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    CWG Issue 1908</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="1908"></A><H4>1908.
  
Dual destructor lookup and <I>template-id</I>s
</H4>
<B>Section: </B>_N4868_.6.5.6&#160; [<A href="https://wg21.link/basic.lookup.classref">basic.lookup.classref</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>Hubert Tong
 &#160;&#160;&#160;

 <B>Date: </B>2014-03-31<BR>


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



<P>According to _N4868_.6.5.6 [<A href="https://wg21.link/basic.lookup.classref#3">basic.lookup.classref</A>] paragraph 3,</P>

<BLOCKQUOTE>

If the <I>unqualified-id</I> is <TT>~</TT><I>type-name</I>,
the <I>type-name</I> is looked up in the context of the
entire <I>postfix-expression</I>.  If the type <TT>T</TT> of the object
expression is of a class type <TT>C</TT>, the <I>type-name</I> is also
looked up in the scope of class <TT>C</TT>. At least one of the lookups
shall find a name that refers to (possibly cv-qualified) <TT>T</TT>.

</BLOCKQUOTE>

<P>This would apply to an example like</P>

<PRE>
  namespace K {
    template &lt;typename T, typename U = char&gt; struct A { };
    A&lt;short&gt; *a;
  }

  template &lt;typename T&gt; using A = K::A&lt;short, T&gt;;

  int main() {
    K::a-&gt;~A&lt;char&gt;();
  }
</PRE>

<P>Current implementations, however, only apply the dual lookup when
the <I>type-name</I> is not a <I>template-id</I>.  The specification
should be changed to reflect current practice.</P>

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