presto-main/src/main/java/io/prestosql/sql/planner/optimizations/UnaliasSymbolReferences.java/Rewriter/visitDistinctLimit
class Rewriter:        @Override
        public PlanNode visitDistinctLimit(DistinctLimitNode node, RewriteContext<Void> context)
        {
            return new DistinctLimitNode(node.getId(), context.rewrite(node.getSource()), node.getLimit(), node.isPartial(), canonicalizeAndDistinct(node.getDistinctSymbols()), canonicalize(node.getHashSymbol()));
        }