title: NullPointerException - Attempt to invoke virtual method RecyclerView$ViewHolder.shouldIgnore()' on a null object reference
body: <p>Several developers have reported seeing the following stack trace since upgrading to Android Support 23.2.0:</p>
  
  <pre><code>java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$ViewHolder.shouldIgnore()' on a null object reference
      at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2913)
      at android.support.v7.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1445)
      at android.support.v7.widget.RecyclerView.access$400(RecyclerView.java:144)
      at android.support.v7.widget.RecyclerView$1.run(RecyclerView.java:282)
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:821)
      at android.view.Choreographer.doCallbacks(Choreographer.java:606)
      at android.view.Choreographer.doFrame(Choreographer.java:575)
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:807)
      at android.os.Handler.handleCallback(Handler.java:739)
      at android.os.Handler.dispatchMessage(Handler.java:95)
      at android.os.Looper.loop(Looper.java:145)
      at android.app.ActivityThread.main(ActivityThread.java:6895)
      at java.lang.reflect.Method.invoke(Native Method)
      at java.lang.reflect.Method.invoke(Method.java:372)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
  </code></pre>
  
  <p>This occurs when RecyclerView's change animation is enabled and corresponding RecyclerView.Adapter methods notifyItemInserted(), notifyItemRemoved(), etc., are called to indicate that an isolated change was made to the list managed by the adapter (as opposed to a wholesale change, as indicated by notifyDataSetChanged()).</p>
  
  <p>Is this due to a bug in RecyclerView, or are we developers doing something wrong?</p>