Check for return type of overload implementation is too strict?

Consider this simplified example:

from typing import overload, Optional, List
  
@overload
def f(x: int) -> List[int]: ...
@overload
def f(x: None) -> List[Optional[int]]: ...

def f(x: Optional[int]) -> List[Optional[int]]:
    return [x]

Mypy currently complains about it that:

Overloaded function implementation cannot produce return type of signature 1

Although I understand why this happens, it is a bit annoying and can be perceived as a false positive. Maybe we should use is_overlapping_types() instead of is_subtype() for the check?

cc @Michael0x2a

Start by reproducing the simplified overload example and trace the implementation return-type check in mypy. Compare the current is_subtype() check with the proposed is_overlapping_types() behavior, then determine whether the example should be accepted and validate the decision with regression coverage.