Feature or bug? bidirectional inference when using typeguard

[bukzor]

I can't see why pyright doesn't complain at return g here. I had expected it would say that Callable[P, R] isn't necessarily F.

from typing import Callable
from typing import TypeGuard


class DecoratorProblem[F, **P, R]:
    def is_pr(self, f: object) -> TypeGuard[Callable[P, R]]:
        return isinstance(f, Callable)

    def decorator(self, f: F) -> F:
        assert self.is_pr(f)
        g = self._decorator(f)
        return g  # pyright allows Callable[P, R] to be assigned to F? Why?

    def _decorator(self, f: Callable[P, R]) -> Callable[P, R]:
        def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
            return f(*args, **kwargs)
        return wrapper

[erictraut]

Yeah, that looks like a bug — a false negative. Could you please file a bug report so it's tracked? Thanks!

[bukzor]

Done: #10725

I found this while trying to figure out #10722