Generated by SassMeister.com.

SassMeister-input.scss

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

@mixin v-spacing($margin: 30px, $padding: 0) {
  
  $selector-chain: &;
  $top-level-selector: false;

  @each $selector in $selector-chain {
    $top-level-selector: nth($selector, length($selector))
  }

  @if($top-level-selector) {
    + #{$top-level-selector} {
      margin-top: $margin;
      padding-top: $padding;
      
      @content;
    }
  }
  @else {
    @error "mixin cannot be called in root document";
  }
}

.toggle-list {
  @include v-spacing(30px);

  .toggle {
    @include v-spacing(30px);
  }
  
  .test .foo .bar {
    @include v-spacing(30px);
  }
}

SassMeister-output.css

.toggle-list + .toggle-list {
  margin-top: 30px;
  padding-top: 0;
}
.toggle-list .toggle + .toggle {
  margin-top: 30px;
  padding-top: 0;
}
.toggle-list .test .foo .bar + .bar {
  margin-top: 30px;
  padding-top: 0;
}