diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 0f6711aefe..a70c980948 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -30,6 +30,58 @@
 #include <cmath>
 #include <optional>
 
+// Helpers for modifying CTxMemPool::mapTx, which is a boost multi_index.
+struct update_descendant_state
+{
+    update_descendant_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount) :
+        modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount)
+    {}
+
+    void operator() (CTxMemPoolEntry &e)
+        { e.UpdateDescendantState(modifySize, modifyFee, modifyCount); }
+
+    private:
+        int64_t modifySize;
+        CAmount modifyFee;
+        int64_t modifyCount;
+};
+
+struct update_ancestor_state
+{
+    update_ancestor_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount, int64_t _modifySigOpsCost) :
+        modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount), modifySigOpsCost(_modifySigOpsCost)
+    {}
+
+    void operator() (CTxMemPoolEntry &e)
+        { e.UpdateAncestorState(modifySize, modifyFee, modifyCount, modifySigOpsCost); }
+
+    private:
+        int64_t modifySize;
+        CAmount modifyFee;
+        int64_t modifyCount;
+        int64_t modifySigOpsCost;
+};
+
+struct update_fee_delta
+{
+    explicit update_fee_delta(int64_t _feeDelta) : feeDelta(_feeDelta) { }
+
+    void operator() (CTxMemPoolEntry &e) { e.UpdateFeeDelta(feeDelta); }
+
+private:
+    int64_t feeDelta;
+};
+
+struct update_lock_points
+{
+    explicit update_lock_points(const LockPoints& _lp) : lp(_lp) { }
+
+    void operator() (CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
+
+private:
+    const LockPoints& lp;
+};
+
 CTxMemPoolEntry::CTxMemPoolEntry(const CTransactionRef& tx, CAmount fee,
                                  int64_t time, unsigned int entry_height,
                                  bool spends_coinbase, int64_t sigops_count, LockPoints lp)
@@ -285,7 +337,7 @@ bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry,
 
 void CTxMemPool::UpdateAncestorsOf(bool add, txiter it, setEntries &setAncestors)
 {
-    CTxMemPoolEntry::Parents parents = it->GetMemPoolParents();
+    const CTxMemPoolEntry::Parents& parents = it->GetMemPoolParentsConst();
     // add or remove this tx as a child of each parent
     for (const CTxMemPoolEntry& parent : parents) {
         UpdateChild(mapTx.iterator_to(parent), it, add);
diff --git a/src/txmempool.h b/src/txmempool.h
index 5193856924..dda669f576 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -171,58 +171,6 @@ public:
     mutable Epoch::Marker m_epoch_marker; //!< epoch when last touched, useful for graph algorithms
 };
 
-// Helpers for modifying CTxMemPool::mapTx, which is a boost multi_index.
-struct update_descendant_state
-{
-    update_descendant_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount) :
-        modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount)
-    {}
-
-    void operator() (CTxMemPoolEntry &e)
-        { e.UpdateDescendantState(modifySize, modifyFee, modifyCount); }
-
-    private:
-        int64_t modifySize;
-        CAmount modifyFee;
-        int64_t modifyCount;
-};
-
-struct update_ancestor_state
-{
-    update_ancestor_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount, int _modifySigOps) :
-        modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount), modifySigOps(_modifySigOps)
-    {}
-
-    void operator() (CTxMemPoolEntry &e)
-        { e.UpdateAncestorState(modifySize, modifyFee, modifyCount, modifySigOps); }
-
-    private:
-        int64_t modifySize;
-        CAmount modifyFee;
-        int64_t modifyCount;
-        int modifySigOps;
-};
-
-struct update_fee_delta
-{
-    explicit update_fee_delta(int64_t _feeDelta) : feeDelta(_feeDelta) { }
-
-    void operator() (CTxMemPoolEntry &e) { e.UpdateFeeDelta(feeDelta); }
-
-private:
-    int64_t feeDelta;
-};
-
-struct update_lock_points
-{
-    explicit update_lock_points(const LockPoints& _lp) : lp(_lp) { }
-
-    void operator() (CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
-
-private:
-    const LockPoints& lp;
-};
-
 // extracts a transaction hash from CTxMemPoolEntry or CTransactionRef
 struct mempoolentry_txid
 {