pan><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">terminal</span><span class="special">&lt;</span><span class="identifier">repo</span><span class="special">::</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">distinct</span><span class="special">(</span><span class="identifier">Tail</span><span class="special">)&gt;</span>
    <span class="special">{};</span>

    <span class="comment">// Metafunction allowing 