diff --git a/src/solidity/types/Mapping.js b/src/solidity/types/Mapping.js
index 66a848fefb..73d606d7c9 100644
--- a/src/solidity/types/Mapping.js
+++ b/src/solidity/types/Mapping.js
@@ -3,7 +3,7 @@ var RefType = require('./RefType')
 
 class Mapping extends RefType {
   constructor () {
-    super(1, 32, 'mapping')
+    super(1, 32, 'mapping', 'storage')
   }
 
   decodeFromStorage (location, storageContent) {