https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106369
--- Comment #14 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:6b7d570a5001bb79e34c0d1626a8c7f55386dac7 commit r12-8684-g6b7d570a5001bb79e34c0d1626a8c7f55386dac7 Author: Jason Merrill <ja...@redhat.com> Date: Tue Jul 26 11:02:21 2022 -0400 c++: constexpr, empty base after non-empty [PR106369] Here the CONSTRUCTOR we were providing for D{} had an entry for the B base subobject at offset 0 following the entry for the C base, causing output_constructor_regular_field to ICE due to going backwards. It might be nice for that function to be more tolerant of empty fields, but it also seems reasonable for the front end to prune the useless entry. PR c++/106369 gcc/cp/ChangeLog: * constexpr.cc (reduced_constant_expression_p): Return false if a CONSTRUCTOR initializes an empty field. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/constexpr-lambda27.C: New test. (cherry picked from commit 9efe4e153d994974afcbba09c3c683f5f4a19c63)