Should overloaded function to ParamSpec work with argument type expansion? #2568
Description
In astral-sh/ruff#21946, there's a test case which ty passes but other type checkers raise an error:
from typing import Callable, overload
@overload
def int_int(x: int) -> int: ...
@overload
def int_int(x: str) -> int: ...
def with_parameters[**P](f: Callable[P, int], *args: P.args, **kwargs: P.kwargs) -> Callable[P, str]:
def nested(*args: P.args, **kwargs: P.kwargs) -> str:
return str(f(*args, **kwargs))
return nested
def foo(int_or_str: int | str):
# Argument type expansion leads to matching both overloads.
# TODO: Should this be an error instead?
# revealed: Overload[(x: int) -> str, (x: str) -> str]
reveal_type(with_parameters(int_int, int_or_str))Other type checkers emit a diagnostic here:
I'm not exactly sure why do other type checkers emit a diagnostic here, maybe there's an unsoundness argument to this behavior?