https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118799
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Nathaniel Shead <nsh...@gcc.gnu.org>: https://gcc.gnu.org/g:2eb3d7454ee578335b7719aadfb9e37a8456f1f1 commit r15-8013-g2eb3d7454ee578335b7719aadfb9e37a8456f1f1 Author: Nathaniel Shead <nathanielosh...@gmail.com> Date: Sun Feb 9 00:37:48 2025 +1100 c++/modules: Better handle no-linkage decls in unnamed namespaces [PR118799] There are two issues with no-linkage decls (e.g. explicit type aliases) in unnamed namespaces that this patch fixes. Firstly, we don't currently handle exporting no-linkage decls in unnamed namespaces. This should be ill-formed in [module.export], since having an exported declaration within a namespace-definition makes the namespace definition exported (p2), but an unnamed namespace has internal linkage thus violating p3. Secondly, by the standard it appears to be possible to emit unnamed namespaces from named modules in certain scenarios, for instance when they contain a type alias (which is not itself an entity). This patch makes the adjustments needed to ensure we don't error in this scenario. PR c++/118799 gcc/cp/ChangeLog: * module.cc (depset::hash::is_tu_local_entity): Only types, functions, variables, and template (specialisations) can be TU-local. Explicit type aliases are TU-local iff the type they refer to are. (module_state::write_namespaces): Allow unnamed namespaces in named modules. (check_module_decl_linkage): Error for all exported declarations in an unnamed namespace. gcc/testsuite/ChangeLog: * g++.dg/modules/export-6.C: Adjust error message, add check for no-linkage decls in namespace. * g++.dg/modules/internal-4_b.C: Allow exposing a namespace with internal linkage. Type aliases are not entities and so never exposures. * g++.dg/modules/using-30_a.C: New test. * g++.dg/modules/using-30_b.C: New test. * g++.dg/modules/using-30_c.C: New test. Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> Reviewed-by: Jason Merrill <ja...@redhat.com>
