title: Template Class derived from Non-template base class: No access to base class variables?
body: <p>I have the following class structure:</p>
  
  <pre><code>class Base {
  public:
      std::set&lt;Index&gt; openIndices;
      Base() {};
  };
  
  
  template&lt;typename lhs_t, typename rhs_t&gt;
  class Derived : public Base {
  public:
      lhs_t &amp;lhs;
      rhs_t &amp;rhs;
  
      Derived(lhs_t &amp;_lhs, rhs_t &amp;_rhs) : 
              Base(), 
              lhs(_lhs),
              rhs(_rhs),
              openIndices(std::set_symmetric_difference(lhs.openIndices, rhs.openIndices)) 
      {
      }
  };
  </code></pre>
  
  <p>So basicly a template Class <code>Derived</code>derived from the base class <code>Base</code>. When accessing the member variables ob the baser class I get the following error:</p>
  
  <pre><code>test.h:34:88: error: class ‘Derived&lt;lhs_t, rhs_t&gt;’ does not have any field named ‘openIndices’
  </code></pre>
  
  <p>I am aware of <a href="https://stackoverflow.com/q/1120833/991425">this question</a>: I cannot access the member variables in case my class is derived from a template class. But in my case I am not derived from a template class, still I can't access the member variables. Could anyone tell me why?</p>