https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94485
--- Comment #4 from Dimitri Gorokhovik <dimitri.gorokhovik at free dot fr> --- To be clear, the braces here: outer_ = { tess_.begin () }; are the leftover of the simplification. Plain assignment also gets removed, only it is slightly harder to reproduce (-O3 only).