[Bug c++/50870] New: [C++0x] ICE with decltype, operator->, and default template arguments

[Bug c++/50870] New: [C++0x] ICE with decltype, operator->, and default template arguments

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

             Bug #: 50870
           Summary: [C++0x] ICE with decltype, operator->, and default
                    template arguments
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: daniel.kruegler@googlemail.com
                CC: jason@redhat.com


This is a follow-up of bug 50864.

gcc 4.7.0 20111022 (experimental) with compiler option 

-std=c++0x -Wall

(with or without -pedantic) causes an ICE for the following code 

//---
struct impl {
  template <class T> static T create();
};

#define USE_CLASS

#ifdef USE_CLASS
template<class T, class U,
  class = decltype(impl::create<T>()->impl::create<U>()) // line 9
>
struct tester{};

tester<impl*, int> ti;
#else
template<class T, class U,
  class = decltype(impl::create<T>()->impl::create<U>()) // line 16
>
int test() { return 0; }

int i = test<impl*, int>();
#endif
//---

If USE_CLASS is defined:

"main.cpp|9|internal compiler error: Segmentation fault"

otherwise:

"main.cpp|16|internal compiler error: Segmentation fault"

Both code branches should be accepted.

[Bug c++/50870] [C++0x] ICE with decltype, operator->, and default template arguments

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-26 18:03:20 UTC ---
Fixed for 4.7.0.

[Bug c++/50870] [C++0x] ICE with decltype, operator->, and default template arguments

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

--- Comment #1 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2011-10-26 17:59:42 UTC ---
Author: paolo
Date: Wed Oct 26 17:59:36 2011
New Revision: 180531

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180531
Log:
2011-10-26  Paolo Carlini  <paolo.carlini@oracle.com>

    * typeck.c (cp_build_addr_expr_1): Use BASELINK_P.
    * class.c (instantiate_type): Likewise.
    * pt.c (convert_nontype_argument_function, uses_template_parms,
    tsubst_copy, resolve_nondeduced_context, type_dependent_expression_p):
    Likewise.
    * semantics.c (finish_decltype_type): Likewise.
    * decl2.c (mark_used): Likewise.
    * name-lookup.c (arg_assoc): Likewise.

/cp
2011-10-26  Paolo Carlini  <paolo.carlini@oracle.com>

    PR c++/50870
    * typeck.c (non_reference): Pass NULL_TREE through.

/testsuite
2011-10-26  Paolo Carlini  <paolo.carlini@oracle.com>

    PR c++/50870
    * g++.dg/cpp0x/decltype34.C: New.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/decltype34.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/class.c
    trunk/gcc/cp/decl2.c
    trunk/gcc/cp/name-lookup.c
    trunk/gcc/cp/pt.c
    trunk/gcc/cp/semantics.c
    trunk/gcc/cp/typeck.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2011-10-26
                 CC|paolo.carlini at oracle dot |
                   |com                         |
         Resolution|FIXED                       |
         AssignedTo|unassigned at gcc dot       |paolo.carlini at oracle dot
                   |gnu.org                     |com
   Target Milestone|4.7.0                       |4.6.3
            Summary|[C++0x] ICE with decltype,  |[C++0x] [4.6/4.7
                   |operator->, and default     |Regression] ICE with
                   |template arguments          |decltype, operator->, and
                   |                            |default template arguments
     Ever Confirmed|0                           |1

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-26 22:10:11 UTC ---
Uhhm, let's reopen this: first it's a 4.6 Regression too, second we are still
not Ok for impl template, eg:

template <class V>
  struct impl
  {
    template <class T> static T create();
  };

template <class T, class U, class V, class
      = decltype(impl<V>::template create<T>()
             -> impl<V>::template create<U>())>
struct tester { };

tester<impl<float>*, int, float> ti;

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-28 09:52:14 UTC ---
HJ, any chance you can figure out when we regressed for testcase in Comment #3
?

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> 2011-10-28 15:53:39 UTC ---
(In reply to comment #4)
> HJ, any chance you can figure out when we regressed for testcase in Comment #3
> ?

I tried different versions of GCC, I got

pr50870.cc:8: error: expected type-specifier before ‘decltype’
pr50870.cc:8: error: expected `>' before ‘decltype’
pr50870.cc:12: error: template argument 4 is invalid
pr50870.cc:12: error: invalid type in declaration before ‘;’ token

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-28 16:40:15 UTC ---
HJ, if you are willing to help you have to use -std=c++0x with this (see the
[C++0x] in the Description]. 4_5-branch accepts the snippet, the regression is
rather old.

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dodji at gcc dot gnu.org

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> 2011-10-28 19:41:40 UTC ---
(In reply to comment #3)
> Uhhm, let's reopen this: first it's a 4.6 Regression too, second we are still
> not Ok for impl template, eg:
> 
> template <class V>
>   struct impl
>   {
>     template <class T> static T create();
>   };
> 
> template <class T, class U, class V, class
>       = decltype(impl<V>::template create<T>()
>              -> impl<V>::template create<U>())>
> struct tester { };
> 
> tester<impl<float>*, int, float> ti;

It is caused by revision 166179:

http://gcc.gnu.org/ml/gcc-cvs/2010-11/msg00065.html

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

--- Comment #8 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-28 23:23:43 UTC ---
Thanks HJ.

Dodji, I tried to help a bit with these issues and made some progress, thanks
to Jason's help, of course. But this remaining issue is probably too hard to
debug for me, given my still limited understanding of the front-end. If you
could help it would be great.  Note: now that PR50864 is fixed in mainline, we
don't ICE anymore for the testcase in Comment #3, we reject it.

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |ASSIGNED
                 CC|                            |jason at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

--- Comment #9 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-07 22:52:27 UTC ---
Author: jason
Date: Mon Nov  7 22:52:23 2011
New Revision: 181131

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=181131
Log:
    PR c++/50870
    * pt.c (tsubst_copy): Handle NAMESPACE_DECL.
    (tsubst_copy_and_build) [COMPONENT_REF]: Handle a still-dependent
    object.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/decltype35.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/pt.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

--- Comment #10 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-08 00:46:10 UTC ---
Author: jason
Date: Tue Nov  8 00:46:06 2011
New Revision: 181140

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=181140
Log:
    PR c++/50870
    * pt.c (tsubst_copy): Handle NAMESPACE_DECL.
    (tsubst_copy_and_build) [COMPONENT_REF]: Handle a still-dependent
    object.

Added:
    branches/gcc-4_6-branch/gcc/testsuite/g++.dg/cpp0x/decltype35.C
Modified:
    branches/gcc-4_6-branch/gcc/cp/ChangeLog
    branches/gcc-4_6-branch/gcc/cp/pt.c
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog

[Bug c++/50870] [C++0x] [4.6/4.7 Regression] ICE with decltype, operator->, and default template arguments

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50870

Jason Merrill <jason at gcc dot gnu.org> changed:

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

--- Comment #11 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-08 01:11:42 UTC ---
Fixed.