Cannot use `override` keyword to override methods of `Object` without explicitly extending `Object`

Bug Report

🔎 Search Terms

override, TS4112

🕗 Version & Regression Information

It happens in 4.4.2 and has been there since the introduction of override keyword (#39669).

⏯ Playground Link

https://www.typescriptlang.org/play?#code/MYGwhgzhAECC0G8BQ1oHsBuBTATjglgCZbQAuaAyqQQHYDmAFAJSKo5akCuON0A5ADM0aPgG5oAXyQSgA

💻 Code

class A {
  override toString() { return 'foo'; }
}

🙁 Actual behavior

TS4112: This member cannot have an 'override' modifier because its containing class 'A' does not extend another class.

🙂 Expected behavior

It should be allowed, since the method overrides Object.prototype.toString.

Per ECMAScript spec §15.7.12.7, a class without an explicit extends clause would be implicitly inheriting from Object. Therefore, such classes should be allowed to explicitly override methods declared in Object.

Reproduisez le cas dans le TypeScript Playground lié et examinez la déclaration de Object dans lib/lib.es5.d.ts. Suivez le comportement de vérification de override pour une classe sans clause extends explicite. C’est terminé lorsque l’exemple est accepté, tout en maintenant les vérifications de override pour les autres cas.