https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100134
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:9736a42e1fb8df30d72cf28594d9046bf50200c1 commit r13-3236-g9736a42e1fb8df30d72cf28594d9046bf50200c1 Author: Patrick Palka <ppa...@redhat.com> Date: Tue Oct 11 15:02:23 2022 -0400 c++ modules: ICE with templated friend and std namespace [PR100134] The function depset::hash::add_binding_entity has an assert verifying that if a namespace contains an exported entity, then the namespace must have been opened in the module purview: if (data->hash->add_namespace_entities (decl, data->partitions)) { /* It contains an exported thing, so it is exported. */ gcc_checking_assert (DECL_MODULE_PURVIEW_P (decl)); DECL_MODULE_EXPORT_P (decl) = true; } We're tripping over this assert in the below testcase because by instantiating and exporting std::A<int>, we in turn define and export the hidden friend std::f(A<int>) without ever having opened the enclosing namespace std within the module purview, and thus DECL_MODULE_PURVIEW_P for std is false. It's important that the enclosing namespace is std here: if we use a different namespace then the ICE disappears. This probably has something to do with us predefining std via push_namespace from cxx_init_decl_processing (which makes it look like we've opened it within the TU), whereas with another namespace we would instead lazily create its NAMESPACE_DECL from add_imported_namespace. Since templated friend functions are special in that they give us a way to introduce a namespace-scope function without having to explicitly open the namespace, this patch proposes to fix this ICE by propagating DECL_MODULE_PURVIEW_P from the introduced function to the enclosing namespace during tsubst_friend_function. PR c++/100134 gcc/cp/ChangeLog: * pt.cc (tsubst_friend_function): Propagate DECL_MODULE_PURVIEW_P from the introduced namespace-scope function to the namespace. gcc/testsuite/ChangeLog: * g++.dg/modules/tpl-friend-8_a.H: New test. * g++.dg/modules/tpl-friend-8_b.C: New test.
