(*   classify_cast (typeof e1) t1 <> cast_case_p2bool -> *)

(* Specifications: *)
Lemma res_option_core: forall r, res_option (core r) = None.
Lemma writable0_lub_retainer_Rsh:
forall sh, writable0_share sh ->
Share.lub (retainer_part sh) Share.Rsh = sh.