<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<TITLE>
    CWG Issue 1593</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="1593"></A><H4>1593.
  
&#8220;Parameter type&#8221; of special member functions
</H4>
<B>Section: </B>11.4.5.3&#160; [<A href="https://wg21.link/class.copy.ctor">class.copy.ctor</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++14
 &#160;&#160;&#160;

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

 <B>Date: </B>2012-12-03<BR>


<P>[Moved to DR at the September, 2013 meeting.]</P>

<P>Paragraphs 12 and 25 of 11.4.5.3 [<A href="https://wg21.link/class.copy.ctor">class.copy.ctor</A>] both say that the
function</P>

<BLOCKQUOTE>

is trivial if it is not user-provided, its declared parameter type is
the same as if it had been implicitly declared, and...

</BLOCKQUOTE>

<P>However, a non-user-provided function might have more than one
parameter if default arguments are used.  The phrasing would be better
as something like &#8220;its parameter-type-list is equivalent to the
parameter-type-list of an implicit declaration.&#8221;  (For
consistency, the same phrasing should be used in 11.4.5 [<A href="https://wg21.link/class.ctor#5">class.ctor</A>] paragraph 5.
)</P>

<P><B>Proposed resolution (June, 2013):</B></P>

<OL>
<LI><P>Change 11.4.5.3 [<A href="https://wg21.link/class.copy.ctor#12">class.copy.ctor</A>] paragraph 12 as follows:</P></LI>

<BLOCKQUOTE>

A copy/move constructor for class <TT>X</TT> is trivial if it is not
user-provided, its <DEL>declared parameter type is the same as if it had been
implicitly declared</DEL> <INS>parameter-type-list is equivalent to the
parameter-type-list of an implicit declaration</INS>, and if...

</BLOCKQUOTE>

<LI><P>Change 11.4.5.3 [<A href="https://wg21.link/class.copy.ctor#25">class.copy.ctor</A>] paragraph 25 as follows:</P></LI>

<BLOCKQUOTE>

A copy/move assignment operator for class <TT>X</TT> is trivial if it is
not user-provided, its <DEL>declared parameter type is the same as if it
had been implicitly declared</DEL> <INS>parameter-type-list is equivalent
to the parameter-type-list of an implicit declaration</INS>, and if...

</BLOCKQUOTE>

</OL>

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