[Bug c++/95956] New: ICE in check_bases, at cp/class.c:1689

[Bug c++/95956] New: ICE in check_bases, at cp/class.c:1689

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95956

            Bug ID: 95956
           Summary: ICE in check_bases, at cp/class.c:1689
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: error-recovery, 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: ---

This code, bug.cc, reduced by C-Reduce, makes GCC-trunk ICE.

$cat bug.cc
a ( auto struct : decltype ( auto  ) { {

$g++ bug.cc
bug.cc:1:5: warning: use of ‘auto’ in parameter declaration only available with
‘-fconcepts-ts’
    1 | a ( auto struct : decltype ( auto  ) { {
      |     ^~~~
bug.cc:1:38: error: types may not be defined in parameter types
    1 | a ( auto struct : decltype ( auto  ) { {
      |                                      ^
bug.cc:1:40: error: expected unqualified-id before ‘{’ token
    1 | a ( auto struct : decltype ( auto  ) { {
      |                                        ^
bug.cc:2: error: expected ‘}’ at end of input
bug.cc:1:38: note: to match this ‘{’
    1 | a ( auto struct : decltype ( auto  ) { {
      |                                      ^
bug.cc:1:17: internal compiler error: in check_bases, at cp/class.c:1689
    1 | a ( auto struct : decltype ( auto  ) { {
      |                 ^
0x5ed0ac check_bases
        ../../gcc/cp/class.c:1689
0x5ed0ac check_bases_and_members
        ../../gcc/cp/class.c:5900
0x89eca3 finish_struct_1(tree_node*)
        ../../gcc/cp/class.c:7269
0x8a06d4 finish_struct(tree_node*, tree_node*)
        ../../gcc/cp/class.c:7573
0x99f973 cp_parser_class_specifier_1
        ../../gcc/cp/parser.c:23955
0x9a1aa3 cp_parser_class_specifier
        ../../gcc/cp/parser.c:24254
0x9a1aa3 cp_parser_type_specifier
        ../../gcc/cp/parser.c:17762
0x9a2a02 cp_parser_decl_specifier_seq
        ../../gcc/cp/parser.c:14410
0x9bf3ef cp_parser_parameter_declaration
        ../../gcc/cp/parser.c:22818
0x9bfdd2 cp_parser_parameter_declaration_list
        ../../gcc/cp/parser.c:22641
0x9c01bc cp_parser_parameter_declaration_clause
        ../../gcc/cp/parser.c:22568
0x9ad617 cp_parser_direct_declarator
        ../../gcc/cp/parser.c:21245
0x9ad617 cp_parser_declarator
        ../../gcc/cp/parser.c:21109
0x9c1ba6 cp_parser_init_declarator
        ../../gcc/cp/parser.c:20609
0x9a36d2 cp_parser_simple_declaration
        ../../gcc/cp/parser.c:13785
0x9cc926 cp_parser_declaration
        ../../gcc/cp/parser.c:13484
0x9cd06a cp_parser_translation_unit
        ../../gcc/cp/parser.c:4761
0x9cd06a c_parse_file()
        ../../gcc/cp/parser.c:44043
0xae4dbb 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.

$g++ --version
g++ (GCC) 11.0.0 20200626 (experimental)
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[Bug c++/95956] ICE in check_bases, at cp/class.c:1689

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95956

W E Brown <webrown.cpp at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |webrown.cpp at gmail dot com

--- Comment #1 from Haoxin Tu <haoxintu at gmail dot com> ---
Add a more readable case.

$cat p.cc
int a ( auto struct : decltype ( auto ) {{}}){}


$g++ -w p.cc
p.cc:1:41: error: types may not be defined in parameter types
    1 | int a ( auto struct : decltype ( auto ) {{}}){}
      |                                         ^
p.cc:1:42: error: expected unqualified-id before ‘{’ token
    1 | int a ( auto struct : decltype ( auto ) {{}}){}
      |                                          ^
p.cc:1:21: internal compiler error: in check_bases, at cp/class.c:1689
    1 | int a ( auto struct : decltype ( auto ) {{}}){}
      |                     ^
0x658963 check_bases
        ../../gcc/cp/class.c:1689
0x658963 check_bases_and_members
        ../../gcc/cp/class.c:5900

[Bug c++/95956] ICE in check_bases, at cp/class.c:1689

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95956

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
                 CC|                            |mpolacek at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
           Priority|P3                          |P5
   Last reconfirmed|                            |2020-07-08