<===> input.scss
#{a==b}

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

<===> error-dart-sass
Error: expected "{".
  ,
1 | #{a==b}
  |        ^
  '
  input.scss 1:8  root stylesheet