title: PhpStorm Trait method autocompletion does not work
body: <p>I have a problem with an autocompletion in PhpStorm...</p>
  
  <pre><code>class Main
  {
      use Something;
  
      /**
       * @var SplObjectStorage
       */
      private $container;
  
      public function __construct()
      {
          $this-&gt;container = new SplObjectStorage();
      }
  
      public function addSth()
      {
          $this-&gt;add();
      }
  }
  
  
  trait Something
  {
      public function add()
      {
          $this-&gt;container-&gt;attach(new stdClass());
      }
  }
  
  $m = new Main();
  $m-&gt;add();
  
  var_dump($m);  
  </code></pre>
  
  <p>Everything works fine but <code>$this-&gt;container-&gt;attach(new stdClass());</code> throws that method <code>attach</code> is not found... Anyone can help? I think that properly configured PHPDoc should help.</p>