Paul Berry
8d2b2a197d
In rare circumstances involving syntax errors, the `parsePattern` method inserts a synthetic token but does not consume any tokens. Usually when this happens it's not a problem, because whatever method is calling `parsePattern` consumes some tokens, so the parser always makes progress. However, when parsing list patterns, after calling `parsePattern`, the parser would look for a `,`, and if it didn't find one, it would supply a synthetic `,` and call `parsePattern` again, resulting in an infinite loop. A similar situation happened with map patterns, though the situation was more complex because in between the calls to `parsePattern`, the parser would also create synthetic key expressions and `:`s. To fix the problem, when parsing a list or map pattern, after the call to `parsePattern`, the parser checks whether any tokens were consumed. If no tokens were consumed, it ignores the next token from the input stream in order to make progress. I also investigated whether there were similar issues with parenthesized/record patterns and switch expressions, since those constructs also consist of a sequence of patterns separated by tokens and other things that could in principle be supplied synthetically. Fortunately, parser recovery doesn't get into an infinite loop in those cases, so I didn't make any further changes. But I did include test cases to make sure. Fixes #52352. Bug: https://github.com/dart-lang/sdk/issues/52352 Change-Id: Idc8140236f6054deb1fd3c862036fe47dd84f30b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/302803 Reviewed-by: Konstantin Shcheglov <scheglov@google.com> Commit-Queue: Paul Berry <paulberry@google.com>
FE/analyzer shared code
This package contains logic that is shared between the front_end and analyzer packages. It is intended solely to facilitate development of the Dart SDK, and is not intended for use by end users. In particular, this package has no public API, so no guarantee is made of compatibility between one version of the package and the next.
End users should consider using the analyzer package to analyze Dart source code.