Can't extend mixin constructor that constructs a generic type

This applies regardless of whether or not I intersect it with some bogus type, or have a reasonable constraint. So none of the following works.

Returning a plain T

export type Constructor<T> = new (...args: any[]) => T

export interface Timestamp {
    timestamp: Date;
}

// plain old T
export function Timestamp<T, CT extends Constructor<T>>(Base: CT): Constructor<Timestamp> & Constructor<T> {
    return class extends Base {
        timestamp = new Date();
    }
}

Constructor of T with a bogus object type ({})

export type Constructor<T> = new (...args: any[]) => T

export interface Timestamp {
    timestamp: Date;
}

// Constructor of T with a bogus object type
export function Timestamp<T, CT extends Constructor<T & {}>>(Base: CT): Constructor<Timestamp> & Constructor<T> {
    return class extends Base {
        timestamp = new Date();
    }
}

Constructor of T where T is constrained to {}

export type Constructor<T> = new (...args: any[]) => T

export interface Timestamp {
    timestamp: Date;
}

export function Timestamp<T extends {}, CT extends Constructor<T>>(Base: CT): Constructor<Timestamp> & Constructor<T> {
    return class extends Base {
        timestamp = new Date();
    }
}

Constructor of T where T is constrained to object (see also #13805)

export type Constructor<T> = new (...args: any[]) => T

export interface Timestamp {
    timestamp: Date;
}

export function Timestamp<T extends object, CT extends Constructor<T>>(Base: CT): Constructor<Timestamp> & Constructor<T> {
    return class extends Base {
        timestamp = new Date();
    }
}

Beginne damit, die vier allgemeinen Beispiele für generische Konstruktoren und Mixins im Issue zu reproduzieren und die daraus resultierenden Typprüfungsfehler zu untersuchen. Verfolge, wie der Compiler generische Konstruktorsignaturen und Klassenausdrücke verarbeitet; die Arbeit ist abgeschlossen, wenn das beabsichtigte generische Mixin-Konstruktormuster mit dem angegebenen Rückgabetyp akzeptiert wird, ohne andere Prüfungen abzuschwächen.