Inheriting class with __slots__ defined

• Are you reporting a bug, or opening a feature request?

Feature request

• Please insert below the code you are checking with mypy.

class Base():
    __slots__: List[str] = ['foo', 'bar']
    if TYPE_CHECKING:
        foo: int
        bar: int

class Derived(Base):
    __slots__: List[str] = ['bar']

• What is the actual behavior/output?

Success: no issues found in 1 source file

• What is the behavior/output you expect?

I believe it would be nice if mypy generated an error on __slots__ declaration in Derived class because 'bar' slot was already declared in Base class.

• What are the versions of mypy and Python you are using?

Python 3.8.0, mypy 0.761

Commencez par reproduire avec mypy l’exemple fourni de Base et Derived avec slots. Suivez le traitement de slots par le vérificateur de types entre les classes héritées, puis vérifiez qu’un slot hérité en double produit un diagnostic, tandis que les déclarations de slots valides restent acceptées.