Use boost::enable_if_has_type instead.

include/boost/fusion/functional/invocation/invoke.hpp

@@ -39,9 +39,9 @@
 #include <boost/function_types/parameter_types.hpp>
 
 #include <boost/utility/result_of.hpp>
+#include <boost/core/enable_if.hpp>
 
 #include <boost/fusion/support/category_of.hpp>
-#include <boost/fusion/support/detail/enabler.hpp>
 #include <boost/fusion/sequence/intrinsic/at.hpp>
 #include <boost/fusion/sequence/intrinsic/size.hpp>
 #include <boost/fusion/sequence/intrinsic/front.hpp>
@@ -148,7 +148,7 @@ namespace boost { namespace fusion
 
         template <typename Function, class Sequence>
         struct invoke<Function, Sequence,
-                      typename detail::enabler<
+                      typename enable_if_has_type<
                           typename detail::invoke_impl<
                               typename boost::remove_reference<Function>::type, Sequence
                           >::result_type
@@ -195,7 +195,7 @@ namespace boost { namespace fusion
 
         template <typename Function, class Sequence>
         struct invoke_impl<Function,Sequence,N,false,true,
-            typename enabler<
+            typename enable_if_has_type<
                 typename boost::result_of<Function(BOOST_PP_ENUM(N,M,~)) >::type
               >::type>
         {
@@ -289,7 +289,7 @@ namespace boost { namespace fusion
 
         template <typename Function, class Sequence>
         struct invoke_impl<Function,Sequence,N,false,false,
-            typename enabler<
+            typename enable_if_has_type<
 #define L(z,j,data) typename invoke_param_types<Sequence,N>::BOOST_PP_CAT(T, j)
                 typename boost::result_of<Function(BOOST_PP_ENUM(N,L,~))>::type
               >::type>

include/boost/fusion/functional/invocation/invoke_function_object.hpp

@@ -18,14 +18,12 @@
 #include <boost/preprocessor/repetition/enum_params.hpp>
 
 #include <boost/utility/result_of.hpp>
+#include <boost/core/enable_if.hpp>
 
 #include <boost/type_traits/remove_reference.hpp>
 #include <boost/type_traits/remove_const.hpp>
 
-#include <boost/utility/result_of.hpp>
-
 #include <boost/fusion/support/category_of.hpp>
-#include <boost/fusion/support/detail/enabler.hpp>
 #include <boost/fusion/sequence/intrinsic/size.hpp>
 #include <boost/fusion/sequence/intrinsic/at.hpp>
 #include <boost/fusion/sequence/intrinsic/begin.hpp>
@@ -62,7 +60,7 @@ namespace boost { namespace fusion
 
         template <class Function, class Sequence>
         struct invoke_function_object<Function, Sequence,
-            typename detail::enabler<
+            typename enable_if_has_type<
                 typename detail::invoke_function_object_impl<
                     typename boost::remove_reference<Function>::type, Sequence
                 >::result_type
@@ -110,7 +108,7 @@ namespace boost { namespace fusion
 
         template <class Function, class Sequence>
         struct invoke_function_object_impl<Function,Sequence,N,true,
-            typename enabler<
+            typename enable_if_has_type<
                 typename boost::result_of<Function (BOOST_PP_ENUM(N,M,~)) >::type
             >::type>
         {
@@ -151,7 +149,7 @@ namespace boost { namespace fusion
 
         template <class Function, class Sequence>
         struct invoke_function_object_impl<Function,Sequence,N,false,
-            typename enabler<
+            typename enable_if_has_type<
                 typename boost::result_of<Function (BOOST_PP_ENUM(N,M,~)) >::type
             >::type>
 #undef M

include/boost/fusion/functional/invocation/invoke_procedure.hpp

@@ -20,6 +20,7 @@
 #include <boost/preprocessor/repetition/enum_shifted_params.hpp>
 
 #include <boost/type_traits/remove_reference.hpp>
+#include <boost/core/enable_if.hpp>
 
 #include <boost/mpl/front.hpp>
 
@@ -28,7 +29,6 @@
 #include <boost/function_types/parameter_types.hpp>
 
 #include <boost/fusion/support/category_of.hpp>
-#include <boost/fusion/support/detail/enabler.hpp>
 #include <boost/fusion/sequence/intrinsic/at.hpp>
 #include <boost/fusion/sequence/intrinsic/size.hpp>
 #include <boost/fusion/sequence/intrinsic/begin.hpp>
@@ -66,7 +66,7 @@ namespace boost { namespace fusion
 
         template <typename Function, class Sequence>
         struct invoke_procedure<Function, Sequence,
-            typename detail::enabler<
+            typename enable_if_has_type<
                 typename detail::invoke_procedure_impl<
                     typename boost::remove_reference<Function>::type,Sequence
                 >::result_type

include/boost/fusion/support/detail/enabler.hpp

@@ -1,18 +0,0 @@
-/*=============================================================================
-    Copyright (c) 2015 Kohei Takahashi
-
-    Use modification and distribution are subject to 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).
-==============================================================================*/
-#ifndef FUSION_DETAIL_ENABLER_02082015_163810
-#define FUSION_DETAIL_ENABLER_02082015_163810
-
-namespace boost { namespace fusion { namespace detail
-{
-    template <typename, typename T = void>
-    struct enabler { typedef T type; };
-}}}
-
-#endif
-

test/compile_time/sfinae_friendly.hpp

@@ -13,6 +13,7 @@
 #include <boost/mpl/bool.hpp>
 #include <boost/mpl/assert.hpp>
 #include <boost/utility/result_of.hpp>
+#include <boost/core/enable_if.hpp>
 
 #if !defined(BOOST_NO_SFINAE) && defined(BOOST_RESULT_OF_USE_DECLTYPE)
 
@@ -20,8 +21,6 @@
 
 namespace sfinae_friendly
 {
-    template <typename, typename T = void> struct void_ { typedef T type; };
-
     template <typename> struct arg_;
     template <typename R, typename T> struct arg_<R(T)> { typedef T type; };
 
@@ -30,7 +29,7 @@ namespace sfinae_friendly
         : boost::mpl::true_ { };
 
     template <typename Traits>
-    struct check<Traits, typename void_<typename Traits::type>::type>
+    struct check<Traits, typename boost::enable_if_has_type<typename Traits::type>::type>
         : boost::mpl::false_ { };
 
     struct unspecified {};