diff --git a/region.hpp b/region.hpp
index 3aa6ce10..81b6b759 100644
--- a/region.hpp
+++ b/region.hpp
@@ -30,6 +30,7 @@ namespace util {
      */
     template <typename T>
     struct region {
+        typedef T position_type;
         typedef typename always_unsigned<T>::type size_type;
 
         T x, y;