https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114275
--- Comment #11 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-14 branch has been updated by Nathaniel Shead <nsh...@gcc.gnu.org>: https://gcc.gnu.org/g:fd6fd88b1a93f4fb38f095688255ab5c00122810 commit r14-10240-gfd6fd88b1a93f4fb38f095688255ab5c00122810 Author: Nathaniel Shead <nathanielosh...@gmail.com> Date: Mon Apr 29 17:00:13 2024 +1000 c++: Fix instantiation of imported temploid friends [PR114275] This patch fixes a number of issues with the handling of temploid friend declarations. The primary issue is that instantiations of friend declarations should attach the declaration to the same module as the befriending class, by [module.unit] p7.1 and [temp.friend] p2; this could be a different module from the current TU, and so needs special handling. The other main issue here is that we can't assume that just because name lookup didn't find a definition for a hidden class template, that it doesn't exist at all: it could be a non-exported entity that we've nevertheless streamed in from an imported module. We need to ensure that when instantiating template friend classes that we return the same TEMPLATE_DECL that we got from our imports, otherwise we will get later issues with 'duplicate_decls' (rightfully) complaining that they're different when trying to merge. This doesn't appear necessary for function templates due to the existing name lookup handling already finding these hidden declarations. (cherry-picked from commits b5f6a56940e70838a07e885de03a92e2bd64674a and ec2365e07537e8b17745d75c28a2b45bf33be119) PR c++/105320 PR c++/114275 gcc/cp/ChangeLog: * cp-tree.h (propagate_defining_module): Declare. (remove_defining_module): Declare. (lookup_imported_hidden_friend): Declare. * decl.cc (duplicate_decls): Also check if hidden decls can be redeclared in this module. Call remove_defining_module on to-be-freed newdecl. * module.cc (imported_temploid_friends): New. (init_modules): Initialize it. (trees_out::decl_value): Write it; don't consider imported temploid friends as attached to a module. (trees_in::decl_value): Read it for non-discarded decls. (get_originating_module_decl): Follow the owning decl for an imported temploid friend. (propagate_defining_module): New. (remove_defining_module): New. * name-lookup.cc (get_mergeable_namespace_binding): New. (lookup_imported_hidden_friend): New. * pt.cc (tsubst_friend_function): Propagate defining module for new friend functions. (tsubst_friend_class): Lookup imported hidden friends. Check for valid module attachment of existing names. Propagate defining module for new classes. gcc/testsuite/ChangeLog: * g++.dg/modules/tpl-friend-10_a.C: New test. * g++.dg/modules/tpl-friend-10_b.C: New test. * g++.dg/modules/tpl-friend-10_c.C: New test. * g++.dg/modules/tpl-friend-10_d.C: New test. * g++.dg/modules/tpl-friend-11_a.C: New test. * g++.dg/modules/tpl-friend-11_b.C: New test. * g++.dg/modules/tpl-friend-12_a.C: New test. * g++.dg/modules/tpl-friend-12_b.C: New test. * g++.dg/modules/tpl-friend-12_c.C: New test. * g++.dg/modules/tpl-friend-12_d.C: New test. * g++.dg/modules/tpl-friend-12_e.C: New test. * g++.dg/modules/tpl-friend-12_f.C: New test. * g++.dg/modules/tpl-friend-13_a.C: New test. * g++.dg/modules/tpl-friend-13_b.C: New test. * g++.dg/modules/tpl-friend-13_c.C: New test. * g++.dg/modules/tpl-friend-13_d.C: New test. * g++.dg/modules/tpl-friend-13_e.C: New test. * g++.dg/modules/tpl-friend-13_f.C: New test. * g++.dg/modules/tpl-friend-13_g.C: New test. * g++.dg/modules/tpl-friend-14_a.C: New test. * g++.dg/modules/tpl-friend-14_b.C: New test. * g++.dg/modules/tpl-friend-14_c.C: New test. * g++.dg/modules/tpl-friend-14_d.C: New test. * g++.dg/modules/tpl-friend-9.C: New test. Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> Reviewed-by: Jason Merrill <ja...@redhat.com> Reviewed-by: Patrick Palka <ppa...@redhat.com>
