diff --git a/src/txmempool.cpp b/src/txmempool.cpp
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -780,7 +780,7 @@
         // Check children against mapNextTx
         CTxMemPool::setEntries setChildrenCheck;
         auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetId(), 0));
-        int64_t childSizes = 0;
+        uint64_t child_sizes = 0;
         for (; iter != mapNextTx.end() &&
                iter->first->GetTxId() == it->GetTx().GetId();
              ++iter) {
@@ -788,14 +788,14 @@
             // mapNextTx points to in-mempool transactions
             assert(childit != mapTx.end());
             if (setChildrenCheck.insert(childit).second) {
-                childSizes += childit->GetTxSize();
+                child_sizes += childit->GetTxSize();
             }
         }
         assert(setChildrenCheck == GetMemPoolChildren(it));
         // Also check to make sure size is greater than sum with immediate
         // children. Just a sanity check, not definitive that this calc is
         // correct...
-        assert(it->GetSizeWithDescendants() >= childSizes + it->GetTxSize());
+        assert(it->GetSizeWithDescendants() >= child_sizes + it->GetTxSize());
 
         if (fDependsWait) {
             waitingOnDependants.push_back(&(*it));