The trait bound `&(): qt_core::connect::AsReceiver` is not satisfied

[ONiel]

Hello

I tried to bind a button to a slot following this example.
I'm getting one error I don't understand.

Code:

#![windows_subsystem = "windows"]

//Importing the required stuff
use cpp_core::{Ptr, Ref, StaticUpcast};
use qt_core::{qs, slot, ContextMenuPolicy, QBox, QObject, QPoint, SlotNoArgs, QString};
use qt_widgets::{
    QAction, QApplication, QLineEdit, QMenu, QMessageBox, QPushButton, QLabel, QTableWidget,
    QTableWidgetItem, QVBoxLayout, QWidget, SlotOfQPoint, SlotOfQTableWidgetItemQTableWidgetItem,
};
use std::rc::Rc;

//Struct for Main window
struct MainWindow {
    widget: QBox<QWidget>,
    button: QBox<QPushButton>,
}

//From form-struct to base-struct ??? 
impl StaticUpcast<QObject> for MainWindow {
    unsafe fn static_upcast(ptr: Ptr<Self>) -> Ptr<QObject> {
        ptr.widget.as_ptr().static_upcast()
    }
}

//Implementing functions for MainWindow
impl MainWindow {
    //Defining all the graphical elements in MainWindow
    //Returns the MainWindow in a Reference Counted Smart Pointer so it can have multiple owners
    //and doesn't get destroyed until it has no owners anymore
    fn new() -> Rc<MainWindow> {
        unsafe {
            //Widget
            let widget = QWidget::new_0a();
            let layout = QVBoxLayout::new_1a(&widget);

            //Label
            let label = QLabel::new();
            label.set_text(&qs("Fucking cool label!"));
            layout.add_widget(&label);

            //Button
            let button = QPushButton::from_q_string(&qs("Click me."));
            layout.add_widget(&button);

            let this = Rc::new(Self {
                widget,
                button,
            });
            this.init();
            this
        }
    }

    //Binding functions/slots to elements etc
    unsafe fn init(self: &Rc<Self>) {
        self.button
            .clicked()
            .connect(&self.test());
    }

    //Slots/Functions for buttons
    #[slot(SlotNoArgs)]
    unsafe fn test(self: &Rc<Self>) {
        println!("{}", "Test 123...");
    }
}

fn main() {
    QApplication::init(|_| unsafe {
        let _mw = MainWindow::new();
        QApplication::exec()
    })
}

Error

error[E0277]: the trait bound `&(): qt_core::connect::AsReceiver` is not satisfied
  --> src/main.rs:58:22
   |
58 |             .connect(&self.test());
   |                      ^^^^^^^^^^^^ the trait `qt_core::connect::AsReceiver` is not implemented for `&()`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
error: could not compile `qt_rs_3`.

I followed the example, so I don't see what I'm doing wrong.

Thanks.

[alice]

Notice that the functions used in the example have slot_ at the start of the name. I assume this is something related to that #[slot(SlotNoArgs)] attribute, and it generates an extra invisible function or something.

[ONiel]

This is correct. You define your functions without slot_ before it. But when you call them you put slot_ before the function.