_sass/common/classes/_link.scss

@mixin link-colors($clr, $hover-clr: default, $active-clr: default, $focus-clr: null, $theme: default, $ignore-path: false) {
  @include plain() {
    text-decoration: none;
  }
  @include hover() {
    text-decoration: underline;
  }
  @include active() {
    text-decoration: none;
  }
  @include clickable($clr, null, $hover-clr, null, $active-clr, null, $focus-clr, null, $theme, $ignore-path);
}