title: Clang won't compile a template specialization that gcc will
body: <p>Gcc compiles this fine, but Clang (trunk) refuses with the message:</p>
  
  <pre><code>&lt;source&gt;:7:8: error: class template partial specialization is not more specialized than the primary template [-Winvalid-partial-specialization]
  </code></pre>
  
  <p><a href="https://godbolt.org/g/h8rsWC" rel="noreferrer">https://godbolt.org/g/h8rsWC</a></p>
  
  <pre><code>template&lt;class T, T x&gt;
  struct S{};
  
  template&lt;int&amp; x&gt;
  struct S&lt;int&amp;, x&gt; { };
  </code></pre>
  
  <p>Is this code correct or not? </p>