presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/TransformCorrelatedInPredicateToJoin.java/DecorrelatingVisitor/isCorrelatedShallowly
class DecorrelatingVisitor:        private boolean isCorrelatedShallowly(PlanNode node)
        {
            return SymbolsExtractor.extractUniqueNonRecursive(node).stream().anyMatch(correlation::contains);
        }