ss="special">::</span><span class="identifier">placeholders</span><span class="special">::</span><span class="identifier">_1</span><span class="special">;</span>

    <span class="identifier">assert</span><span class="special">((</span><span class="identifier">_1</span> <span class="special">+</span> <span class="identifier">foo</span><span class="special">())(</span><span class="number">1</span><span class="special">)</span> <span class="special">==</span> <span class="number">43</span><span class="special