presto-main/src/main/java/io/prestosql/sql/planner/optimizations/PruneUnreferencedOutputs.java/PruneUnreferencedOutputs/visitAssignUniqueId
class PruneUnreferencedOutputs:        @Override
        public PlanNode visitAssignUniqueId(AssignUniqueId node, RewriteContext<Set<Symbol>> context)
        {
            if (!context.get().contains(node.getIdColumn())) {
                return context.rewrite(node.getSource(), context.get());
            }
            return context.defaultRewrite(node, context.get());
        }