Using SASS to write a compound selector to the parent within a child

sass-compound-parent-selector.scss

// ----
// Sass (v3.4.21)
// ----

.parent {
  content: 'set parent style';
  color: red;
  
  .child {
    content: 'set child style';
    
    &.child-compound{
      content: 'override child style with compound selector';
    }
    
    .grandparent & {
      content: 'override child style with grandparent specificity';
    }
    
    #{&} {
      content: 'see a pattern here?';
    }
    
    @at-root.compound-parent#{&} {
      content: 'YES! Finally a way to compound the parent!';
      color: blue;
    }
  }
}

.current-selector {
  #{&} { 
    content: '#{interpolation brackets} is the key to compound selector the parent!';
    content: 'oh and @at-root is nice too.';
  }
}

I've always wondered how write a compound selector to the parent that affects your current selector.

checkout it out in action if you dont get it. http://www.sassmeister.com/gist/c82d4675ef4d4ebc56362547dc23cb1d

i'd love to see if this is possible any other way.