diff --git a/src/evdev-middle-button.c b/src/evdev-middle-button.c
index 78a19ef8..9ef4b27a 100644
--- a/src/evdev-middle-button.c
+++ b/src/evdev-middle-button.c
@@ -497,7 +497,7 @@ evdev_middlebutton_handle_event(struct evdev_device *device,
 				uint64_t time,
 				enum evdev_middlebutton_event event)
 {
-	int rc;
+	int rc = 0;
 	enum evdev_middlebutton_state current;
 
 	current = device->middlebutton.state;
@@ -545,6 +545,11 @@ evdev_middlebutton_handle_event(struct evdev_device *device,
 							      time,
 							      event);
 		break;
+	default:
+		evdev_log_bug_libinput(device,
+				       "Invalid middle button state %d\n",
+				       current);
+		break;
 	}
 
 	evdev_log_debug(device,