diff --git a/quic/quartc/quartc_fakes.h b/quic/quartc/quartc_fakes.h
index abf2a43..be45400 100644
--- a/quic/quartc/quartc_fakes.h
+++ b/quic/quartc/quartc_fakes.h
@@ -63,12 +63,13 @@
     sent_datagram_ids_.push_back(datagram_id);
   }
 
-  void OnMessageAcked(int64_t datagram_id, QuicTime receive_timestamp) {
+  void OnMessageAcked(int64_t datagram_id,
+                      QuicTime receive_timestamp) override {
     acked_datagram_id_to_receive_timestamp_.emplace(datagram_id,
                                                     receive_timestamp);
   }
 
-  void OnMessageLost(int64_t datagram_id) {
+  void OnMessageLost(int64_t datagram_id) override {
     lost_datagram_ids_.push_back(datagram_id);
   }