Currently we have

class A(Generic[T]):
    x = None

A[int].x = 1
A[str].x = 'a'

print(A[int].x) # prints 1
print(A[int]().x) # prints None, since type is erased on instantiation

@JukkaL argues and I agree with him, that this looks wrong. Conceptually, there should be only one runtime class. I think we can implement this without loosing the current runtime generic information by tweaking descriptor __dict__ of GenericMeta, so that all assignments and look-ups on subscripted class objects like A[int] will be transferred to the original class object A.

@gvanrossum What do you think?