<span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Context</span><span class="special">&gt;</span>
    <span class="identifier">info</span> <span class="identifier">what</span><span class="special">(</span><span class="identifier">Context</span><span class="special">&amp;</span> <span class="identifier">context</span><span class="special">)</span> <span class="keyword">const</span>
    <span class="special">{</span>
        <