f="weak_ptr.html" title="Class template weak_ptr">weak_ptr</a> <span class="special">&amp;</span> <a class="link" href="weak_ptr.html#idp50639392-bb"><span class="keyword">operator</span><span class="special">=</span></a><span class="special">(</span><a class="link" href="weak_ptr.html" title="Class template weak_ptr">weak_ptr</a><span class="special">&lt;</span> <span class="identifier">Y</span><span class="special">,</span> <span class="identifier">A</span><span class="special">,</span> <span class="ident