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    CWG Issue 1800</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="1800"></A><H4>1800.
  
Pointer to member of nested anonymous union
</H4>
<B>Section: </B>7.6.2.2&#160; [<A href="https://wg21.link/expr.unary.op">expr.unary.op</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD4
 &#160;&#160;&#160;

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

 <B>Date: </B>2013-10-22<BR>


<P>[Moved to DR at the November, 2014 meeting.]</P>



<P>According to 7.6.2.2 [<A href="https://wg21.link/expr.unary.op#3">expr.unary.op</A>] paragraph 3,</P>

<BLOCKQUOTE>

The result of the unary <TT>&amp;</TT> operator is a pointer
to its operand. The operand shall be an lvalue or
a <I>qualified-id</I>. If the operand is
a <I>qualified-id</I> naming a non-static member <TT>m</TT>
of some class <TT>C</TT> with type <TT>T</TT>, the result
has type &#8220;pointer to member of class <TT>C</TT> of type
<TT>T</TT>&#8221; and is a prvalue designating <TT>C::m</TT>.

</BLOCKQUOTE>

<P>It is not clear whether this wording applies to variant
members of <TT>C</TT> (i.e., members of nested anonymous
unions) or only to its non-variant members.  For example,
given</P>

<PRE>
  struct A { union { int n; }; };
  auto x = &amp;A::n;
</PRE>

<P>should the type of <TT>x</TT> be <TT>int A::*</TT> or
<TT>int A::</TT><I>anon</I><TT>::*</TT>?  Current implementations
choose the former.</P>

<P><B>Proposed resolution (February, 2014):</B></P>

<P>Change 7.6.2.2 [<A href="https://wg21.link/expr.unary.op#3">expr.unary.op</A>] paragraph 3 as follows:</P>

<BLOCKQUOTE>

The result of the unary <TT>&amp;</TT> operator is a pointer to its
operand. The operand shall be an lvalue or a <I>qualified-id</I>. If the
operand is a <I>qualified-id</I> naming a non-static <INS>or variant</INS>
member <TT>m</TT> of some class <TT>C</TT> with type <TT>T</TT>, the result
has type &#8220;pointer to member of class <TT>C</TT> of type
<TT>T</TT>&#8221; and is a prvalue designating <TT>C::m</TT>. Otherwise...

</BLOCKQUOTE>

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