Mypy not detecting abstract methods returning undefined types

Bug Report

I have a class with a couple of abstract methods that return a particular custom type. That custom type is then defined right after the class. Then a global variable referencing that class is created:

To Reproduce

# test.py
from abc import ABC, abstractmethod
from typing import NamedTuple, List

class F(ABC):
    @abstractmethod
    async def m1(self) -> Result:
        pass
    
    @abstractmethod
    async def m2(self) -> Result:
        pass

class Result(NamedTuple):
    f1: str
    f2: int
    
foo: List[F] = []

> mypy --strict test.py
Success: no issues found in 1 source file

> python test.py
Traceback (most recent call last):
  File "test.py", line 4, in <module>
    class F(ABC):
  File "test.py", line 6, in F
    async def m1(self) -> Result:
NameError: name 'Result' is not defined

Expected Behavior

I would expect mypy to detect that Result is not defined before its use in class F.

Actual Behavior

Mypy is happy with the code as it is, even under --strict, while Python can't even run the code as is. Moving the declaration of Result above class F solves the problem and both Python and mypy are then happy.

Your Environment

• Mypy version used: 0.991
• Mypy command-line flags: --strict
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.9.13

Reproduisez le comportement de test.py en exécutant mypy --strict, puis Python, afin de comparer le résultat statique avec le NameError à l’exécution. Suivez la manière dont mypy analyse les annotations de retour de la méthode abstraite avant que Result ne soit déclaré. Le travail est terminé lorsque mypy signale la référence Result non définie dans ce cas sans casser les annotations valides.