slint-ui/slint · error

LibGlobal not found

Error message

LibGlobal not found

What it means

This `expect` lives in `mark_library_globals_marks_properties_as_externally_used` (internal/compiler/passes/collect_globals.rs:119), a test helper that searches the document's used globals for the compiler-internal `LibGlobal` global and asserts it is present. `LibGlobal` is a synthetic global the compiler injects; if it is missing from `used_types.globals` at this point, the compiler's global-collection invariant is broken.

Solutions

1. Ensure `mark_used_globals` (or the equivalent pass) ran on the document before this lookup so `LibGlobal` is registered as used.
2. Keep the `expose_in_public_api`/`is_constant_impl` conditions as the test intends so the marking short-circuit doesn't skip `LibGlobal`.
3. Verify the `LibGlobal` id string and injection code in the compiler were not renamed or removed.
4. Run `cargo test -p i-slint-compiler collect_globals` to confirm the fix.

// Contributors: assert the precondition in tests
assert!(doc.used_types.borrow().globals.iter().any(|g| g.id == "LibGlobal"),
    "run mark_used_globals before mark_library_globals");

When it happens

Trigger: Running this collect_globals test path (or code sharing its assumption) after `mark_used_globals`/`mark_library_globals` when `LibGlobal` was never collected — e.g. `is_constant_impl` short-circuiting marked properties, global marking skipped for the document, or a contributor change that removed/renamed `LibGlobal` injection.

Common situations: Slint compiler development and CI; changes to global marking or constant evaluation that alter which globals land in `used_types`; test setups that bypass normal document compilation.

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

• Component should cleanly upgrade here
• constraint must have binding
• EmbedTextures builds the shared font collection
• internal compiler error: more than one strong reference…
• named struct declarations have symbol counters

AI-assisted analysis of slint-ui/slint@bb937076de (2026-09-16). Data as JSON: /api/errors/f4cd0107779c728c. Report an issue: GitHub.

Appendix: source

Thrown at internal/compiler/passes/collect_globals.rs:119

export component App {
    out property <string> text-out: "\{LibGlobal.value} \{LibGlobal.count} \{LibGlobal.ready}";
}
"#
            .into(),
            Some(std::path::Path::new("test.slint")),
            &mut diag,
        );
        let (mut doc, diag, _) =
            spin_on::spin_on(crate::compile_syntax_node(doc_node, diag, compiler_config));
        assert!(!diag.has_errors(), "compile error: {:?}", diag.to_string_vec());

        let global = doc
            .used_types
            .borrow()
            .globals
            .iter()
            .find(|g| g.id == "LibGlobal")
            .expect("LibGlobal not found")
            .clone();

        // Simulate a library import by adding `LibGlobal` to `library_exports`
        // and re-running `mark_library_globals`. Clear `expose_in_public_api`
        // so the `is_constant_impl` short-circuit doesn't mask the result.
        doc.library_exports.insert(
            "LibGlobal".to_string(),
            crate::typeloader::LibraryInfo {
                name: "Lib".into(),
                package: "lib".into(),
                module: None,
                exports: Vec::new(),
            },
        );
        for (_, d) in global.root_element.borrow_mut().property_declarations.iter_mut() {
            d.expose_in_public_api = false;
        }
        global.root_element.borrow().property_analysis.borrow_mut().clear();

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