     /// reachable from `startIndex` by zero or more applications of
     /// `index(after:)`.
     var endIndex: Int {
-      return Int(count)
+      return Int(_count)
     }
 
     /// Access the code unit at `position`.

    init(_ u8: UInt64) {
      let utf8Count = Character._smallSize(u8)
      _sanityCheck(utf8Count <= 8, "Character with more than 8 UTF-8 code units")
      self.count = UInt16(utf8Count)
      self.data = u8
    }

    /// The position of the first element in a non-empty collection.

        from: UTF8.self, to: UTF16.self,
        stoppingOnError: false,
        into: output)
      self._data = u16
    }

    /// The position of the first element in a non-empty collection.
