title: std::vector::emplace_back and std::move
body: <p>Is there any advantage of using <code>std::vector::emplace_back</code> and <code>std::move</code> together? or it is just redundant since <code>std::vector::emplace_back</code> will do an inplace-construction?</p>
  
  <p>Cases for clarification:</p>
  
  <pre><code>std::vector&lt;std::string&gt; bar;
  </code></pre>
  
  <p><strong>First:</strong></p>
  
  <pre><code>bar.emplace_back(std::move(std::string("some_string")));
  </code></pre>
  
  <p><strong>Second:</strong></p>
  
  <pre><code>std::string str("some_string");
  bar.emplace_back(std::move(str));
  </code></pre>
  
  <p><strong>Third:</strong></p>
  
  <pre><code>bar.emplace_back(std::move("some_string"));
  </code></pre>