https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104527
--- Comment #2 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:9413bb55185b9e88d84e91d5145d59f9f83b884a commit r12-7631-g9413bb55185b9e88d84e91d5145d59f9f83b884a Author: Patrick Palka <ppa...@redhat.com> Date: Sat Mar 12 15:00:40 2022 -0500 c++: return-type-req in constraint using only outer tparms [PR104527] Here the template context for the atomic constraint has two levels of template parameters, but since it depends only on the innermost parameter T we use a single-level argument vector (built by get_mapped_args) during substitution into the atom. We eventually pass this vector to do_auto_deduction as part of checking the return-type-requirement within the atom, but do_auto_deduction expects outer_targs to be a full set of arguments for sake of satisfaction. This patch fixes this by making get_mapped_args always return an argument vector whose depth corresponds to the template depth of the context in which the atomic constraint expression was written, instead of the highest parameter level that the expression happens to use. PR c++/104527 gcc/cp/ChangeLog: * constraint.cc (normalize_atom): Set ATOMIC_CONSTR_EXPR_FROM_CONCEPT_P appropriately. (get_mapped_args): Make static, adjust parameters. Always return a vector whose depth corresponds to the template depth of the context of the atomic constraint expression. Micro-optimize by passing false as exact to safe_grow_cleared and by collapsing a multi-level depth-one argument vector. (satisfy_atom): Adjust call to get_mapped_args and diagnose_atomic_constraint. (diagnose_atomic_constraint): Replace map parameter with an args parameter. * cp-tree.h (ATOMIC_CONSTR_EXPR_FROM_CONCEPT_P): Define. (get_mapped_args): Remove declaration. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-return-req4.C: New test.
