ruff/crates/ruff_python_parser
Brent Westbrook c2b2e42ad3
[syntax-errors] Invalid syntax in annotations (#17101)
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.
2025-04-03 17:56:55 -04:00
..
resources [syntax-errors] Invalid syntax in annotations (#17101) 2025-04-03 17:56:55 -04:00
src [syntax-errors] Invalid syntax in annotations (#17101) 2025-04-03 17:56:55 -04:00
tests [syntax-errors] Invalid syntax in annotations (#17101) 2025-04-03 17:56:55 -04:00
Cargo.toml Allow passing ParseOptions to inline tests (#16357) 2025-02-27 10:23:15 -05:00
CONTRIBUTING.md Update pre-commit dependencies (#17073) 2025-03-31 07:42:15 +00:00
README.md Add basic docs for the parser crate (#11199) 2024-04-29 17:08:07 +00:00

Ruff Python Parser

Ruff's Python parser is a hand-written recursive descent parser which can parse Python source code into an Abstract Syntax Tree (AST). It also utilizes the Pratt parsing technique to parse expressions with different precedence.

Try out the parser in the playground.

Python version support

The parser supports the latest Python syntax, which is currently Python 3.12. It does not throw syntax errors if it encounters a syntax feature that is not supported by the target-version. This will be fixed in a future release (see https://github.com/astral-sh/ruff/issues/6591).

Contributing

Refer to the contributing guidelines to get started and GitHub issues with the parser label for issues that need help.