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    CWG Issue 1478</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="1478"></A><H4>1478.
  
<TT>template</TT> keyword for dependent template template arguments
</H4>
<B>Section: </B>13.3&#160; [<A href="https://wg21.link/temp.names">temp.names</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD6
 &#160;&#160;&#160;

 <B>Submitter: </B>Johannes Schaub
 &#160;&#160;&#160;

 <B>Date: </B>2012-03-10<BR>


<P>[Accepted at the November, 2020 meeting as part of paper P1787R6 and
moved to DR at the February, 2021 meeting.]</P>



<P>According to 13.3 [<A href="https://wg21.link/temp.names#4">temp.names</A>] paragraph 4,</P>

<BLOCKQUOTE>

When the name of a member template specialization appears after <TT>.</TT> or
<TT>-&gt;</TT> in a <I>postfix-expression</I> or after a
<I>nested-name-specifier</I> in a <I>qualified-id</I>, and the object
expression of the <I>postfix-expression</I> is type-dependent or the
<I>nested-name-specifier</I> in the <I>qualified-id</I> refers to a
dependent type, but the name is not a member of the current
instantiation (13.8.3.2 [<A href="https://wg21.link/temp.dep.type">temp.dep.type</A>]), the member template
name must be prefixed by the keyword <TT>template</TT>.

</BLOCKQUOTE>

<P>In other words, the <TT>template</TT> keyword is only required when
forming a <I>template-id</I>.  However, current compilers reject an
example like:</P>

<PRE>
  template&lt;typename T, template&lt;typename&gt; class U = T::X&gt; struct A;
</PRE>

<P>and require the <TT>template</TT> keyword before <TT>X</TT>.
Should the rule be amended to require the <TT>template</TT> keyword in
cases like this?</P>

<BR><BR>
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