   }
 }
 
-extension UTF8.ReverseDecoder : _UTF8Decoder {
+extension UTF8.ReverseDecoder : _UTFDecoder {
   public typealias Encoding = Unicode.UTF8
 
   public // @testable

//===--- UTF-16 Decoders --------------------------------------------------===//
//===----------------------------------------------------------------------===//

public protocol _UTF16Decoder : _UTFDecoder where Encoding.CodeUnit == UTF16.CodeUnit {
}

extension _UTF16Decoder {
  public static func _isScalar(_ x: Encoding.CodeUnit) -> Bool {
    return x & 0xf800 != 0xd800
  }
}

extension Unicode.UTF16 : UnicodeEncoding {
  public typealias EncodedScalar = _UIntBuffer<UInt32, UInt16>


  }
}

extension UTF16.ReverseDecoder : _UTFDecoder {
  public typealias Encoding = Unicode.UTF16

  public // @testable
