special">+</span> <span class="string">" here:"</span><span class="special">;</span>
        <span class="identifier">error_handler</span><span class="special">(</span><span class="identifier">x</span><span class="special">.</span><span class="identifier">where</span><span class="special">(),</span> <span class="identifier">message</span><span class="special">);</span>
        <span class="keyword">return</span> <span class="identifier">x3</span><span class="special">::</span><span class="identifier">error_