https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121865
Nathaniel Shead <nshead at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |nshead at gcc dot gnu.org
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2025-09-09
--- Comment #2 from Nathaniel Shead <nshead at gcc dot gnu.org> ---
Confirmed. Reduction:
// a.cpp
module;
template <typename T> struct S;
template <typename T> void foo(S<T>);
template <typename T> struct S {
friend void foo<>(S);
};
export module M;
export using ::S;
// b.cpp
import M;
template struct S<int>;
int main() {}
$ g++ -fmodules -flto=auto a.cpp b.cpp
a.cpp:2:1: warning: global module fragment contents must be from preprocessor
inclusion [-Wglobal-module]
2 | template <typename T> struct S;
| ^~~~~~~~
during IPA pass: *free_lang_data
In module M, imported at b.cpp:1:
a.cpp:5:15: internal compiler error: tree check: expected template_decl, have
overload in maybe_template_info, at cp/mangle.cc:311
5 | friend void foo<>(S);
| ^~~~~
0x3dfb522 internal_error(char const*, ...)
../../gcc/gcc/diagnostic-global-context.cc:786
0x2306ed1 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
../../gcc/gcc/tree.cc:9184
0xf5c679 tree_check(tree_node*, char const*, int, char const*, tree_code)
../../gcc/gcc/tree.h:3733
0x1177987 maybe_template_info
../../gcc/gcc/cp/mangle.cc:311
0x117a6a1 mangle_return_type_p(tree_node*)
../../gcc/gcc/cp/mangle.cc:853
0xfa8b87 check_abi_tags(tree_node*)
../../gcc/gcc/cp/class.cc:1941
0x1179f48 write_mangled_name
../../gcc/gcc/cp/mangle.cc:801
0x118fc0e mangle_decl_string
../../gcc/gcc/cp/mangle.cc:4534
0x118fc6b get_mangled_id
../../gcc/gcc/cp/mangle.cc:4550
0x118ffbc mangle_decl(tree_node*)
../../gcc/gcc/cp/mangle.cc:4588
0x22e5105 decl_assembler_name(tree_node*)
../../gcc/gcc/tree.cc:851
0x22e56f6 assign_assembler_name_if_needed(tree_node*)
../../gcc/gcc/tree.cc:967
0x3870cde free_lang_data_in_cgraph
../../gcc/gcc/ipa-free-lang-data.cc:1082
0x3870f35 free_lang_data
../../gcc/gcc/ipa-free-lang-data.cc:1127
0x38710f4 execute
../../gcc/gcc/ipa-free-lang-data.cc:1194
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
