diff --git a/include/boost/iterator/advance.hpp b/include/boost/iterator/advance.hpp
index e23a244..81799dc 100644
--- a/include/boost/iterator/advance.hpp
+++ b/include/boost/iterator/advance.hpp
@@ -7,12 +7,12 @@
 #ifndef BOOST_ITERATOR_ADVANCE_HPP
 #define BOOST_ITERATOR_ADVANCE_HPP
 
+#include <type_traits>
+
 #include <boost/config.hpp>
 #include <boost/iterator/is_iterator.hpp>
 #include <boost/iterator/iterator_categories.hpp>
 
-#include <type_traits>
-
 namespace boost {
 namespace iterators {
 namespace detail {
@@ -59,8 +59,7 @@ inline BOOST_CXX14_CONSTEXPR void advance_impl(RandomAccessIterator& it, Distanc
 namespace advance_adl_barrier {
 
 template< typename InputIterator, typename Distance >
-inline BOOST_CXX14_CONSTEXPR
-typename std::enable_if< boost::is_iterator< InputIterator >::value, void >::type
+inline BOOST_CXX14_CONSTEXPR typename std::enable_if< is_iterator< InputIterator >::value >::type
 advance(InputIterator& it, Distance n)
 {
     detail::advance_impl(it, n, typename iterator_traversal< InputIterator >::type());
diff --git a/include/boost/iterator/distance.hpp b/include/boost/iterator/distance.hpp
index 6e4dac1..e24e10c 100644
--- a/include/boost/iterator/distance.hpp
+++ b/include/boost/iterator/distance.hpp
@@ -8,13 +8,13 @@
 #ifndef BOOST_ITERATOR_DISTANCE_HPP
 #define BOOST_ITERATOR_DISTANCE_HPP
 
+#include <type_traits>
+
 #include <boost/config.hpp>
 #include <boost/iterator/is_iterator.hpp>
 #include <boost/iterator/iterator_categories.hpp>
 #include <boost/iterator/iterator_traits.hpp>
 
-#include <type_traits>
-
 namespace boost {
 namespace iterators {
 namespace detail {
@@ -44,12 +44,10 @@ distance_impl(RandomAccessIterator first, RandomAccessIterator last, random_acce
 namespace distance_adl_barrier {
 
 template< typename SinglePassIterator >
-inline BOOST_CXX14_CONSTEXPR
-typename std::enable_if<
-    boost::is_iterator< SinglePassIterator >::value,
+inline BOOST_CXX14_CONSTEXPR typename std::enable_if<
+    is_iterator< SinglePassIterator >::value,
     iterator_difference< SinglePassIterator >
->::type::type
-distance(SinglePassIterator first, SinglePassIterator last)
+>::type::type distance(SinglePassIterator first, SinglePassIterator last)
 {
     return detail::distance_impl(first, last, typename iterator_traversal< SinglePassIterator >::type());
 }