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    CWG Issue 1410</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="1410"></A><H4>1410.
  
Reference overload tiebreakers should apply to rvalue references
</H4>
<B>Section: </B>12.2.4.3&#160; [<A href="https://wg21.link/over.ics.rank">over.ics.rank</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD3
 &#160;&#160;&#160;

 <B>Submitter: </B>Michael Wong
 &#160;&#160;&#160;

 <B>Date: </B>2011-10-26<BR>


<P>[Moved to DR at the October, 2012 meeting.]</P>

<P>In bullet 3 of paragraph 4 of 12.2.4.3 [<A href="https://wg21.link/over.ics.rank">over.ics.rank</A>] are
two sub-bullets dealing with overload tiebreakers:</P>

<UL>
<LI><P>binding of an expression of type <TT>C</TT> to a
reference of type <TT>B&amp;</TT> is better than binding an
expression of type <TT>C</TT> to a reference of type
<TT>A&amp;</TT>,</P></LI>

<LI><P>...</P></LI>

<LI><P>binding of an expression of type <TT>B</TT> to a reference
of type <TT>A&amp;</TT> is better than binding an expression of
type <TT>C</TT> to a reference of type <TT>A&amp;</TT>,</P></LI>

</UL>

<P>Presumably both of these tiebreakers should apply to rvalue
references as well as lvalue references.</P>

<P><B>Proposed resolution (February, 2012):</B></P>

<P>Change 12.2.4.3 [<A href="https://wg21.link/over.ics.rank#4.3">over.ics.rank</A>] bullet 4.3 as follows:</P>

<UL>
<LI><P>If class <TT>B</TT> is derived directly or indirectly from
class <TT>A</TT> and class <TT>C</TT> is derived directly or
indirectly from <TT>B</TT>,</P></LI>

<UL>
<LI><P>conversion of <TT>C*</TT> to <TT>B*</TT> is better...</P></LI>

<LI><P>binding of an expression of type <TT>C</TT> to a reference
<DEL>of</DEL> <INS>to</INS> type <TT>B<DEL>&amp;</DEL></TT> is better
than binding an expression of type C to a reference <DEL>of</DEL>
<INS>to</INS> type <TT>A<DEL>&amp;</DEL></TT>,</P></LI>

<LI><P>...</P></LI>

<LI><P>binding of an expression of type <TT>B</TT> to a reference
<DEL>of</DEL> <INS>to</INS> type <TT>A<DEL>&amp;</DEL></TT> is better
than binding an expression of type <TT>C</TT> to a reference
<DEL>of</DEL> <INS>to</INS> type <TT>A<DEL>&amp;</DEL></TT>,</P></LI>

<LI><P>...</P></LI>

</UL>

</UL>

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