Pylance showing error for @classmethod which works during execution

Question

The following code works exactly as expected:

from abc import ABCMeta

from typing import Dict, Any

class Singleton(ABCMeta):
    __instances: Dict[Any, Any] = {}
    def __call__(cls, *args: Any, **kwargs: Any) -> Any:
        if cls not in cls.__instances:
            cls.__instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
        return cls.__instances[cls]

    @classmethod
    def delete_all_instances(cls: Any) -> None:
        cls.__instances = {}
        print("Deleted")

class Class1(metaclass=Singleton):
    def __init__(self) -> None:
        print("Constructor")
        self.__name = 'Class1'

    def say_name(self) -> str:
        return self.__name


if __name__ == "__main__":
    obj1 = Class1()
    print(obj1.say_name())
    Singleton.delete_all_instances()
    obj1 = Class1()
    print(obj1.say_name())

Output:

Constructor
Class1
Deleted
Constructor
Class1

But Pylance (v2023.5.10) installed in Visual Studio Code 1.78.0 complains in line 29 Singleton.delete_all_instances(), that Argument missing for parameter "cls". It doesn't matter, if the Any behind the cls-parameter in the function definition is there, or not.

Is this a bug in Pylance, or am I just too blind to see the issue?

Answer 1

Seems like a real bug in Pyright. See bug report on Github