SubElements := Rectangle {
    signal foobar;

    TouchArea {
        clicked => { foobar() }
    }

    TouchArea {
        clicked: 45;
//      ^error{'clicked' is a signal. Use `=>` to connect}
        x => {}
//      ^error{'x' is not a signal in TouchArea}
    }

    TouchArea {
        clicked => { foobar() }
        clicked => { foobar() }
//      ^error{Duplicated signal}
    }


}