<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<TITLE>
    CWG Issue 1000</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="1000"></A><H4>1000.
  
Mistaking member typedefs for constructors
</H4>
<B>Section: </B>6.5.5.2&#160; [<A href="https://wg21.link/class.qual">class.qual</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD2
 &#160;&#160;&#160;

 <B>Submitter: </B>Jason Merrill
 &#160;&#160;&#160;

 <B>Date: </B>20 November, 2009<BR>


<P>[Voted into WP at March, 2010 meeting.]</P>



<P>The recent addition to support inherited constructors changed
6.5.5.2 [<A href="https://wg21.link/class.qual#2">class.qual</A>] paragraph 2 to say that</P>

<BLOCKQUOTE>

if the name specified after the <I>nested-name-specifier</I> is
the same as the <I>identifier</I> or the
<I>simple-template-id</I>'s <I>template-name</I> in the last
component of the <I>nested-name-specifier</I>,

</BLOCKQUOTE>

<P>the <I>qualified-id</I> is considered to name a constructor.  This
causes problems for a common naming scheme used in some class libraries:</P>

<PRE>
  struct A {
    typedef int type;
  };
  struct B {
    typedef A type;
  };
  B::type::type t;
</PRE>

<P>This change causes this to name the <TT>A</TT> constructor instead
of the <TT>A::type</TT> typedef.</P>

<P><B>Proposed resolution (February, 2010):</B></P>

<P>Change 6.5.5.2 [<A href="https://wg21.link/class.qual#2">class.qual</A>] paragraph 2 as follows:</P>

<BLOCKQUOTE>

<P>In a lookup in which the constructor is an acceptable lookup
result and the <I>nested-name-specifier</I> nominates a class
<TT>C</TT>:</P>

<UL>
<LI><P>if the name specified after the
<I>nested-name-specifier</I>, when looked up in <TT>C</TT>, is
the injected-class-name of <TT>C</TT> (Clause 11 [<A href="https://wg21.link/class">class</A>]), or</P></LI>

<LI><P>
<INS>in a <I>using-declaration</I> (9.10 [<A href="https://wg21.link/namespace.udecl">namespace.udecl</A>]) that is a <I>member-declaration</I>,</INS> if the
name specified after the <I>nested-name-specifier</I> is the same
as the <I>identifier</I> or the <I>simple-template-id</I>'s
<I>template-name</I> in the last component of the
<I>nested-name-specifier</I>,</P></LI>

</UL>

<P>the name is instead considered to name the constructor of
class <TT>C</TT>...</P>

</BLOCKQUOTE>

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