@Override
        public Type visitWildcardType(WildcardType t, Void s) {
            Type bound = high ? t.getExtendsBound() :
                                t.getSuperBound();
            if (bound == null)
            bound = high ? syms.objectType : syms.botType;
            return rewriteAsWildcardType(visit(bound), t.bound);
        }