`asyncio.gather` is sometimes erroneously type-checked

Bug Report

I'm adding typing to a large codebase, and have noticed weird asyncio.gather behavior.

To Reproduce

Here's a self-contained test:

from asyncio import gather


async def returns_dict() -> dict:
    return {}


async def returns_int() -> int:
    return 1


async def test():
    tasks = (returns_dict(), returns_int())
    reveal_type(await gather(*tasks))  # note: Revealed type is "Any"

Expected Behavior

The revealed type should be: note: Revealed type is "Tuple[builtins.dict*[Any, Any], builtins.int*]"

Actual Behavior

The correct return type is not recognized.

If the example is slightly changed:

from asyncio import gather


async def returns_dict() -> dict:
    return {}


async def returns_int() -> int:
    return 1


async def test():
    reveal_type(await gather(returns_dict(), returns_int()))

it works properly.

Your Environment

• Mypy version used: 0.902
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): allow_redefinition, check_untyped_defs, namespace_packages, warn_unreachable
• Python version used: 3.9.5
• Operating system and version: macOs Big Sur

Comienza con el reproductor autocontenido de asyncio.gather incluido en el issue y compara los tipos revelados para un tuple pasado con *tasks frente a argumentos directos. Sigue el punto de entrada de la comprobación de tipos para las llamadas a gather; el trabajo estará terminado cuando la forma con tuple revele el resultado esperado dict-and-int en lugar de Any, manteniendo el comportamiento existente de los argumentos directos.