diff --git a/region.cpp b/region.cpp
index e01dd215..9472e91d 100644
--- a/region.cpp
+++ b/region.cpp
@@ -103,9 +103,9 @@ util::region<S,T>::magnitude (extent_t _e)
 //-----------------------------------------------------------------------------
 template <size_t S, typename T>
 void
-util::region<S,T>::scale (T factor)
+util::region<S,T>::scale (size_type factor)
 {
-    auto o = (e * factor - e) / T{2};
+    auto o = (e * factor - e) / T(2);
     p -= o;
     e *= factor;
 }
diff --git a/region.hpp b/region.hpp
index 483357a4..12792f34 100644
--- a/region.hpp
+++ b/region.hpp
@@ -77,7 +77,7 @@ namespace util {
         extent_t magnitude (void) const;
         extent_t magnitude (extent_t);
 
-        void scale (T factor);
+        void scale (size_type factor);
 
         bool empty (void) const;