   public func replacingOccurrencesOf(
     _ target: String,
     withString replacement: String,
-    options: CompareOptions = [],
+    options: String.CompareOptions = [],
     range searchRange: Range<Index>? = nil
   ) -> String {
     fatalError("unavailable function can't be called")

  @available(*, unavailable, renamed: "range(of:options:range:locale:)")
  public func rangeOf(
    _ aString: String,
    options mask: CompareOptions = [],
    range searchRange: Range<Index>? = nil,
    locale: Locale? = nil
  ) -> Range<Index>? {

  }

  @available(*, unavailable, renamed: "canBeConverted(to:)")
  public func canBeConvertedToEncoding(_ encoding: String.Encoding) -> Bool {
    fatalError("unavailable function can't be called")
  }

