diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index c37faf49f0..4bee13a7bf 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -50,6 +50,7 @@ struct IteratorComparator
 };
 
 struct COrphanTx {
+    // When modifying, adapt the copy of this definition in tests/DoS_tests.
     CTransaction tx;
     NodeId fromPeer;
     int64_t nTimeExpire;
diff --git a/src/test/DoS_tests.cpp b/src/test/DoS_tests.cpp
index 1a818a5756..a8c3c4ebb9 100644
--- a/src/test/DoS_tests.cpp
+++ b/src/test/DoS_tests.cpp
@@ -29,6 +29,7 @@ extern unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans);
 struct COrphanTx {
     CTransaction tx;
     NodeId fromPeer;
+    int64_t nTimeExpire;
 };
 extern std::map<uint256, COrphanTx> mapOrphanTransactions;
 extern std::map<uint256, std::set<uint256> > mapOrphanTransactionsByPrev;