More relaxed require-subclass option

[ariebovenberg]

Currently slotscheck has the require-subclass option, which enforces the use of __slots__ wherever slotted classes are subclassed. However, this greatly depends on whether builtin/extension classes are considered "slotted". For example, object has no __dict__. Flagging all direct object subclasses would essentially require slots for all classes in a module (that don't subclass from a non-slot class outside the module).

[dantownsend]

I think it should be if someone explicitly declares slots in a parent class.

class Animal:
    __slots__ = ('colour',)

class Dog(Animal):
    pass  # This is likely to be a mistake.

You could do something like check whether the class and parent class exist in the same module.