[Bug c++/12831] New: passing reference to pointer-to-member-function crashes gcc 3.3.2

[Bug c++/12831] New: passing reference to pointer-to-member-function crashes gcc 3.3.2

[waldeinburg at yahoo dot com]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 1866 bytes --]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831

           Summary: passing reference to pointer-to-member-function crashes
                    gcc 3.3.2
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: waldeinburg at yahoo dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i486-debian-linux-gnu
  GCC host triplet: i486-debian-linux-gnu
GCC target triplet: i486-debian-linux-gnu

The example attached compiles with gcc 2.95 (I hope this is correct behavior).

gcc 3.2 says:
 conditional expression between distinct pointer types `int 
   (**)(...)' and `void (foo::**)()' lacks a cast


gcc 3.3.2 (the newest version provided by Debian - unstable) will crash with a
segmentation fault:
 test2.cpp: I function 'int main()':
 test2.cpp:25: internal compiler error: Lagersegmentfejl

It is simply compiled with
 gcc -o test2 test2.cpp

About the example:
I made quz a template class because I discovered the problem using a container
class, but you can also make it crash by declaring it as
 void qoo ( void (foo::* & p) (void) )

Output from gcc -v:
Læser specifikationer fra /usr/lib/gcc-lib/i486-linux/3.3.2/specs
Konfigureret med: ../src/configure -v
--enable-languages=c,c++,java,f77,pascal,objc,ada,treelang --prefix=/usr
--mandir=/usr/share/man --infodir=/usr/share/info
--with-gxx-include-dir=/usr/include/c++/3.3 --enable-shared --with-system-zlib
--enable-nls --without-included-gettext --enable-__cxa_atexit
--enable-clocale=gnu --enable-debug --enable-java-gc=boehm
--enable-java-awt=xlib --enable-objc-gc i486-linux
Trådmodel: posix
GCC version 3.3.2 (Debian)

[Bug c++/12831] passing reference to pointer-to-member-function crashes gcc 3.3.2

[waldeinburg at yahoo dot com]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831



------- Additional Comments From waldeinburg at yahoo dot com  2003-10-29 20:43 -------
Created an attachment (id=5017)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5017&action=view)
preprocessed file that triggers the bug

[Bug c++/12831] passing reference to pointer-to-member-function crashes gcc 3.3.2

[waldeinburg at yahoo dot com]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831



------- Additional Comments From waldeinburg at yahoo dot com  2003-10-29 20:44 -------
Created an attachment (id=5018)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5018&action=view)
the code that triggers the bug

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[bangerth at dealii 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=12831


bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|critical                    |normal
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |ice-on-invalid-code
   Last reconfirmed|0000-00-00 00:00:00         |2003-10-29 21:43:15
               date|                            |
            Summary|passing reference to        |[3.3 regression] ICE with
                   |pointer-to-member-function  |passing reference to bound
                   |crashes gcc 3.3.2           |pointer-to-member-function
   Target Milestone|---                         |3.3.3


------- Additional Comments From bangerth at dealii dot org  2003-10-29 21:43 -------
The code is illegal: you are calling quz::qoo with
  ifoo.*fun
which is a bound pointer to member (another ill-advised gcc extension).
You should really call it as
  iquz.qoo (fun)
in which case all gcc versions accept the code.

Alas, the present state is not good either. 3.3.x ICEs on the code, which
one can consider a regression against 2.95 that silently accepted wrong
code. Present mainline states
  g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc
  x.cc: In function `int main()':
  x.cc:16: error: no matching function for call to `quz<void
(foo::*)()>::qoo(void (foo::)())'
  x.cc:7: note: candidates are: void quz<T>::qoo(T&) [with T = void (foo::*)()]
which is confusing because the data types do not reflect that we try to
call the function with a bound pointer.

That raises an interesting question, though: does there exist a standard
conversion from a bound pointer to an unbound one? If this were the case,
then the message would suddenly make sense: we would convert the bound
reference to member to an unbound reference to member and call quz::qoo with
that. It would take a reference-to-pointer conversion then.

To wrap up: don't invent half-baked extensions to the language (a message to
gcc developers)!

W.

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[waldeinburg at yahoo dot com]

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831



------- Additional Comments From waldeinburg at yahoo dot com  2003-10-30 15:31 -------
So the following is also a bug (the same bug)?

class foo
{
public:
  void bar (void)
  {
  }
};


int main (void)
{
  foo ifoo;
  void (foo::* pfun) (void) = & foo::bar;
  pfun = ifoo.*pfun;
  return 0;
}

I compiles, but I guess it does the same as
  void (foo::* pfun) (void) = & ifoo.bar;
which of course triggers an error.

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[bangerth at dealii 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=12831



------- Additional Comments From bangerth at dealii dot org  2003-10-30 15:58 -------
That code should be just as invalid. ifoo.*pfun has no meaning unless
followed by function arguments. The same holds for ifoo.bar, and taking the
address of the latter makes no sense as well.

W.

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-12-16 20:24 -------
>From Phil's regression hunter: Search converges between 2003-06-25-3.3 (#149) and 2003-06
-26-3.3 (#150).
Fixed on the mainline: Search converges between 2003-07-03-trunk (#332) and 2003-07-04-
trunk (#333).

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2003-10-29 21:43:15         |2003-12-16 20:24:23
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2003-12-24 21:37 -------
Will investigate.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |gdr at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-02-15 12:36 -------
Adjust milestone

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|3.3.3                       |3.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831

[Bug c++/12831] [3.3 regression] ICE with passing reference to bound pointer-to-member-function

[gdr at gcc dot gnu dot org]

------- Additional Comments From gdr at gcc dot gnu dot org  2004-04-27 06:26 -------
Unfortunate bug/extension.  Fixed in 3.4.0 and 3.5.0.
Won't fix in 3.3.x.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|3.3.4                       |3.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12831