title: Template method enable_if specialization
body: <p>i have following code that does not compile.
  This are two functions in a template class that takes the arguments </p>
  
  <pre><code>typename std::enable_if&lt;std::is_void&lt;Ret&gt;::value, Ret&gt;::type _on_dispatched() {
      // ...
  }
  
  typename std::enable_if&lt;!std::is_void&lt;Ret&gt;::value, Ret&gt;::type _on_dispatched() {
      // ....
  }
  </code></pre>
  
  <p>I want to have a specialization in a member method depending on what type Ret is.</p>
  
  <p>Has anybody some idea?</p>