[Bug c++/70286] New: ICE on template specialization

[rippey.e at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70286

            Bug ID: 70286
           Summary: ICE on template specialization
           Product: gcc
           Version: 5.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rippey.e at gmail dot com
  Target Milestone: ---

When the following code:

template<int>struct A B;
template<>struct B<>:

is run with g++ 5.3.0, with the argument "--std=c++14", the following is
produced:

a.cpp:2:18: internal compiler error: Segmentation fault
 template<>struct B<>:
                  ^
0xacecef crash_signal
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/toplev.c:383
0x66180e maybe_process_partial_specialization(tree_node*)
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/pt.c:834
0x696177 cp_parser_class_head
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:20428
0x696177 cp_parser_class_specifier_1
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:19816
0x696177 cp_parser_class_specifier
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:20108
0x696177 cp_parser_type_specifier
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:14727
0x6a9a87 cp_parser_decl_specifier_seq
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:11958
0x6ae998 cp_parser_single_declaration
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:23776
0x6af33d cp_parser_explicit_specialization
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:14623
0x691bbf cp_parser_declaration
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:11332
0x6b87ea cp_parser_declaration_seq_opt
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:11265
0x6b8aff cp_parser_translation_unit
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:4100
0x6b8aff c_parse_file()
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:33229
0x76bb92 c_common_parse_file()
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/c-family/c-opts.c:1057
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

A similar report is produced if the compiler is given the flag "--std=c++11":

a.cpp:1:23: warning: variable templates only available with -std=c++14 or
-std=gnu++14
 template<int>struct A B;
                       ^
a.cpp:2:18: internal compiler error: Segmentation fault
 template<>struct B<>:
                  ^
0xacecef crash_signal
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/toplev.c:383
0x66180e maybe_process_partial_specialization(tree_node*)
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/pt.c:834
0x696177 cp_parser_class_head
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:20428
0x696177 cp_parser_class_specifier_1
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:19816
0x696177 cp_parser_class_specifier
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:20108
0x696177 cp_parser_type_specifier
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:14727
0x6a9a87 cp_parser_decl_specifier_seq
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:11958
0x6ae998 cp_parser_single_declaration
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:23776
0x6af33d cp_parser_explicit_specialization
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:14623
0x691bbf cp_parser_declaration
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:11332
0x6b87ea cp_parser_declaration_seq_opt
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:11265
0x6b8aff cp_parser_translation_unit
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:4100
0x6b8aff c_parse_file()
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/cp/parser.c:33229
0x76bb92 c_common_parse_file()
        /disk/0/erippey/gcc/objdir/../gcc-5.3.0/gcc/c-family/c-opts.c:1057
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

Running gcc 4.8.5 with "--std=c++11" does not produce an ICE.