https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99238
--- Comment #1 from Alexander Lelyakin <alexander.lelyakin at googlemail dot com> --- There is a shorter sequence: g++ -std=c++20 -fmodules-ts -x c++-system-header fstream g++ -std=c++20 -fmodules-ts -x c++-system-header string_view g++ -std=c++20 -fmodules-ts -x c++-system-header locale ---- /usr/local/include/c++/11.0.1/locale: internal compiler error: Segmentation fault 0x10fc36f crash_signal ../../gcc/gcc/toplev.c:327 0x6de73c trees_out::get_tag(tree_node*) ../../gcc/gcc/cp/module.cc:4898 0x6de73c trees_out::ref_node(tree_node*) ../../gcc/gcc/cp/module.cc:7205 0x6de73c trees_out::ref_node(tree_node*) ../../gcc/gcc/cp/module.cc:7188 0xa5c4dc trees_out::tree_node(tree_node*) ../../gcc/gcc/cp/module.cc:9055 0xa5e411 trees_out::type_node(tree_node*) ../../gcc/gcc/cp/module.cc:8778 0xa5c8da trees_out::tree_node(tree_node*) ../../gcc/gcc/cp/module.cc:9138 0xa5e1cc trees_out::type_node(tree_node*) ../../gcc/gcc/cp/module.cc:8696 0xa5c8da trees_out::tree_node(tree_node*) ../../gcc/gcc/cp/module.cc:9138 0xa5e654 trees_out::type_node(tree_node*) ../../gcc/gcc/cp/module.cc:8805 0xa5c8da trees_out::tree_node(tree_node*) ../../gcc/gcc/cp/module.cc:9138 0xa5e1cc trees_out::type_node(tree_node*) ../../gcc/gcc/cp/module.cc:8696 0xa5c8da trees_out::tree_node(tree_node*) ../../gcc/gcc/cp/module.cc:9138 0xa5d20f trees_out::core_vals(tree_node*) ../../gcc/gcc/cp/module.cc:6108 0xa5e0ec trees_out::tree_node_vals(tree_node*) ../../gcc/gcc/cp/module.cc:7168 0xa5e0ec trees_out::fn_parms_init(tree_node*) ../../gcc/gcc/cp/module.cc:10069 0xa5b086 trees_out::decl_value(tree_node*, depset*) ../../gcc/gcc/cp/module.cc:7765 0xa625c3 depset::hash::find_dependencies(module_state*) ../../gcc/gcc/cp/module.cc:13237 0xa62c28 module_state::write(elf_out*, cpp_reader*) ../../gcc/gcc/cp/module.cc:17652 0xa640cf finish_module_processing(cpp_reader*) ../../gcc/gcc/cp/module.cc:19922 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 20210228 (experimental)