diff --git a/include/boost/fusion/container/vector/vector.hpp b/include/boost/fusion/container/vector/vector.hpp
index f22dc464..df306714 100644
--- a/include/boost/fusion/container/vector/vector.hpp
+++ b/include/boost/fusion/container/vector/vector.hpp
@@ -36,6 +36,7 @@
 #include <boost/core/enable_if.hpp>
 #include <boost/mpl/int.hpp>
 #include <boost/mpl/bool.hpp>
+#include <boost/type_traits/declval.hpp>
 #include <boost/type_traits/is_same.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 #include <boost/type_traits/remove_cv.hpp>
@@ -272,7 +273,7 @@ namespace boost { namespace fusion
 
             template <std::size_t N, typename U>
             static BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
-            U value_at_impl(store<N, U>*);
+            U value_at_impl(store<N, U>*) { return boost::declval<U>(); }
         };
 
         template <typename V, typename... T>
diff --git a/include/boost/fusion/view/detail/strictest_traversal.hpp b/include/boost/fusion/view/detail/strictest_traversal.hpp
index 9ad1f7aa..d1aa7883 100644
--- a/include/boost/fusion/view/detail/strictest_traversal.hpp
+++ b/include/boost/fusion/view/detail/strictest_traversal.hpp
@@ -17,6 +17,9 @@
 #include <boost/fusion/algorithm/iteration/fold.hpp>
 #include <boost/type_traits/remove_reference.hpp>
 #include <boost/type_traits/is_convertible.hpp>
+#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
+#include <boost/type_traits/declval.hpp>
+#endif
 
 namespace boost { namespace fusion
 {
@@ -61,7 +64,10 @@ namespace boost { namespace fusion
             template<typename StrictestSoFar, typename Next>
             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
             typename result<strictest_traversal_impl(StrictestSoFar, Next)>::type
-            operator()(StrictestSoFar&&, Next&&) const;
+            operator()(StrictestSoFar&&, Next&&) const
+            {
+                return boost::declval<typename result<strictest_traversal_impl(StrictestSoFar, Next)>::type>();
+            }
 #endif
         };