[Bug c++/18604] [3.4/4.0/4.1 Regression] Strong using lookup conflicts

["giovannibajo at libero dot it" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From giovannibajo at libero dot it  2005-05-09 07:25 -------
I analyzed this PR again. The problem seems not related to attribute strong 
itself, but rather the way v3 namespaces work. Basically, without debug 
support, the failing code looks like:

---------------------------------
namespace std {
   struct A {};
};

struct A;

namespace std {
   A a;    // std::A, OK!
};
---------------------------------

Instead, with debug support, we end up with code like this:

---------------------------------
namespace std {
   struct A {};
};

namespace __gnu_norm {
   using namespace std;
};

struct A;

namespace __gnu_norm {
   A a;    // ambiguous!
};
---------------------------------

hence the failure. There are at least two ways to fix this in v3:

- Fully qualify all references to std names from code within namespace 
_GLIBCXX_STD (which expands to __gnu_norm in debug mode). This is hard because 
it's impossible to fully check it, and it's pervasive. E.g. bits/stl_set.h:69, 
use "std::less" instead of "less".

- Define namespace __gnu_norm within namespace std. This could be easier 
because you probably have to touch *only* namespace definitions.

Comments?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bkoz at gcc dot gnu dot org,
                   |                            |mmitchel at gcc dot gnu dot
                   |                            |org, pcarlini at suse dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18604