Rust error "non-primitive cast" with a weird key-pressed handler

[elipsitz]

Adding the following code to a .slint (I just did the template and it repro'd)

    FocusScope {
        key-pressed(event) => {
            if (event.text == "a") {
                accept
            }
            reject
        }
    }

causes a Rust compilation error:

    --> .../slint-bug-1-f45ed77926121a04/out/appwindow.rs:2471:34
     |
2471 | / ...                    ({
2472 | | ...                        }
2473 | | ...                   ) as _ }
     | |____________________________^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object

For more information about this error, try `rustc --explain E0605`.
error: could not compile `slint-bug-1` (bin "slint-bug-1") due to 1 previous error

I'm using Slint 1.5.1 on macOS, with Rust.

This looks very similar to #3962

[tronical]

Oops, that looks like a bug to me. I can reproduce this. That said, I think there's also a bug in your code :-), which has the positive side-effect that it'll work around the bug and make it work as you probably expected:

    FocusScope {
        key-pressed(event) => {
            if (event.text == "a") {
                return accept; // <-- The return statement was missing here :-)
            }
            reject
        }
    }

[ogoffart]

We probably should make a warning for statement that don't do anything.

[ogoffart]

The rust compilation error is fixed. But opened #4954 to add a warning on useless statements