diff --git a/runtime/primitive.h b/runtime/primitive.h
index ca42c47..2454a21 100644
--- a/runtime/primitive.h
+++ b/runtime/primitive.h
@@ -46,6 +46,7 @@
     kPrimFloat,
     kPrimDouble,
     kPrimVoid,
+    kPrimLast = kPrimVoid
   };
 
   static Type GetType(char type) {