[Bug c++/96467] New: [8/9/10/11 Regression] in finish_member_declaration, at cp/semantics.c:3240

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96467

            Bug ID: 96467
           Summary: [8/9/10/11 Regression] in finish_member_declaration,
                    at cp/semantics.c:3240
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: haoxintu at gmail dot com
  Target Milestone: ---

Hi, all.

This code makes GCC-9.1 onwards versions ICE without any error messages. I
guess this case is more seriously because this makes released versions ICE
rather than "confused by earlier errors".

Input:
//small.cc
union a;
a :: b () alignas (enum {c});

Command:
g++ small.cc

Output:
small.cc:2:26: internal compiler error: in finish_member_declaration, at
cp/semantics.c:3240
    2 | a :: b () alignas (enum {c});
      |                          ^
0x5c82c0 finish_member_declaration(tree_node*)
        ../../gcc/cp/semantics.c:3240
0x67d578 build_enumerator(tree_node*, tree_node*, tree_node*, tree_node*,
unsigned int)
        ../../gcc/cp/decl.c:15887
0x6e8b47 cp_parser_enumerator_definition
        ../../gcc/cp/parser.c:19493
0x6e8b47 cp_parser_enumerator_list
        ../../gcc/cp/parser.c:19422
0x6e8b47 cp_parser_enum_specifier
        ../../gcc/cp/parser.c:19353
0x6e8b47 cp_parser_type_specifier
        ../../gcc/cp/parser.c:17683
0x6fb6f9 cp_parser_type_specifier_seq
        ../../gcc/cp/parser.c:22386
0x6f5c84 cp_parser_type_id_1
        ../../gcc/cp/parser.c:22203
0x6f5ecf cp_parser_type_id
        ../../gcc/cp/parser.c:22282
0x6f5ecf cp_parser_std_attribute_spec
        ../../gcc/cp/parser.c:27079
0x6f5ecf cp_parser_std_attribute_spec_seq
        ../../gcc/cp/parser.c:27142
0x6f3b43 cp_parser_direct_declarator
        ../../gcc/cp/parser.c:21234
0x6f3b43 cp_parser_declarator
        ../../gcc/cp/parser.c:21057
0x706577 cp_parser_init_declarator
        ../../gcc/cp/parser.c:20557
0x6e9c32 cp_parser_simple_declaration
        ../../gcc/cp/parser.c:13734
0x70f952 cp_parser_declaration
        ../../gcc/cp/parser.c:13433
0x710074 cp_parser_translation_unit
        ../../gcc/cp/parser.c:4734
0x710074 c_parse_file()
        ../../gcc/cp/parser.c:43975
0x7d84fb c_common_parse_file()
        ../../gcc/c-family/c-opts.c:1190
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

My GCC version is
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/home/haoxin/corpus-compilers/gcc-trunk/gcc-master/build/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure
--prefix=/home/haoxin/corpus-compilers/gcc-trunk/gcc-master/build/
--enable-languages=c,c++ CC=gcc CXX=g++
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20200801 (experimental) (GCC) 

Thanks,
Haoxin