我担心这可能是一个愚蠢的错误，但我没有看到它。下面的代码：

let key_handler = gtk::EventControllerKey::new();
controller.obj().add_controller(&key_handler);
key_handler.connect_key_pressed(clone!(@weak controller => move |_ctlr, key, _code, state| {
    controller.keyboard_input(key, state);
    gtk::Inhibit(false)
}));

不会编译。它会得到错误：

error[E0069]: `return;` in a function whose return type is not `()`
  --> src/controller/imp.rs:80:45
   |
80 |               key_handler.connect_key_pressed(clone!(@weak controller => move |_ctlr, key, _code, state| {
   |  _____________________________________________^
81 | |                 controller.keyboard_input(key, state);
82 | |                 gtk::Inhibit(false)
83 | |             }
84 | |             )
   | |_____________^ return type is not `()`
   |
   = note: this error originates in the macro `clone` (in Nightly builds, run with -Z macro-backtrace for more info)

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

我认为问题出在clone!扩展中，但我不确定。我是不是错过了一些简单的方法来修复这个问题，或者这不是使用clone的正确方法？就在它上面，我有

controller.start_buttonx.connect_clicked(clone!(@weak controller => move |xx| BOARDS[1].emit_by_name::<()>("test-signal", &[&x])));

看起来非常相似，这没有问题。