generic mutable class attributes introduce a vent in the type system #11538
Description
from typing import Generic, TypeVar
T = TypeVar("T")
class A(Generic[T]):
shared_attr: list[T] = []
a1 = A[str]()
a1.shared_attr.append("AMONGUS")
a2 = A[int]()
a2.shared_attr.append(1)
value = a2.class_attr[0]
reveal_type(value) # revealed type: int, actual value: AMONGUSIn this example the shared attribute shared_attr is imposted upon by different instantiations of that class, causing a sus amongus to be appeared.