This is to track the regression introduced in master, which needs fixing for 0.14. See #9240, #9371, etc.
{
public:
    bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b)
    {
        return a.GetTime() < b.GetTime();
    }
};
class CompareTxMemPoolEntryByAncestorFee
{
public:
    bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b)
    {
        double aFees = a.GetModFeesWithAncestors();
        double aSize = a.GetSizeWithAncestors();
        double bFees = b.GetModFeesWithAncestors();
        double bSize = b.GetSizeWithAncestors();
        
        double f1 = aFees * bSize;
        double f2 = aSize * bFees;
        if (f1 == f2) {
            return a.GetTx().GetHash() < b.GetTx().GetHash();
        }
        return f1 > f2;
    }
};
struct descendant_score {};
struct entry_time {};
struct mining_score {};
struct ancestor_score {};
class CBlockPolicyEstimator;