False positive when assigning to Final instance attribute in __init__ #1409
Description
From the conformance suite (and 44 instances across the ecosystem once type-of-self lands):
from typing import Final, Self
class ClassA:
ID4: Final[int] # OK because initialized in __init__
def __init__(self: Self):
self.ID4 = 1 # Cannot assign to final attribute `ID4` on type `Self@__init__` (invalid-assignment)