              | MObj (_phat, Root(_, PVar(Offset _, _), _)) -> (print_string "whnf MObj 827 crash -- PVar Offset\n"; exit 190)
              | MObj (_phat, Root(_, PVar(PInst _, _), _)) -> (print_string "whnf MObj 827 crash -- PVar PInst\n"; exit 190)
              | MObj (_phat, Root(_, MVar(Inst({contents = None}, _, _, _), _), _)) -> (print_string "whnf MObj 827 crash -- MVar Inst None\n"; exit 190)
              | MObj (_phat, Root(_, MVar(Inst({contents = Some (Root (_, head, _))}, _, _, _), _), _)) -> (print_string "whnf MObj 827 crash -- MVar Inst Some Root\n"; exit 190)
              | MObj (_phat, Root(_, MVar(Inst({contents = Some normal}, _, _, _), _), _)) -> (print_string "whnf MObj 827 crash -- MVar Inst Some\n"; exit 190)
