c++/2184: using declarations for classes in function templates

[Sylvain dot Pion at sophia dot inria dot fr]

>Number:         2184
>Category:       c++
>Synopsis:       using declarations for classes in function templates
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Mon Mar 05 10:26:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     
>Release:        3.0 20010305 (prerelease)
>Organization:
>Environment:
System: Linux zosma 2.2.14 #1 SMP Fri Jan 14 14:39:36 MET 2000 i686 unknown
Architecture: i686

	
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: /u/zosma/0/prisme/spion/gcc/gcc/configure --with-as=/u/zosma/0/prisme/spion/gcc/Binutils/Linux/bin/as --with-ld=/u/zosma/0/prisme/spion/gcc/Binutils/Linux/bin/ld --enable-languages=c++ --prefix=/u/zosma/0/prisme/spion/gcc/Linux_CVS_v3
>Description:

The following code doesn't compile on the 3.0 branch.  It's a regression
compared to 2.95.2.  It gives :

pr_vector.C: In function `void f(const J&)':
pr_vector.C:9: ISO C++ forbids declaration of `vector' with no type
pr_vector.C:9: template-id `vector<int>' used as a declarator
pr_vector.C:9: parse error before `;' token
pr_vector.C: In function `void f(const J&) [with J = int]':
pr_vector.C:13:   instantiated from here
pr_vector.C:9: `typedef int vector' redeclared as different kind of symbol
pr_vector.C:3: previous declaration of `template<class T> class std::vector'
pr_vector.C:9: declaration of `typedef vector vector'
pr_vector.C:3: conflicts with previous declaration `template<class T> class
   std::vector'

Note 1 : it works when f() is not template.

Note 2 : it's similar to the PR c++/1981, which was fixed by Nathan Sidwell,
         but this new one concerns classes instead of functions.

>How-To-Repeat:

namespace std {
template <class T>
class vector {};
}

template <class J>
void f(const J&) {
  using std::vector;
  typedef vector<int> V;
}

int main() {
  f(0);
}

>Fix:

I don't know of any workaround, except not using "using", and using
std::vector directly.

>Release-Note:
>Audit-Trail:
>Unformatted: