https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58616 Bug 58616 depends on bug 88165, which changed state.
Bug 88165 Summary: error: default member initializer for 'A::B::m' required before the end of its enclosing class https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88165 What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |DUPLICATE