he answer is clear: it binds to <code class="computeroutput"><span class="identifier">x</span></code>
          (we now have another reference to <code class="computeroutput"><span class="identifier">x</span></code>).
          But what if <code class="computeroutput"><span class="identifier">a</span></code> is already
          <span class="emphasis"><em>initialized</em></span>? it would change the value of the referenced
          object (whatever that is); which is inconsistent with the other possible
  