presto-main/src/main/java/io/prestosql/sql/planner/sanity/NoDuplicatePlanNodeIdsChecker.java/NoDuplicatePlanNodeIdsChecker/reportDuplicateId
class NoDuplicatePlanNodeIdsChecker:    private PlanNode reportDuplicateId(PlanNode first, PlanNode second)
    {
        requireNonNull(first, "first is null");
        requireNonNull(second, "second is null");
        checkArgument(first.getId().equals(second.getId()));

        throw new IllegalStateException(format(
                "Generated plan contains nodes with duplicated id %s: %s and %s",
                first.getId(),
                first,
                second));
    }