ecial">:</span> <span class="identifier">base</span><span class="special">()</span> <span class="special">{}</span>
             <span class="identifier">compressed_pair</span><span class="special">(</span><span class="identifier">first_param_type</span> <span class="identifier">x</span><span class="special">,</span> <span class="identifier">second_param_type</span> <span class="identifier">y</span><span class="special">);</span>
    <span class="keyword">explicit</span> <span class="identifier">compressed_