<===> options.yml
---
:todo:
- libsass

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

foo {
  @include foo;
}

<===> error
Error: Invalid CSS after "@mixin foo($bar:#{": expected expression (e.g. 1px, bold), was "}) {"

<===> error-dart-sass
Error: Expected expression.
  ,
1 | @mixin foo($bar:#{}) {
  |                 ^^
  '
  input.scss 1:17  root stylesheet