<===> input.scss
@mixin foo($bar) {
  a: $bar;
}

foo {
  @include foo(#{});
}

<===> error
Error: Invalid CSS after "  @include foo(#{": expected expression (e.g. 1px, bold), was "});"
        on line 6 of input.scss
  Use --trace for backtrace.

<===> error-dart-sass
Error: Expected expression.
  ,
6 |   @include foo(#{});
  |                ^^
  '
  input.scss 6:16  root stylesheet