presto-main/src/main/java/io/prestosql/sql/planner/optimizations/DistinctOutputQueryUtil.java/DistinctOutputQueryUtil/visitFilter
class DistinctOutputQueryUtil:        @Override
        public Boolean visitFilter(FilterNode node, Void context)
        {
            return lookupFunction.apply(node.getSource()).accept(this, null);
        }