ntegral_constant.html" title="integral_constant">false_type</a>.
        Type <code class="computeroutput"><span class="identifier">T</span></code> must be a complete
        type.
      </p>
<p>
        Formally the trait answers the question, is the expression:
      </p>
<pre class="programlisting"><span class="identifier">T</span> <span class="identifier">t</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">declval</span><span c