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    CWG Issue 2919</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="2919"></A><H4>2919.
  
Conversion function candidates for initialization of const lvalue reference
</H4>
<B>Section: </B>12.2.2.7&#160; [<A href="https://wg21.link/over.match.ref">over.match.ref</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD7
 &#160;&#160;&#160;

 <B>Submitter: </B>Brian Bi
 &#160;&#160;&#160;

 <B>Date: </B>2024-07-18<BR>


<P>[Accepted as a DR at the November, 2024 meeting.]</P>



<P>There is implementation divergence handling the following example:</P>

<PRE>
  struct A {
    A(const A&amp;) = delete;
  };
  struct B {
    operator A&amp;&amp;();
  };
  const A&amp; r = B();
</PRE>

<P>Conversion to an lvalue pursuant to 9.5.4 [<A href="https://wg21.link/dcl.init.ref#5.1">dcl.init.ref</A>] bullet 5.1 fails due to the attempt to invoke a deleted function,
but conversion to an rvalue according to 9.5.4 [<A href="https://wg21.link/dcl.init.ref#5.3">dcl.init.ref</A>] bullet 5.3 would succeed, except that 12.2.2.7 [<A href="https://wg21.link/over.match.ref#1.1">over.match.ref</A>] bullet 1.1 hinges on the target type of the initialization, not
the target type of the conversion.</P>

<P><B>Proposed resolution (approved by CWG 2024-08-16):</B></P>

<P>Change in 12.2.2.7 [<A href="https://wg21.link/over.match.ref#1.1">over.match.ref</A>] bullet 1.1 as follows:</P>

<BLOCKQUOTE>

Let R be a set of types including
<UL>
<LI>&#8220;lvalue reference to cv2 T2&#8221;
(when <DEL>initializing</DEL> <INS>converting to</INS> an
lvalue <DEL>reference or an rvalue reference to function</DEL>)
and</LI>
<LI>&#8220;cv2 T2&#8221; and &#8220;rvalue reference to cv2 T2&#8221;
(when <DEL>initializing</DEL> <INS>converting to</INS> an
rvalue <DEL>reference</DEL> or an lvalue <DEL>reference
to</DEL> <INS>of</INS> function <INS>type</INS>)</LI>
</UL>
for any T2.

</BLOCKQUOTE>

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