diff --git a/point.hpp b/point.hpp
index c6e6e165..5b21aba6 100644
--- a/point.hpp
+++ b/point.hpp
@@ -45,13 +45,13 @@ namespace util {
 
     // distance operators
     template <size_t S, typename T, typename U>
-    constexpr typename std::common_type<T,U>::type distance  (point<S,T>, point<S,U>);
+    typename std::common_type<T,U>::type distance  (point<S,T>, point<S,U>);
 
     template <size_t S, typename T, typename U>
     constexpr typename std::common_type<T,U>::type distance2 (point<S,T>, point<S,U>);
 
-    template <size_t S, typename T, typename U>
-    constexpr typename std::common_type<T,U>::type octile (point<S,T>, point<S,U>);
+    template <typename T, typename U>
+    typename std::common_type<T,U>::type octile (point<2,T>, point<2,U>);
 
     template <size_t S, typename T, typename U>
     constexpr typename std::common_type<T,U>::type manhattan (point<S,T>, point<S,U>);
diff --git a/point.ipp b/point.ipp
index e816c9c9..119e150b 100644
--- a/point.ipp
+++ b/point.ipp
@@ -48,7 +48,7 @@ namespace util {
 
     //-------------------------------------------------------------------------
     template <size_t S, typename T, typename U>
-    constexpr typename std::common_type<T,U>::type
+    typename std::common_type<T,U>::type
     distance (point<S,T> a, point<S,U> b)
     {
         using type_t = typename std::common_type<T,U>::type;
@@ -74,9 +74,9 @@ namespace util {
 
 
     //-------------------------------------------------------------------------
-    template <size_t S, typename T, typename U>
-    constexpr typename std::common_type<T,U>::type
-    octile (point<S,T> a, point<S,U> b)
+    template <typename T, typename U>
+    typename std::common_type<T,U>::type
+    octile (point2<T> a, point2<U> b)
     {
         using type_t = typename std::common_type<T,U>::type;
         static_assert (!std::is_integral<type_t>::value,