https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120012
--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-15 branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:809c5d7486f91d59e798e0c70ac887f837039ece commit r15-9635-g809c5d7486f91d59e798e0c70ac887f837039ece Author: Jason Merrill <ja...@redhat.com> Date: Wed Apr 30 10:18:46 2025 -0400 c++: C++17/20 class layout divergence [PR120012] C++20 made a class with only explicitly defaulted constructors no longer aggregate, and this wrongly affected whether the class is considered "POD for layout purposes" under the ABI. Conveniently, we already have check_non_pod_aggregate to diagnose cases where this makes a difference, due to PR103681 around a C++14 aggregate change. This backport is the same code change as the trunk version, but since -fabi-version=21 cannot be selected, the fix is not available, only the warning, so the first testcase is different. PR c++/120012 gcc/cp/ChangeLog: * cp-tree.h (struct lang_type): Add non_aggregate_pod. (CLASSTYPE_NON_AGGREGATE_POD): New. * class.cc (check_bases_and_members): Set it. (check_non_pod_aggregate): Diagnose it. gcc/testsuite/ChangeLog: * g++.dg/abi/base-defaulted1.C: New test. * g++.dg/abi/base-defaulted1a.C: New test. (cherry picked from commit e6e3b0772ed40cc65a544bbe744ece62d8b9713e)
