slotted dataclasses not calling descriptor field `__set__`

Bug report

Bug description:

(Sorry to be finding these funny little dudes)

import dataclasses


class DescriptorFieldType:
    def __set_name__(self, owner, name: str) -> None:
        self.name = name

    def __get__(self, instance, owner):
        if instance is None:
            return None
        return instance.__dict__[self.name]

    def __set__(self, instance, value) -> None:
        raise ValueError("Unsettable")


@dataclasses.dataclass(slots=True)
class Slotted:
    field: DescriptorFieldType = DescriptorFieldType()

Slotted()

@dataclasses.dataclass
class Unslotted:
    field: DescriptorFieldType = DescriptorFieldType()

Unslotted()

Will error with:

Traceback (most recent call last):
  File "[...]", line 27, in <module>
    Unslotted()
  File "<string>", line 3, in __init__
  File "[...]", line 14, in __set__
    raise ValueError("Unsettable")
ValueError: Unsettable

(errors on Unslotted but not Slotted)

CPython versions tested on:

3.11

Operating systems tested on:

No response

Linked PRs

• gh-133002