diff --git a/include/boost/mpl/arg.hpp b/include/boost/mpl/arg.hpp
index 960f90a..bda6d4a 100644
--- a/include/boost/mpl/arg.hpp
+++ b/include/boost/mpl/arg.hpp
@@ -21,8 +21,8 @@
 
 #if !defined(BOOST_MPL_PREPROCESSING_MODE)
 #   include <boost/mpl/arg_fwd.hpp>
-#   include <boost/mpl/assert.hpp>
 #   include <boost/mpl/aux_/na.hpp>
+#   include <boost/mpl/aux_/na_assert.hpp>
 #   include <boost/mpl/aux_/arity_spec.hpp>
 #   include <boost/mpl/aux_/arg_typedef.hpp>
 #endif
@@ -103,7 +103,7 @@ template<> struct arg<i_>
     struct apply
     {
         typedef BOOST_PP_CAT(U,i_) type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -121,7 +121,7 @@ template<> struct arg<-1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/na.hpp b/include/boost/mpl/aux_/na.hpp
index 178cfdd..840515b 100644
--- a/include/boost/mpl/aux_/na.hpp
+++ b/include/boost/mpl/aux_/na.hpp
@@ -19,6 +19,7 @@
 #include <boost/mpl/aux_/config/msvc.hpp>
 #include <boost/mpl/aux_/config/ctps.hpp>
 
+
 BOOST_MPL_AUX_ADL_BARRIER_NAMESPACE_OPEN
 
 // n.a. == not available
diff --git a/include/boost/mpl/aux_/na_assert.hpp b/include/boost/mpl/aux_/na_assert.hpp
new file mode 100644
index 0000000..ec76448
--- /dev/null
+++ b/include/boost/mpl/aux_/na_assert.hpp
@@ -0,0 +1,33 @@
+
+#ifndef BOOST_MPL_AUX_NA_ASSERT_HPP_INCLUDED
+#define BOOST_MPL_AUX_NA_ASSERT_HPP_INCLUDED
+
+// Copyright Aleksey Gurtovoy 2001-2004
+//
+// Distributed under the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at 
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/mpl for documentation.
+
+// $Source$
+// $Date$
+// $Revision$
+
+#include <boost/mpl/aux_/na.hpp>
+#include <boost/mpl/aux_/config/msvc.hpp>
+#include <boost/mpl/aux_/config/workaround.hpp>
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+#   include <boost/mpl/assert.hpp>
+#   define BOOST_MPL_AUX_ASSERT_NOT_NA(x) \
+    BOOST_MPL_ASSERT_NOT((is_na<type>)) \
+/**/
+#else
+#   include <boost/static_assert.hpp>
+#   define BOOST_MPL_AUX_ASSERT_NOT_NA(x) \
+    BOOST_STATIC_ASSERT(!is_na<x>::value) \
+/**/
+#endif
+
+#endif // BOOST_MPL_AUX_NA_ASSERT_HPP_INCLUDED
diff --git a/include/boost/mpl/aux_/preprocessed/bcc/arg.hpp b/include/boost/mpl/aux_/preprocessed/bcc/arg.hpp
index 7a7ebf4..9a766e7 100644
--- a/include/boost/mpl/aux_/preprocessed/bcc/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/bcc/arg.hpp
@@ -23,7 +23,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -40,7 +40,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -57,7 +57,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -74,7 +74,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -91,7 +91,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -108,7 +108,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/bcc551/arg.hpp b/include/boost/mpl/aux_/preprocessed/bcc551/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/bcc551/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/bcc551/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/dmc/arg.hpp b/include/boost/mpl/aux_/preprocessed/dmc/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/dmc/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/dmc/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/gcc/arg.hpp b/include/boost/mpl/aux_/preprocessed/gcc/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/gcc/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/gcc/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/msvc60/arg.hpp b/include/boost/mpl/aux_/preprocessed/msvc60/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/msvc60/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/msvc60/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/msvc70/arg.hpp b/include/boost/mpl/aux_/preprocessed/msvc70/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/msvc70/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/msvc70/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/mwcw/arg.hpp b/include/boost/mpl/aux_/preprocessed/mwcw/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/mwcw/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/mwcw/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/no_ctps/arg.hpp b/include/boost/mpl/aux_/preprocessed/no_ctps/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/no_ctps/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/no_ctps/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/no_ttp/arg.hpp b/include/boost/mpl/aux_/preprocessed/no_ttp/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/no_ttp/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/no_ttp/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
diff --git a/include/boost/mpl/aux_/preprocessed/plain/arg.hpp b/include/boost/mpl/aux_/preprocessed/plain/arg.hpp
index 6eaf95d..6f2f8a8 100644
--- a/include/boost/mpl/aux_/preprocessed/plain/arg.hpp
+++ b/include/boost/mpl/aux_/preprocessed/plain/arg.hpp
@@ -24,7 +24,7 @@ template<> struct arg< -1 >
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -42,7 +42,7 @@ template<> struct arg<1>
     struct apply
     {
         typedef U1 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -60,7 +60,7 @@ template<> struct arg<2>
     struct apply
     {
         typedef U2 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -78,7 +78,7 @@ template<> struct arg<3>
     struct apply
     {
         typedef U3 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -96,7 +96,7 @@ template<> struct arg<4>
     struct apply
     {
         typedef U4 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };
 
@@ -114,7 +114,7 @@ template<> struct arg<5>
     struct apply
     {
         typedef U5 type;
-        BOOST_MPL_ASSERT_NOT((is_na<type>));
+        BOOST_MPL_AUX_ASSERT_NOT_NA(type);
     };
 };