[Bug c++/54440] New: [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[Bug c++/54440] New: [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[eric.niebler at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54440

             Bug #: 54440
           Summary: [c++11] g++ prematurely applying rule that a template
                    parameter pack cannot be followed by a template
                    parameter
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: eric.niebler@gmail.com


The following code:

  template<int...I>
  struct S
  {
    template<template<decltype(I)> class...A, template<int> class B>
    struct T;
  };

yields:

  main.cpp:5:12: error: parameter pack ‘A’ must be at the end of the template
parameter list

I believe this is erroneous, as does clang developer Richard Smith. After S is
instantiated, A instantiates to a non-pack.

[Bug c++/54440] [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54440

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2013-02-22
         AssignedTo|unassigned at gcc dot       |jason at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Jason Merrill <jason at gcc dot gnu.org> 2013-02-22 14:48:06 UTC ---
Created attachment 29523
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29523
patch

Here's a patch for after 4.8 branches.

[Bug c++/54440] [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54440

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Hi Jason. Noticed your patch here scheduled for 4.9...

[Bug c++/54440] [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[richard-gccbugzilla at metafoo dot co.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54440

Richard Smith <richard-gccbugzilla at metafoo dot co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |richard-gccbugzilla@metafoo
                   |                            |.co.uk

--- Comment #3 from Richard Smith <richard-gccbugzilla at metafoo dot co.uk> ---
Ping? Can the patch be applied now (or has this missed the boat for 4.9 as
well)?

[Bug c++/54440] [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54440

--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> ---
Author: jason
Date: Wed Feb 26 17:08:20 2014
New Revision: 208178

URL: http://gcc.gnu.org/viewcvs?rev=208178&root=gcc&view=rev
Log:
    PR c++/54440
    * pt.c (get_template_parm_index): New.
    (fixed_parameter_pack_p_1, fixed_parameter_pack_p): New.
    (process_template_parm): Allow bare packs in template template
    parm template parms.
    (coerce_template_parameter_pack): Handle fixed template template
    parm packs and fixed packs not at the end of the parm list.
    (coerce_template_parms): Handle template parm packs not at the end
    of the parm list.
    (gen_elem_of_pack_expansion_instantiation): Handle a decl expansion.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic151.C
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic152.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/pt.c
    trunk/gcc/testsuite/g++.dg/cpp0x/variadic74.C

[Bug c++/54440] [c++11] g++ prematurely applying rule that a template parameter pack cannot be followed by a template parameter

[jason at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54440

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |4.9.0

--- Comment #5 from Jason Merrill <jason at gcc dot gnu.org> ---
Applied (with minor tweaks).