(🐞) Call to function decorated with a `Callable` causes inner function to fail to infer type of variable

from typing import Any, Callable, TypeVar, _T as T

def bar() -> None:
    def inner() -> None:
        it.encode()  # error: Cannot determine type of 'it'
    breaks()
    it = ""
    
deco: Callable[[T], T]

@deco
def breaks() -> None: ...

It appears that the order of the function declarations affects the result(:trollface:):

from typing import Any, Callable, TypeVar

T = TypeVar("T")

deco: Callable[[T], T]

@deco
def doesnt_break() -> None: ...

def bar() -> None:
    def inner() -> None:
        it.encode()  # no error
    doesnt_break()
    it = ""

I have determined that this only happens when the deco is a Callable, when it is a function there is no error:

from typing import Any, TypeVar, _T as T

def bar() -> None:
    def inner() -> None:
        it.encode()  # no error
    doesnt_break()
    it = ""
    
def deco(fn: T) -> T: ...

@deco
def doesnt_break() -> None: ...

playground

Empieza ejecutando las dos reproducciones en Python del issue, o utiliza el playground enlazado, y compara la decoración basada en Callable con el decorador basado en funciones. Sigue la ruta de inferencia de tipos para la función interna anidada y la llamada al decorador; se considera terminado cuando el primer ejemplo se infiere como str sin provocar regresiones en los ejemplos que ya funcionan.