" [arg-type] Found 2 errors in 1 file (checked 1 source file)

Your Environment

  • Mypy version used: 1.10.0
  • Mypy command-line flags: mypy test.py
  • Mypy configuration options from mypy.ini (and other config files):
  • Python version used: Python 3.11.4

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