gistfile1.txt

struct MyTensor<T: Equatable & AdditiveArithmetic>: Equatable & AdditiveArithmetic {
  var value: T
}

extension MyTensor : Differentiable where T : AdditiveArithmetic & Differentiable {
  typealias TangentVector = MyTensor
  typealias CotangentVector = MyTensor
  typealias AllDifferentiableVariables = MyTensor
  func tangentVector(from cotangentVector: CotangentVector) -> TangentVector {
    return cotangentVector
  }
}

struct Wrapper<T: Differentiable>: Differentiable {
  var value: T
}

struct MyRNNCell<Scalar: AdditiveArithmetic & Differentiable>: Differentiable {
  @differentiable
  func call(_ input: Wrapper<MyTensor<Scalar>>) -> Wrapper<MyTensor<Scalar>> {
    return Wrapper(value: input.value)
  }
}