presto-main/src/main/java/io/prestosql/sql/planner/optimizations/PlanNodeDecorrelator.java/PlanNodeDecorrelator/getCorrelatedPredicates
class PlanNodeDecorrelator:        public Optional<Expression> getCorrelatedPredicates()
        {
            if (correlatedPredicates.isEmpty()) {
                return Optional.empty();
            }
            return Optional.of(ExpressionUtils.and(correlatedPredicates));
        }