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    CWG Issue 1372</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="1372"></A><H4>1372.
  
Cross-references incorrect in conversion function template argument deduction
</H4>
<B>Section: </B>13.10.3.4&#160; [<A href="https://wg21.link/temp.deduct.conv">temp.deduct.conv</A>]
 &#160;&#160;&#160;

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

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

 <B>Date: </B>2011-08-15<BR>


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

<P>According to 13.10.3.4 [<A href="https://wg21.link/temp.deduct.conv#1">temp.deduct.conv</A>] paragraph 1,</P>

<BLOCKQUOTE>

Template argument deduction is done by comparing the return type
of the conversion function template (call it <TT>P</TT>; see
9.5 [<A href="https://wg21.link/dcl.init">dcl.init</A>], 12.2.2.6 [<A href="https://wg21.link/over.match.conv">over.match.conv</A>], and
12.2.2.7 [<A href="https://wg21.link/over.match.ref">over.match.ref</A>] for the determination of that type)
with the type that is required as the result of the conversion
(call it <TT>A</TT>) as described in 13.10.3.6 [<A href="https://wg21.link/temp.deduct.type">temp.deduct.type</A>].

</BLOCKQUOTE>

<P>It would seem that the cross-references should apply to the
determination of the type &#8220;required as the result of the
conversion&#8221; (i.e., <TT>A</TT>) instead of the return type
of the conversion function.</P>

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

<P>Change 13.10.3.4 [<A href="https://wg21.link/temp.deduct.conv#1">temp.deduct.conv</A>] paragraph 1 as follows:</P>

<BLOCKQUOTE>

Template argument deduction is done by comparing the return type of
the conversion function template (call it <TT>P</TT><DEL>; see
9.5 [<A href="https://wg21.link/dcl.init">dcl.init</A>], 12.2.2.6 [<A href="https://wg21.link/over.match.conv">over.match.conv</A>], and
12.2.2.7 [<A href="https://wg21.link/over.match.ref">over.match.ref</A>] for the determination of that
type</DEL>) with the type that is required as the result of the
conversion (call it A<INS>; see 9.5 [<A href="https://wg21.link/dcl.init">dcl.init</A>], 12.2.2.6 [<A href="https://wg21.link/over.match.conv">over.match.conv</A>], and 12.2.2.7 [<A href="https://wg21.link/over.match.ref">over.match.ref</A>] for the
determination of that type</INS>) as described in 13.10.3.6 [<A href="https://wg21.link/temp.deduct.type">temp.deduct.type</A>].

</BLOCKQUOTE>

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