diff --git a/src/decoder.js b/src/decoder.js
index 491dd3059..f55451f25 100644
--- a/src/decoder.js
+++ b/src/decoder.js
@@ -33,7 +33,7 @@ function decoder(mtype) {
         var field = mtype._fieldsArray[i].resolve(),
             type  = field.resolvedType instanceof Enum ? "int32" : field.type,
             ref   = "m" + util.safeProp(field.name); gen
-            ("case %i:", field.id);
+            ("case %i: {", field.id);
 
         // Map fields
         if (field.map) { gen
@@ -104,8 +104,9 @@ function decoder(mtype) {
         else gen
                 ("%s=r.%s()", ref, type);
         gen
-                ("break");
-    // Unknown fields
+                ("break")
+            ("}");
+        // Unknown fields
     } gen
             ("default:")
                 ("r.skipType(t&7)")