[Bug c++/12115] New: arena new does not accept "struct" or "class" keywords.

["thor at math dot tu-berlin dot de" <gcc-bugzilla at gcc dot gnu dot org>]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12115

           Summary: arena new does not accept "struct" or "class" keywords.
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: thor at math dot tu-berlin dot de
                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

g++ does not accept code that allocates an object with an explicit struct/class
keyword thru area new. To reproduce this bug, enter the following program:

/* snip */
#include <stdlib.h>

class PrecinctKeeper {   
public:
  void *operator new(size_t size,int)
  {
    return malloc(size);
  }
  void operator delete(void *arg)
  {
    free(arg);
  }
  PrecinctKeeper(void)
  {
  }
};

class Band {
  struct PrecinctKeeper *blocks;
  //
public:
  void Alloc()
  {
    blocks = new(5) class PrecinctKeeper;
  }
};


int main(int argc,char **argv)
{
  return 0;
}
/* snip */ 

and compile with g++-3.3 foo.cpp. The resulting error is:

band.cpp: In member function `void Band::Alloc()':
band.cpp:24: error: invalid use of undefined type `struct 
   Band::Alloc()::PrecinctKeeper'
band.cpp:24: error: forward declaration of `struct 
   Band::Alloc()::PrecinctKeeper'
band.cpp:24: error: ISO C++ forbids defining types within new

Workaround:

Replace
    blocks = new(5) class PrecinctKeeper;
by
    blocks = new(5) PrecinctKeeper;

i.e. drop the explicit "class" keyword.

This bug also appears in g++-2.95 and g++-3.2, maybe other releases are
affected as well.