text: //
  //  NSMutableCopying.h
  //  MulleObjCContainerFoundation
  //
  //  Copyright (c) 2016 Nat! - Mulle kybernetiK.
  //  Copyright (c) 2016 Codeon GmbH.
  //  All rights reserved.
  //
  //
  //  Redistribution and use in source and binary forms, with or without
  //  modification, are permitted provided that the following conditions are met:
  //
  //  Redistributions of source code must retain the above copyright notice, this
  //  list of conditions and the following disclaimer.
  //
  //  Redistributions in binary form must reproduce the above copyright notice,
  //  this list of conditions and the following disclaimer in the documentation
  //  and/or other materials provided with the distribution.
  //
  //  Neither the name of Mulle kybernetiK nor the names of its contributors
  //  may be used to endorse or promote products derived from this software
  //  without specific prior written permission.
  //
  //  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  //  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  //  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  //  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  //  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  //  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  //  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  //  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  //  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  //  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  //  POSSIBILITY OF SUCH DAMAGE.
  //
  #import "NSObject.h"
  
  struct NSZone;
  
  
  //
  // This an ill-conceived legacy protocol. It breaks the possibilty of
  // returning nil for empty containers. (-copy is fine though).
  //
  @protocol NSMutableCopying
  
  @optional  // only optional if derived from NSObject
  - (id) mutableCopy
     __attribute__((deprecated( "mutableCopy does not work as expected, if the receiver is nil",
                                "Use a NSMutable<Class> constructor instead")));
  
  @end
  
  