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    CWG Issue 602</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="602"></A><H4>602.
  
When is the injected-class-name of a class template a template?
</H4>
<B>Section: </B>13.8.2&#160; [<A href="https://wg21.link/temp.local">temp.local</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++11
 &#160;&#160;&#160;

 <B>Submitter: </B>Daveed Vandevoorde
 &#160;&#160;&#160;

 <B>Date: </B>23 October 2006<BR>


<P>[Voted into the WP at the March, 2011 meeting as part of paper N3262.]</P>



<P>Consider the following example:</P>

<PRE>
    template&lt;class T&gt;
    struct A {
         template&lt;class U&gt;
             friend struct A; // Which A?
    };
</PRE>

<P>Presumably the lookup for <TT>A</TT> in the friend declaration finds
the injected-class-name of the template.  However, according to
13.8.2 [<A href="https://wg21.link/temp.local#1">temp.local</A>] paragraph 1,</P>

<BLOCKQUOTE>

The injected-class-name can be used with or without a
<I>template-argument-list</I>. When it is used without a
<I>template-argument-list</I>, it is equivalent to the
injected-class-name followed by the <I>template-parameter</I>s of the
class template enclosed in <TT>&lt;&gt;</TT>. When it is used with a
<I>template-argument-list</I>, it refers to the specified class
template specialization, which could be the current specialization or
another specialization.

</BLOCKQUOTE>

<P>If that rule applies, then this example is ill-formed (because you
can't have a <I>template-argument-list</I> in a class template
declaration that is not a partial specialization).</P>

<P>
<U>Mike Miller</U>: The injected-class-name has a dual nature, as
described in 13.8.2 [<A href="https://wg21.link/temp.local">temp.local</A>], acting as either a
template name or a class name, depending on the context; a template
argument list forces the name to be interpreted as a template.  It
seems reasonable that in this example the injected-class-name has to
be understood as referring to the class template; a template header is
at least as strong a contextual indicator as a template argument list.
However, the current wording doesn't say that.</P>

<P>(See also <A HREF="1004.html">issue 1004</A>.)</P>

<P><B>Proposed resolution (November, 2010) [SUPERSEDED]:</B></P>

<P>This issue is resolved by the resolution of
<A HREF="1004.html">issue 1004</A>.</P>

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