title: How to alias a nested template class with variadic parameter packs
body: <p>Is there any way one can alias a nested template class with a <code>using</code> keyword?  Something like this</p>
  
  <pre><code>template &lt;typename... Types&gt;
  struct Something {
      template &lt;typename... TypesTwo&gt;
      struct Another {};
  };
  
  template &lt;typename... Types&gt;
  template &lt;typename... TypesTwo&gt;
  using Something_t = typename Something&lt;Types...&gt;::template Another&lt;TypesTwo...&gt;;
  
  int main() {
      Something_t&lt;int&gt;&lt;double&gt;{};
      return 0;
  }
  </code></pre>
  
  <p>This answer <a href="https://stackoverflow.com/questions/18699973/template-template-alias-to-a-nested-template">template template alias to a nested template?</a> shows a way to do that but that will no longer work if both the parameter packs are variadic, as the compiler will not know where to start and where to end the type lists.   </p>