[Bug c++/104470] internal compiler error: Segmentation fault compiling std::variant with -std=c++20

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104470

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
here is the full backtrace:
In file included from t.cc:2:
/home/apinski/upstream-gcc/include/c++/12.0.1/variant: In substitution of
‘template<class ... _Types> template<class _Tp, class> using __accepted_type =
std::variant<_Types>::__to_type<__accepted_index<_Tp> > [with _Tp = _Tp&&;
<template-parameter-2-2> = typename std::enable_if<std::variant<Foo<T>, Bar<T>
>::__not_self<_Tp&&>, void>::type; _Types = {Foo<T>, Bar<T>}]’:
t.cc:21:15:   required from here
/home/apinski/upstream-gcc/include/c++/12.0.1/variant:1384:43: internal
compiler error: Segmentation fault
 1384 |         using __accepted_type = __to_type<__accepted_index<_Tp>>;
      |                                           ^~~~~~~~~~~~~~~~~~~~
0x11fceef crash_signal
        /home/apinski/src/upstream-gcc-git/gcc/gcc/toplev.cc:322
0xba5a12 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:19883
0xbb95df tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:19316
0xbc306e tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:13423
0xbc3292 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:13405
0xbb4a9e tsubst(tree_node*, tree_node*, int, tree_node*)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:15461
0xbc4197 tsubst_decl
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:14815
0xbb3792 instantiate_template_1
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:21470
0xbb4b7f instantiate_template(tree_node*, tree_node*, int)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:21529
0xbb4b7f instantiate_alias_template
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:21567
0xbb4b7f tsubst(tree_node*, tree_node*, int, tree_node*)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:15462
0xbd278e rewrite_tparm_list
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:29006
0xbddce4 alias_ctad_tweaks
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:29484
0xb9e9aa deduction_guides_for
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:29646
0xb9ec34 do_class_deduction
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:29777
0xb9ec34 do_auto_deduction(tree_node*, tree_node*, tree_node*, int,
auto_deduction_context, tree_node*, int)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/pt.cc:29934
0xa84b86 cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/decl.cc:7947
0xb767e4 cp_parser_init_declarator
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/parser.cc:22811
0xb51428 cp_parser_simple_declaration
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/parser.cc:15284
0xb531d0 cp_parser_declaration_statement
        /home/apinski/src/upstream-gcc-git/gcc/gcc/cp/parser.cc:14365
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