diff --git a/gms/failure_detector.cc b/gms/failure_detector.cc
index 0eff6a264a..3399816fa2 100644
--- a/gms/failure_detector.cc
+++ b/gms/failure_detector.cc
@@ -20,6 +20,12 @@
  */
 
 #include "gms/failure_detector.hh"
+#include "gms/gossiper.hh"
+#include "gms/i_failure_detector.hh"
+#include "gms/i_failure_detection_event_listener.hh"
+#include "gms/endpoint_state.hh"
+#include "gms/application_state.hh"
+#include "gms/inet_address.hh"
 #include <iostream>
 
 namespace gms {
diff --git a/gms/failure_detector.hh b/gms/failure_detector.hh
index 2f19a61c25..580a3d050b 100644
--- a/gms/failure_detector.hh
+++ b/gms/failure_detector.hh
@@ -23,21 +23,20 @@
 
 #include "unimplemented.hh"
 #include "db_clock.hh"
-#include "gms/inet_address.hh"
-#include "gms/i_failure_detector.hh"
-#include "gms/application_state.hh"
-#include "gms/endpoint_state.hh"
 #include "core/sstring.hh"
 #include "core/shared_ptr.hh"
 #include "core/distributed.hh"
-#include "gms/gossiper.hh"
 #include "utils/bounded_stats_deque.hh"
+#include "gms/i_failure_detector.hh"
 #include <iostream>
 #include <cmath>
 #include <list>
 #include <map>
 
 namespace gms {
+class inet_address;
+class i_failure_detection_event_listener;
+class endpoint_state;
 
 class failure_detector_helper {
 public: