[Bug c++/60065] New: [c++1y] ICE with auto parameter pack

[Bug c++/60065] New: [c++1y] ICE with auto parameter pack

[reichelt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60065

            Bug ID: 60065
           Summary: [c++1y] ICE with auto parameter pack
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: reichelt at gcc dot gnu.org

The following line of code (compiled with "-std=c++1y") triggers an ICE on
trunk:

========================================
template<int> void foo(auto... x);
========================================

bug.cc:1:32: internal compiler error: tree check: expected template_type_parm
or template_template_parm or bound_template_template_parm, have integer_type in
convert_generic_types_to_packs, at cp/pt.c:21726
 template<int> void foo(auto... x);
                                ^
0xdc4824 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
        ../../gcc/gcc/tree.c:9192
0x64ad63 tree_check3
        ../../gcc/gcc/tree.h:2749
0x64ad63 convert_generic_types_to_packs(tree_node*, int, int)
        ../../gcc/gcc/cp/pt.c:21726
0x6c8f47 cp_parser_parameter_declaration_list
        ../../gcc/gcc/cp/parser.c:18279
0x6c9532 cp_parser_parameter_declaration_clause
        ../../gcc/gcc/cp/parser.c:18179
0x6bfd05 cp_parser_direct_declarator
        ../../gcc/gcc/cp/parser.c:17072
0x6bfd05 cp_parser_declarator
        ../../gcc/gcc/cp/parser.c:16943
0x6ca599 cp_parser_init_declarator
        ../../gcc/gcc/cp/parser.c:16496
0x6cb41a cp_parser_single_declaration
        ../../gcc/gcc/cp/parser.c:23113
0x6cb704 cp_parser_template_declaration_after_export
        ../../gcc/gcc/cp/parser.c:22915
0x6d6af9 cp_parser_declaration
        ../../gcc/gcc/cp/parser.c:10947
0x6d55e8 cp_parser_declaration_seq_opt
        ../../gcc/gcc/cp/parser.c:10869
0x6d6eca cp_parser_translation_unit
        ../../gcc/gcc/cp/parser.c:4014
0x6d6eca c_parse_file()
        ../../gcc/gcc/cp/parser.c:31528
0x7f6973 c_common_parse_file()
        ../../gcc/gcc/c-family/c-opts.c:1060
Please submit a full bug report, [etc.]

The code compiles if I remove the 'x' or replace 'int' by 'typename'.
I'm not sure whether the code is valid or not, though.

[Bug c++/60065] [c++1y] ICE with auto parameter pack

[abutcher at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60065

Adam Butcher <abutcher at gcc dot gnu.org> changed:

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

--- Comment #1 from Adam Butcher <abutcher at gcc dot gnu.org> ---
I think it is valid.  It should be considered equivalent to:

  template <int, typename... T> void foo(T... x);

Looks like the generic parameter pack 'auto...' is replacing the template
argument list rather than extending it.  I'll look into it.

[Bug c++/60065] [c++1y] ICE with auto parameter pack

[abutcher at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60065

--- Comment #2 from Adam Butcher <abutcher at gcc dot gnu.org> ---
Turns out the base template parameter index was not been initialized correctly
so it was trying to convert the 'int' parameter to a pack as well as the
invented template parameter generated for the 'auto'.  See
http://gcc.gnu.org/ml/gcc-patches/2014-02/msg01197.html

[Bug c++/60065] [c++1y] ICE with auto parameter pack

[abutcher at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60065

--- Comment #3 from Adam Butcher <abutcher at gcc dot gnu.org> ---
Author: abutcher
Date: Tue Feb 25 03:47:24 2014
New Revision: 208106

URL: http://gcc.gnu.org/viewcvs?rev=208106&root=gcc&view=rev
Log:
Fix PR c++/60065.

    PR c++/60065
    * parser.c (cp_parser_direct_declarator): Don't save and
    restore num_template_parameter_lists around call to
    cp_parser_parameter_declaration_list.
    (function_being_declared_is_template_p): New predicate.
    (cp_parser_parameter_declaration_list): Use
    function_being_declared_is_template_p as predicate for
    inspecting current function template parameter list length
    rather than num_template_parameter_lists.

    PR c++/60065
    * g++.dg/cpp1y/pr60065.C: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/cpp1y/pr60065.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/parser.c
    trunk/gcc/testsuite/ChangeLog

[Bug c++/60065] [c++1y] ICE with auto parameter pack

[reichelt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60065

Volker Reichelt <reichelt at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
             Status|UNCONFIRMED                 |RESOLVED
      Known to work|                            |4.9.0
         Resolution|---                         |FIXED
   Target Milestone|---                         |4.9.0
      Known to fail|4.9.0                       |

--- Comment #4 from Volker Reichelt <reichelt at gcc dot gnu.org> ---
Fixed by Adam's patch.