Conditional decorated functions are not type checked

[davidhalter]

Bug Report

Going through Mypy's tests, I realized that some tests are passing that shouldn't. This involves for example:

• testConditionalFunctionDefinitionUsingDecorator3 (there's an error in the test that the test author probably didn't notice: Positional only args of a callable are never assignable to a normal function with positional-or-keyword params; typically an error in Mypy would look like this: Incompatible redefinition (redefinition with type "Callable[[int], None]", original type "Callable[[Arg(int, 'x')], None]"))
• testConditionalFunctionDefinitionUsingDecorator4 (there's even a TODO in there that complains about this not being done)
• testNewAnalyzerConditionalDecoratedFunc

To Reproduce

from typing import Callable
def dec(f) -> Callable[[int], None]: raise NotImplementedError

if int():
    def f(x: str): pass
else:
    @dec
    def f() -> None: pass   

https://mypy-play.net/?mypy=latest&python=3.12&gist=18b131da809d740eced20dd7652ea213

Expected Behavior

It would be nice if Mypy complained here (like in AFAIK all other conditional definitions).

I'm happy to assist if somebody wants to fix this.