title: Non const lvalue references
body: <p>Why can you do this</p>
  
  <pre><code>int a;
  const double &amp;m = a;
  </code></pre>
  
  <p>But when you do this</p>
  
  <pre><code>int a;
  double &amp;m = a;
  </code></pre>
  
  <p>you get an error?</p>
  
  <pre><code>error: non-const lvalue reference to type 'double' cannot bind to a value of unrelated type 'int'
  </code></pre>
  
  <p>Edit:</p>
  
  <p>To be more specific I am trying to understand the reason non-const references can't bind temp objects.</p>