https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106259
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Looks like struct A<int>::W<U> isn't in the class2loc hash table so we crash here: 33894 tree spec = specialization_of (type); 33895 cdlguide = class2loc.get (spec); 33896 gcc_assert (cdlguide != NULL);