GLib-GIO-CRITICAL **: g_application_quit: assertion 'G_IS_APPLICATION (application)' failed

g_signal_connect(app_window, "destroy", G_CALLBACK(g_application_quit), app);

g_signal_connect(app_window, "destroy", G_CALLBACK(g_application_quit), G_APPLICATION(app));

GtkApplication *app = gtk_application_new("my.ne.sweeper", G_APPLICATION_FLAGS_NONE);