 }
 
 // Pre-Swift-3 method names
-extension StringProtocol {
-
+extension String {
   @available(*, unavailable, renamed: "localizedName(of:)")
   public static func localizedNameOfStringEncoding(
     _ encoding: String.Encoding

  public static func pathWithComponents(_ components: [String]) -> String {
    fatalError("unavailable function can't be called")
  }

  @available(*, unavailable, renamed: "canBeConverted(to:)")
  public func canBeConvertedToEncoding(_ encoding: String.Encoding) -> Bool {

  ) -> String {
    return String(format: format, locale: Locale.current,
      arguments: arguments)
  }

  //===--------------------------------------------------------------------===//
