<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<TITLE>
    CWG Issue 1288</TITLE>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<STYLE TYPE="text/css">
  INS { text-decoration:none; font-weight:bold; background-color:#A0FFA0 }
  .INS { text-decoration:none; background-color:#D0FFD0 }
  DEL { text-decoration:line-through; background-color:#FFA0A0 }
  .DEL { text-decoration:line-through; background-color: #FFD0D0 }
  @media (prefers-color-scheme: dark) {
    HTML { background-color:#202020; color:#f0f0f0; }
    A { color:#5bc0ff; }
    A:visited { color:#c6a8ff; }
    A:hover, a:focus { color:#afd7ff; }
    INS { background-color:#033a16; color:#aff5b4; }
    .INS { background-color: #033a16; }
    DEL { background-color:#67060c; color:#ffdcd7; }
    .DEL { background-color:#67060c; }
  }
  SPAN.cmnt { font-family:Times; font-style:italic }
</STYLE>
</HEAD>
<BODY>
<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="1288"></A><H4>1288.
  
Reference list initialization
</H4>
<B>Section: </B>9.5.5&#160; [<A href="https://wg21.link/dcl.init.list">dcl.init.list</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>Daniel Kr&#252;gler
 &#160;&#160;&#160;

 <B>Date: </B>2011-04-06<BR>


<P>[Voted into the WP at the February, 2012 meeting;
moved to DR at the October, 2012 meeting.]</P>



<P>One might expect that in an example like</P>

<PRE>
  int i;
  int &amp; ir{i};
</PRE>

<P>
<TT>ir</TT> would bind directly to <TT>i</TT>.  However, according
to 9.5.5 [<A href="https://wg21.link/dcl.init.list#3">dcl.init.list</A>] paragraph 3, this example creates a
temporary of type <TT>int</TT> and binds the reference to that
temporary:</P>

<BLOCKQUOTE>

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

<LI><P>Otherwise, if <TT>T</TT> is a reference type, a prvalue
temporary of the type referenced by <TT>T</TT> is list-initialized,
and the reference is bound to that temporary...
</P></LI>

<LI><P>Otherwise, if the initializer list has a single element, the
object or reference is initialized from that element...
</P></LI>

</UL>

</BLOCKQUOTE>

<P>Also, the &#8220;or reference&#8221; in the last bullet is dead
code, as a reference initialization is always handled by the preceding
bullet.</P>

<P><B>Proposed resolution (August, 2011):</B></P>

<P>Change 9.5.5 [<A href="https://wg21.link/dcl.init.list#3">dcl.init.list</A>] paragraph 3 as follows:</P>

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

<LI><P>Otherwise, if <TT>T</TT> is a class type, constructors are
considered...</P></LI>

<LI><P><DEL>Otherwise, if <TT>T</TT> is a reference type, a prvalue
temporary of the type referenced by <TT>T</TT> is list-initialized,
and the reference is bound to that temporary. [<I>Note:</I> As usual,
the binding will fail and the program is ill-formed if the reference
type is an lvalue reference to a non-const type. &#8212;<I>end
note</I>] [<I>Example:</I> ... &#8212;<I>end
example</I>]</DEL></P></LI>

<LI><P>Otherwise, if the initializer list has a single element <INS>of
type <TT>E</TT> and either <TT>T</TT> is not a reference type or its
referenced type is reference-related to <TT>E</TT></INS>, the object
or reference is initialized from that element; if a narrowing
conversion (see below) is required to convert the element to
<TT>T</TT>, the program is ill-formed. [<I>Example:</I>...</P></LI>

<LI><P><INS>Otherwise, if <TT>T</TT> is a reference type, a prvalue
temporary of the type referenced by <TT>T</TT> is list-initialized,
and the reference is bound to that temporary. [<I>Note:</I> As usual,
the binding will fail and the program is ill-formed if the reference
type is an lvalue reference to a non-const type. &#8212;<I>end
note</I>] [<I>Example:</I> ... &#8212;<I>end
example</I>]</INS></P></LI>

<LI><P>Otherwise, if the initializer list has no elements...</P></LI>

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

</UL>

<BR><BR>
</BODY>
</HTML>
