title: Cannot resolve symbol 'NonNull' after Android Studio update
body: <p>I recently updated Android Studio. Afterwards it seems to no longer being able to resolve some support annotations, such as <code>@NonNull</code> or <code>@Nullable</code>. It did work just fine before updating. However, everything is still compiling and I am able to execute Code, but still it shows the symbol cannot be resolved message at my imports.</p>
  
  <p>What I have already tried so far:</p>
  
  <ol>
  <li><p>Included the dependency in build.gradle (Module: Application):</p>
  
  <pre><code>compile 'com.android.support:support-annotations:27.0.0'
  </code></pre></li>
  <li>I have invalidated Caches and restarted</li>
  <li>Cleaning and rebuilding the project</li>
  <li>(Edit) Synched Gradle</li>
  </ol>
  
  <p>I have no idea why this is not working and would really appreciate your help.</p>