title: Whats the point of a move-constructor taking a constans rvalue?
body: <p>According to <a href="http://en.cppreference.com/w/cpp/language/move_constructor" rel="nofollow">http://en.cppreference.com/w/cpp/language/move_constructor</a>; <em>"A class can have multiple move constructors, e.g. both <code>T::T(const T&amp;&amp;)</code> and <code>T::T(T&amp;&amp;)</code>"</em></p>
  
  <p>When would one want to pass a constant rvalue to the move-constructor? </p>