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    CWG Issue 2007</TITLE>
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<P><EM>This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21
  Core Issues List revision 118b.
  See http://www.open-std.org/jtc1/sc22/wg21/ for the official
  list.</EM></P>
<P>2025-09-28</P>
<HR>
<A NAME="2007"></A><H4>2007.
  
Argument-dependent lookup for <TT>operator=</TT>
</H4>
<B>Section: </B>12.2.2.3&#160; [<A href="https://wg21.link/over.match.oper">over.match.oper</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD6
 &#160;&#160;&#160;

 <B>Submitter: </B>Richard Smith
 &#160;&#160;&#160;

 <B>Date: </B>2014-09-23<BR>


<P>[Accepted at the November, 2020 meeting as part of paper P1787R6 and
moved to DR at the February, 2021 meeting.]</P>



<P>Consider an example like:</P>

<PRE>
  template&lt;typename T&gt; struct A { typename T::error e; };
  template&lt;typename T&gt; struct B { };
  B&lt;A&lt;void&gt;&gt; b1, &amp;b2 = (b1 = b1);
</PRE>

<P>If the assignment operator performs argument-dependent lookup,
<TT>A&lt;void&gt;</TT> will be an associated class and will be
instantiated, producing an error.  Similar questions apply to
the other member-only overloaded operators, <TT>operator-&gt;</TT>
and <TT>operator[]</TT>.  Bullet 3.2 of 12.2.2.3 [<A href="https://wg21.link/over.match.oper">over.match.oper</A>]
should be changed not to perform unqualified lookup for these
operators.</P>

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