dataclasses: frozen dataclasses with slots' `__setattr__` and `__delattr__` does not work.

[avboag]

Bug report

The check in frozen dataclasses' __setattr__ and __delattr__ does not work when slots=True:

@dataclass(frozen=True, slots=True)
class C:
 i: int

C(10).j = 5

crashes with

Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "<string>", line 5, in __setattr__
TypeError: super(type, obj): obj must be an instance or subtype of type

instead of raising a FrozenInstanceError.

Likewise,

@dataclass(frozen=True, slots=True)
class C:
 i: int

class D(C):
 pass

D(10).j = 5

crashes with the same error instead of working.

Linked PRs

• gh-105936: Fix frozen dataclasses with slots' __setattr__ and __delattr_ #105937
• gh-105936: Properly update closure cells for __setattr__ and __detattr__ in frozen dataclasses with slots #144021