Referencing name not defined yet allowed by mypy, yet error at runtime.

[MarioIshac]

To Reproduce

from collections.abc import Callable

class A:
    @staticmethod
    def b(c: Callable[[], None]) -> Callable[[], None]:
        return c
    
    @A.b
    @staticmethod
    def c() -> None:
        pass

mypy playground

Expected Behavior

Invoking mypy catches error.

Actual Behavior

Success: no issues found in 1 source file

However, at runtime:

NameError: name 'A' is not defined