Incorrect mapping of actual to formal arguments. #19692
Description
def takes_at_least3(a1: str, a2: str, a3: str, *args: str) -> None: ...
def test(
x0: tuple[str, ...],
x1: tuple[str, *tuple[str, ...]],
x2: tuple[str, str, *tuple[str, ...]],
x3: tuple[str, str, str, *tuple[str, ...]],
) -> None:
takes_at_least3(*x0) # no error
takes_at_least3(*x1) # Missing positional arguments "x2", "x3"
takes_at_least3(*x2) # no error
takes_at_least3(*x3) # no errorhttps://mypy-play.net/?mypy=latest&python=3.12&gist=34662974552c517610691a6b5a792ba2
There are only 2 logically sensible results here:
- All of x0-x3 should be accepted
- Only x3 should be accepted, since it is the only type that is guaranteed to provide at least 3 items
The choice depends on whether we consider tuple[str, ...] as equal to
- The union type
tuple[()] | tuple[str] | tuple[str, str] | ... - The gradual
AnyOf[tuple[()], tuple[str], tuple[str, str], ... ](AnyOf - Union for return types typing#566)