https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107864
--- 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:36cabc257dfb7dd4f7625896891f6c5b195a0241 commit r13-4390-g36cabc257dfb7dd4f7625896891f6c5b195a0241 Author: Patrick Palka <ppa...@redhat.com> Date: Tue Nov 29 09:55:21 2022 -0500 c++: explicit specialization and trailing requirements [PR107864] Here we're crashing when using the explicit specialization of the function template g with trailing requirements ultimately because earlier decls_match (called indirectly from register_specialization) for for the explicit specialization returned false since the template has trailing requirements whereas the specialization doesn't. In r12-2230-gddd25bd1a7c8f4, we fixed a similar issue concerning template requirements instead of trailing requirements. We could extend that fix to ignore trailing requirement mismatches for explicit specializations as well, but it seems cleaner to just propagate constraints from the specialized template to the specialization when declaring an explicit specialization so that decls_match will naturally return true in this case. And it looks like determine_specialization already does this, albeit inconsistently (only when specializing a non-template member function of a class template as in cpp2a/concepts-explicit-spec4.C). So this patch makes determine_specialization consistently propagate constraints from the specialized template to the specialization, which in turn lets us get rid of the function_requirements_equivalent_p special case added by r12-2230. PR c++/107864 gcc/cp/ChangeLog: * decl.cc (function_requirements_equivalent_p): Don't check DECL_TEMPLATE_SPECIALIZATION. * pt.cc (determine_specialization): Propagate constraints when specializing a function template too. Simplify by using add_outermost_template_args. gcc/testsuite/ChangeLog: * g++.dg/concepts/explicit-spec1a.C: New test.
