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    CWG Issue 1439</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="1439"></A><H4>1439.
  
Lookup and friend template declarations
</H4>
<B>Section: </B>_N4868_.9.8.2.3&#160; [<A href="https://wg21.link/namespace.memdef">namespace.memdef</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>Richard Smith
 &#160;&#160;&#160;

 <B>Date: </B>2012-01-04<BR>


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



<P>According to _N4868_.9.8.2.3 [<A href="https://wg21.link/namespace.memdef#3">namespace.memdef</A>] paragraph 3,</P>

<BLOCKQUOTE>

If a <TT>friend</TT> declaration in a non-local class first
declares a class or function<SUP>95</SUP> the friend class or
function is a member of the innermost enclosing namespace. The
name of the friend is not found by unqualified lookup
(6.5.3 [<A href="https://wg21.link/basic.lookup.unqual">basic.lookup.unqual</A>]) or by qualified lookup (6.5.5 [<A href="https://wg21.link/basic.lookup.qual">basic.lookup.qual</A>]) until a matching declaration is provided in that
namespace scope (either before or after the class definition
granting friendship).

</BLOCKQUOTE>

<P>This wording does not, but probably should, apply to friend
declarations of function templates and class templates as well.</P>

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

<OL>
<LI><P>Change 6.5.4 [<A href="https://wg21.link/basic.lookup.argdep#1">basic.lookup.argdep</A>] paragraph 1 as follows:</P></LI>

<BLOCKQUOTE>

...in those namespaces, namespace-scope friend function <INS>or
function template</INS> declarations (11.3) not otherwise visible may
be found...

</BLOCKQUOTE>

<LI><P>Change _N4868_.9.8.2.3 [<A href="https://wg21.link/namespace.memdef#3">namespace.memdef</A>] paragraph 3 as follows:</P></LI>

<BLOCKQUOTE>

Every name first declared in a namespace is a member of that
namespace. If a <TT>friend</TT> declaration in a non-local class first
declares a class<INS>,</INS> <DEL>or</DEL> function<INS>, class
template, or function template</INS><SUP>95</SUP> the friend
<DEL>class or function</DEL> is a member of the innermost enclosing
namespace. The name of the friend is not found by unqualified lookup
(6.5.3 [<A href="https://wg21.link/basic.lookup.unqual">basic.lookup.unqual</A>]) or by qualified lookup (6.5.5 [<A href="https://wg21.link/basic.lookup.qual">basic.lookup.qual</A>]) until a matching declaration is provided in that
namespace scope (either before or after the class definition granting
friendship). If a friend function <INS>or function template</INS> is
called, its name may be found by the name lookup that considers
functions from namespaces and classes associated with the types of the
function arguments (6.5.4 [<A href="https://wg21.link/basic.lookup.argdep">basic.lookup.argdep</A>]).  If the name in a
<TT>friend</TT> declaration...

</BLOCKQUOTE>

</OL>

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