diff --git a/include/boost/type_traits/config.hpp b/include/boost/type_traits/config.hpp
index a2bf635..b54af77 100644
--- a/include/boost/type_traits/config.hpp
+++ b/include/boost/type_traits/config.hpp
@@ -25,69 +25,6 @@
 #   define BOOST_TT_DECL /**/
 #endif
 
-//
-// Helper macros for builtin compiler support.
-// If your compiler has builtin support for any of the following
-// traits concepts, then redefine the appropriate macros to pick
-// up on the compiler support:
-//
-// (these should largely ignore cv-qualifiers)
-// BOOST_IS_CLASS(T) should evaluate to true if T is a class or struct type
-// BOOST_IS_ENUM(T) should evaluate to true if T is an enumerator type
-// BOOST_IS_UNION(T) should evaluate to true if T is a union type
-// BOOST_IS_POD(T) should evaluate to true if T is a POD type
-// BOOST_IS_EMPTY(T) should evaluate to true if T is an empty struct or union
-// BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) should evaluate to true if "T x;" has no effect
-// BOOST_HAS_TRIVIAL_COPY(T) should evaluate to true if T(t) <==> memcpy
-// BOOST_HAS_TRIVIAL_ASSIGN(T) should evaluate to true if t = u <==> memcpy
-// BOOST_HAS_TRIVIAL_DESTRUCTOR(T) should evaluate to true if ~T() has no effect
-
-#ifdef BOOST_HAS_SGI_TYPE_TRAITS
-#   include "boost/type_traits/is_same.hpp"
-#   include <type_traits.h>
-#   define BOOST_IS_POD(T) ::boost::is_same< typename ::__type_traits<T>::is_POD_type, ::__true_type>::value
-#   define BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_default_constructor, ::__true_type>::value
-#   define BOOST_HAS_TRIVIAL_COPY(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_copy_constructor, ::__true_type>::value
-#   define BOOST_HAS_TRIVIAL_ASSIGN(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_assignment_operator, ::__true_type>::value
-#   define BOOST_HAS_TRIVIAL_DESTRUCTOR(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_destructor, ::__true_type>::value
-#endif
-
-#ifndef BOOST_IS_CLASS
-#   define BOOST_IS_CLASS(T) false
-#endif
-
-#ifndef BOOST_IS_ENUM
-#   define BOOST_IS_ENUM(T) false
-#endif
-
-#ifndef BOOST_IS_UNION
-#   define BOOST_IS_UNION(T) false
-#endif
-
-#ifndef BOOST_IS_POD
-#   define BOOST_IS_POD(T) false
-#endif
-
-#ifndef BOOST_IS_EMPTY
-#   define BOOST_IS_EMPTY(T) false
-#endif
-
-#ifndef BOOST_HAS_TRIVIAL_CONSTRUCTOR
-#   define BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) false
-#endif
-
-#ifndef BOOST_HAS_TRIVIAL_COPY
-#   define BOOST_HAS_TRIVIAL_COPY(T) false
-#endif
-
-#ifndef BOOST_HAS_TRIVIAL_ASSIGN
-#   define BOOST_HAS_TRIVIAL_ASSIGN(T) false
-#endif
-
-#ifndef BOOST_HAS_TRIVIAL_DESTRUCTOR
-#   define BOOST_HAS_TRIVIAL_DESTRUCTOR(T) false
-#endif
-
 # if (defined(__MWERKS__) && __MWERKS__ >= 0x3000) || BOOST_MSVC > 1301 || defined(BOOST_NO_COMPILER_CONFIG)
 #   define BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
 #endif
diff --git a/include/boost/type_traits/has_trivial_assign.hpp b/include/boost/type_traits/has_trivial_assign.hpp
index a6afb52..71c4ae6 100644
--- a/include/boost/type_traits/has_trivial_assign.hpp
+++ b/include/boost/type_traits/has_trivial_assign.hpp
@@ -10,13 +10,14 @@
 #ifndef BOOST_TT_HAS_TRIVIAL_ASSIGN_HPP_INCLUDED
 #define BOOST_TT_HAS_TRIVIAL_ASSIGN_HPP_INCLUDED
 
+#include "boost/type_traits/config.hpp"
+#include "boost/type_traits/intrinsics.hpp"
 #include "boost/type_traits/is_pod.hpp"
 #include "boost/type_traits/is_const.hpp"
 #include "boost/type_traits/is_volatile.hpp"
 #include "boost/type_traits/detail/ice_and.hpp"
 #include "boost/type_traits/detail/ice_or.hpp"
 #include "boost/type_traits/detail/ice_not.hpp"
-#include "boost/type_traits/config.hpp"
 
 // should be the last #include
 #include "boost/type_traits/detail/bool_trait_def.hpp"
diff --git a/include/boost/type_traits/has_trivial_constructor.hpp b/include/boost/type_traits/has_trivial_constructor.hpp
index 4dabab4..3a74f17 100644
--- a/include/boost/type_traits/has_trivial_constructor.hpp
+++ b/include/boost/type_traits/has_trivial_constructor.hpp
@@ -10,9 +10,10 @@
 #ifndef BOOST_TT_HAS_TRIVIAL_CONSTRUCTOR_HPP_INCLUDED
 #define BOOST_TT_HAS_TRIVIAL_CONSTRUCTOR_HPP_INCLUDED
 
+#include "boost/type_traits/config.hpp"
+#include "boost/type_traits/intrinsics.hpp"
 #include "boost/type_traits/is_pod.hpp"
 #include "boost/type_traits/detail/ice_or.hpp"
-#include "boost/type_traits/config.hpp"
 
 // should be the last #include
 #include "boost/type_traits/detail/bool_trait_def.hpp"
diff --git a/include/boost/type_traits/has_trivial_copy.hpp b/include/boost/type_traits/has_trivial_copy.hpp
index 9bc8421..ffd475c 100644
--- a/include/boost/type_traits/has_trivial_copy.hpp
+++ b/include/boost/type_traits/has_trivial_copy.hpp
@@ -10,12 +10,13 @@
 #ifndef BOOST_TT_HAS_TRIVIAL_COPY_HPP_INCLUDED
 #define BOOST_TT_HAS_TRIVIAL_COPY_HPP_INCLUDED
 
+#include "boost/type_traits/config.hpp"
+#include "boost/type_traits/intrinsics.hpp"
 #include "boost/type_traits/is_volatile.hpp"
 #include "boost/type_traits/is_pod.hpp"
 #include "boost/type_traits/detail/ice_and.hpp"
 #include "boost/type_traits/detail/ice_or.hpp"
 #include "boost/type_traits/detail/ice_not.hpp"
-#include "boost/type_traits/config.hpp"
 
 // should be the last #include
 #include "boost/type_traits/detail/bool_trait_def.hpp"
diff --git a/include/boost/type_traits/has_trivial_destructor.hpp b/include/boost/type_traits/has_trivial_destructor.hpp
index b0f9d16..97aab19 100644
--- a/include/boost/type_traits/has_trivial_destructor.hpp
+++ b/include/boost/type_traits/has_trivial_destructor.hpp
@@ -10,9 +10,10 @@
 #ifndef BOOST_TT_HAS_TRIVIAL_DESTRUCTOR_HPP_INCLUDED
 #define BOOST_TT_HAS_TRIVIAL_DESTRUCTOR_HPP_INCLUDED
 
+#include "boost/type_traits/config.hpp"
+#include "boost/type_traits/intrinsics.hpp"
 #include "boost/type_traits/is_pod.hpp"
 #include "boost/type_traits/detail/ice_or.hpp"
-#include "boost/type_traits/config.hpp"
 
 // should be the last #include
 #include "boost/type_traits/detail/bool_trait_def.hpp"
diff --git a/include/boost/type_traits/intrinsics.hpp b/include/boost/type_traits/intrinsics.hpp
new file mode 100644
index 0000000..58a31c2
--- /dev/null
+++ b/include/boost/type_traits/intrinsics.hpp
@@ -0,0 +1,92 @@
+
+// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
+// Permission to copy, use, modify, sell and distribute this software is 
+// granted provided this copyright notice appears in all copies. This software 
+// is provided "as is" without express or implied warranty, and with no claim 
+// as to its suitability for any purpose.
+//
+// See http://www.boost.org for most recent version including documentation.
+
+#ifndef BOOST_TT_INTRINSICS_HPP_INCLUDED
+#define BOOST_TT_INTRINSICS_HPP_INCLUDED
+
+#ifndef BOOST_TT_CONFIG_HPP_INCLUDED
+#include "boost/type_traits/config.hpp"
+#endif
+
+//
+// Helper macros for builtin compiler support.
+// If your compiler has builtin support for any of the following
+// traits concepts, then redefine the appropriate macros to pick
+// up on the compiler support:
+//
+// (these should largely ignore cv-qualifiers)
+// BOOST_IS_CLASS(T) should evaluate to true if T is a class or struct type
+// BOOST_IS_ENUM(T) should evaluate to true if T is an enumerator type
+// BOOST_IS_UNION(T) should evaluate to true if T is a union type
+// BOOST_IS_POD(T) should evaluate to true if T is a POD type
+// BOOST_IS_EMPTY(T) should evaluate to true if T is an empty struct or union
+// BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) should evaluate to true if "T x;" has no effect
+// BOOST_HAS_TRIVIAL_COPY(T) should evaluate to true if T(t) <==> memcpy
+// BOOST_HAS_TRIVIAL_ASSIGN(T) should evaluate to true if t = u <==> memcpy
+// BOOST_HAS_TRIVIAL_DESTRUCTOR(T) should evaluate to true if ~T() has no effect
+
+#ifdef BOOST_HAS_SGI_TYPE_TRAITS
+#   include "boost/type_traits/is_same.hpp"
+#   include <type_traits.h>
+#   define BOOST_IS_POD(T) ::boost::is_same< typename ::__type_traits<T>::is_POD_type, ::__true_type>::value
+#   define BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_default_constructor, ::__true_type>::value
+#   define BOOST_HAS_TRIVIAL_COPY(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_copy_constructor, ::__true_type>::value
+#   define BOOST_HAS_TRIVIAL_ASSIGN(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_assignment_operator, ::__true_type>::value
+#   define BOOST_HAS_TRIVIAL_DESTRUCTOR(T) ::boost::is_same< typename ::__type_traits<T>::has_trivial_destructor, ::__true_type>::value
+#endif
+
+#if defined(__MSL_CPP__) && (__MSL_CPP__ >= 0x8000)
+#   include <msl_utility>
+#   define BOOST_IS_UNION(T) BOOST_STD_EXTENSION_NAMESPACE::is_union<T>::value
+#   define BOOST_IS_POD(T) BOOST_STD_EXTENSION_NAMESPACE::is_POD<T>::value
+#   define BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) BOOST_STD_EXTENSION_NAMESPACE::has_trivial_constructor<T>::value
+#   define BOOST_HAS_TRIVIAL_COPY(T) BOOST_STD_EXTENSION_NAMESPACE::has_trivial_copy<T>::value
+#   define BOOST_HAS_TRIVIAL_ASSIGN(T) BOOST_STD_EXTENSION_NAMESPACE::has_trivial_assign<T>::value
+#   define BOOST_HAS_TRIVIAL_DESTRUCTOR(T) BOOST_STD_EXTENSION_NAMESPACE::has_trivial_destructor<T>::value
+#endif
+
+#ifndef BOOST_IS_CLASS
+#   define BOOST_IS_CLASS(T) false
+#endif
+
+#ifndef BOOST_IS_ENUM
+#   define BOOST_IS_ENUM(T) false
+#endif
+
+#ifndef BOOST_IS_UNION
+#   define BOOST_IS_UNION(T) false
+#endif
+
+#ifndef BOOST_IS_POD
+#   define BOOST_IS_POD(T) false
+#endif
+
+#ifndef BOOST_IS_EMPTY
+#   define BOOST_IS_EMPTY(T) false
+#endif
+
+#ifndef BOOST_HAS_TRIVIAL_CONSTRUCTOR
+#   define BOOST_HAS_TRIVIAL_CONSTRUCTOR(T) false
+#endif
+
+#ifndef BOOST_HAS_TRIVIAL_COPY
+#   define BOOST_HAS_TRIVIAL_COPY(T) false
+#endif
+
+#ifndef BOOST_HAS_TRIVIAL_ASSIGN
+#   define BOOST_HAS_TRIVIAL_ASSIGN(T) false
+#endif
+
+#ifndef BOOST_HAS_TRIVIAL_DESTRUCTOR
+#   define BOOST_HAS_TRIVIAL_DESTRUCTOR(T) false
+#endif
+
+#endif // BOOST_TT_INTRINSICS_HPP_INCLUDED
+
+
diff --git a/include/boost/type_traits/is_class.hpp b/include/boost/type_traits/is_class.hpp
index c652491..15d8df9 100644
--- a/include/boost/type_traits/is_class.hpp
+++ b/include/boost/type_traits/is_class.hpp
@@ -11,18 +11,18 @@
 #define BOOST_TT_IS_CLASS_HPP_INCLUDED
 
 #include "boost/type_traits/config.hpp"
+#   include "boost/type_traits/is_union.hpp"
+#   include "boost/type_traits/detail/ice_and.hpp"
+#   include "boost/type_traits/detail/ice_not.hpp"
 
 #ifdef BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
 #   include "boost/type_traits/detail/yes_no_type.hpp"
 #else
-#   include "boost/type_traits/is_union.hpp"
 #   include "boost/type_traits/is_scalar.hpp"
 #   include "boost/type_traits/is_array.hpp"
 #   include "boost/type_traits/is_reference.hpp"
 #   include "boost/type_traits/is_void.hpp"
 #   include "boost/type_traits/is_function.hpp"
-#   include "boost/type_traits/detail/ice_and.hpp"
-#   include "boost/type_traits/detail/ice_not.hpp"
 #endif
 
 // should be the last #include
@@ -52,7 +52,10 @@ struct is_class_impl
     template <class U> static ::boost::type_traits::no_type is_class_tester(...);
 
     BOOST_STATIC_CONSTANT(bool, value = 
-        sizeof(is_class_tester<T>(0)) == sizeof(::boost::type_traits::yes_type)
+        (::boost::type_traits::ice_and<
+            sizeof(is_class_tester<T>(0)) == sizeof(::boost::type_traits::yes_type),
+            ::boost::type_traits::ice_not< ::boost::is_union<T>::value >::value
+        >::value)
         );
 };
 
diff --git a/include/boost/type_traits/is_pod.hpp b/include/boost/type_traits/is_pod.hpp
index 700d1e4..606a2e8 100644
--- a/include/boost/type_traits/is_pod.hpp
+++ b/include/boost/type_traits/is_pod.hpp
@@ -10,10 +10,11 @@
 #ifndef BOOST_TT_IS_POD_HPP_INCLUDED
 #define BOOST_TT_IS_POD_HPP_INCLUDED
 
+#include "boost/type_traits/config.hpp"
 #include "boost/type_traits/is_void.hpp"
 #include "boost/type_traits/is_scalar.hpp"
 #include "boost/type_traits/detail/ice_or.hpp"
-#include "boost/type_traits/config.hpp"
+#include "boost/type_traits/intrinsics.hpp"
 
 #include <cstddef>
 
diff --git a/include/boost/type_traits/is_union.hpp b/include/boost/type_traits/is_union.hpp
index 507c000..5a2c3f9 100644
--- a/include/boost/type_traits/is_union.hpp
+++ b/include/boost/type_traits/is_union.hpp
@@ -13,6 +13,7 @@
 
 #include "boost/type_traits/remove_cv.hpp"
 #include "boost/type_traits/config.hpp"
+#include "boost/type_traits/intrinsics.hpp"
 
 // should be the last #include
 #include "boost/type_traits/detail/bool_trait_def.hpp"