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    CWG Issue 2226</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="2226"></A><H4>2226.
  
Xvalues vs lvalues in conditional expressions
</H4>
<B>Section: </B>7.6.16&#160; [<A href="https://wg21.link/expr.cond">expr.cond</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD5
 &#160;&#160;&#160;

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

 <B>Date: </B>2016-02-01<BR>


<P>[Accepted as a DR at the March, 2018 (Jacksonville) meeting.]</P>



<P>In the following example,</P>

<PRE>
   const T a;
   T b;
   false ? a : std::move(b);
</PRE>

<P>the most appropriate result would seem to be that the expression is
an lvalue of type <TT>const T</TT> that refers to either <TT>a</TT> or
<TT>b</TT>. However, because 7.6.16 [<A href="https://wg21.link/expr.cond#4.1">expr.cond</A>] bullet 4.1
requires that the conversion bind directly to an lvalue, while
<TT>std::move(b)</TT> is an xvalue, the result is a <TT>const T</TT>
temporary copy-initialized from <TT>std::move(b)</TT>.</P>

<P><B>Proposed resolution (November, 2017)</B></P>

<P>Change 7.6.16 [<A href="https://wg21.link/expr.cond#4.1">expr.cond</A>] bullet 4.1 as follows:</P>

<BLOCKQUOTE>

<P>Attempts are made to form an implicit conversion sequence from an
operand expression <TT>E1</TT> of type <TT>T1</TT> to a target type related
to the type <TT>T2</TT> of the operand expression <TT>E2</TT> as
follows:</P>

<UL>
<LI><P>If <TT>E2</TT>
is an lvalue, the target type is &#8220;lvalue reference to
<TT>T2</TT>&#8221;, subject to the constraint that in the conversion the
reference must bind directly (9.5.4 [<A href="https://wg21.link/dcl.init.ref">dcl.init.ref</A>]) to <DEL>an
lvalue</DEL> <INS>a glvalue</INS>.</P></LI>

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

</UL>

</BLOCKQUOTE>

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