">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">must_not_be_instantiated</span>
<span class="special">{</span>
   <span class="comment">// this will be triggered if this type is instantiated</span>
   <span class="identifier">BOOST_STATIC_ASSERT</span><span class="special">(</span><span class="keyword">sizeof</span><span class="special">(</span