[Bug c++/57239] cannot handle inner/nested class templates with non-type parameter packs that were declared in the outer/containing class

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57239

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
N.B. Clang trunk aborts on Daniel's testcase and your first one.