title: c++ template using declaration from base class
body: <p>Why does the following code not work (using VS2013)?</p>
  
  <pre><code>class Test1
  {
  public:
    template&lt;typename T&gt;
    using my_type = T;
  };
  
  template&lt;typename T, typename V&gt;
  class My : public T
  {
  public:
    using t_type = T;
    using my_type2 = t_type::my_type&lt;V&gt;;
  };
  
  int main()
  {
    const My&lt;Test1, double&gt;::my_type2 x = 5.5;
  
    return 0;
  }
  </code></pre>
  
  <p>Test1::my_type would have a more complex type. My would be a policy based class where Test1 would be one of the policies. my_type2 should become a specific type based on the policy. And Test1 can't be a template directly taking the type of V. Thanks.</p>