https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65608 Bug 65608 depends on bug 52625, which changed state.
Bug 52625 Summary: [9/10 Regression] Incorrect specialization semantics of friend class template declaration https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52625 What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED