Overlapping Overload with Literals Question

[to-ph]

Hello! I've got a quick question about overloading in a scenario like this:

@overload
def greet(s: Literal["hello"]) -> Literal["hi!"]:
    ...

@overload
def greet(s: str) -> Literal["what?"]:
    ...

def greet(s: str):
    if s == "hello":
        return "hi!"
    else:
        return "what?"

The str in the second greet overlaps the literal "hello", and pyright (correctly) complains about an incompatible return type. Is there any way to make this scenario valid, or is it just a limit with python's type system that I would need to work around?

Thanks!

[erictraut]

I guess you could consider it a limitation of the type system. There's no way to say "any str that is not Literal["hello"], so it's not possible to make the two overloaded signatures distinct (not overlapping).

Here are some options:

1. Change the return type of the second overload (and the implementation) to str.
2. Suppress the reportOverlappingOverloads diagnostic check for this file (or use # type: ignore to suppress the diagnostic on a single line).