Help needed on EventControllerKey use

[philippe06150]

Hello, I'm stuck and need help

I try to understand EventControllerKey, so I wrote a test which works:

	let coucou = gtk::EventControllerKey::new();
	window.add_controller(coucou.clone());
	//
	// connects
	//
	coucou.connect_key_pressed( clone! ( move |_, key, _, _| {
		match key {
			// https://gtk-rs.org/gtk4-rs/stable/latest/docs/gdk4/struct.Key.html
			gdk::Key::Right => println!("Flèche droite"),
			gdk::Key::Left => println!("Flèche gauche"),
			gdk::Key::Up => println!("Flèche haute"),
			gdk::Key::Down => println!("Flèche basse"),
			gdk::Key::Return => println!("RETURN"),
			_ => {let a: String = key.name().unwrap().to_string(); println!("{}", a)},
		}
		glib::Propagation::Stop
	}));
	//

glib::clone! is already inserted because the next step is to add the window object, so the line is
coucou.connect_key_pressed( clone! ( #[weak] window, move |_, key, _, _| {
and then compil failed

   Compiling menu_drawing v0.1.0 (E:\RUST\menu_drawing)
error[E0069]: `return;` in a function whose return type is not `()`
  --> src\main.rs:66:30
   |
66 |       coucou.connect_key_pressed( clone! ( #[weak] window, move |_, key, _, _...
   |                                   ^
   - expected `` because of this return type
   |  _________________________________|
   | |
67 | |         match key {
68 | |             // https://gtk-rs.org/gtk4-rs/stable/latest/docs/gdk4/struct.Key.h...
69 | |             gdk::Key::Right => println!("Flèche droite"),
...  |
77 | |         glib::Propagation::Stop
78 | |     }));
   | |______^ return type is not `()`
   |
   = note: this error originates in the macro `clone` (in Nightly builds, run with -Z macro-backtrace for more info)
help: give the `return` a value of the expected type
   |
78 |     }) /* value */);
   |        +++++++++++

For more information about this error, try `rustc --explain E0069`.

I do not understand the mistake, if someone may explain ...