[Bug c++/70037] [concepts] comdat group error and an ICE with a conceptified tuple implementation

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70037

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Created attachment 47038
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47038&action=edit
New testcase

I tried updating the attachment to C++2a syntax and it crashes differently:

g++ -std=gnu++20 70037.ii -Wno-deprecated-declarations -Wno-literal-suffix

70037.ii:20114:37: internal compiler error: in push_access_scope, at
cp/pt.c:233
20114 |       : _Inherited(__elements...) { }
      |                                     ^
0x9a00a6 push_access_scope(tree_node*)
        /home/jwakely/src/gcc/gcc/gcc/cp/pt.c:232
0x89f53d constraints_satisfied_p
        /home/jwakely/src/gcc/gcc/gcc/cp/constraint.cc:2528
0x86c493 add_method(tree_node*, tree_node*, bool)
        /home/jwakely/src/gcc/gcc/gcc/cp/class.c:1097
0x9f8773 finish_member_declaration(tree_node*)
        /home/jwakely/src/gcc/gcc/gcc/cp/semantics.c:3275
0x98c46a cp_parser_template_declaration_after_parameters
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28664
0x98cd8d cp_parser_explicit_template_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28838
0x98cd8d cp_parser_template_declaration_after_export
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28857
0x98e20d cp_parser_member_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:24583
0x9655fa cp_parser_member_specification_opt
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:24510
0x9655fa cp_parser_class_specifier_1
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:23597
0x967a39 cp_parser_class_specifier
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:23913
0x967a39 cp_parser_type_specifier
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:17511
0x968964 cp_parser_decl_specifier_seq
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:14203
0x98c055 cp_parser_single_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28909
0x98c3ef cp_parser_template_declaration_after_parameters
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28572
0x98cd8d cp_parser_explicit_template_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28838
0x98cd8d cp_parser_template_declaration_after_export
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28857
0x98fad9 cp_parser_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:13241
0x99057c cp_parser_declaration_seq_opt
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:13168
0x99057c cp_parser_namespace_body
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:19479
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