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    CWG Issue 2825</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="2825"></A><H4>2825.
  
Range-based for statement using a <I>braced-init-list</I>
</H4>
<B>Section: </B>8.6.5&#160; [<A href="https://wg21.link/stmt.ranged">stmt.ranged</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>Arthur O'Dwyer
 &#160;&#160;&#160;

 <B>Date: </B>2023-11-08
  &#160;&#160;&#160;
  <B>Liaison: </B>EWG<BR>


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

<P>Consider:</P>

<PRE>
  for (int i : { 1, 2, 3 })  // <SPAN CLASS="cmnt">argument-dependent lookup for </SPAN>begin(std::initializer_list&lt;int&gt;)
    /* ... */;
</PRE>

<P>This is undesirable; instead, a member function <TT>begin</TT> should be preferred.</P>

<P><B>Proposed resolution (approved by CWG 2023-11-09):</B></P>

<P>Change in 8.6.5 [<A href="https://wg21.link/stmt.ranged#1.3">stmt.ranged</A>] bullet 1.3 as follows:</P>

<BLOCKQUOTE>

<I>begin-expr</I> and <I>end-expr</I> are determined as follows:

<UL>
<LI>if the <DEL><I>for-range-initializer</I> is an expression of</DEL>
<INS>type of <I>range</I> is a reference to an</INS> array type
R, <I>begin-expr</I> and <I>end-expr</I> are range and range + N,
respectively, where N is the array bound. If R is an array of unknown
bound or an array of incomplete type, the program is ill-formed;</LI>

<LI>if the <DEL><I>for-range-initializer</I> is an expression of</DEL>
<INS>type of <I>range</I> is a reference to a</INS> class type
C, and searches in the scope of C (6.5.2 [<A href="https://wg21.link/class.member.lookup">class.member.lookup</A>]) for the
names begin and end each find at least one
declaration, <I>begin-expr</I> and <I>end-expr</I> are range .begin()
and range .end(), respectively;</LI>

<LI>otherwise, <I>begin-expr</I> and <I>end-expr</I> are begin(range )
and end(range ), respectively, where begin and end undergo
argument-dependent lookup (6.5.4 [<A href="https://wg21.link/basic.lookup.argdep">basic.lookup.argdep</A>]).  [<I>Note
1:</I> Ordinary unqualified lookup (6.5.3 [<A href="https://wg21.link/basic.lookup.unqual">basic.lookup.unqual</A>]) is not
performed. &#8212;<I>end note</I>]</LI>
</UL>

</BLOCKQUOTE>

<P><B>Additional notes (November, 2023)</B></P>

<P>Forwarded to EWG via
<A HREF="https://github.com/cplusplus/papers/issues/1694">paper issue 1694</A>
for confirmation of the design direction.</P>

<P><B>EWG 2023-11-09</B></P>

<P>Approved by EWG.</P>

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