https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93470
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:08ed34284f4e6ac9a4e647d9caa82ee4b4de0fa3 commit r9-8345-g08ed34284f4e6ac9a4e647d9caa82ee4b4de0fa3 Author: Jonathan Wakely <jwak...@redhat.com> Date: Thu Mar 5 16:52:19 2020 +0000 libstdc++: Avoid using sizeof with function types (PR 93470) Backport from mainline 2020-01-28 Jonathan Wakely <jwak...@redhat.com> PR libstdc++/93470 * include/bits/refwrap.h (reference_wrapper::operator()): Restrict static assertion to object types.