import _Differentiation

// checked_cast_br
func typeCheckOperator<T>(_ x: Float, _ metatype: T.Type) -> Float {
  if metatype is Int.Type {
    return x + x
  }
  return x * x
}
print(valueWithGradient(at: 3, in: { typeCheckOperator($0, Int.self) }))
// (value: 6.0, gradient: 2.0)
print(valueWithGradient(at: 3, in: { typeCheckOperator($0, Float.self) }))
// (value: 9.0, gradient: 6.0)

// checked_cast_addr_br
func conditionalCast<T: Differentiable>(_ x: T) -> T {
  if let _ = x as? Float {
    // Without enum differentiation support (TF-1004), using `y: Float?` value
    // produces a non-differentiability error.
  }
  return x
}
print(valueWithGradient(at: Float(3), in: conditionalCast))
// (value: 3.0, gradient: 1.0)