title: PHP: phpdoc for elements of a class which extends ArrayObject
body: <p>I have a class which is a simple extension of the <strong><a href="http://php.net/manual/en/class.arrayobject.php" rel="nofollow noreferrer">ArrayObject</a></strong> class: </p>
  
  <pre><code>/**
   * what to put here? :)
   */
  class Collection extends \ArrayObject
  {
      /**
       * @param Item
       */
      public function add(Item $item)
      {
          $this-&gt;append($item);
      }
  }
  </code></pre>
  
  <p>Is it possible to get my IDE to use code completion for the elements of my ArrayObject-extended class?</p>
  
  <pre><code>foreach ($collection as $item)
  {
      $item-&gt;getPrice(); //my IDE doesn't not know the object here
  }
  </code></pre>