presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/LambdaCaptureDesugaringRewriter.java/LambdaCaptureDesugaringRewriter/getReferencedSymbols
class LambdaCaptureDesugaringRewriter:        public LinkedHashSet<Symbol> getReferencedSymbols()
        {
            return referencedSymbols;
        }