presto-main/src/main/java/io/prestosql/sql/planner/optimizations/HashGenerationOptimizer.java/HashGenerationOptimizer/equals
class HashGenerationOptimizer:        @Override
        public boolean equals(Object o)
        {
            if (this == o) {
                return true;
            }
            if (o == null || getClass() != o.getClass()) {
                return false;
            }
            HashComputation that = (HashComputation) o;
            return Objects.equals(fields, that.fields);
        }