diff --git a/src/msgpack/object.hpp b/src/msgpack/object.hpp
index 97c8d4aa..76fe4cae 100644
--- a/src/msgpack/object.hpp
+++ b/src/msgpack/object.hpp
@@ -212,11 +212,20 @@ inline T& operator>> (object o, T& v)
 	return v;
 }
 
+namespace detail {
+template <typename Stream, typename T>
+struct packer_serializer {
+	static packer<Stream>& pack(packer<Stream>& o, const T& v) {
+		v.msgpack_pack(o);
+		return o;
+	}
+};
+}
+
 template <typename Stream, typename T>
 inline packer<Stream>& operator<< (packer<Stream>& o, const T& v)
 {
-	v.msgpack_pack(o);
-	return o;
+	return detail::packer_serializer<Stream, T>::pack(o, v);
 }
 
 template <typename T>
diff --git a/src/msgpack/type/define.hpp.erb b/src/msgpack/type/define.hpp.erb
index c8a86512..0e0cea04 100644
--- a/src/msgpack/type/define.hpp.erb
+++ b/src/msgpack/type/define.hpp.erb
@@ -48,8 +48,15 @@
     template <> \
     void operator<< (object::with_zone& o, const enum& v) \
     { \
-      int tmp = static_cast<enum>(v); \
-      o << tmp; \
+      o << static_cast<int>(v); \
+    } \
+    namespace detail { \
+      template <typename Stream> \
+      struct packer_serializer<Stream, enum> { \
+        static packer<Stream>& pack(packer<Stream>& o, const enum& v) { \
+          return o << static_cast<int>(v); \
+        } \
+      }; \
     } \
   }