[Bug c++/26448] New: unnecessary namespace-alias ambiguity

[emilp at mac dot com]

namespace lib1
{
namespace part
{
typedef int result;
}
}

namespace lib2
{
namespace part = lib1::part;
}

using namespace lib1;
using namespace lib2;

int main()
{
part::result val = 0;
return val;
}

The above code results in a compilation error,  "error: `part' has not been
declared", but should it really? I can't say the parts of the C++ standard I've
read has been clear on the point, but it seems reasonable that the compiler
should recognize that "part" is not ambiguous in this case.


-- 
   Summary: unnecessary namespace-alias ambiguity
   Product: gcc
   Version: 4.0.1
Status: UNCONFIRMED
  Severity: enhancement
  Priority: P3
 Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: emilp at mac dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26448

[Bug c++/26448] unnecessary namespace-alias ambiguity

[emilp at mac dot com]

--- Comment #2 from emilp at mac dot com  2006-03-08 08:45 ---
But isn't this problem already solved for the "using" directive. The code below
compiles fine and works as expected. In fact, in the days of gcc 3, "using"
could be used for namespaces and behaved exactly the way I would prefer.

namespace lib1
{
typedef int integer;
}

namespace lib2
{
using lib1::integer;
}

using namespace lib1;
using namespace lib2;

int main()
{
integer val = 0;
return val;
}

It seems limiting to introduce new (and often obscure) ambiguities when using
namespace aliases, the very problem namespaces are meant to alleviate...

E.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26448

[Bug c++/26448] unnecessary namespace-alias ambiguity

[emilp at mac dot com]

--- Comment #4 from emilp at mac dot com  2006-03-08 15:23 ---
I did come on a bit strong, didn't I?  Sorry about that, I'm just a bit
frustrated since it used to work better in the gcc 3 series :-)

Do you have a suggestion as to where I could continue this discussion?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26448

[Bug c++/26448] unnecessary namespace-alias ambiguity

[emilp at mac dot com]

--- Comment #6 from emilp at mac dot com  2006-03-08 16:47 ---
I'm considering filing a defect report (for a standard clarification) to the
commitee but I would like to make sure I'm not climbing any trees here... In
your first reply you said "My understanding is that this code is in fact
invalid...", which part of the C++ standard did you base this on?

I'm just wondering because section 7.3.2 seems not to mention any lookup rules
at all? Am I missing something obvious?

E.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26448