type DropProbe {
    marker: MutSpan<u8>,
    fn drop(self: mutref<Self>) -> Void {
        self.marker[0] = 1
    }
}

fn maybe_fail(should_fail: Bool, marker: MutSpan<u8>) -> i32 raises [BadInput] {
    let probe: owned<DropProbe> = DropProbe { marker: marker }
    if should_fail {
        raise BadInput
    }
    return 42
}

fn run(marker: MutSpan<u8>) -> Void raises [BadInput] {
    check maybe_fail(false, marker)
}

pub fn main(world: World) -> Void raises {
    var marker: [1]u8 = [0]
    check run(marker)
    if marker[0] == 1_u8 {
        check world.out.write("fallibility error sets ok\n")
    }
}