Invalid Code

[GtkTemplate (ui = "/org/example/gtktemplate.ui")]
public class GtkTemplateTest : Gtk.ApplicationWindow {
	[GtkChild]
	public unowned Gtk.Button button0;

	void foo () {
		bar (out button0);
	}

	void bar (out unowned Gtk.Button b) {
	}
}

void main () {
}