[Bug c++/54466] New: Recursive Type Alias, Member Function Pointer, Segmentation Fault

[Bug c++/54466] New: Recursive Type Alias, Member Function Pointer, Segmentation Fault

[mattyclarkson at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

             Bug #: 54466
           Summary: Recursive Type Alias, Member Function Pointer,
                    Segmentation Fault
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mattyclarkson@gmail.com


Created attachment 28122
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28122
The preprocessed dump from the error.

The following code fails with a segmentation fault:

#include <memory>

template<typename T>
using CallbackPtr = const std::shared_ptr<const T>;

template<typename C, typename T>
using CallbackFunPtr = void (C::*)(CallbackPtr<T>);

int main () {
    return 0;
}

[matt test] g++ --std=c++11 -Wall -Wextra -Werror -pedantic -pedantic-errors
main.cpp
main.cpp:7:49: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://bugzilla.redhat.com/bugzilla> for instructions.
Preprocessed source stored into /tmp/ccuw4zjD.out file, please attach this to
your bugreport.

However changing CallbackFunPtr to:

template<typename C, typename T>
using CallbackFunPtr = void (C::*)(const std::shared_ptr<const T>);

It's OK.

[matt test] uname -r
3.5.2-3.fc17.x86_64
[matt test] gcc --version
gcc (GCC) 4.7.0 20120507 (Red Hat 4.7.0-5)
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[Bug c++/54466] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[mattyclarkson at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #1 from Matt Clarkson <mattyclarkson at gmail dot com> 2012-10-16 15:46:31 UTC ---
This is still an error on 4.7.2.

It is the const before the std::shared_ptr<const T> that is the problem:

        template<typename T>
#if (__GNUC__ <= 4) && (__GNUC_MINOR__ <= 7) && (__GNUC_PATCHLEVEL__ <= 2)
        using CallbackPtr = std::shared_ptr<const T>;
#else
        // This causes a segmentation fault on G++ 4.7.2
        // Bug Report: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466
        using CallbackPtr = const std::shared_ptr<const T>;
#endif

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-10-16
                 CC|                            |dodji at gcc dot gnu.org
            Summary|Recursive Type Alias,       |[C++11] Recursive Type
                   |Member Function Pointer,    |Alias, Member Function
                   |Segmentation Fault          |Pointer, Segmentation Fault
     Ever Confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-16 15:55:41 UTC ---
confirmed

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-10-16 22:32:02 UTC ---
A shorter self contained testcase, not involving the whole std::shared_ptr,
would certainly help. Dodji, are there any chances you can look into this
issue? The alias decls seem determinant.

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-16 23:09:30 UTC ---
template<typename T>
  struct X { };

template<typename T>
  using Y = const X<T>;

template<typename T>
  using Z = Y<T>;

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-10-16 23:13:18 UTC ---
Excellent.

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-10-16 23:16:48 UTC ---
The second alias doesn't even have to be a template to show the problem:

template<typename T>
  struct X { };

template<typename T>
  using Y = const X<T>;

using Z = Y<int>;

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[mattyclarkson at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #7 from Matt Clarkson <mattyclarkson at gmail dot com> 2012-10-17 08:19:20 UTC ---
Sorry about the bloated bug report - that was how I came across it.  In the
future I'll submit smaller test cases.

Thanks for looking into this.

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

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

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[dodji at seketeli dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #8 from dodji at seketeli dot org <dodji at seketeli dot org> 2012-10-26 15:13:10 UTC ---
"paolo.carlini at oracle dot com" <gcc-bugzilla@gcc.gnu.org> a écrit:

> Dodji, are there any chances you can look into this
> issue? The alias decls seem determinant.

Sure.  Sorry for the delay, I was buried into something else.  I am
looking into this now.

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[dodji at seketeli dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #9 from dodji at seketeli dot org <dodji at seketeli dot org> 2012-10-27 07:59:12 UTC ---
A candidate patch has been sent to
http://gcc.gnu.org/ml/gcc-patches/2012-10/msg02472.html.

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #10 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-11-13 16:07:50 UTC ---
Author: dodji
Date: Tue Nov 13 16:07:39 2012
New Revision: 193479

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193479
Log:
PR c++/54466 - ICE with alias template which type-id is const qualified

Consider this short example:

    template<typename T>
      struct X { };

    template<typename T>
      using Y = const X<T>;

    using Z = Y<int>;

G++ crashes in lookup_class_template_1 while trying to build the alias
template instantiation Y<int>.

I think this is indirectly due to the fact that that
lookup_class_template_1 can now yield a const qualified type like
'const X<T>'.

As a consequence, the code in lookup_template_class_1 that was trying
to access the TYPE_STUB_DECL field of the result of
lookup_template_class_1 should now be adjusted to access the
TYPE_STUB_DECL of the main variant of the resulting type instead (and
that is TYPE_MAIN_DECL); because qualified types (constructed with
build_qualified_type) have their TYPE_STUB_DECL set to NULL.

Fixed thus and tested on x86_64-unknown-linux-gnu against trunk.

gcc/cp

    PR c++/54466
    * pt.c (lookup_template_class_1): TYPE_STUB_DECL should be
    accessed on the main variant of the type.

gcc/testsuite/

    * g++.dg/cpp0x/alias-decl-26.C: New test file.

In the example of this patch, g++ crashes when trying to build the
alias template Y<int

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/alias-decl-26.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/pt.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[dodji at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

Dodji Seketeli <dodji at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #11 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-11-13 16:09:27 UTC ---
Fixed in trunk (4.8).

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[mattyclarkson at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #12 from Matt Clarkson <mattyclarkson at gmail dot com> 2012-11-14 14:24:11 UTC ---
@Dodji, thanks for fixing this :)  What release will this be in? 4.8.1?

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.8.0

--- Comment #13 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-11-14 14:29:19 UTC ---
4.8.0

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[dodji at seketeli dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

--- Comment #14 from dodji at seketeli dot org <dodji at seketeli dot org> 2012-11-15 13:52:18 UTC ---
"mattyclarkson at gmail dot com" <gcc-bugzilla@gcc.gnu.org> a écrit:

> @Dodji, thanks for fixing this :)

You are welcome.  Sorry for the delay.

>  What release will this be in? 4.8.1?

As Jon said, 4.8.0.

Cheers.

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mattipee at yahoo dot co.uk

--- Comment #15 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-12-05 13:05:34 UTC ---
*** Bug 53026 has been marked as a duplicate of this bug. ***

[Bug c++/54466] [C++11] Recursive Type Alias, Member Function Pointer, Segmentation Fault

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54466

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ali.rostai at gmail dot com

--- Comment #16 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-05-03 09:06:07 UTC ---
*** Bug 57152 has been marked as a duplicate of this bug. ***