Presence of function call prevents project from building regardless of function content

[alexf13e]

Hello, I have the below code using two globals to manage some of my ui for handling different screens. I have reduced it to the relevant parts, the file with the full contents can be found here https://github.com/alexf13e/tv-remote/blob/screen_history_issue/main/ui/globals.slint

export global ScreenHistory { //manage the previously visited screens
    out property <ScreenHistoryData> history;

    ...
   
    public function append_screen(screen_id: RemoteScreenID) {
        if (history.front == history.capacity - 1) {
            //we are at capacity of history, need to forget oldest screen

            //shift array elements down by 1 so the first one is forgotten
            Logic.shift_history_screens(history.screens);

            history.front -= 1; //move front backwards by 1 space, as though the last space in the array was empty
        }

        history.front += 1;
        history.screens[history.front] = screen_id; //put the new screen in the next empty space

        history.length = history.front + 1; //update length to match where front currently is
        //e.g. if we had remembered 10 screens (front = 9), then went back by 3 (front = 6), then went to a new screen
        //(front = 7), the screens after front are no longer part of this branch of history, so length should jump back
        //from 10 to 8 and going forward can't reach the now invalid screens
    }
}


export global CurrentDisplayedScreen { //manage the currently displayed screen
    out property <RemoteScreenID> id: RemoteScreenID.TV_CHANNELS; //initialised by native code, placeholder for previewing

    ...

    //change the displayed screen and update the history if relevant
    public function set(new_id: RemoteScreenID) {
        if (new_id != RemoteScreenID.SAME) {
            check_special_screen_changes(id, new_id);

            id = new_id;

            if (new_id != RemoteScreenID.SCREEN_LIST) {
                ScreenHistory.append_screen(new_id);                  <------- problem line
            }
        }
    }
}

It seems that regardless of the contents of ScreenHistory.append_screen() (even when empty) the build fails if any function in CurrentDisplayedScreen calls it. I am using idf.py to build for esp32-s3, running RUST_BACKTRACE=full idf.py build produces this output

thread 'main' panicked at internal/compiler/llr/lower_to_item_tree.rs:114:65:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0:     0x55d726b28efa - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h1b9dad2a88e955ff
   1:     0x55d72662ddfb - core::fmt::write::h4b5a1270214bc4a7
   2:     0x55d726afc1b2 - std::io::Write::write_fmt::hd04af345a50c312d
   3:     0x55d726b2d777 - std::panicking::default_hook::{{closure}}::h96ab15e9936be7ed
   4:     0x55d726b2e9af - std::panicking::rust_panic_with_hook::hfe205f6954b2c97b
   5:     0x55d726b2e1e2 - std::panicking::begin_panic_handler::{{closure}}::h6cb44b3a50f28c44
   6:     0x55d726b2e179 - std::sys::backtrace::__rust_end_short_backtrace::hf1c1f2a92799bb0e
   7:     0x55d726b2e164 - rust_begin_unwind
   8:     0x55d7265a41d2 - core::panicking::panic_fmt::h3d8fc78294164da7
   9:     0x55d7265a436b - core::panicking::panic::hec978767ec2d35ff
  10:     0x55d7265a4768 - core::option::unwrap_failed::hba6b08832f9ce30b
  11:     0x55d72681a6dd - i_slint_compiler::llr::lower_to_item_tree::LoweredSubComponentMapping::map_property_reference::ha620fc14028d1a2a
  12:     0x55d7268f37fa - i_slint_compiler::llr::lower_expression::ExpressionContext::map_property_reference::h5a61b3bc92eec0ec
  13:     0x55d7268f4b2f - i_slint_compiler::llr::lower_expression::lower_expression::h6ac70bf1543244b7
  14:     0x55d7268f413e - i_slint_compiler::llr::lower_expression::lower_expression::h6ac70bf1543244b7
  15:     0x55d72682c9de - i_slint_compiler::llr::lower_to_item_tree::lower_to_item_tree::h00b67ece8c7dbba3
  16:     0x55d7268abb10 - i_slint_compiler::generator::cpp::generate::h3ef1f4f8a1e2fa05
  17:     0x55d726ad5934 - slint_compiler::main::he6731876baca7548
  18:     0x55d726adbd43 - std::sys::backtrace::__rust_begin_short_backtrace::hc31a497c4f6adac6
  19:     0x55d726acfc32 - main
  20:     0x7f36507f724a - __libc_start_call_main
                               at ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
  21:     0x7f36507f7305 - __libc_start_main_impl
                               at ./csu/../csu/libc-start.c:360:3
  22:     0x55d7265ce95e - _start
  23:                0x0 - <unknown>

I am unsure what the issue is. When that line is commented out, the build succeeds and everything else functions perfectly fine. Perhaps there is something I have missed about how functions in globals work. Any help appreciated

[ogoffart]

Thanks for reporting, this is clearly a bug.
I've been reproducing it and reduced it. I've filled #6984

BTW, i think you forgot to add some icons in your repo because i had to comment out some @image-url to get it work.

[alexf13e]

i think you forgot to add some icons

Yes, sorry I should have mentioned I deliberately exclude the channel icons in my .gitignore in case of copyright issues (not that I expect any of them would ever see this or care).
Should I mark this as answer or leave it until the issue is resolved?

[alexf13e]

This has been fixed in version 1.9
Thank you