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    CWG Issue 1814</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="1814"></A><H4>1814.
  
Default arguments in <I>lambda-expression</I>s
</H4>
<B>Section: </B>9.3.4.7&#160; [<A href="https://wg21.link/dcl.fct.default">dcl.fct.default</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD4
 &#160;&#160;&#160;

 <B>Submitter: </B>Jonathan Caves
 &#160;&#160;&#160;

 <B>Date: </B>2013-11-21<BR>


<P>[Moved to DR at the November, 2014 meeting.]</P>

<P>The resolution for <A HREF="974.html">issue 974</A> permitting
default arguments in <I>lambda-expression</I>s overlooked
9.3.4.7 [<A href="https://wg21.link/dcl.fct.default#3">dcl.fct.default</A>] paragraph 3:</P>

<BLOCKQUOTE>

A default argument shall be specified only in
the <I>parameter-declaration-clause</I> of a function
declaration or in a <I>template-parameter</I>
(13.2 [<A href="https://wg21.link/temp.param">temp.param</A>])...

</BLOCKQUOTE>

<P><B>Proposed resolution (February, 2014):</B></P>

<P>Change 9.3.4.7 [<A href="https://wg21.link/dcl.fct.default#3">dcl.fct.default</A>] paragraph 3 as follows:</P>

<BLOCKQUOTE>

A default argument shall be specified only in
the <I>parameter-declaration-clause</I> of a function
declaration <INS>or <I>lambda-declarator</I></INS> or in
a <I>template-parameter</I> (13.2 [<A href="https://wg21.link/temp.param">temp.param</A>]); in the latter
case, the <I>initializer-clause</I> shall be
an <I>assignment-expression</I>.  A default argument shall not be specified
for a parameter pack. If it is specified in
a <I>parameter-declaration-clause</I>, it shall not occur within a
declarator or <I>abstract-declarator</I> of
a <I>parameter-declaration</I>.<SUP>103</SUP>

</BLOCKQUOTE>

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