slint-ui/slint · error

there should be a popup menu if we want to show it

Error message

there should be a popup menu if we want to show it

What it means

Rust generator mirror of the C++ popup-menu panic: compiling the builtin `show-popup-menu` call requires `ctx.compilation_unit.popup_menu` to hold the auto-generated popup menu item tree. A None value panics because the builtin cannot be lowered without the popup menu component registered by an earlier compiler pass.

Solutions

1. Run the pass that populates `CompilationUnit::popup_menu` before code generation
2. Assert earlier (at unit finalization) that any `show_popup_menu` usage implies a registered popup menu
3. Return a clear compile diagnostic instead of panicking when the popup menu is missing

Example fix

// before
let popup = ctx.compilation_unit.popup_menu.as_ref().expect("there should be a popup menu if we want to show it");
// after
let popup = ctx.compilation_unit.popup_menu.as_ref().unwrap_or_else(||
    panic!("show_popup_menu used but compilation_unit.popup_menu was never registered"));

if ctx.compilation_unit.popup_menu.is_none() {
    panic!("show_popup_menu lowered but popup_menu never registered in this unit");
}

let popup_menu = match ctx.compilation_unit.popup_menu.as_ref() {
    Some(p) => p,
    None => panic!("cannot lower show_popup_menu: no popup menu item tree registered"),
};

When it happens

Trigger: `compile_builtin_function_call` lowers a `show_popup_menu` call in a unit where `popup_menu` was never collected — the collection pass did not run (e.g. a partial pipeline like LSP or tooling), or registration failed upstream.

Common situations: Compiler/tooling development: running codegen on units that skipped the popup-menu registration pass; refactoring how builtin functions register their supporting item trees.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• Expression::StructFieldAccess: Cannot find a key in an…
• ShowPopupWindow is invoked on a sub-component
• there should be a popup menu if we want to show it
• Expression::ObjectAccess: Cannot find a key in an object
• model two-way bindings only exist on sub-components

AI-assisted analysis of slint-ui/slint@3a7e700487 (2026-09-16). Data as JSON: /api/errors/60cf22c5d5073335. Report an issue: GitHub.

Appendix: source

Thrown at internal/compiler/generator/rust.rs:4750

                )
            } else {
                panic!("internal error: invalid args to ClosePopupWindow {arguments:?}")
            }
        }
        BuiltinFunction::ShowPopupMenu | BuiltinFunction::ShowPopupMenuInternal => {
            let [Expression::PropertyReference(context_menu_ref), entries, position] = arguments
            else {
                panic!("internal error: invalid args to ShowPopupMenu {arguments:?}")
            };

            let context_menu = access_member(context_menu_ref, ctx);
            let position = compile_expression(position, ctx);

            let popup = ctx
                .compilation_unit
                .popup_menu
                .as_ref()
                .expect("there should be a popup menu if we want to show it");
            let popup_id =
                inner_component_id(&ctx.compilation_unit.sub_components[popup.item_tree.root]);
            let window_adapter_tokens = access_window_adapter_field(ctx);

            let popup_ctx = EvaluationContext::new_sub_component(
                ctx.compilation_unit,
                popup.item_tree.root,
                RustGeneratorContext { global_access: quote!(_self.globals()) },
                None,
            );
            let access_entries = access_member(&popup.entries, &popup_ctx).unwrap();
            let access_sub_menu = access_member(&popup.sub_menu, &popup_ctx).unwrap();
            let access_activated = access_member(&popup.activated, &popup_ctx).unwrap();
            let access_close = access_member(&popup.close, &popup_ctx).unwrap();

            let close_popup = context_menu.clone().then(|context_menu| quote!{
                if let Some(current_id) = #context_menu.popup_id.take() {
                    sp::WindowInner::from_pub(#window_adapter_tokens.window()).close_popup(current_id);

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