We already have initial support for dataclasses, but some more advanced features are still missing. The following list is most probably not complete:

• Make sure that dataclass can be used as a non-decorator: class C: …; C = dataclass(C). See empty test here.
• Emit an error if >=2 variables in a dataclass class body are annotated with KW_ONLY (failing test here)
• Support for dataclasses.KW_ONLY
• Support for Final[…] fields and ClassVar[Final[…]] fields.
• Improve support for frozen dataclasses to handle subclasses of frozen dataclasses also
• Support for dataclasses.InitVar [ty] Support dataclasses.InitVar ruff#19527
• Support for dataclass fields
• Add support for other synthesized functions / arguments
  • unsafe_hash
  • match_args
  • kw_only
  • slots: [ty] initial support for slots=True in dataclasses ruff#20278
  • weakref_slot
  • The synthesized __replace__ method on Python 3.13+ [ty] synthesize __replace__ for dataclasses (>=3.13) ruff#19545
• Emit diagnostic when defining a field without a default after a field with a default, see existing TODO: [ty] diagnostic for dataclass field order ruff#19825
• Emit diagnostic when setting order=True on a dataclass that has a custom __lt__ (or similar), see existing TODO
• Verify signature of methods such as __post_init__, see this comment
• Emit diagnostic if frozen=True but the class has a custom __setattr__ or __delattr__ method in the class body (this raises TypeError at runtime)
• Add support for dataclasses.field(kw_only=True)