c++/6331: g++ 3.1 looses const qualifiers

c++/6331: g++ 3.1 looses const qualifiers

[pthomas]

>Number:         6331
>Category:       c++
>Synopsis:       g++ 3.1 looses const qualifiers
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 17 02:46:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Philipp Thomas, SuSE Linux Ag
>Release:        3.1
>Organization:
>Environment:
suse-linux-gnu
>Description:
Gcc rejects the attached code, stating that the conversion is illegal. Output of 'c++ -v -c gcc31_bug_const.cc' is:

Using built-in specs.
Configured with: ../configure --enable-threads=posix --prefix=/usr --with-local-prefix=/usr/local --infodir=/usr/share/info --mandir=/usr/share/man --enable-languages=c,c++,f77,objc,java,ada --with-gxx-include-dir=/usr/include/g++ --with-slibdir=/lib --with-system-zlib --enable-shared i486-suse-linux
Thread model: posix
gcc version 3.1 20020408 (prerelease)
 /usr/lib/gcc-lib/i486-suse-linux/3.1/cc1plus -v -D__GNUC__=3 -D__GNUC_MINOR__=1 -D__GNUC_PATCHLEVEL__=0 -D__ELF__ -Dunix -Dlinux -D__ELF__ -D__unix__ -D__linux__ -D__unix -D__linux -Asystem=posix -D__NO_INLINE__ -D__STDC_HOSTED__=1 -D_GNU_SOURCE -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -D__tune_i486__ gcc31_bug_const.cc -D__GNUG__=3 -D__DEPRECATED -D__EXCEPTIONS -D__GXX_ABI_VERSION=100 -quiet -dumpbase gcc31_bug_const.cc -version -fmessage-length=0 -o /tmp/ccVQg0M0.s
GNU CPP version 3.1 20020408 (prerelease) (cpplib) (i386 Linux/ELF)
GNU C++ version 3.1 20020408 (prerelease) (i486-suse-linux)
        compiled by GNU C version 3.1 20020408 (prerelease).
ignoring nonexistent directory "/usr/i486-suse-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/g++
 /usr/include/g++/i486-suse-linux
 /usr/include/g++/backward
 /usr/local/include
 /usr/lib/gcc-lib/i486-suse-linux/3.1/include
 /usr/include
End of search list.
gcc31_bug_const.cc: In member function `int Collision::automatic_shift()':
gcc31_bug_const.cc:38: invalid conversion from `int (*)(int* const&, int* const&)' to `int (*)(int*&, int*&)'
gcc31_bug_const.cc:38:   initializing argument 1 of `void Link_array<T>::sort(int (*)(T*&, T*&), int, int) [with T = int]'
gcc31_bug_const.cc: In member function `void Link_array<T>::sort(int (*)(T*&, T*&), int, int) [with T = int]':
gcc31_bug_const.cc:38:   instantiated from here
gcc31_bug_const.cc:29: invalid conversion from `int (*)(int* const&, int* const&)' to `int (*)(int*&, int*&)'
gcc31_bug_const.cc:29:   initializing argument 1 of `void Link_array<T>::sort(int (*)(T*&, T*&), int, int) [with T = int]'
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="gcc31_bug_const.cc"
Content-Disposition: inline; filename="gcc31_bug_const.cc"

template<class T>
class Link_array
{
public:
  Link_array () {}
  Link_array (Link_array<T> const &src) {}
  // quicksort.
  void sort (int (*compare) (T *const&,T *const&),
	     int lower = -1, int upper = -1);
};

class Note_column
{
public:
  static int shift_compare (int *const &, int *const &) {};
};

class Collision			// interface
{
public:
  int automatic_shift ();
};

template<class T> void
Link_array<T>::sort (int (*compare) (T *const&,T *const&),
		int lower, int upper) 
{
  int last = lower;
  sort (compare, lower, last-1);
}

int
Collision::automatic_shift ()
{
  int d = 1;
  Link_array<int> clashes;

  clashes.sort (Note_column::shift_compare);
  return 1;
}

int main()
{
  return 0;
}

Re: c++/6331: g++ 3.1 looses const qualifiers

[jason]

Synopsis: g++ 3.1 looses const qualifiers

State-Changed-From-To: open->closed
State-Changed-By: jason
State-Changed-When: Thu Apr 25 01:27:46 2002
State-Changed-Why:
    fixed

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6331

Re: c++/6331: g++ 3.1 looses const qualifiers

[Jason Merrill]

The following reply was made to PR c++/6331; it has been noted by GNATS.

From: Jason Merrill <jason@redhat.com>
To: Mark Mitchell <mark@codesourcery.com>
Cc: "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>,
	"gcc-gnats@gcc.gnu.org" <gcc-gnats@gcc.gnu.org>
Subject: Re: c++/6331: g++ 3.1 looses const qualifiers
Date: Wed, 24 Apr 2002 18:27:15 +0100

 I'll handle it.
 
 Jason

Re: c++/6331: g++ 3.1 looses const qualifiers

[Mark Mitchell]

The following reply was made to PR c++/6331; it has been noted by GNATS.

From: Mark Mitchell <mark@codesourcery.com>
To: Jason Merrill <jason@redhat.com>
Cc: "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>,
   "gcc-gnats@gcc.gnu.org" <gcc-gnats@gcc.gnu.org>
Subject: Re: c++/6331: g++ 3.1 looses const qualifiers
Date: Wed, 24 Apr 2002 10:26:17 -0700

 --On Wednesday, April 24, 2002 06:27:15 PM +0100 Jason Merrill 
 <jason@redhat.com> wrote:
 
 > I'll handle it.
 
 Thanks!
 
 --
 Mark Mitchell                   mark@codesourcery.com
 CodeSourcery, LLC               http://www.codesourcery.com
 

Re: c++/6331: g++ 3.1 looses const qualifiers

[Mark Mitchell]

The following reply was made to PR c++/6331; it has been noted by GNATS.

From: Mark Mitchell <mark@codesourcery.com>
To: Jason Merrill <jason@redhat.com>
Cc: "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>,
   "gcc-gnats@gcc.gnu.org" <gcc-gnats@gcc.gnu.org>
Subject: Re: c++/6331: g++ 3.1 looses const qualifiers
Date: Wed, 24 Apr 2002 10:21:16 -0700

 > The original bug report that the testcase is derived from complained about
 > the error; the customer said that either the extension should be dropped
 > or the testcase should be accepted.  Neither of those came to pass.
 >
 > I wouldn't object to making the pedwarn unconditional.
 
 I agree; let's just kill this extension -- it is totally undocumented,
 and provides no real power since memcpy/loops do the same thing.
 
 Do you have time to make that change, or do you want me to do it?
 
 Thanks,
 
 --
 Mark Mitchell                   mark@codesourcery.com
 CodeSourcery, LLC               http://www.codesourcery.com
 

Re: c++/6331: g++ 3.1 looses const qualifiers

[Jason Merrill]

The following reply was made to PR c++/6331; it has been noted by GNATS.

From: Jason Merrill <jason@redhat.com>
To: Mark Mitchell <mark@codesourcery.com>
Cc: "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>,
	"gcc-gnats@gcc.gnu.org" <gcc-gnats@gcc.gnu.org>
Subject: Re: c++/6331: g++ 3.1 looses const qualifiers
Date: Wed, 24 Apr 2002 18:18:04 +0100

 >>>>> "Mark" == Mark Mitchell <mark@codesourcery.com> writes:
 
 > Shucks, we were duplicating work; I was working on that too.
 
 Oops.  I was guessing that you hadn't started on it yet.
 
 > When I tried the change you made to build_modify_expr, I got a failure in
 > this g++.benjamin/14664-1.c, which tests that we cannot assign a string
 > literal to an array of characters (because the array of characters is
 > const).  This is probably a goofy test; what should be interesting is
 > whether we can assign the element types and it looks like the logic
 > for creating this test was that EDG issues an error -- but about array
 > assignment in general.
 
 I agree.
 
 > Anyhow, did you change the test, or did it still pass for you?
 
 Neither; I failed to notice the failure in my testrun.  Double oops.
 
 The original bug report that the testcase is derived from complained about
 the error; the customer said that either the extension should be dropped or
 the testcase should be accepted.  Neither of those came to pass.
 
 I wouldn't object to making the pedwarn unconditional.
 
 Jason

Re: c++/6331: g++ 3.1 looses const qualifiers

[Mark Mitchell]

The following reply was made to PR c++/6331; it has been noted by GNATS.

From: Mark Mitchell <mark@codesourcery.com>
To: "jason@gcc.gnu.org" <jason@gcc.gnu.org>, "aj@suse.de" <aj@suse.de>,
   "gcc-bugs@gcc.gnu.org" <gcc-bugs@gcc.gnu.org>,
   "gcc-prs@gcc.gnu.org" <gcc-prs@gcc.gnu.org>,
   "mmitchel@gcc.gnu.org" <mmitchel@gcc.gnu.org>,
   "pmladek@suse.cz" <pmladek@suse.cz>, "pthomas@suse.de" <pthomas@suse.de>,
   "schwab@suse.de" <schwab@suse.de>,
   "gcc-gnats@gcc.gnu.org" <gcc-gnats@gcc.gnu.org>
Cc:  
Subject: Re: c++/6331: g++ 3.1 looses const qualifiers
Date: Wed, 24 Apr 2002 08:55:26 -0700

 --On Wednesday, April 24, 2002 09:05:06 AM +0000 "jason@gcc.gnu.org" 
 <jason@gcc.gnu.org> wrote:
 
 > Synopsis: g++ 3.1 looses const qualifiers
 >
 > Responsible-Changed-From-To: mmitchel->jason
 > Responsible-Changed-By: jason
 > Responsible-Changed-When: Wed Apr 24 02:05:05 2002
 > Responsible-Changed-Why:
 >     got the second bug
 >
 > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gc
 > c&pr=6331
 
 Shucks, we were duplicating work; I was working on that too.
 
 When I tried the change you made to build_modify_expr, I got a failure in
 this g++.benjamin/14664-1.c, which tests that we cannot assign a string
 literal to an array of characters (because the array of characters is
 const).  This is probably a goofy test; what shoudl be interesting is
 whether we can assign the element types and it looks like the logic
 for creating this test was that EDG issues an error -- but about array
 assignment in general.
 
 Anyhow, did you change the test, or did it still pass for you?
 
 --
 Mark Mitchell                   mark@codesourcery.com
 CodeSourcery, LLC               http://www.codesourcery.com
 

Re: c++/6331: g++ 3.1 looses const qualifiers

[jason]

Synopsis: g++ 3.1 looses const qualifiers

Responsible-Changed-From-To: mmitchel->jason
Responsible-Changed-By: jason
Responsible-Changed-When: Wed Apr 24 02:05:05 2002
Responsible-Changed-Why:
    got the second bug

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6331

Re: c++/6331: g++ 3.1 looses const qualifiers

[schwab]

Synopsis: g++ 3.1 looses const qualifiers

State-Changed-From-To: closed->open
State-Changed-By: schwab
State-Changed-When: Tue Apr 23 15:24:15 2002
State-Changed-Why:
    Still not fixed

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6331

Re: c++/6331: g++ 3.1 looses const qualifiers

[mmitchel]

Synopsis: g++ 3.1 looses const qualifiers

State-Changed-From-To: analyzed->closed
State-Changed-By: mmitchel
State-Changed-When: Tue Apr 23 01:43:04 2002
State-Changed-Why:
    Fixed.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6331

Re: c++/6331: g++ 3.1 looses const qualifiers

[mmitchel]

Synopsis: g++ 3.1 looses const qualifiers

Responsible-Changed-From-To: unassigned->mmitchel
Responsible-Changed-By: mmitchel
Responsible-Changed-When: Mon Apr 22 11:14:09 2002
Responsible-Changed-Why:
    Working on fix.
State-Changed-From-To: open->analyzed
State-Changed-By: mmitchel
State-Changed-When: Mon Apr 22 11:14:09 2002
State-Changed-Why:
    Confirmed.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6331