slint-ui/slint · error · CompileError

Could not compile " + filePath

Error message

Could not compile " + filePath

What it means

Thrown by loadSlint when the Slint compiler returned error-level diagnostics for the given file. The CompileError carries the filtered diagnostics so callers can inspect them. It means the .slint source failed to compile, not a runtime failure.

Solutions

1. Read the diagnostics array attached to the CompileError; each entry has file, line, column and message.
2. Fix the reported .slint syntax/type errors at the indicated locations.
3. Verify the file path passed to loadFile exists and is the intended component file.
4. Ensure the installed slint-ui native binding version matches the .slint feature usage.

Example fix

// before
const ui = await slint.loadFile('app.slint');
// after
try {
  const ui = await slint.loadFile('app.slint');
} catch (e) {
  if (e instanceof slint.CompileError) {
    for (const d of e.diagnostics) console.error(`${d.fileName}:${d.line}:${d.column}: ${d.message}`);
  }
}

import fs from 'fs';
if (!fs.existsSync(filePath)) throw new Error(`missing slint file: ${filePath}`);

function isCompileError(e: unknown): e is slint.CompileError {
  return e instanceof slint.CompileError && Array.isArray(e.diagnostics);
}

try {
  const ui = await slint.loadFile(filePath);
} catch (e) {
  if (e instanceof slint.CompileError) {
    e.diagnostics.forEach(d => console.error(`${d.fileName}:${d.line}:${d.column}: ${d.message}`));
  } else throw e;
}

When it happens

Trigger: Calling loadFile or loadSource on a .slint file/source that has syntax errors, unknown properties or elements, type errors, or other compile diagnostics at level Error.

Common situations: Typos in .slint markup, referencing a missing component or property, version drift between the native binding and markup features, loading a file with a stale or broken path producing compiler errors.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Callback ' ' in global ' ' cannot be used with a callback…
• Cannot create component instance
• Cannot create placeholder
• Cannot show component
• Cannot show placeholder

AI-assisted analysis of slint-ui/slint@bb937076de (2026-09-16). Data as JSON: /api/errors/7bf0feea03157825. Report an issue: GitHub.

Appendix: source

Thrown at api/node/typescript/index.ts:341

            ? compiler.buildFromPath(filePath)
            : compiler.buildFromSource(loadData.fileData.source, filePath);
    const diagnostics = compiler.diagnostics;

    if (diagnostics.length > 0) {
        const warnings = diagnostics.filter(
            (d) => d.level === napi.DiagnosticLevel.Warning,
        );

        if (typeof options !== "undefined" && options.quiet !== true) {
            warnings.forEach((w) => console.warn("Warning: " + w));
        }

        const errors = diagnostics.filter(
            (d) => d.level === napi.DiagnosticLevel.Error,
        );

        if (errors.length > 0) {
            throw new CompileError("Could not compile " + filePath, errors);
        }
    }

    const slint_module = Object.create({});

    // generate structs
    const structs = compiler.structs;

    for (const key in compiler.structs) {
        Object.defineProperty(slint_module, translateName(key), {
            value: function (properties: any) {
                const defaultObject = structs[key] as any;
                const newObject = Object.create({});

                for (const propertyKey in defaultObject) {
                    const propertyName = translateName(propertyKey);
                    const propertyValue =
                        properties !== undefined &&

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