Report error when accessing generic instance variable from class object #7051
Description
The typing spec indicates that if an instance variable within a generic class is generic, an attempt to access it through the class object should generate an error because the type is erased at runtime for the class.
from typing import Generic, TypeVar
T = TypeVar("T")
class Node(Generic[T]):
label: T
def __init__(self, label: T | None = None) -> None:
...
Node[int].label = 1 # Should be type error
Node[int].label # Should be type error
Node.label # Should be type error