MyPy doesn't seem to know that dataclasses add __eq__

Bug Report

MyPy doesn't seem to understand that dataclasses can generate an __eq__ method. If it's required (such as in an ABC), then it doesn't know that it was created.

To Reproduce

import dataclasses
import abc

@dataclasses.dataclass(eq=False)
class AbstractEq(abc.ABC):
    @abc.abstractmethod
    def __eq__(self, other: object) -> bool:
        pass

@dataclasses.dataclass
class ConcreteEq(AbstractEq):
    x: int

print(ConcreteEq(1) == ConcreteEq(1))

Gist URL: https://gist.github.com/89d988a5c8d37bd10d17445d5e344e63
Playground URL: https://mypy-play.net/?mypy=latest&python=3.10&gist=89d988a5c8d37bd10d17445d5e344e63

Expected Behavior

This should pass. It does at runtime. dataclasses do add __eq__ unless eq=False.

Actual Behavior

main.py:14: error: Cannot instantiate abstract class "ConcreteEq" with abstract attribute "__eq__"
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 0.981 (playground) and 0.982 (local)
• Mypy command-line flags: None
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.10

I didn't see any other issues that were exactly this issue.

Start by running the supplied Python 3.10 reproducer with mypy and inspect how dataclasses and abstract eq are analyzed. Done means the example passes type checking without an abstract-class instantiation error, while preserving the eq=False behavior shown in the issue.