------- Comment #4 from jakub at gcc dot gnu dot org 2007-09-27 16:33 ------- This is a special case of PR33509. regenerate_decl_from_template doesn't handle error_mark_node returned from tsubst_pack_expansion. As tsubst_pack_expansion doesn't issue any error in this case (it hits the /* We could not find any argument packs that work. */ if (len < 0) return error_mark_node; case), I believe it is up to regenerate_decl_from_template to issue some diagnostics.
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31434