dataclasses_match_args error

Access to __match_args__ on a dataclass with match_args=False

When @dataclass(match_args=False) is specified, Python does **not** generate the __match_args__ class variable. Accessing ClassName.__match_args__ on such a class is an AttributeError at runtime and a static type error.

from dataclasses import dataclass

@dataclass(match_args=False)
class DC4:
    x: int

DC4.__match_args__  # E: attribute not generated

How to handle it

Every rule is on by default — strict is the default, not a cage. You can dial dataclasses_match_args down per-file or per-path from your editor or pyproject.toml, or fix the code so it type-checks. See the Type System rules and the complete diagnostic reference.

Canonical URL: https://www.basilisk-python.dev/errors/dataclasses_match_args