title: Pycharm not detecting errors
body: <p>I've encountered with an strange issue. I'm currently running Pycharm 5 for development of a Django project. There exists a specific file that Pycharm does not catch errors of it. For instance, if I read a variable that does not exist, Pycharm does not detect it. If I call an unresolved reference, Pycharm does not  detect it. It does not detect anything. But things get stranger when I want to edit another file that is inside the directory where the previous file exists. But in this case, Everthing is OK.</p>
  
  <p>I tried both removing .idea folder and also invalidating cache and restarting Pycharm but non of them worked!</p>
  
  <p>Any idea how to fix this weird issue?</p>
  
  <p><strong>Update 1:</strong></p>
  
  <p>For instance, Pycharm does not detect that the variable used in <code>if</code> statement is not previously defind:</p>
  
  <pre><code>if dfsdffsdfdsf:
     a = 2
  </code></pre>