P&gt;::type;</div><div class="line"><a name="l00098"></a><span class="lineno">   98</span>&#160;    <span class="keyword">using</span> reference = <span class="keyword">typename</span> std::add_lvalue_reference&lt;P&gt;::type;</div><div class="line"><a name="l00099"></a><span class="lineno">   99</span>&#160;    <span class="keyword">using</span> const_reference = reference;</div><div class="line"><a name="l00100"></a><span class="lineno">  100</span>&#160;</div><div class="line"><a name="l00101"></a><span 