Re: #17526
## Summary
Adds tests to red knot and `linter.rs` for the semantic syntax.
Specifically add tests for `ReboundComprehensionVariable`,
`DuplicateTypeParameter`, and `MultipleCaseAssignment`.
Refactor the `test_async_comprehension_in_sync_comprehension` →
`test_semantic_error` to be more general for all semantic syntax test
cases.
## Test Plan
This is a test.
## Question
I'm happy to contribute more tests the coming days.
Should that happen here or should we merge this PR such that the
refactor `test_async_comprehension_in_sync_comprehension` →
`test_semantic_error` is available on main and others can chime in, too?
## Summary
While adding semantic error support to red-knot, I noticed duplicate
diagnostics for code like this:
```py
# error: [invalid-syntax] "cannot use an asynchronous comprehension outside of an asynchronous function on Python 3.9 (syntax was added in 3.11)"
# error: [invalid-syntax] "`asynchronous comprehension` outside of an asynchronous function"
[reveal_type(x) async for x in AsyncIterable()]
```
Beyond the duplication, the first error message doesn't make much sense
because this syntax is _not_ allowed on Python 3.11 either.
To fix this, this PR renames the
`async-comprehension-outside-async-function` semantic syntax error to
`async-comprehension-in-sync-comprehension` and fixes the rule to avoid
applying outside of sync comprehensions at all.
## Test Plan
New linter test demonstrating the false positive. The mdtests from my red-knot
PR also reflect this change.
Summary
--
This PR extends semantic syntax error detection to red-knot. The main
changes here are:
1. Adding `SemanticSyntaxChecker` and `Vec<SemanticSyntaxError>` fields
to the `SemanticIndexBuilder`
2. Calling `SemanticSyntaxChecker::visit_stmt` and `visit_expr` in the
`SemanticIndexBuilder`'s `visit_stmt` and `visit_expr` methods
3. Implementing `SemanticSyntaxContext` for `SemanticIndexBuilder`
4. Adding new mdtests to test the context implementation and show
diagnostics
(3) is definitely the trickiest and required (I think) a minor addition
to the `SemanticIndexBuilder`. I tried to look around for existing code
performing the necessary checks, but I definitely could have missed
something or misused the existing code even when I found it.
There's still one TODO around `global` statement handling. I don't think
there's an existing way to look this up, but I'm happy to work on that
here or in a separate PR. This currently only affects detection of one
error (`LoadBeforeGlobalDeclaration` or
[PLE0118](https://docs.astral.sh/ruff/rules/load-before-global-declaration/)
in ruff), so it's not too big of a problem even if we leave the TODO.
Test Plan
--
New mdtests, as well as new errors for existing mdtests
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
We mostly keep things the same here, but the message has been moved from
the annotation to the diagnostic's top-line message. I think this is
perhaps a little worse, but some bigger improvements could be made here.
Indeed, we could perhaps even add a "fix" here.
This tests the diagnostic rendering of a case that wasn't previously
covered by snapshots: when unpacking fails because there are too few
values, but where the left hand side can tolerate "N or more." In the
code, this is a distinct diagnostic, so we capture it here.
(Sorry about the diff here, but it made sense to rename the other
sections and that changes the name of the snapshot file.)
## Summary
This PR extends version-related syntax error detection to red-knot. The
main changes here are:
1. Passing `ParseOptions` specifying a `PythonVersion` to parser calls
2. Adding a `python_version` method to the `Db` trait to make this
possible
3. Converting `UnsupportedSyntaxError`s to `Diagnostic`s
4. Updating existing mdtests to avoid unrelated syntax errors
My initial draft of (1) and (2) in #16090 instead tried passing a
`PythonVersion` down to every parser call, but @MichaReiser suggested
the `Db` approach instead
[here](https://github.com/astral-sh/ruff/pull/16090#discussion_r1969198407),
and I think it turned out much nicer.
All of the new `python_version` methods look like this:
```rust
fn python_version(&self) -> ruff_python_ast::PythonVersion {
Program::get(self).python_version(self)
}
```
with the exception of the `TestDb` in `ruff_db`, which hard-codes
`PythonVersion::latest()`.
## Test Plan
Existing mdtests, plus a new mdtest to see at least one of the new
diagnostics.
## Summary
A follow-up to https://github.com/astral-sh/ruff/pull/16705 which
documents various kinds of diagnostics that can appear when assigning to
an attribute.
## Test Plan
New snapshot tests.
This updates the `Signature` and `CallBinding` machinery to support
multiple overloads for a callable. This is currently only used for
`KnownFunction`s that we special-case in our type inference code. It
does **_not_** yet update the semantic index builder to handle
`@overload` decorators and construct a multi-signature `Overloads`
instance for real Python functions.
While I was here, I updated many of the `try_call` special cases to use
signatures (possibly overloaded ones now) and `bind_call` to check
parameter lists. We still need some of the mutator methods on
`OverloadBinding` for the special cases where we need to update return
types based on some Rust code.
This uses the refactoring and support for secondary diagnostic messages
to improve the diagnostic for "invalid argument type." The main
improvement here is that we show where the function being called is
defined, and annotate the span corresponding to the invalid parameter.
## Summary
I noticed that the diagnostic range in specific unpacking assignments is
wrong. For this example
```py
a, b = 1
```
we previously got (see first commit):
```
error: lint:not-iterable
--> /src/mdtest_snippet.py:1:1
|
1 | a, b = 1
| ^^^^ Object of type `Literal[1]` is not iterable
|
```
and with this change, we get:
```
error: lint:not-iterable
--> /src/mdtest_snippet.py:1:8
|
1 | a, b = 1
| ^ Object of type `Literal[1]` is not iterable
|
```
## Test Plan
New snapshot tests.
This causes the diagnostic to highlight the actual unresovable import
instead of the entire `from ... import ...` statement.
While we're here, we expand the test coverage to cover all of the
possible ways that an `import` or a `from ... import` can fail.
Some considerations:
* The first commit in this PR adds a regression test for the current
behavior.
* This creates a new `mdtest/diagnostics` directory. Are folks cool
with this? I guess the idea is to put tests more devoted to diagnostics
than semantics in this directory. (Although I'm guessing there will
be some overlap.)
Fixes#15866
