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

Tái hiện hành vi từ test.py bằng cách chạy mypy --strict rồi Python để so sánh kết quả tĩnh với NameError khi chạy. Theo dõi cách mypy phân tích các chú thích kiểu trả về của phương thức trừu tượng trước khi Result được khai báo. Được xem là hoàn tất khi mypy báo cáo tham chiếu Result chưa được định nghĩa trong trường hợp này mà không làm hỏng các chú thích hợp lệ.