[Bug libstdc++/52433] [C++11] debug mode iterators need to move

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52433

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.8.0
   Target Milestone|---                         |4.6.4

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-03-04 
12:59:33 UTC ---
Fixed on trunk so far.

I realised swapping isn't actually very simple, because the iterators need to
be unlinked/relinked into their container's lists so I just implemented it with
_M_attach and _M_detach instead.