Allow subclasses to declare overloads of methods

Suggestion

Allow subclasses to declare an overload of a superclass method:

This would be useful with addEventListener() in order to provide the correct event type for an event name:

class MyElement extends HTMLElement {
  declare addEventListener(type: 'my-event', listener: (this: MyElement, ev: MyEvent) => any, options?: boolean | AddEventListenerOptions): void;
}

🔍 Search Terms

Various combinations: addEventListener subclass declare overload method

A lot of issues were returned from queries, I could have missed something.

✅ Viability Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

See above. I'm not sure the reason for not allowing declare on methods currently, so hopefully that could be relaxed.

📃 Motivating Example

See above.

Right now you would have to augment the HTMLElementEventNameMap, but that makes events global, which they might not be if they don't bubble.

💻 Use Cases

See above.

Beginne mit der Untersuchung, wie TypeScript declare-Methoden und geerbte Methodenüberladungen behandelt. Vergleiche die vorgeschlagene addEventListener-Deklaration der Unterklasse mit dem aktuellen Verhalten und ermittle die erforderlichen Regeln für die Typprüfung. Die fertige Lösung sollte die Überladung der Unterklasse ermöglichen, ohne das erzeugte JavaScript zu ändern, und gleichzeitig die Kompatibilität mit der Methode der Oberklasse wahren.