Type variable across types gives an error when using Generics

Bug Report

When using a TypeVar defined in another local file, to parameterize a Generic, the following error is given:

Free type variable expected in Generic[...]

To Reproduce

Create file value.py:

from typing import TypeVar, Protocol

TValue = TypeVar('TValue', covariant=True)

# As an example, this does not give me any errors
class IValueProcessor(Protocol, Generic[TValue]):
    ...

Create service.py:

from abc import ABC
from typing import Generic

from  .value import TValue

class Service(ABC, Generic[TValue]):  # Error occurs here, on `Generic`
    ...

Expected Behavior

Should not give any errors (I think).

Actual Behavior

An error is produced, when parameterizing Generic:

Free type variable expected in Generic[...]

Your Environment

• Mypy version used: 0.930
• Mypy command-line flags: (none)
• Mypy configuration options from mypy.ini (and other config files): (none was created, at least explicitly)
• Python version used: CPython 3.8.10
• Operating system and version: Ubuntu 20.04 LTS on WSL2

Inizia con la riproduzione nei due file value.py e service.py, quindi esegui mypy 0.930 senza configurazione né flag da riga di comando per confermare l’errore. Traccia come viene gestito il TValue importato durante l’elaborazione di Generic[TValue] e aggiungi un test di regressione basato su questo esempio; il lavoro è terminato quando la dichiarazione generica valida non segnala più “Free type variable expected in Generic[...]”.