https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99243
--- Comment #1 from Alexander Lelyakin <alexander.lelyakin at googlemail dot com> --- There is a shorter sequence /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header concepts /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header utility /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header regex ---- In file included from /usr/local/include/c++/11.0.1/bits/stl_iterator_base_types.h:71, from /usr/local/include/c++/11.0.1/bits/stl_algobase.h:65, from /usr/local/include/c++/11.0.1/algorithm:61, from /usr/local/include/c++/11.0.1/regex:38: /usr/local/include/c++/11.0.1/bits/iterator_concepts.h:34: internal compiler error: in set_filename, at cp/module.cc:19100 34 | | 0x6e0cbb module_state::set_filename(Cody::Packet const&) ../../gcc/gcc/cp/module.cc:19100 0xa5a979 maybe_translate_include ../../gcc/gcc/cp/module.cc:19143 0xa5a979 maybe_translate_include ../../gcc/gcc/cp/module.cc:19114 0x1cf5606 _cpp_stack_file ../../gcc/libcpp/files.c:913 0x1ced69e do_include_common ../../gcc/libcpp/directives.c:853 0x1cedbe8 _cpp_handle_directive ../../gcc/libcpp/directives.c:541 0x1cfca60 _cpp_lex_token ../../gcc/libcpp/lex.c:2809 0x1d048c7 cpp_get_token_1 ../../gcc/libcpp/macro.c:2839 0xbf070e c_lex_with_flags(tree_node**, unsigned int*, unsigned char*, int) ../../gcc/gcc/c-family/c-lex.c:470 0xa8ee76 cp_lexer_get_preprocessor_token ../../gcc/gcc/cp/parser.c:864 0xad93af cp_lexer_new_main ../../gcc/gcc/cp/parser.c:663 0xad93af c_parse_file() ../../gcc/gcc/cp/parser.c:45253 0xbfd98d c_common_parse_file() ../../gcc/gcc/c-family/c-opts.c:1218 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++ (GCC) 11.0.1 20210326 (experimental) Copyright (C) 2021 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.