## Summary
This PR resolves the way diagnostics are reported for an invalid call to
an overloaded function.
If any of the steps in the overload call evaluation algorithm yields a
matching overload but it's type checking that failed, the
`no-matching-overload` diagnostic is incorrect because there is a
matching overload, it's the arguments passed that are invalid as per the
signature. So, this PR improves that by surfacing the diagnostics on the
matching overload directly.
It also provides additional context, specifically the matching overload
where this error occurred and other non-matching overloads. Consider the
following example:
```py
from typing import overload
@overload
def f() -> None: ...
@overload
def f(x: int) -> int: ...
@overload
def f(x: int, y: int) -> int: ...
def f(x: int | None = None, y: int | None = None) -> int | None:
return None
f("a")
```
We get:
<img width="857" alt="Screenshot 2025-06-18 at 11 07 10"
src="https://github.com/user-attachments/assets/8dbcaf13-2a74-4661-aa94-1225c9402ea6"
/>
## Test Plan
Update test cases, resolve existing todos and validate the updated
snapshots.
This makes an easy tweak to allow our diagnostics for unmatched
overloads to apply to method calls. Previously, they only worked for
function calls.
There is at least one other case worth addressing too, namely, class
literals. e.g., `type()`. We had a diagnostic snapshot test case to
track it.
Closesastral-sh/ty#274
The diagnostic now includes a pointer to the implementation definition
along with each possible overload.
This doesn't include information about *why* each overload failed. But
given the emphasis on concise output (since there can be *many*
unmatched overloads), it's not totally clear how to include that
additional information.
Fixes#274
## Summary
If the user tries to use a new builtin on an old Python version, tell
them what Python version the builtin was added on, what our inferred
Python version is for their project, and what configuration settings
they can tweak to fix the error.
## Test Plan
Snapshots and screenshots:
Re: #17526
## Summary
Add integration test for semantic syntax for `IrrefutableCasePattern`,
`SingleStarredAssignment`, `WriteToDebug`, and `InvalidExpression`.
## Notes
- Following @ntBre's suggestion, I will keep the test coming in batches
like this over the next few days in separate PRs to keep the review load
per PR manageable while also not spamming too many.
- I did not add a test for `del __debug__` which is one of the examples
in `crates/ruff_python_parser/src/semantic_errors.rs:1051`.
For python version `<= 3.8` there is no error and for `>=3.9` the error
is not `WriteToDebug` but `SyntaxError: cannot delete __debug__ on
Python 3.9 (syntax was removed in 3.9)`.
- The `blacken-docs` bypass is necessary because otherwise the test does
not pass pre-commit checks; but we want to check for this faulty syntax.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
This is a test.
This makes one very simple change: we report all call binding
errors from each union variant.
This does result in duplicate-seeming diagnostics. For example,
when two union variants are invalid for the same reason.
Summary
--
This PR resolves both the typing-related and syntax error TODOs added in
#17563 by tracking a set of `global` bindings for each scope. As
discussed below, we avoid the additional AST traversal from ruff by
collecting `Name`s from `global` statements while building the semantic
index and emit a syntax error if the `Name` is already bound in the
current scope at the point of the `global` statement. This has the
downside of separating the error from the `SemanticSyntaxChecker`, but I
plan to explore using this approach in the `SemanticSyntaxChecker`
itself as a follow-up. It seems like this may be a better approach for
ruff as well.
Test Plan
--
Updated all of the related mdtests to remove the TODOs (and add quotes I
forgot on the messages).
There is one remaining TODO, but it requires `nonlocal` support, which
isn't even incorporated into the `SemanticSyntaxChecker` yet.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Co-authored-by: Carl Meyer <carl@astral.sh>
Re: #17526
## Summary
Add integration tests for Python Semantic Syntax for
`InvalidStarExpression`, `DuplicateMatchKey`, and
`DuplicateMatchClassAttribute`.
## Note
- Red knot integration tests for `DuplicateMatchKey` exist already in
line 89-101.
<!-- What's the purpose of the change? What does it do, and why? -->
## Test Plan
This is a test.
<!-- How was it tested? -->
