behaviour of typeof () changed

[Jan Nieuwenhuizen]

Hi,

I'm not sure if it's a bug, but gcc-2.95's typeof () now respects
constness.  This may seem right, but it's different from gcc-2.8
and egcs-1.1.2.  In particular, it breaks the use of macros for 
simple clone () functionality.

In this example, typeof (*this) returns 'class A const*', and
it seems that this constness cannot be cast/tricked away.
LilyPond makes heavy use of the former typeof () functionlity.

Help.

Greetings,

Jan

clone.cc:
/*
    20:27:46 appel ~/usr/src/c++$ g++ --version
    2.95
    20:28:02 appel ~/usr/src/c++$ uname -a
    Linux appel.flower 2.2.6-15apmac #1 Fri Apr 30 12:52:03 EDT 1999 ppc unknown
    20:28:06 appel ~/usr/src/c++$ make clone
    g++  clone.cc -o clone
    clone.cc: In method `class A * A::clone() const':
    clone.cc:25: return to `A *' from `const A *' discards qualifiers
    make: *** [clone] Error 1
 */

#include <stdio.h>

#define VIRTUAL_COPY_CONS(base) \
  virtual base* clone () const \
  { \
    return new typeof(*this) (*this); \
  }

class A
{
public:
  VIRTUAL_COPY_CONS (A);
  virtual void print () { puts ("A"); }
};

int
main ()
{
  A a;
  A* b = a.clone ();
  return 0;
}


Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond - The music typesetter
http://www.xs4all.nl/~jantien/      | http://www.lilypond.org/