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    CWG Issue 314</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="314"></A><H4>314.
  
<TT>template</TT> in base class specifier
</H4>
<B>Section: </B>13.3&#160; [<A href="https://wg21.link/temp.names">temp.names</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++17
 &#160;&#160;&#160;

 <B>Submitter: </B>Mark Mitchell
 &#160;&#160;&#160;

 <B>Date: </B>23 Aug 2001<BR>


<P>[Adopted at the February/March, 2017 meeting.]</P>

<P>The EDG front-end accepts:</P>
<PRE>
template &lt;typename T&gt;
struct A {
  template &lt;typename U&gt;
  struct B {};
};

template &lt;typename T&gt;
struct C : public A&lt;T&gt;::template B&lt;T&gt; {
};
</PRE>
<P>It rejects this code if the base-specifier is spelled
<TT>A&lt;T&gt;::B&lt;T&gt;</TT>.</P>

<P>However, the grammar for a base-specifier does not allow the
<TT>template</TT> keyword.</P>

<P><B>Suggested resolution:</B></P>

It seems to me that a consistent approach to the solution that looks like
it will be adopted for <A HREF="180.html">issue 180</A> (which deals
with the <TT>typename</TT> keyword in similar contexts) would be to
assume that <TT>B</TT> is a template if it is followed by a
"&lt;".  After all, an expression cannot appear in this context.

<P><B>Notes from the 4/02 meeting:</B></P>

<P>We agreed that <TT>template</TT> must be allowed in this context.
The syntax needs to be changed.  We also opened the related
<A HREF="343.html">issue 343</A>.</P>

<P><B>Additional note (August, 2010):</B></P>

<P>The same considerations apply to <I>mem-initializer-id</I>s, as noted
in <A HREF="1019.html">issue 1019</A>.</P>

<P><B>Additional note (January, 2014):</B></P>

<P>See also <A HREF="1710.html">issue 1710</A>.</P>

<P><B>Proposed resolution (March, 2017):</B></P>

<P>This issue is resolved by the resolution of
<A HREF="1710.html">issue 1710</A>.</P>

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