ON</span></a>, which doesn&#8217;t require an reinterpret cast:</p>
<div class="highlight-cpp"><div class="highlight"><pre><span></span><span class="k">struct</span> <span class="n">sum_factory</span>
<span class="p">{</span>
    <span class="k">auto</span> <span class="k">operator</span><span class="o">*</span><span class="p">()</span> <span class="k">const</span>
    <span class="p">{</span>
        <span class="k">return</span> <span class="p">[](</span><span class="k">auto</span> <span class="n">x</span