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    CWG Issue 2061</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="2061"></A><H4>2061.
  
Inline namespace after simplifications
</H4>
<B>Section: </B>9.9.2&#160; [<A href="https://wg21.link/namespace.def">namespace.def</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD4
 &#160;&#160;&#160;

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

 <B>Date: </B>2014-12-18<BR>


<P>[Adopted at the February, 2016 meeting.]</P>

<P>After the resolution of <A HREF="1795.html">issue 1795</A>,
9.9.2 [<A href="https://wg21.link/namespace.def#3">namespace.def</A>] paragraph 3 now says:</P>

<BLOCKQUOTE>

In a <I>named-namespace-definition</I>, the <I>identifier</I> is
the name of the namespace. If the <I>identifier</I>, when looked up
(6.5.3 [<A href="https://wg21.link/basic.lookup.unqual">basic.lookup.unqual</A>]), refers to
a <I>namespace-name</I> (but not a <I>namespace-alias</I>)
introduced in the declarative region in which
the <I>named-namespace-definition</I> appears,
the <I>namespace-definition</I> <I>extends</I> the
previously-declared namespace. Otherwise, the <I>identifier</I> is
introduced as a <I>namespace-name</I> into the declarative
region in which the <I>named-namespace-definition</I>
appears.

</BLOCKQUOTE>

<P>This appears to break code like the following:</P>

<PRE>
  namespace A {
    inline namespace b {
      namespace C {
        template&lt;typename T&gt; void f();
      }
    }
  }

  namespace A {
    namespace C {
      template&lt;&gt; void f&lt;int&gt;() { }
    }
  }
</PRE>

<P>because (by definition of &#8220;declarative region&#8221;)
<TT>C</TT> cannot be used as an unqualified name to refer to
<TT>A::b::C</TT> within <TT>A</TT> if its declarative region is
<TT>A::b</TT>.</P>

<P><B>Proposed resolution (September, 2015):</B></P>

<P>Change 9.9.2 [<A href="https://wg21.link/namespace.def#3">namespace.def</A>] paragraph 3 as follows:</P>

<BLOCKQUOTE>

In a <I>named-namespace-definition</I>, the <I>identifier</I> is the name
of the namespace. If the <I>identifier</I>, when looked up
(6.5.3 [<A href="https://wg21.link/basic.lookup.unqual">basic.lookup.unqual</A>]), refers to a <I>namespace-name</I> (but not
a <I>namespace-alias</I>) <INS>that was</INS> introduced in
the <DEL>declarative region</DEL> <INS>namespace</INS> in which
the <I>named-namespace-definition</I> appears <INS>or that was introduced
in a member of the inline namespace set of that namespace</INS>,
the <I>namespace-definition</I> extends the previously-declared
namespace. Otherwise, the <I>identifier</I> is introduced as
a <I>namespace-name</I> into the declarative region in which
the <I>named-namespace-definition</I> appears.

</BLOCKQUOTE>

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