diff --git a/src/validation.cpp b/src/validation.cpp
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3146,15 +3146,12 @@
 
     // The resulting new best tip may not be in setBlockIndexCandidates anymore,
     // so add it again.
-    BlockMap::iterator it = mapBlockIndex.begin();
-    while (it != mapBlockIndex.end()) {
-        if (it->second->IsValid(BlockValidity::TRANSACTIONS) &&
-            it->second->nChainTx &&
-            !setBlockIndexCandidates.value_comp()(it->second,
-                                                  chainActive.Tip())) {
-            setBlockIndexCandidates.insert(it->second);
+    for (const std::pair<const uint256, CBlockIndex *> &it : mapBlockIndex) {
+        CBlockIndex *i = it.second;
+        if (i->IsValid(BlockValidity::TRANSACTIONS) && i->nChainTx &&
+            !setBlockIndexCandidates.value_comp()(i, chainActive.Tip())) {
+            setBlockIndexCandidates.insert(i);
         }
-        it++;
     }
 
     InvalidChainFound(pindex);