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    CWG Issue 1500</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="1500"></A><H4>1500.
  
Name lookup of dependent conversion function
</H4>
<B>Section: </B>13.8.4.2&#160; [<A href="https://wg21.link/temp.dep.candidate">temp.dep.candidate</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>Johannes Schaub
 &#160;&#160;&#160;

 <B>Date: </B>2012-04-27<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 the following example:</P>

<PRE>
  template&lt;typename T&gt;
  struct A {
   operator int() { return 0; }

   void f() {
    operator T();
   }
  };

  int main() {
   A&lt;int&gt; a;
   a.f();
  }
</PRE>

<P>One might expect this to call <TT>operator int</TT> when
instantiating. But since <TT>operator T</TT> is a dependent name, it
is looked up by unqualified lookup only in the definition context,
where it will find no declaration. Argument-dependent lookup will not
find anything in the instantiation context either, so this code is
ill-formed. If we change <TT>operator&#160;int()</TT> to
<TT>operator&#160;T()</TT>, which is a seemingly unrelated change, the
code becomes well-formed.</P>

<P>There is implementation variability on this point.</P>

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