Invalid argument to fields from dataclasses #92
Description
Summary
When using fields from dataclasses, ty gives a lint:invalid-argument-type error.
https://play.ty.dev/331a08e9-3adf-41f4-a4a5-483a964a1b64
from dataclasses import dataclass, fields
@dataclass
class Foo:
x: int
y: float
z: str
for field in fields(Foo):
print(field.name, field.type)$ uvx ty check foo.py
error: lint:invalid-argument-type: Argument to this function is incorrect
--> foo.py:11:21
|
11 | for field in fields(Foo):
| ^^^ Expected `DataclassInstance`, found `Literal[Foo]`
12 | print(field.name, field.type)
|
info: Function defined here
--> stdlib\dataclasses.pyi:220:5
|
218 | ) -> Any: ...
219 |
220 | def fields(class_or_instance: DataclassInstance | type[DataclassInstance]) -> tuple[Field[Any], ...]: ...
| ^^^^^^ -------------------------------------------------------------- Parameter declared here
221 |
222 | # HACK: `obj: Never` typing matches if object argument is using `Any` type.
|
There is a similar error for fields from attrs:
from attrs import define, fields
@define
class Foo:
x: int
y: float
z: str
for field in fields(Foo):
print(field.name, field.type)$ uvx ty check foo.py
error: lint:invalid-argument-type: Argument to this function is incorrect
--> foo.py:11:21
|
11 | for field in fields(Foo):
| ^^^ Expected `type[AttrsInstance]`, found `Literal[Foo]`
12 | print(field.name, field.type)
|
info: Function defined here
--> .venv\Lib\site-packages\attr\__init__.pyi:311:5
|
309 | unsafe_hash: bool | None = ...,
310 | ) -> Callable[[_C], _C]: ...
311 | def fields(cls: type[AttrsInstance]) -> Any: ...
| ^^^^^^ ------------------------ Parameter declared here
312 | def fields_dict(cls: type[AttrsInstance]) -> dict[str, Attribute[Any]]: ...
313 | def validate(inst: AttrsInstance) -> None: ...
|
Found 1 diagnostic
Version
ty 0.0.0-alpha.5 (ff90008 2025-05-06)