diff --git a/include/boost/fusion/support/tag_of.hpp b/include/boost/fusion/support/tag_of.hpp
index a8e2ed07..cba06067 100644
--- a/include/boost/fusion/support/tag_of.hpp
+++ b/include/boost/fusion/support/tag_of.hpp
@@ -46,39 +46,6 @@ namespace boost { namespace fusion
     namespace detail
     {
         BOOST_MPL_HAS_XXX_TRAIT_DEF(fusion_tag)
-
-        template<typename Sequence>
-        struct is_specialized
-          : mpl::false_
-        {};
-
-        template <
-            class T0, class T1, class T2, class T3, class T4,
-            class T5, class T6, class T7, class T8, class T9
-        >
-        struct is_specialized<tuples::tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> >
-          : mpl::true_
-        {};
-
-        template <class Head, class Tail>
-        struct is_specialized<tuples::cons<Head, Tail> >
-          : mpl::true_
-        {};
-
-        template <>
-        struct is_specialized<tuples::null_type>
-          : mpl::true_
-        {};
-
-        template <typename T, std::size_t N>
-        struct is_specialized<boost::array<T, N> >
-          : mpl::true_
-        {};
-
-        template<typename T1, typename T2>
-        struct is_specialized<std::pair<T1, T2> >
-          : mpl::true_
-        {};
     }
 
     namespace traits
@@ -88,9 +55,7 @@ namespace boost { namespace fusion
           : mpl::if_< fusion::detail::is_mpl_sequence<Sequence>,
               mpl::identity<mpl_sequence_tag>,
               mpl::identity<non_fusion_tag> >::type
-        {
-            BOOST_MPL_ASSERT_NOT((fusion::detail::is_specialized<Sequence>));
-        };
+        {};
 
         template <typename Sequence>
         struct tag_of<Sequence, typename boost::enable_if<detail::has_fusion_tag<Sequence> >::type>