Summary
--
This PR detects the use of invalid syntax in annotation scopes,
including
`yield` and `yield from` expressions and named expressions. I combined a
few
different types of CPython errors here, but I think the resulting error
messages
still make sense and are even preferable to what CPython gives. For
example, we
report `yield expression cannot be used in a type annotation` for both
of these:
```pycon
>>> def f[T](x: (yield 1)): ...
File "<python-input-26>", line 1
def f[T](x: (yield 1)): ...
^^^^^^^
SyntaxError: yield expression cannot be used within the definition of a generic
>>> def foo() -> (yield x): ...
File "<python-input-28>", line 1
def foo() -> (yield x): ...
^^^^^^^
SyntaxError: 'yield' outside function
```
Fixes https://github.com/astral-sh/ruff/issues/11118.
Test Plan
--
New inline tests, along with some updates to existing tests.
Summary
--
Detects duplicate attributes in a `match` class pattern:
```python
match x:
case Class(x=1, x=2): ...
```
which are more analogous to the similar check for mapping patterns than
to the
multiple assignments rule.
I also realized that both this and the mapping check would only work on
top-level patterns, despite the possibility that they can be nested
inside other
patterns:
```python
match x:
case [{"x": 1, "x": 2}]: ... # false negative in the old version
```
and moved these checks into the recursive pattern visitor instead.
I also tidied up some of the names like the `multiple_case_assignment`
function
and the `MultipleCaseAssignmentVisitor`, which are now doing more than
checking
for multiple assignments.
Test Plan
--
New inline tests for both classes and mappings.
Summary
--
Fixes#17181. The cases being tested with multiple *keys* being equal
are actually a slightly different error, more like the error for
`MatchMapping` than like the other multiple assignment errors:
```pycon
>>> match x:
... case Class(x=x, x=x): ...
...
File "<python-input-249>", line 2
case Class(x=x, x=x): ...
^
SyntaxError: attribute name repeated in class pattern: x
>>> match x:
... case {"x": 1, "x": 2}: ...
...
File "<python-input-251>", line 2
case {"x": 1, "x": 2}: ...
^^^^^^^^^^^^^^^^
SyntaxError: mapping pattern checks duplicate key ('x')
>>> match x:
... case [x, x]: ...
...
File "<python-input-252>", line 2
case [x, x]: ...
^
SyntaxError: multiple assignments to name 'x' in pattern
```
This PR just stops the false positive reported in the issue, but I will
quickly follow it up with a new rule (or possibly combined with the
mapping rule) catching the repeated attributes separately.
Test Plan
--
New inline `test_ok` and updating the `test_err` cases to have duplicate
values instead of keys.
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## Summary
I decided to disable the new
[`needless_continue`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue)
rule because I often found the explicit `continue` more readable over an
empty block or having to invert the condition of an other branch.
## Test Plan
`cargo test`
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Summary
--
Detects duplicate literals in `match` mapping keys.
This PR also adds a `source` method to `SemanticSyntaxContext` to
display the duplicated key in the error message by slicing out its
range.
Test Plan
--
New inline tests.
Summary
--
This PR reimplements
[load-before-global-declaration
(PLE0118)](https://docs.astral.sh/ruff/rules/load-before-global-declaration/)
as a semantic syntax error.
I added a `global` method to the `SemanticSyntaxContext` trait to make
this very easy, at least in ruff. Does red-knot have something similar?
If this approach will also work in red-knot, I think some of the other
PLE rules are also compile-time errors in CPython, PLE0117 in
particular. 0115 and 0116 also mention `SyntaxError`s in their docs, but
I haven't confirmed them in the REPL yet.
Test Plan
--
Existing linter tests for PLE0118. I think this actually can't be tested
very easily in an inline test because the `TestContext` doesn't have a
real way to track globals.
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Summary
--
Fixes https://github.com/astral-sh/ruff/issues/16520 by flagging single,
starred expressions in `return`, `yield`, and
`for` statements.
I thought `yield from` would also be included here, but that error is
emitted by
the CPython parser:
```pycon
>>> ast.parse("def f(): yield from *x")
Traceback (most recent call last):
File "<python-input-214>", line 1, in <module>
ast.parse("def f(): yield from *x")
~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.13/ast.py", line 54, in parse
return compile(source, filename, mode, flags,
_feature_version=feature_version, optimize=optimize)
File "<unknown>", line 1
def f(): yield from *x
^
SyntaxError: invalid syntax
```
And we also already catch it in our parser.
Test Plan
--
New inline tests and updates to existing tests.
Summary
--
Detects starred assignment targets outside of tuples and lists like `*a
= (1,)`.
This PR only considers assignment statements. I also checked annotated
assigment statements, but these give a separate error that we already
catch, so I think they're okay not to consider:
```pycon
>>> *a: list[int] = []
File "<python-input-72>", line 1
*a: list[int] = []
^
SyntaxError: invalid syntax
```
Fixes#13759
Test Plan
--
New inline tests, plus a new `SemanticSyntaxError` for an existing
parser test. I also removed a now-invalid case from an otherwise-valid
test fixture.
The new semantic error leads to two errors for the case below:
```python
*foo() = 42
```
but this matches [pyright] too.
[pyright]: https://pyright-play.net/?code=FQMw9mAUCUAEC8sAsAmAUEA
Summary
--
Detect setting or deleting `__debug__`. Assigning to `__debug__` was a
`SyntaxError` on the earliest version I tested (3.8). Deleting
`__debug__` was made a `SyntaxError` in [BPO 45000], which said it was
resolved in Python 3.10. However, `del __debug__` was also a runtime
error (`NameError`) when I tested in Python 3.9.6, so I thought it was
worth including 3.9 in this check.
I don't think it was ever a *good* idea to try `del __debug__`, so I
think there's also an argument for not making this version-dependent at
all. That would only simplify the implementation very slightly, though.
[BPO 45000]: https://github.com/python/cpython/issues/89163
Test Plan
--
New inline tests. This also required adding a `PythonVersion` field to
the `TestContext` that could be taken from the inline `ParseOptions` and
making the version field on the options accessible.
Summary
--
This PR detects multiple assignments to the same name in `case` patterns
by recursively visiting each pattern.
Test Plan
--
New inline tests.
Summary
--
Detects irrefutable `match` cases before the final case using a modified
version
of the existing `Pattern::is_irrefutable` method from the AST crate. The
modified method helps to retrieve a more precise diagnostic range to
match what
Python 3.13 shows in the REPL.
Test Plan
--
New inline tests, as well as some updates to existing tests that had
irrefutable
patterns before the last block.
Summary
--
Detects duplicate type parameter names in function definitions, class
definitions, and type alias statements.
I also boxed the `type_params` field on `StmtTypeAlias` to make it
easier to
`match` with functions and classes. (That's the reason for the red-knot
code
owner review requests, sorry!)
Test Plan
--
New `ruff_python_syntax_errors` unit tests.
Fixes#11119.
## Summary
This PR implements the "greeter" approach for checking the AST for
syntax errors emitted by the CPython compiler. It introduces two main
infrastructural changes to support all of the compile-time errors:
1. Adds a new `semantic_errors` module to the parser crate with public
`SemanticSyntaxChecker` and `SemanticSyntaxError` types
2. Embeds a `SemanticSyntaxChecker` in the `ruff_linter::Checker` for
checking these errors in ruff
As a proof of concept, it also implements detection of two syntax
errors:
1. A reimplementation of
[`late-future-import`](https://docs.astral.sh/ruff/rules/late-future-import/)
(`F404`)
2. Detection of rebound comprehension iteration variables
(https://github.com/astral-sh/ruff/issues/14395)
## Test plan
Existing F404 tests, new inline tests in the `ruff_python_parser` crate,
and a linter CLI test showing an example of the `Message` output.
I also tested in VS Code, where `preview = false` and turning off syntax
errors both disable the new errors:
And on the playground, where `preview = false` also disables the errors:
Fixes#14395
---------
Co-authored-by: Micha Reiser <micha@reiser.io>
Brent Westbrook
Micha Reiser