presto-main/src/main/java/io/prestosql/sql/planner/RelationPlanner.java/RelationPlanner/translationMapFromSourceOutputs
class RelationPlanner:    private TranslationMap translationMapFromSourceOutputs(List<Symbol> sourceOutputs, Node node, List<Symbol> outputSymbols)
    {
        PlanNode dummy = new ValuesNode(
                idAllocator.getNextId(),
                ImmutableList.copyOf(requireNonNull(sourceOutputs, "sourceOutputs is null")),
                ImmutableList.of());

        RelationPlan dummyRelationPlan = new RelationPlan(dummy, analysis.getScope(node), outputSymbols);
        return new TranslationMap(dummyRelationPlan, analysis, lambdaDeclarationToSymbolMap);
    }