[PATCH] Add tests and docs for LWG 2212 support

[Jonathan Wakely]

        * testsuite/20_util/pair/astuple/astuple.cc: Only include <utility>.
        * testsuite/23_containers/array/tuple_interface/tuple_element.cc:
        Only include <array>.
        * testsuite/23_containers/array/tuple_interface/tuple_size.cc:
        Likewise.
        * doc/xml/manual/intro.xml; Document LWG 2212 support.
        * doc/html*: Regenerate.

We already implement LWG 2212 but this tweaks the tests to verify it.

Tested x86_64-linux, committed to trunk.


commit 8c5a11cb7545d1a701596665392a8f4bf29a1489
Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Tue Jul 12 14:00:26 2016 +0000

    Add tests and docs for LWG 2212 support
    
        * testsuite/20_util/pair/astuple/astuple.cc: Only include <utility>.
        * testsuite/23_containers/array/tuple_interface/tuple_element.cc:
        Only include <array>.
        * testsuite/23_containers/array/tuple_interface/tuple_size.cc:
        Likewise.
        * doc/xml/manual/intro.xml; Document LWG 2212 support.
        * doc/html*: Regenerate.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238244 
138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/libstdc++-v3/doc/xml/manual/intro.xml 
b/libstdc++-v3/doc/xml/manual/intro.xml
index 2aa9ba7..a47a3ec 100644
--- a/libstdc++-v3/doc/xml/manual/intro.xml
+++ b/libstdc++-v3/doc/xml/manual/intro.xml
@@ -934,6 +934,14 @@ requirements of the license of GCC.
     <listitem><para>Use the referenceable type concept.
     </para></listitem></varlistentry>
 
+    <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink"; 
xlink:href="../ext/lwg-defects.html#2212">2212</link>:
+       <emphasis><code>tuple_size</code> for <code>const pair</code> request 
<code>&lt;tuple&gt;</code> header</emphasis>
+    </term>
+    <listitem><para>The <code>tuple_size</code> and <code>tuple_element</code>
+    partial specializations are defined in <code>&lt;utility&gt;</code> which
+    is included by <code>&lt;array&gt;</code>.
+    </para></listitem></varlistentry>
+
     <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink"; 
xlink:href="../ext/lwg-defects.html#2313">2313</link>:
        <emphasis><code>tuple_size</code> should always derive from 
<code>integral_constant&lt;size_t, N&gt;</code></emphasis>
     </term>
diff --git a/libstdc++-v3/testsuite/20_util/pair/astuple/astuple.cc 
b/libstdc++-v3/testsuite/20_util/pair/astuple/astuple.cc
index 8b6fca3..3a458bb 100644
--- a/libstdc++-v3/testsuite/20_util/pair/astuple/astuple.cc
+++ b/libstdc++-v3/testsuite/20_util/pair/astuple/astuple.cc
@@ -18,8 +18,10 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// NB: Don't include any other headers in this file.
+// LWG 2212 requires <utility> to define tuple_size<cv T> and
+// tuple_element<cv T> specializations.
 #include <utility>
-#include <type_traits>
 
 typedef std::pair<int, long> test_type;
 
@@ -32,6 +34,7 @@ static_assert( std::tuple_size<const volatile 
test_type>::value == 2,
 template<std::size_t N, typename T>
   using Tuple_elt = typename std::tuple_element<N, T>::type;
 
+// This relies on the fact that <utility> includes <type_traits>:
 using std::is_same;
 
 static_assert( is_same<Tuple_elt<0, test_type>, test_type::first_type>::value,
diff --git 
a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element.cc 
b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element.cc
index 96e0bfb..65da753 100644
--- 
a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element.cc
+++ 
b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_element.cc
@@ -18,15 +18,18 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// NB: Don't include any other headers in this file.
+// LWG 2212 requires <array> to define tuple_element<cv T> specializations.
 #include <array>
-#include <type_traits>
-#include <testsuite_hooks.h>
 
 void
 test01() 
 { 
   bool test __attribute__((unused)) = true;
-  using namespace std;
+  using std::array;
+  using std::tuple_element;
+  // This relies on the fact that <utility> includes <type_traits>:
+  using std::is_same;
 
   const size_t len = 3;
   typedef array<int, len> array_type;
diff --git 
a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_size.cc 
b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_size.cc
index 4a95fa7..6fe501e 100644
--- a/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_size.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/tuple_interface/tuple_size.cc
@@ -18,14 +18,18 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// NB: Don't include any other headers in this file.
+// LWG 2212 requires <array> to define tuple_size<cv T> specializations.
 #include <array>
-#include <testsuite_hooks.h>
 
 void
 test01() 
 { 
   bool test __attribute__((unused)) = true;
-  using namespace std;
+  using std::array;
+  using std::tuple_size;
+  // This relies on the fact that <utility> includes <type_traits>:
+  using std::is_same;
 
   {
     const size_t len = 5;