presto-main/src/main/java/io/prestosql/sql/planner/optimizations/ImplementIntersectAndExceptAsUnion.java/ImplementIntersectAndExceptAsUnion/project
class ImplementIntersectAndExceptAsUnion:        private ProjectNode project(PlanNode node, List<Symbol> columns)
        {
            return new ProjectNode(
                    idAllocator.getNextId(),
                    node,
                    Assignments.identity(columns));
        }