 
   @transparent
   var _nativeIndex: _NativeIndex {
-    switch self {
+    switch value {
     case ._Native(let nativeIndex):
       return nativeIndex
     case ._Cocoa:


  typealias _NativeIndex = _NativeDictionaryIndex<KeyType, ValueType>
  typealias _CocoaIndex = _CocoaDictionaryIndex
  case _Native(_NativeIndex)
  case _Cocoa(_CocoaIndex)

  @transparent
  var _guaranteedNative: Bool {

  }

  mutating func _nativeNext() -> (KeyType, ValueType)? {
    switch state {
    case ._Native(var startIndex, var endIndex):
      if startIndex == endIndex {
        return .None
      }
      let result = startIndex.nativeStorage.assertingGet(startIndex)
      state = ._Native(start: startIndex.successor(), end: endIndex)
      return result
    case ._Cocoa:
      _fatalError("internal error: not backed by NSDictionary")
    }
  }

