[Bug c++/18276] New: template classes that are friends of template classes

[gcc-bugzilla at gcc dot gnu dot org]

I am not positive about this bug report, but I cannot see what G++
wants from me, and in addition all the other compilers I have access
to accept the following code (including 3.4).

----------------------------------------
template < template<typename> class Traits_ >
struct Factory
{
};

template < template<typename> class Traits_>
struct Product
{
  template < template<typename> class >
  friend class Factory;
};

template<typename Tag_>
struct traits {};

int
main ()
{
  Product<traits> ();
}
----------------------------------------

% g++-3.4 -Wall temp2.cc
% g++-snapshot -Wall temp2.cc
temp2.cc: In instantiation of `Product<traits>':
temp2.cc:19:   instantiated from here
temp2.cc:1: erreur: template parameter 'template<class> class Traits_'
temp2.cc:8: erreur: redeclared here as 'template<template<class> class Traits_> template<class> class<template-parameter-1-1>'
% icc -Wall temp2.cc
%

I do not understand the prototype g++ reports.  It looks as if it
concatenated the outer template to the inner friend template class.

Environment:
System: Linux nostromo 2.4.27-1-k7-smp #1 SMP Fri Sep 3 06:31:15 UTC 2004 i686 GNU/Linux
Architecture: i686

	
host: i486-pc-linux-gnu
build: i486-pc-linux-gnu
target: i486-pc-linux-gnu
configured with: ../src/configure -v --enable-languages=c,c++,java,objc,ada --prefix=/usr/lib/gcc-snapshot --enable-shared --with-system-zlib --enable-nls --enable-threads=posix --without-included-gettext --disable-werror --enable-__cxa_atexit --enable-libstdcxx-allocator=mt --enable-clocale=gnu --enable-libstdcxx-debug --enable-java-gc=boehm --enable-java-awt=gtk i486-linux-gnu

How-To-Repeat:

See above.
------- Additional Comments From akim at epita dot fr  2004-11-02 17:03 -------
Fix:

No idea :)

Unless my code is wrong, but I fail to see the clause in the standard.

-- 
           Summary: template classes that are friends of template classes
           Product: gcc
           Version: 0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: akim at epita dot fr
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i486-pc-linux-gnu
  GCC host triplet: i486-pc-linux-gnu
GCC target triplet: i486-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18276