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    CWG Issue 1398</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="1398"></A><H4>1398.
  
Non-type template parameters of type <TT>std::nullptr_t</TT>
</H4>
<B>Section: </B>13.4.3&#160; [<A href="https://wg21.link/temp.arg.nontype">temp.arg.nontype</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD3
 &#160;&#160;&#160;

 <B>Submitter: </B>Daniel Kr&#252;gler
 &#160;&#160;&#160;

 <B>Date: </B>2011-09-27<BR>


<P>[Moved to DR at the October, 2012 meeting.]</P>

<P>Although 13.2 [<A href="https://wg21.link/temp.param#4">temp.param</A>] paragraph 4 explicitly allows
non-type template parameters of type
<TT>std::nullptr_t</TT>, they cannot actually be used:
13.4.3 [<A href="https://wg21.link/temp.arg.nontype#1">temp.arg.nontype</A>] paragraph 1 does not allow a
<I>template-argument</I> of type <TT>std::nullptr_t</TT>, and
paragraph 5 does not describe any conversions from other types to
<TT>std::nullptr_t</TT>.</P>

<P><B>Proposed resolution (February, 2012):</B></P>

<P>Add the following new bullet in 13.4.3 [<A href="https://wg21.link/temp.arg.nontype#1">temp.arg.nontype</A>] paragraph 1:
</P>

<UL>
<LI><P>...</P></LI>

<LI><P>a pointer to member expressed as described in 7.6.2.2 [<A href="https://wg21.link/expr.unary.op">expr.unary.op</A>].</P></LI>

<LI><P><INS>an address constant expression of type
<TT>std::nullptr_t</TT>.</INS></P></LI>

</UL>

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