       $0.addStructComponent(offset: S<String>.p_offset)
       $0.addType(Point.self)
       $0.addStructComponent(offset: Point.y_offset)
-    } as! WritableKeyPath<S<String>, Double>
+    }
 
 
   // \("") forces the string to be computed at runtime (and therefore allocated)

    .build(capacityInBytes: 8) {
      $0.addHeader(trivial: true, hasReferencePrefix: false)
      $0.addStructComponent(offset: S<String>.x_offset)
    } as! WritableKeyPath<S<String>, Int>

  let s_y = WritableKeyPath<S<String>, LifetimeTracked?>
    .build(capacityInBytes: 8) {
      $0.addHeader(trivial: true, hasReferencePrefix: false)
      $0.addStructComponent(offset: S<String>.y_offset)
    } as! WritableKeyPath<S<String>, LifetimeTracked?>

  let s_z = WritableKeyPath<S<String>, String>
    .build(capacityInBytes: 8) {
      $0.addHeader(trivial: true, hasReferencePrefix: false)
      $0.addStructComponent(offset: S<String>.z_offset)
    } as! WritableKeyPath<S<String>, String>

  let s_p = WritableKeyPath<S<String>, Point>
    .build(capacityInBytes: 8) {
      $0.addHeader(trivial: true, hasReferencePrefix: false)
      $0.addStructComponent(offset: S<String>.p_offset)
    } as! WritableKeyPath<S<String>, Point>

  let twoComponentSize = 12 + MemoryLayout<Int>.size
  let s_p_x = WritableKeyPath<S<String>, Double>

                            endsReferencePrefix: true)
      $0.addType(C<String>.self)
      $0.addClassComponent(offset: C<String>.z_offset)
    }
  
  let c = C(x: 679, y: nil, z: "buffalo\("")")
  let value = S(x: 1738, y: nil, z: "bottles of beer\("")",
