From 7c1dcd51f6c4931ac3f446cb50e9c6b84e47baa1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Sun, 15 Jan 2012 12:25:12 +0000
Subject: [PATCH] Ticket #6396: Implicit instanciation of boost::rv for
 non-cass types generates an error

[SVN r76509]
---
 include/boost/move/move.hpp | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/include/boost/move/move.hpp b/include/boost/move/move.hpp
index 284c58e..4d510f4 100644
--- a/include/boost/move/move.hpp
+++ b/include/boost/move/move.hpp
@@ -225,13 +225,32 @@
 
    namespace boost {
 
+   namespace move_detail {
+      template<class T>
+      struct is_class_or_union
+      {
+         struct twochar { char _[2]; };
+         template <class U>
+         static char is_class_or_union_tester(void(U::*)(void));
+         template <class U>
+         static twochar is_class_or_union_tester(...);
+         static const bool value = sizeof(is_class_or_union_tester<T>(0)) == sizeof(char);
+      };
+      struct empty{};
+   }
+
    //////////////////////////////////////////////////////////////////////////////
    //
    //                            struct rv
    //
    //////////////////////////////////////////////////////////////////////////////
    template <class T>
-   class rv : public T
+   class rv
+      : public BOOST_MOVE_MPL_NS::if_c
+         < ::boost::move_detail::is_class_or_union<T>::value
+         , T
+         , ::boost::move_detail::empty
+         >::type
    {
       rv();
       ~rv();
@@ -239,6 +258,8 @@
       void operator=(rv const&);
    } BOOST_MOVE_ATTRIBUTE_MAY_ALIAS;
 
+
+
    //////////////////////////////////////////////////////////////////////////////
    //
    //                            move_detail::is_rv