[Bug c++/99241] [modules] ICE in install_entity, at cp/module.cc:7584

["alexander.lelyakin at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99241

--- 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 forward_list
g++ -std=c++20 -fmodules-ts -x c++-system-header ios
g++ -std=c++20 -fmodules-ts -x c++-system-header unordered_map
g++ -std=c++20 -fmodules-ts -x c++-system-header condition_variable
g++ -std=c++20 -fmodules-ts -x c++-system-header regex
----
In file included from /usr/local/include/c++/11.0.1/bits/unique_ptr.h:42,
                 from /usr/local/include/c++/11.0.1/bits/locale_conv.h:41,
                 from /usr/local/include/c++/11.0.1/locale:43,
                 from /usr/local/include/c++/11.0.1/regex:44:
/usr/local/include/c++/11.0.1/ostream:58:42: internal compiler error: in
install_entity, at cp/module.cc:7586
   58 |     class basic_ostream : virtual public basic_ios<_CharT, _Traits>
      |                                          ^~~~~~~~~
0xa5a52d trees_in::install_entity(tree_node*)
        ../../gcc/gcc/cp/module.cc:7586
0xa647aa trees_in::decl_value()
        ../../gcc/gcc/cp/module.cc:8108
0xa66317 trees_in::tree_node(bool)
        ../../gcc/gcc/cp/module.cc:9251
0xa6cad3 module_state::read_cluster(unsigned int)
        ../../gcc/gcc/cp/module.cc:14948
0xa6ce7d module_state::load_section(unsigned int, binding_slot*)
        ../../gcc/gcc/cp/module.cc:18148
0xa6d518 lazy_load_binding(unsigned int, tree_node*, tree_node*, binding_slot*)
        ../../gcc/gcc/cp/module.cc:18833
0xa7d39e name_lookup::search_namespace_only(tree_node*)
        ../../gcc/gcc/cp/name-lookup.c:924
0xa7eafb name_lookup::search_unqualified(tree_node*, cp_binding_level*)
        ../../gcc/gcc/cp/name-lookup.c:1155
0xa818f4 lookup_name_1
        ../../gcc/gcc/cp/name-lookup.c:7868
0xa81aba lookup_name(tree_node*, LOOK_where, LOOK_want)
        ../../gcc/gcc/cp/name-lookup.c:7888
0xa907d2 lookup_name(tree_node*, LOOK_want)
        ../../gcc/gcc/cp/name-lookup.h:412
0xa907d2 cp_parser_lookup_name
        ../../gcc/gcc/cp/parser.c:29339
0xab901f cp_parser_template_name
        ../../gcc/gcc/cp/parser.c:17694
0xab955f cp_parser_template_id
        ../../gcc/gcc/cp/parser.c:17303
0xab9dbb cp_parser_class_name
        ../../gcc/gcc/cp/parser.c:24671
0xab134a cp_parser_qualifying_entity
        ../../gcc/gcc/cp/parser.c:6994
0xab134a cp_parser_nested_name_specifier_opt
        ../../gcc/gcc/cp/parser.c:6676
0xaa51dc cp_parser_base_specifier
        ../../gcc/gcc/cp/parser.c:26690
0xaa51dc cp_parser_base_clause
        ../../gcc/gcc/cp/parser.c:26543
0xaa51dc cp_parser_class_head
        ../../gcc/gcc/cp/parser.c:25630
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)