<===> input.scss
@at-root {
  #{&} {
    foo {
      bar: baz;
    }
  }
}

<===> error
Error: Invalid CSS after "": expected selector, was ""
        on line 2 of input.scss
  Use --trace for backtrace.

<===> error-dart-sass
Error: expected selector.
  ,
2 |   {
  |   ^
  '
  input.scss 2:3  root stylesheet