Sample Code from WWDC video does not compile.

The sample code below does not compile:

protocol RequestProtocol {
  associatedtype Input
  associatedtype Output
  
  func evaluate(_: Input) -> Output
}

struct Evaluator<each Request: RequestProtocol> {
  let item: (repeat each Request)
  
  func query(_ input: repeat (each Request).Input) -> (repeat (each Request).Output) {
    return (repeat (each item).evaluate(each input))
  }
}

Code causes two compiler errors:

1. 'each' cannot be applied to non-pack type '(repeat each Request)'
2. Pack expansion requires that 'each Request' and '()' have the same shape

Please advise.