[Bug c++/33255] A warning for "unused" typedefs?

["dodji at seketeli dot org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33255

--- Comment #23 from dodji at seketeli dot org <dodji at seketeli dot org> 2011-07-25 14:29:15 UTC ---
> --- Comment #19 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-07-24 22:49:32 UTC ---
> Just as a note, wanted also to add that if I understand correctly the
> (temporary?!?) small issue with system headers, it would also affect people
> building their code with -D_GLIBCXX_CONCEPT_CHECKS (by itself largely
> deprecated and not being updated for c++0x). Again, I don't see this as a
> serious issue if the new warning remains, for now at least, outside
> -Wall.

Building libstdc++ itself without _GLIBCXX_CONCEPT_CHECKS
raises this warning for e.g:

      typedef typename iterator_traits<_II1>::value_type _ValueType1;
      typedef typename iterator_traits<_II2>::value_type _ValueType2;

 [..]
      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)

(in libstdc++-v3/include/bits/stl_algobase.h)

As the macro __glibcxx_function_requires is defined to nothing (without
-D_GLIBCXX_CONCEPT_CHECKS) _ValueType1 and _ValueType2 appear unused
here.

So yes, -Wunused-local-typedefs definitely needs to be put out of --Wall
-Extra (and -Wunused).

Thanks.