...andaccording to pyright upstream, this is a bug in mypy, rather than in pyright.

Type-checking pytest-asyncio itself yields a great many errors, starting with:

pytest-asyncio/pytest_asyncio/plugin.py:57:60 - error: Type variable "_R" has no meaning in this context (reportGeneralTypeIssues)pytest-asyncio/pytest_asyncio/plugin.py:57:36 - error: TypeVar bound type cannot be genericpytest-asyncio/pytest_asyncio/plugin.py:60:65 - error: Type variable "_R" has no meaning in this context (reportGeneralTypeIssues)pytest-asyncio/pytest_asyncio/plugin.py:60:37 - error: TypeVar bound type cannot be generic

...and type-checking a project that uses pytest-asyncio's decorators withreportUntypedFunctionDecorator set in pyright's configuration:

error: Untyped function decorator obscures type of function; ignoring decorator (reportUntypedFunctionDecorator)

I suspect that the option ofeither passing the function to be used as a fixture as a direct argument tofixture()or returning a function that acts as a proper decorator adds complexity here. If it's not possible to be pyright-friendly with the existing calling convention flexibility, might it make sense to offer a less-flexible, more explicitly-typed alternative?