🐛 CSS parser does not recognize multiple semicolons after a declaration

[blutorange]

Environment information

CLI:
  Version:                      1.8.3
  Color support:                true

Platform:
  CPU Architecture:             x86_64
  OS:                           linux

Environment:
  BIOME_LOG_DIR:                unset
  NO_COLOR:                     unset
  TERM:                         "xterm-256color"
  JS_RUNTIME_VERSION:           "v18.19.1"
  JS_RUNTIME_NAME:              "node"
  NODE_PACKAGE_MANAGER:         "yarn/4.4.0"

Biome Configuration:
  Status:                       Loaded successfully
  Formatter disabled:           false
  Linter disabled:              false
  Organize imports disabled:    false
  VCS disabled:                 true

Workspace:
  Open Documents:               0

What happened?

Biome's CSS parser raises a parser error when a CSS declaration ends with multiple semicolons, e.g.

.foo {
  color: red;;
}

Sorry if it was reported already, but I couldn't find an issue for that.

Expected result

The CSS file parses correctly. The formatter could simply remove multiple semicolons. This is what prettier does

More info

For some context: One of my colleagues use IntelliJ to author a CSS file, and it did not show any errors. During the pre-commit hook, when biome was called to format the CSS file, it reported a syntax error in the CSS file. Took him some time to find the issue. It turned out the issue was that a declaration in the CSS file had 2 semicolons at the (;)

I took a look at the CSS specification. If I understand it correctly, CSS syntax 3, 5.4.5, Consume a list of declarations allows for multiple semicolons:

Repeatedly consume the next input token
  <semicolon-token>
    Do nothing.

Various other tools such as IntelliJ, VSCode or https://jigsaw.w3.org/css-validator/validator also accept multiple semicolons. Biome however produces a parser error (tested with 1.8.3)

According to this comment here in declaration_or_rule_list_block.rs, the parser only seems to consider a single semicolon for now.

Code of Conduct

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[h-a-n-a]

I would be happy to help!

[chansuke]

@h-a-n-a go ahead💪