static bool isSameReType(TypeNode tta, TypeNode ttb)
        {
            HashedMap mHashMap = Microsoft.SpecSharp.Looker.mHashedMap;
            TypeNode ta = mHashMap.Contains(tta.ToString()) ? (TypeNode)mHashMap[tta.ToString()] : tta;
            TypeNode tb = mHashMap.Contains(ttb.ToString()) ? (TypeNode)mHashMap[ttb.ToString()] : ttb;

            if (ta.Equals(tb))
                return true;
            if (ta.IsDerivedFrom(tb) || tb.IsDerivedFrom(ta))
                return true;
            return false;
        }