ss="special">&lt;</span><span class="identifier">value_type</span><span class="special">&gt;(</span><span class="identifier">a</span><span class="special">),</span>
               <span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">value_type</span><span class="special">&gt;(</span><span class="identifier">x</span><span class="special">),</span>
               <span class="identifier">forwarding_policy</span><span class="special">()),</span>
         <span class