build panic: not a rvalue

[lifeRobot]

slint version: 1.6.0
rust version: 1.78.0
system: win11

build panic msg

slint code

export component DrawerCommon {
    in-out property <bool> show: false;
    in property <brush> background: white;

    callback clicked <=> touch.clicked;

    x: 0;
    y: 0;
    width: 50%;
    height: 50%;

    animate width,height,x,y {
         duration: 300ms;
    }

    @children

    // fix that triggers the click effect of covered layer components
    touch:= TouchArea {}
}

export component DrawerLeft inherits DrawerCommon {
    private property <length> logic_width;
    height: 100%;

    cont:= Rectangle {
        background: root.background;
        clip: true;

        animate width {
             duration: 300ms;
        }

        init => {
            logic_width = root.width;
            change_width();
        }

        @children
    }

    public function open() {
        change_show(true);
    }

    public function close() {
        change_show(false);
    }

    public function toggle() {
        change_show(!root.show);
    }

    public function change_show(show:bool) {
        root.show = show;
        change_width();
    }

    function change_width() {
        if root.show {
            root.width = logic_width;
            cont.width = logic_width;
            return;
        }

        root.width = 0;
        cont.width = 0;
    }
}

export component A { 
    dr:= DrawerLeft {
        width: 100px;
        height: 100px;
        background: red;
        Text {
            text: "hello world";
        }
    }

    public function open() {
        dr.open()
    }
}

export component App inherits Window {
    min-width: 300px;
    min-height: 300px;

    dr:= A {
        x:0;
        y:0;
    }
    /*dr:= DrawerLeft {
        width: 100px;
        height: 100px;
        background: red;
        Text {
            text: "hello world";
        }
    }*/

    init => {
        dr.open()
    }
}

Cargo.toml

slint-build = "1.6.0"
slint = "1.6.0"

other issue

1. If I use version 1.5.1 of slint, I can compile and run normally, just modify Cargo.toml to the following content

slint-build = "~1.5.1"
slint = "~1.5.1"

2. If I copy slint code into slintpad, slintpad will no longer have any feedback and will not display error messages

[ogoffart]

Thanks for the bug report.

I was able to reproduce with a minimal testcase:

export component DrawerLeft {
    private property <length> logic_width;
    rect := Rectangle {
        init => {
            logic_width = root.width;
        }
        @children
    }
}

export component A {
    hello := DrawerLeft { }
}

export component App inherits Window {
    world := A { }
}

From a first investigation, the problem is that the const_propagation::const_propagation pass introduces some Invalid expression in the init code. The init code is referencing property such as root.hello-width while at this point, it should be hello-3-width, so something went wrong in one of the compiler pass that had to move properties around.
I will have to investigate this further.