title: Android Studio can't find package or symbol
body: <p>I have a problem when I have move some source code from package 
  com.a.b <strong>To</strong> com.a.c.
  After move I build project and found error:
  Error:(11, 36) error: package com.x.y does not exist
  Error:(113, 13) error: cannot find symbol class MyClass
  (com.x.y -> all my package in my project).</p>
  
  <p>I also search on GG or SO. then I try some ways:</p>
  
  <ol>
  <li><p>Clearn -> Rebuild Prj; </p></li>
  <li><p>File -> Invalidate cache.</p></li>
  <li><p>Clean project -> re-open android studio.</p></li>
  </ol>
  
  <p>I ensure all  module library have plugin:</p>
  
  <pre><code>apply plugin: 'com.android.library'
  </code></pre>
  
  <p><strong>Notes:</strong> AndroidStudio not show error when open class error. (Everything seem ok. It's only error when build).</p>
  
  <p>Please help.
  Thanks !</p>