title: LESS add class with pseudo selector
body: <p>I use LESS and here is my example:</p>
  
  <pre><code>.arrow{
     color: red;
  }
  .arrow:before{
     content: "&gt;";
  }
  
  .button{
    background: blue;
    .arrow;
    &amp;:before{
      border: 1px solid;
    }
  }
  </code></pre>
  
  <p>And this is CSS after parsing:</p>
  
  <pre><code>.button{
     background: blue;
     color: red;
  }
  .button:before{
     border: 1px solid; // HERE IS NO  content: "&gt;" !!!
  }
  </code></pre>
  
  <p>How to add <code>:before</code> pseudo-element from <code>.arrow</code> class to my button?</p>