diff --git a/src/basic/forward.h b/src/basic/forward.h
index 27d248ce9d..666a078eb2 100644
--- a/src/basic/forward.h
+++ b/src/basic/forward.h
@@ -254,6 +254,7 @@ typedef enum UserStorage UserStorage;
 
 typedef struct Bitmap Bitmap;
 typedef struct BPFProgram BPFProgram;
+typedef struct BusObjectImplementation BusObjectImplementation;
 typedef struct CalendarSpec CalendarSpec;
 typedef struct Condition Condition;
 typedef struct ConfigSection ConfigSection;