interface SerializableClass {
    new (...a:any[]): any;
    readonly className: string;
}
interface Serialised<T extends SerializableClass> {
    className: T['className']; // error
    value: InstanceType<T>;
}

class Ok { 
    static readonly className = "Ok"
}

let o: Serialised<typeof Ok> = {
    className: "Ok",
    value: new Ok()
}

let o2: Serialised<typeof Ok> = {
    className: "Okk", //err
    value: new Ok()
}

class Bad{}
let o3: Serialised<typeof Bad> //err Type 'typeof Bad' does not satisfy the constraint 'SerializableClass'.