[Bug libstdc++/49022] [C++0x][DR 2058] std::begin and std::end specialized for std::valarray with some operators are missing.

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49022

--- Comment #19 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-06-14 
13:01:24 UTC ---
Ah, no the problem is std::__addressof<const _Tp>(__ex()[0]) which takes the
address of a temporary returned by operator[]

The range-based for seems to do the right thing