presto-main/src/main/java/io/prestosql/sql/planner/optimizations/UnaliasSymbolReferences.java/UnaliasSymbolReferences/visitEnforceSingleRow
class UnaliasSymbolReferences:        @Override
        public PlanNode visitEnforceSingleRow(EnforceSingleRowNode node, RewriteContext<Void> context)
        {
            PlanNode source = context.rewrite(node.getSource());

            return new EnforceSingleRowNode(node.getId(), source);
        }