https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99246
--- Comment #3 from Alexander Lelyakin <alexander.lelyakin at googlemail dot com> --- This ICE appeared again, gcc at commit bf1f3168f474734400e7a97660d1e7dec664bca9: ---- /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header bit /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header istream /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header cmath /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header locale /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header bitset /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header shared_mutex /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header new /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header ciso646 /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header memory /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header fstream /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header thread /usr/local/bin/g++ -std=c++20 -fmodules-ts -x c++-system-header regex ---- In module imported at /usr/local/include/c++/11.0.1/sstream:38:1, included from /usr/local/include/c++/11.0.1/regex:46: /usr/local/include/c++/11.0.1/istream: note: unable to represent further imported source locations /usr/local/include/c++/11.0.1/regex: internal compiler error: in write_location, at cp/module.cc:15642 0x6e02e9 module_state::write_location(bytes_out&, unsigned int) ../../gcc/gcc/cp/module.cc:15642 0xa60e13 trees_out::core_vals(tree_node*) ../../gcc/gcc/cp/module.cc:5894 0xa64244 trees_out::tree_node_vals(tree_node*) ../../gcc/gcc/cp/module.cc:7044 0xa64244 trees_out::tree_value(tree_node*) ../../gcc/gcc/cp/module.cc:8926 0xa60314 trees_out::tree_node(tree_node*) ../../gcc/gcc/cp/module.cc:9124 0xa6462a trees_out::write_var_def(tree_node*) ../../gcc/gcc/cp/module.cc:11511 0xa658c5 module_state::write_cluster(elf_out*, depset**, unsigned int, depset::hash&, unsigned int*, unsigned int*) ../../gcc/gcc/cp/module.cc:14697 0xa6721e module_state::write(elf_out*, cpp_reader*) ../../gcc/gcc/cp/module.cc:17769 0xa67dff finish_module_processing(cpp_reader*) ../../gcc/gcc/cp/module.cc:19883 0x9fb20b c_parse_final_cleanups() ../../gcc/gcc/cp/decl2.c:5175 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 20210324 (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.