Unhandled rejections when handler is cancelled

[bergus]

Should a promise be reported as unhandled when it had a catch handler installed but that was later cancelled?

const {token, cancel} = CancelToken.source();
setTimeout(cancel, 500);

const promise = new Promise((resolve, reject) => {
    setTimeout(reject, 1000);
});
token.catch(e => { /* do something */ }, token);

The current proposal does not, as [[PromiseIsHandled]] is set to true when the handler is installed, and that's it.