type Delegate<T> = () => T;

function executeGeneric<
    X,
    DelegateT extends Delegate<X> 
>(delegate: DelegateT): ReturnType<DelegateT> {
    //Type 'X' is not assignable to type 'ReturnType<DelegateT>'.
    const x: ReturnType<typeof delegate> = delegate();
    //Type 'X' is not assignable to type 'ReturnType<DelegateT>'.
    const y: ReturnType<DelegateT> = delegate();
    //Type 'X' is not assignable to type 'ReturnType<DelegateT>'.
    return delegate();
}