ruff/crates/ty_python_semantic/resources/mdtest/annotations
Dhruv Manilawala cb2e277482
[ty] Understand legacy and PEP 695 `ParamSpec` (#21139)
## Summary

This PR adds support for understanding the legacy definition and PEP 695
definition for `ParamSpec`.

This is still very initial and doesn't really implement any of the
semantics.

Part of https://github.com/astral-sh/ty/issues/157

## Test Plan

Add mdtest cases.

## Ecosystem analysis

Most of the diagnostics in `starlette` are due to the fact that ty now
understands `ParamSpec` is not a `Todo` type, so the assignability check
fails. The code looks something like:

```py
class _MiddlewareFactory(Protocol[P]):
    def __call__(self, app: ASGIApp, /, *args: P.args, **kwargs: P.kwargs) -> ASGIApp: ...  # pragma: no cover

class Middleware:
    def __init__(
        self,
        cls: _MiddlewareFactory[P],
        *args: P.args,
        **kwargs: P.kwargs,
    ) -> None:
        self.cls = cls
        self.args = args
        self.kwargs = kwargs

# ty complains that `ServerErrorMiddleware` is not assignable to `_MiddlewareFactory[P]`
Middleware(ServerErrorMiddleware, handler=error_handler, debug=debug)
```

There are multiple diagnostics where there's an attribute access on the
`Wrapped` object of `functools` which Pyright also raises:
```py
from functools import wraps

def my_decorator(f):
    @wraps(f)
    def wrapper(*args, **kwds):
        return f(*args, **kwds)

	# Pyright: Cannot access attribute "__signature__" for class "_Wrapped[..., Unknown, ..., Unknown]"
      Attribute "__signature__" is unknown [reportAttributeAccessIssue]
	# ty: Object of type `_Wrapped[Unknown, Unknown, Unknown, Unknown]` has no attribute `__signature__` [unresolved-attribute]
    wrapper.__signature__
    return wrapper
```

There are additional diagnostics that is due to the assignability checks
failing because ty now infers the `ParamSpec` instead of using the
`Todo` type which would always succeed. This results in a few
`no-matching-overload` diagnostics because the assignability checks
fail.

There are a few diagnostics related to
https://github.com/astral-sh/ty/issues/491 where there's a variable
which is either a bound method or a variable that's annotated with
`Callable` that doesn't contain the instance as the first parameter.

Another set of (valid) diagnostics are where the code hasn't provided
all the type variables. ty is now raising diagnostics for these because
we include `ParamSpec` type variable in the signature. For example,
`staticmethod[Any]` which contains two type variables.
2025-11-06 11:14:40 -05:00
..
annotated.md [ty] Fix bug where ty would think all types had an `__mro__` attribute (#20995) 2025-10-27 11:19:12 +00:00
any.md [ty] Use "cannot" consistently over "can not" (#21255) 2025-11-03 10:38:20 -05:00
callable.md [ty] Understand legacy and PEP 695 `ParamSpec` (#21139) 2025-11-06 11:14:40 -05:00
deferred.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
int_float_complex.md [ty] Improve disjointness inference for `NominalInstanceType`s and `SubclassOfType`s (#18864) 2025-06-24 20:27:37 +00:00
invalid.md [syntax-errors] Detect `yield from` inside async function (#20051) 2025-09-03 10:13:05 -04:00
literal.md [ty] support subscripting typing.Literal with a type alias (#21207) 2025-11-02 12:39:55 -05:00
literal_string.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
never.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
new_types.md ty_python_semantic: add union type context to function call type errors 2025-05-09 13:40:51 -04:00
optional.md Rename Red Knot (#17820) 2025-05-03 19:49:15 +02:00
self.md [ty] Infer type of `self` for decorated methods and properties (#21123) 2025-10-29 21:22:38 +00:00
starred.md [ty] Return `Option<TupleType>` from `infer_tuple_type_expression` (#19735) 2025-08-04 13:48:19 +01:00
stdlib_typing_aliases.md [ty] Fix bug where ty would think all types had an `__mro__` attribute (#20995) 2025-10-27 11:19:12 +00:00
string.md [ty] Emit error for invalid binary operations in type expressions (#18991) 2025-06-30 10:06:01 +02:00
union.md [ty] Implicit type aliases: Support for PEP 604 unions (#21195) 2025-11-03 21:50:25 +01:00
unsupported_special_forms.md [ty] Understand legacy and PEP 695 `ParamSpec` (#21139) 2025-11-06 11:14:40 -05:00
unsupported_special_types.md Generalize special-casing for enums constructed with the functional syntax (#17885) 2025-05-06 11:02:55 +01:00
unsupported_type_qualifiers.md [ty] validate constructor call of `TypedDict` (#19810) 2025-08-25 14:45:52 +02:00