https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115378
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-14 branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:ff8105b4910f7dbee326cb36b01c16ac9bf10c4b commit r14-10301-gff8105b4910f7dbee326cb36b01c16ac9bf10c4b Author: Patrick Palka <ppa...@redhat.com> Date: Fri Jun 7 12:12:30 2024 -0400 c++: lambda in pack expansion [PR115378] Here find_parameter_packs_r is incorrectly treating the 'auto' return type of a lambda as a parameter pack due to Concepts-TS specific logic added in r6-4517, leading to confusion later when expanding the pattern. Since we intend on removing Concepts TS support soon anyway, this patch fixes this by restricting the problematic logic with flag_concepts_ts. Doing so revealed that add_capture was relying on this logic to set TEMPLATE_TYPE_PARAMETER_PACK for the 'auto' type of an pack expansion init-capture, which we now need to do explicitly. PR c++/115378 gcc/cp/ChangeLog: * lambda.cc (lambda_capture_field_type): Set TEMPLATE_TYPE_PARAMETER_PACK on the auto type of an init-capture pack expansion. * pt.cc (find_parameter_packs_r) <case TEMPLATE_TYPE_PARM>: Restrict TEMPLATE_TYPE_PARAMETER_PACK promotion with flag_concepts_ts. gcc/testsuite/ChangeLog: * g++.dg/cpp1y/decltype-auto-103497.C: Adjust expected diagnostic. * g++.dg/template/pr95672.C: Likewise. * g++.dg/cpp2a/lambda-targ5.C: New test. Reviewed-by: Jason Merrill <ja...@redhat.com> (cherry picked from commit 5c761395402a730535983a5e49ef1775561ebc61)
