   ///       enumeration by setting `stop = true`.
   public func enumerateSubstrings(
     in range: Range<Index>,
-    options opts: EnumerationOptions = [],
+    options opts: String.EnumerationOptions = [],
     _ body: @escaping (
       _ substring: String?, _ substringRange: Range<Index>,
       _ enclosingRange: Range<Index>, inout Bool

    return _ns.components(separatedBy: separator)
  }


  // - (NSArray *)componentsSeparatedByString:(NSString *)separator

  /// Returns an array containing substrings from the string that have been

        range: _toNSRange(range),
        remaining: $0)
    }
  }

  // - (void)
