[syntax-errors] Assignment expressions before Python 3.8 (#16383)

## Summary
This PR is the first in a series derived from
https://github.com/astral-sh/ruff/pull/16308, each of which add support
for detecting one version-related syntax error from
https://github.com/astral-sh/ruff/issues/6591. This one should be
the largest because it also includes the addition of the 
`Parser::add_unsupported_syntax_error` method

Otherwise I think the general structure will be the same for each syntax
error:
* Detecting the error in the parser
* Inline parser tests for the new error
* New ruff CLI tests for the new error

## Test Plan
As noted above, there are new inline parser tests, as well as new ruff
CLI
tests. Once https://github.com/astral-sh/ruff/pull/16379 is resolved,
there should also be new mdtests for red-knot,
but this PR does not currently include those.
This commit is contained in:
Brent Westbrook 2025-02-28 17:13:46 -05:00 committed by GitHub
parent ba44e9de13
commit 4431978262
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9 changed files with 182 additions and 28 deletions

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@ -11,7 +11,7 @@ use crate::parser::progress::{ParserProgress, TokenId};
use crate::token::TokenValue;
use crate::token_set::TokenSet;
use crate::token_source::{TokenSource, TokenSourceCheckpoint};
use crate::{Mode, ParseError, ParseErrorType, TokenKind};
use crate::{Mode, ParseError, ParseErrorType, TokenKind, UnsupportedSyntaxErrorKind};
use crate::{Parsed, Tokens};
pub use crate::parser::options::ParseOptions;
@ -438,6 +438,16 @@ impl<'src> Parser<'src> {
inner(&mut self.errors, error, ranged.range());
}
/// Add an [`UnsupportedSyntaxError`] with the given [`UnsupportedSyntaxErrorKind`] and
/// [`TextRange`].
fn add_unsupported_syntax_error(&mut self, kind: UnsupportedSyntaxErrorKind, range: TextRange) {
self.unsupported_syntax_errors.push(UnsupportedSyntaxError {
kind,
range,
target_version: self.options.target_version,
});
}
/// Returns `true` if the current token is of the given kind.
fn at(&self, kind: TokenKind) -> bool {
self.current_token_kind() == kind