Index: boost/function_types/function_arity.hpp
===================================================================
--- boost/function_types/function_arity.hpp	(revision 84534)
+++ boost/function_types/function_arity.hpp	(working copy)
@@ -9,7 +9,6 @@
 #ifndef BOOST_FT_FUNCTION_ARITY_HPP_INCLUDED
 #define BOOST_FT_FUNCTION_ARITY_HPP_INCLUDED
 
-#include <boost/blank.hpp>
 #include <boost/mpl/if.hpp>
 
 #include <boost/mpl/aux_/lambda_support.hpp>
@@ -25,7 +24,8 @@
     template<typename T> struct function_arity
       : mpl::if_
         < function_types::is_callable_builtin<T>
-        , typename components<T>::function_arity, boost::blank
+        , typename components<T>::function_arity
+        , struct not_a_callable_builtin
         >::type
     {
       BOOST_MPL_AUX_LAMBDA_SUPPORT(1,function_arity,(T)) 
Index: boost/function_types/parameter_types.hpp
===================================================================
--- boost/function_types/parameter_types.hpp	(revision 84534)
+++ boost/function_types/parameter_types.hpp	(working copy)
@@ -9,7 +9,6 @@
 #ifndef BOOST_FT_PARAMETER_TYPES_HPP_INCLUDED
 #define BOOST_FT_PARAMETER_TYPES_HPP_INCLUDED
 
-#include <boost/blank.hpp>
 #include <boost/mpl/if.hpp>
 
 #include <boost/mpl/aux_/lambda_support.hpp>
@@ -42,7 +41,8 @@
     template<typename T, typename ClassTypeTransform> struct parameter_types
       : mpl::if_
         < function_types::is_callable_builtin<T>
-        , detail::parameter_types_impl<T,ClassTypeTransform>, boost::blank
+        , detail::parameter_types_impl<T,ClassTypeTransform>
+        , struct not_a_callable_builtin
         >::type
     {
       BOOST_MPL_AUX_LAMBDA_SUPPORT(2,parameter_types,(T,ClassTypeTransform)) 
Index: boost/function_types/result_type.hpp
===================================================================
--- boost/function_types/result_type.hpp	(revision 84534)
+++ boost/function_types/result_type.hpp	(working copy)
@@ -9,8 +9,8 @@
 #ifndef BOOST_FT_RESULT_TYPE_HPP_INCLUDED
 #define BOOST_FT_RESULT_TYPE_HPP_INCLUDED
 
-#include <boost/blank.hpp>
 #include <boost/mpl/if.hpp>
+#include <boost/mpl/void.hpp>
 
 #include <boost/mpl/aux_/lambda_support.hpp>
 #include <boost/type_traits/detail/template_arity_spec.hpp>
@@ -37,7 +37,7 @@
     template<typename T> struct result_type
       : mpl::if_
         < function_types::is_callable_builtin<T>
-        , detail::result_type_impl<T>, boost::blank
+        , detail::result_type_impl<T>, struct not_a_callable_builtin
         >::type
     { 
       BOOST_MPL_AUX_LAMBDA_SUPPORT(1,result_type,(T))