[Bug libstdc++/52540] std::use_facet throws bad_cast when compiled with _GLIBCXX_DEBUG

["pluto at agmk dot net" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52540

--- Comment #11 from Pawel Sikora <pluto at agmk dot net> 2012-03-11 19:49:41 UTC ---
(In reply to comment #9)
> Then this is a very old issue, isn't it? Why nobody noticed it before? To be
> clear, in debug-mode we don't use extern templates only for basic_string
> (because _GLIBCXX_EXTERN_TEMPLATE becomes -1 when _GLIBCXX_DEBUG is defined),
> all the other facilities remain the same still use extern tamplate. This is in
> order to enable debug-mode checks also at -O0 for basic_string. Now, I don't
> see why a few less extern template can make a difference on mingw in terms of
> correctness of use_facet or anything else, but if that's really the case due to
> fundamental limitations somehwhere, we can trade it for the -O0 basic_string
> checks on the affected systems, I have no problems with that (note that,
> AFAICS, the problem will not go away with a new C++11 conforming string class,
> unless we decide to not export from the .so parts of basic_string)

i'm not sure the problem is in std::string details. in the debug-mode
the use_facet is no more extern template and instantiates in client code,
especially the static facet's field like std::locale::id. is this 'id'
and other static details correctly initialized in (non-extern-template)
debug-mode?