carto/test/rendering-mss/issue_284.mss

#roads_high::outline {
  [type='primary'] {
    line-color: red;
  }
  [foo='bar'] {
    line-width: 10;
  }
}

#roads_high {
  [type='primary'] {
    line-color: red;
  }
  [foo='bar'] {
    line-width: 10;
  }
}