presto-main/src/main/java/io/prestosql/sql/planner/optimizations/OptimizeMixedDistinctAggregations.java/AggregateInfo/getNewDistinctAggregateSymbol
class AggregateInfo:        public Symbol getNewDistinctAggregateSymbol()
        {
            return newDistinctAggregateSymbol;
        }