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## 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. |
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| classes.md | ||
| functions.md | ||
| variables.md | ||
| variance.md | ||