[Bug c++/80008] New: internal compiler error: in cp_parser_direct_declarator, at cp/parser.c:20031 [C++17]

["julien at lecomte dot at" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80008

            Bug ID: 80008
           Summary: internal compiler error: in
                    cp_parser_direct_declarator, at cp/parser.c:20031
                    [C++17]
           Product: gcc
           Version: 7.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: julien at lecomte dot at
  Target Milestone: ---

Created attachment 40947
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40947&action=edit
json_scanner.ii

gcc (GCC) 7.0.1 20170305 (experimental)
libtoolize (GNU libtool) 2.4.2

$ cat /etc/debian_version
8.7

# command:
libtool: compile:  g++ -DHAVE_CONFIG_H -I. -Iinclude -std=c++17 -Wfatal-errors
-MT src/json_scanner.lo -MD -MP -MF src/.deps/json_scanner.Tpo -c
src/json_scanner.cxx  -fPIC -DPIC -o src/.libs/json_scanner.o

# notable env:
CXXFLAGS=-std=c++17 -Wfatal-errors
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games



src/json_scanner.cxx:6:1: internal compiler error: in
cp_parser_direct_declarator, at cp/parser.c:20031
 json_scanner(std::istream& is)
 ^~~~~~~~~~~~
0x77e21f cp_parser_direct_declarator
        ../../gcc/cp/parser.c:20031
0x77e21f cp_parser_declarator
        ../../gcc/cp/parser.c:19502
0x792c7d cp_parser_init_declarator
        ../../gcc/cp/parser.c:19047
0x793bd8 cp_parser_simple_declaration
        ../../gcc/cp/parser.c:12781
0x7948b1 cp_parser_block_declaration
        ../../gcc/cp/parser.c:12599
0x79b6a0 cp_parser_declaration
        ../../gcc/cp/parser.c:12496
0x79baa4 cp_parser_declaration_seq_opt
        ../../gcc/cp/parser.c:12372
0x79c17c cp_parser_namespace_body
        ../../gcc/cp/parser.c:18274
0x79c17c cp_parser_namespace_definition
        ../../gcc/cp/parser.c:18250
0x79b7cb cp_parser_declaration
        ../../gcc/cp/parser.c:12480
0x79baa4 cp_parser_declaration_seq_opt
        ../../gcc/cp/parser.c:12372
0x79bde8 cp_parser_translation_unit
        ../../gcc/cp/parser.c:4366
0x79bde8 c_parse_file()
        ../../gcc/cp/parser.c:38427
0x901eb2 c_common_parse_file()
        ../../gcc/c-family/c-opts.c:1107