title: reference to 'list' is ambiguous
body: <p>I created a list and want to check it's size, like this</p>
  
  <pre><code> 1.  list&lt;State&gt; list;  
   2.  list.push_back (state1);
   3.  list.push_back (state2);
   4.  list.push_back (state2);
   5.  int l = list.size();
  </code></pre>
  
  <p>Then I got those error:</p>
  
  <pre><code> "[Error] candidates are: std::list&lt;State&gt; list" in line 1.
   "[Error] reference to 'list' is ambiguous " in line 5.
  </code></pre>
  
  <p>How can I fix it?</p>