e</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.33.5.12.6.4.10.4"></a><h2>Description</h2>
<p>So that <code class="computeroutput">boost::result_of&lt;&gt;</code>
            can compute the return type of <code class="computeroutput">proto::extends::operator()</code>.
          </p>
</div>
</div>
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