--- a/src/parallel_execution/Stack.cbc	Wed Jun 07 15:17:36 2017 +0900
+++ b/src/parallel_execution/Stack.cbc	Thu Jun 08 15:44:39 2017 +0900
@@ -1,14 +1,14 @@
-typedef struct Stack<Impl>{
-        union Data* stack;
-        union Data* data;
-        union Data* data1;
+typedef struct Stack<Type, Impl>{
+        Type* stack;
+        Type* data;
+        Type* data1;
         __code whenEmpty(...);
         __code clear(Impl* stack,__code next(...));
-        __code push(Impl* stack,union Data* data, __code next(...));
-        __code pop(Impl* stack, __code next(union Data*, ...));
-        __code pop2(Impl* stack, union Data** data, union Data** data1, __code next(union Data**, union Data**, ...));
+        __code push(Impl* stack,Type* data, __code next(...));
+        __code pop(Impl* stack, __code next(Type* data, ...));
+        __code pop2(Impl* stack, Type** data, Type** data1, __code next(Type** data, Type** data1, ...));
         __code isEmpty(Impl* stack, __code next(...), __code whenEmpty(...));
-        __code get(Impl* stack, union Data** data, __code next(...));
+        __code get(Impl* stack, Type** data, __code next(...));
         __code get2(Impl* stack,..., __code next(...));
         __code next(...);
 } Stack;