Subclass using @dataclass(order=True) have unavoidable "not using @override" error for __lt__ etc, with --enable-error-code=explicit-override

[huonw]

Bug Report

If one has one dataclass B inherit from another A and both are annotated with order=True, enabling the explicit-override error code gives errors attached to the subclass B about missing @overrides on __lt__ (etc.) errors. They seem to be unavoidable: there's no method to attach @override to.

To Reproduce

Run this with mypy --enable-error-code=explicit-override:

from dataclasses import dataclass

@dataclass(order=True)
class A:
    pass

@dataclass(order=True)
class B(A):
    pass

All-in-one reproducer:

# Setup:
cd $(mktemp -d)

python3 -m venv .venv
.venv/bin/python -m pip install mypy==1.10.0 mypy-extensions==1.0.0 typing_extensions==4.11.0

cat > test_mypy.py <<EOF
from dataclasses import dataclass

@dataclass(order=True)
class A:
    pass

@dataclass(order=True)
class B(A):
    pass
EOF

# BUG:
.venv/bin/python -m mypy --enable-error-code=explicit-override ./test_mypy.py

Expected Behavior

Actual Behavior

Output:

test_mypy.py:10: error: Method "__lt__" is not using @override but is overriding a method in class "test_mypy.A"  [explicit-override]
test_mypy.py:10: error: Method "__gt__" is not using @override but is overriding a method in class "test_mypy.A"  [explicit-override]
test_mypy.py:10: error: Method "__le__" is not using @override but is overriding a method in class "test_mypy.A"  [explicit-override]
test_mypy.py:10: error: Method "__ge__" is not using @override but is overriding a method in class "test_mypy.A"  [explicit-override]
Found 4 errors in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.10.0
• Mypy command-line flags: --enable-error-code=explicit-overide
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.12

[hauntsaninja]

If someone wants to attempt a PR, I think there's a plugin_generated attribute that could be used to gate this error. You'd need to look at dataclasses.py and checker.py