title: How to fix "reference cannot be bound to dereferenced null pointer" warning
body: <p>Xcode 6.3 (beta) gives me new warnings, any suggestions how to fix the problem? I don't think removing the check completely as void is a correct answer, since in some cases "camera" has been NULL and caused crashing later elsewhere.</p>
  
  <blockquote>
    <p>Reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to false</p>
  </blockquote>
  
  <p>Here's the code. How else could I verify camera exists?</p>
  
  <pre class="lang-cpp prettyprint-override"><code>Camera&amp; camera = sceneEngine-&gt;camera();
  // FIXME: this triggers an undefined-bool-conversion warning in Xcode 6.3 BETA
  if (&amp;camera == NULL) return;
  </code></pre>
  
  <p>And the related method from SceneEngine:</p>
  
  <pre class="lang-cpp prettyprint-override"><code>// HEADER
  class SceneEngine
  {
  public:
      Camera&amp; camera();
  protected:
      Camera camera_;
  }
  
  // CPP
  Camera&amp; SceneEngine::camera() {
      return camera_;
  }
  </code></pre>