Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.14)
// Compass (v1.0.3)
// ----

@mixin limit-to($limit-to...) {
  @at-root {
    @each $selector in $limit-to {
      #{$selector}#{&} {
        @content;
      }
    }
  }
}

.button {
  background-color: red;
  
  @include limit-to(button) {
    &::-moz-focus-inner {
      margin-top: -4px;
      padding: 0;
      border: 0;
    }
  }
}

.button-2 {
  background-color: red;
  
  @include limit-to(button, a) {
    &::-moz-focus-inner {
      margin-top: -4px;
      padding: 0;
      border: 0;
    }
  }
}

SassMeister-output.css

.button {
  background-color: red;
}
button.button::-moz-focus-inner {
  margin-top: -4px;
  padding: 0;
  border: 0;
}

.button-2 {
  background-color: red;
}
button.button-2::-moz-focus-inner {
  margin-top: -4px;
  padding: 0;
  border: 0;
}

a.button-2::-moz-focus-inner {
  margin-top: -4px;
  padding: 0;
  border: 0;
}