https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114275
--- Comment #6 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:b5f6a56940e70838a07e885de03a92e2bd64674a commit r15-59-gb5f6a56940e70838a07e885de03a92e2bd64674a 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. PR c++/105320 PR c++/114275 gcc/cp/ChangeLog: * cp-tree.h (propagate_defining_module): Declare. (lookup_imported_hidden_friend): Declare. * decl.cc (duplicate_decls): Also check if hidden decls can be redeclared in this module. * 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. (get_originating_module_decl): Follow the owning decl for an imported temploid friend. (propagate_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>
