Sass incorrectly parses adjacent compound selectors as descendant combinators

Currently, if two compound selectors are directly next to one another, Sass will parse them as though they're separated by a descendant combinator. This is contrary to the text of the selector syntax specification which requires that compound selectors be separated by a combinator, and doesn't match the behavior of browsers.

For example, Sass currently parses [a]b and [a] b the same way. The former should be a syntax error instead.

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• Proposal (https://github.com/sass/sass/pull/4212)

Deprecation

• Specification (https://github.com/sass/sass/pull/4219)
• Dart Sass (https://github.com/sass/dart-sass/pull/2765)
• Tests (https://github.com/sass/sass-spec/pull/2134)
• Documentation (https://github.com/sass/sass-site/pull/1587)

Removal

• Dart Sass
• Tests
• Documentation