Typescript: incorrect syntax highlighting

[gameroman]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version:
  Version: 1.103.2 (user setup)
  Commit: 6f17636
  Date: 2025-08-20T16:45:34.255Z (1 wk ago)
  Electron: 37.2.3
  ElectronBuildId: 12035395
  Chromium: 138.0.7204.100
  Node.js: 22.17.0
  V8: 13.8.500258-electron.0
  OS: Windows_NT x64 10.0.19045

• OS Version:
  OS Name: Microsoft Windows 10 Pro
  OS Version: 10.0.19045 N/A Build 19045

Steps to Reproduce:

// Syntax hilighting is INCORRECT ❌
const a = async (params?: {
  arg?: string | number;
  arg2?: string | number;
  arg3?: string | number;
}) => {
  return params;
};

// Syntax hilighting is CORRECT ✅
const b = async (params: {
  arg?: string | number;
  arg2?: string | number;
  arg3?: string | number;
}) => {
  return params;
};

// Syntax hilighting is CORRECT ✅
const c = async (params?: { arg?: string | number }) => {
  return params;
};

// Syntax hilighting is CORRECT ✅
const d = async (params: { arg?: string | number }) => {
  return params;
};

[RedCMD]

caused by the optional operator ?
should move issue to upstream grammar repo https://github.com/microsoft/TypeScript-TmLanguage

thank you for the excellent screenshot and code snippet

[vs-code-engineering]

Thanks for creating this issue! We figured it's covering the same as another one we already have. Thus, we closed this one as a duplicate. You can search for similar existing issues. See also our issue reporting guidelines.

Happy Coding!

[RedCMD]

• Combination of optional operator and new line breaks syntax higlighting in function arguments TypeScript-TmLanguage#1059