https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123393
Nathaniel Shead <nshead at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
CC| |nshead at gcc dot gnu.org
Last reconfirmed| |2026-01-08
Ever confirmed|0 |1
Keywords| |ice-on-valid-code
Assignee|unassigned at gcc dot gnu.org |nshead at gcc dot
gnu.org
--- Comment #1 from Nathaniel Shead <nshead at gcc dot gnu.org> ---
Confirmed. Reduced:
// a.cpp
export module fmt;
inline namespace ns {
export template <typename = int> void format();
namespace {}
}
// b.cpp
export module m;
import fmt;
inline void test() { format(); }
$ g++ -fmodules -S [ab].cpp
b.cpp:1:8: internal compiler error: in operator(), at cp/module.cc:17853
1 | export module m;
| ^~~~~~
0x3e9f7f0 internal_error(char const*, ...)
../../gcc/gcc/diagnostic-global-context.cc:787
0x3eaf502 fancy_abort(char const*, int, char const*)
../../gcc/gcc/diagnostics/context.cc:1805
0x122f934 operator()
../../gcc/gcc/cp/module.cc:17853
0x122fb0f module_state::write_using_directives(elf_out*, depset::hash&,
vec<depset*, va_heap, vl_ptr>, unsigned int*)
../../gcc/gcc/cp/module.cc:17868
0x123984b module_state::write_begin(elf_out*, cpp_reader*,
module_state_config&, unsigned int&)
../../gcc/gcc/cp/module.cc:20991
0x12420e1 finish_module_processing(cpp_reader*)
../../gcc/gcc/cp/module.cc:23587
0x114a68d c_parse_final_cleanups()
../../gcc/gcc/cp/decl2.cc:5830
0x15805f9 c_common_parse_file()
../../gcc/gcc/c-family/c-opts.cc:1440
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.
The issue is that the implicit using-directive for the anonymous namespace is
not considered imported, because make_namespace_finish calls
add_using_namespace without propagating 'from_import'. The following patch
should fix the ICE; I'll test and submit soon:
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index 8a7a81a9e32..9cf8a38980f 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -9288,7 +9288,8 @@ make_namespace_finish (tree ns, tree *slot, bool
from_import = false)
/* An unnamed namespace implicitly has a using-directive inserted so
that its contents are usable in the surrounding context. */
if (!DECL_NAMESPACE_INLINE_P (ns) && !DECL_NAME (ns))
- add_using_namespace (NAMESPACE_LEVEL (ctx)->using_directives, ns);
+ add_using_namespace (NAMESPACE_LEVEL (ctx)->using_directives, ns,
+ from_import);
}
/* NS is a possibly-imported namespace that is now needed for
