import _Differentiation

@propertyWrapper
struct Wrapper<Value> {
  var wrappedValue: Value
}
// No `Differentiable` conformance should be necessary necessary:
// extension Wrapper: Differentiable where Value: Differentiable {}

struct Struct {
  @Wrapper var x: Float = 0
  // Compiler generates:
  // var _x: Wrapper<Float>
  // var x: Float {
  //   get { _x.wrappedValue }
  //   set { _x.wrappedValue = newValue }
  // }

  @Wrapper var y: Float = 1
  var z: Float = 2
}

extension Struct: Differentiable {
  // Compiler currently synthesizes:
  // struct TangentVector: Differentiable & AdditiveArithmetic {
  //   var x: Wrapper<Float>.TangentVector
  //   var y: Wrapper<Float>.TangentVector
  //   var z: Float
  //   ...
  // }

  // Compiler should synthesize:
  // struct TangentVector: Differentiable & AdditiveArithmetic {
  //   var x: Float
  //   var y: Float
  //   var z: Float
  //   ...
  // }
}