This is to track the regression introduced in master, which needs fixing for 0.14. See #9240, #9371, etc.
{
private:
    std::vector<CTransactionRef> conflictedTxs;
    CTxMemPool &pool;
public:
    MemPoolConflictRemovalTracker(CTxMemPool &_pool) : pool(_pool) {
        pool.NotifyEntryRemoved.connect(boost::bind(&MemPoolConflictRemovalTracker::NotifyEntryRemoved, this, _1, _2));
    }
    void NotifyEntryRemoved(CTransactionRef txRemoved, MemPoolRemovalReason reason) {
        if (reason == MemPoolRemovalReason::CONFLICT) {
            conflictedTxs.push_back(txRemoved);
        }
    }
    ~MemPoolConflictRemovalTracker() {