diff --git a/include/boost/move/detail/type_traits.hpp b/include/boost/move/detail/type_traits.hpp
index cef0f20..11b0478 100644
--- a/include/boost/move/detail/type_traits.hpp
+++ b/include/boost/move/detail/type_traits.hpp
@@ -70,6 +70,7 @@
     // user defined specializations as well as compiler intrinsics as
     // and when they become available:
 #   include <msl_utility>
+#   define BOOST_MOVE_IS_UNION(T) BOOST_STD_EXTENSION_NAMESPACE::is_union<T>::value
 #   define BOOST_MOVE_IS_POD(T) BOOST_STD_EXTENSION_NAMESPACE::is_POD<T>::value
 #   define BOOST_MOVE_HAS_TRIVIAL_CONSTRUCTOR(T) BOOST_STD_EXTENSION_NAMESPACE::has_trivial_default_ctor<T>::value
 #   define BOOST_MOVE_HAS_TRIVIAL_COPY(T) BOOST_STD_EXTENSION_NAMESPACE::has_trivial_copy_ctor<T>::value
@@ -79,7 +80,9 @@
 
 #if (defined(BOOST_MSVC) && defined(BOOST_MSVC_FULL_VER) && (BOOST_MSVC_FULL_VER >=140050215))\
          || (defined(BOOST_INTEL) && defined(_MSC_VER) && (_MSC_VER >= 1500))
+#   define BOOST_MOVE_IS_UNION(T) __is_union(T)
 #   define BOOST_MOVE_IS_POD(T)                    (__is_pod(T) && __has_trivial_constructor(T))
+#   define BOOST_MOVE_IS_EMPTY(T)                  __is_empty(T)
 #   define BOOST_MOVE_HAS_TRIVIAL_CONSTRUCTOR(T)   __has_trivial_constructor(T)
 #   define BOOST_MOVE_HAS_TRIVIAL_COPY(T)          (__has_trivial_copy(T)|| ::boost::move_detail::is_pod<T>::value)
 #   define BOOST_MOVE_HAS_TRIVIAL_ASSIGN(T)        (__has_trivial_assign(T) || ::boost::move_detail::is_pod<T>::value)
@@ -97,9 +100,15 @@
 
 #if defined(BOOST_CLANG) && defined(__has_feature)
 
+#   if __has_feature(is_union)
+#     define BOOST_MOVE_IS_UNION(T) __is_union(T)
+#   endif
 #   if (!defined(__GLIBCXX__) || (__GLIBCXX__ >= 20080306 && __GLIBCXX__ != 20080519)) && __has_feature(is_pod)
 #     define BOOST_MOVE_IS_POD(T) __is_pod(T)
 #   endif
+#   if (!defined(__GLIBCXX__) || (__GLIBCXX__ >= 20080306 && __GLIBCXX__ != 20080519)) && __has_feature(is_empty)
+#     define BOOST_MOVE_IS_EMPTY(T) __is_empty(T)
+#   endif
 #   if __has_feature(has_trivial_constructor)
 #     define BOOST_MOVE_HAS_TRIVIAL_CONSTRUCTOR(T) __has_trivial_constructor(T)
 #   endif
@@ -143,7 +152,9 @@
 #  define BOOST_MOVE_INTEL_TT_OPTS
 #endif
 
+#   define BOOST_MOVE_IS_UNION(T) __is_union(T)
 #   define BOOST_MOVE_IS_POD(T) __is_pod(T)
+#   define BOOST_MOVE_IS_EMPTY(T) __is_empty(T)
 #   define BOOST_MOVE_HAS_TRIVIAL_CONSTRUCTOR(T) ((__has_trivial_constructor(T) BOOST_MOVE_INTEL_TT_OPTS))
 #   define BOOST_MOVE_HAS_TRIVIAL_COPY(T) ((__has_trivial_copy(T) BOOST_MOVE_INTEL_TT_OPTS))
 #   define BOOST_MOVE_HAS_TRIVIAL_ASSIGN(T) ((__has_trivial_assign(T) BOOST_MOVE_INTEL_TT_OPTS) )
@@ -163,7 +174,9 @@
 
 #if defined(__ghs__) && (__GHS_VERSION_NUMBER >= 600)
 
+#   define BOOST_MOVE_IS_UNION(T) __is_union(T)
 #   define BOOST_MOVE_IS_POD(T) __is_pod(T)
+#   define BOOST_MOVE_IS_EMPTY(T) __is_empty(T)
 #   define BOOST_MOVE_HAS_TRIVIAL_CONSTRUCTOR(T) __has_trivial_constructor(T)
 #   define BOOST_MOVE_HAS_TRIVIAL_COPY(T) (__has_trivial_copy(T))
 #   define BOOST_MOVE_HAS_TRIVIAL_ASSIGN(T) (__has_trivial_assign(T))
@@ -177,7 +190,9 @@
 #endif
 
 # if defined(__CODEGEARC__)
+#   define BOOST_MOVE_IS_UNION(T) __is_union(T)
 #   define BOOST_MOVE_IS_POD(T) __is_pod(T)
+#   define BOOST_MOVE_IS_EMPTY(T) __is_empty(T)
 #   define BOOST_MOVE_HAS_TRIVIAL_CONSTRUCTOR(T) (__has_trivial_default_constructor(T))
 #   define BOOST_MOVE_HAS_TRIVIAL_COPY(T) (__has_trivial_copy_constructor(T))
 #   define BOOST_MOVE_HAS_TRIVIAL_ASSIGN(T) (__has_trivial_assign(T))
@@ -192,6 +207,13 @@
 #endif
 
 //Fallback definitions
+
+#ifdef BOOST_MOVE_IS_UNION
+   #define BOOST_MOVE_IS_UNION_IMPL(T) BOOST_MOVE_IS_UNION(T)
+#else
+   #define BOOST_MOVE_IS_UNION_IMPL(T) false
+#endif
+
 #ifdef BOOST_MOVE_IS_POD
    #define BOOST_MOVE_IS_POD_IMPL(T) BOOST_MOVE_IS_POD(T)
 #else
@@ -199,6 +221,12 @@
       (::boost::move_detail::is_scalar<T>::value || ::boost::move_detail::is_void<T>::value)
 #endif
 
+#ifdef BOOST_MOVE_IS_EMPTY
+   #define BOOST_MOVE_IS_EMPTY_IMPL(T) BOOST_MOVE_IS_EMPTY(T)
+#else
+   #define BOOST_MOVE_IS_EMPTY_IMPL(T)    ::boost::move_detail::is_empty_nonintrinsic<T>::value
+#endif
+
 #ifdef BOOST_MOVE_HAS_TRIVIAL_COPY
    #define BOOST_MOVE_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)   BOOST_MOVE_HAS_TRIVIAL_COPY(T)
 #else
@@ -421,6 +449,21 @@ struct is_integral
    : public is_integral_cv<typename remove_cv<T>::type>
 {};
 
+//////////////////////////////////////
+//          remove_all_extents
+//////////////////////////////////////
+template <class T>
+struct remove_all_extents
+{  typedef T type;};
+
+template <class T>
+struct remove_all_extents<T[]>
+{  typedef typename remove_all_extents<T>::type type; };
+
+template <class T, size_t N>
+struct remove_all_extents<T[N]>
+{  typedef typename remove_all_extents<T>::type type;};
+
 //////////////////////////
 //    is_scalar
 //////////////////////////
@@ -531,6 +574,28 @@ struct is_function
    : is_function_impl<T>
 {};
 
+//////////////////////////////////////
+//       is_union
+//////////////////////////////////////
+template<class T>
+struct is_union_noextents_cv
+{  static const bool value = BOOST_MOVE_IS_UNION_IMPL(T); };
+
+template<class T>
+struct is_union
+   : is_union_noextents_cv<typename remove_cv<typename remove_all_extents<T>::type>::type>
+{};
+
+//////////////////////////////////////
+//             is_class
+//////////////////////////////////////
+template <class T>
+struct is_class
+{
+   static const bool value = is_class_or_union<T>::value && ! is_union<T>::value;
+};
+
+
 //////////////////////////////////////
 //             is_arithmetic
 //////////////////////////////////////
@@ -584,21 +649,6 @@ template <class T>
 struct is_enum
 {  static const bool value = BOOST_MOVE_IS_ENUM_IMPL(T);  };
 
-//////////////////////////////////////
-//          remove_all_extents
-//////////////////////////////////////
-template <class T>
-struct remove_all_extents
-{  typedef T type;};
-
-template <class T>
-struct remove_all_extents<T[]>
-{  typedef typename remove_all_extents<T>::type type; };
-
-template <class T, size_t N>
-struct remove_all_extents<T[N]>
-{  typedef typename remove_all_extents<T>::type type;};
-
 //////////////////////////////////////
 //       is_pod
 //////////////////////////////////////
@@ -611,6 +661,41 @@ struct is_pod
    : is_pod_noextents_cv<typename remove_cv<typename remove_all_extents<T>::type>::type>
 {};
 
+//////////////////////////////////////
+//             is_empty
+//////////////////////////////////////
+#if !defined(BOOST_MOVE_IS_EMPTY)
+
+template <typename T>
+struct empty_helper_t1 : public T
+{
+   empty_helper_t1();  // hh compiler bug workaround
+   int i[256];
+   private:
+
+   empty_helper_t1(const empty_helper_t1&);
+   empty_helper_t1& operator=(const empty_helper_t1&);
+};
+
+struct empty_helper_t2 { int i[256]; };
+
+template <typename T, bool IsClass = false>
+struct is_empty_nonintrinsic
+{
+   static const bool value = false;
+};
+
+template <typename T>
+struct is_empty_nonintrinsic<T, true>
+{
+   static const bool value = sizeof(empty_helper_t1<T>) == sizeof(empty_helper_t2);
+};
+#endif
+
+template <class T>
+struct is_empty
+{  static const bool value = BOOST_MOVE_IS_EMPTY_IMPL(T);  };
+
 //////////////////////////////////////
 //       is_copy_constructible
 //////////////////////////////////////