Library bug - Problem with string(string::reverse_iterator, string::reverse_iterator)

[Paolo Carlini]

Hi all, hi Benjamin,

indeed I could reproduce the produce and I'm convinced it is regression 
wrt 3.0.4 which must be fixed ASAP.

I could also confirm that the problem is due to this check:

    // NB: Not required, but considered best practice.
    if (__builtin_expect(__beg == _InIter(0), 0))
      __throw_logic_error("attempt to create string with null pointer");

which was introduced with:

    http://gcc.gnu.org/ml/gcc-cvs/2002-03/msg00516.html

Benjamin, could you possibly explain to me a bit the structure of that 
kind of check? We should find a way to modify it to work well also with 
reverse_iterator, IMO.

Ciao, Paolo.