Steal back from r destructively and return it.
http://forum.dlang.org/thread/jkbhlezbcrufowxtthmy@forum.dlang.org#post-konhvblwbmpdrbeqhyuv:40forum.dlang.org http://forum.dlang.org/thread/onibkzepudfisxtrigsi@forum.dlang.org#post-dafmzroxvaeejyxrkbon:40forum.dlang.org
See Implementation
Steal back from r destructively and return it.