title: PhpStorm does not highlight unimported classes
body: <p>I'm using PhpStorm 2016.2 and recently I've noticed that it has stopped highlighting errors when a class is not imported from any namespace.</p>
  
  <p>Let's say a namespaced class and inside I have a call like this:</p>
  
  <pre><code>$user = User::findOne(123);
  </code></pre>
  
  <p>In order for the above to work, I would need to do <code>use common\models\User</code>. But there is no error highlight and if I try to execute the code, it would of course fail. I'm confident that previously I got such errors highlighted. I'm not sure however when that happened - since update to 2016.2 or after doing something unintended.</p>