Definition bupd_ret_assert (Q: ret_assert): ret_assert :=
          {| RA_normal := fun rho => bupd (RA_normal Q rho);
             RA_break := fun rho => bupd (RA_break Q rho);
             RA_continue := fun rho => bupd (RA_continue Q rho);
             RA_return := fun v rho => bupd (RA_return Q v rho) |}.

Lemma rguard_allp_fun_id: forall {Espec: OracleKind} ge Delta' Delta (F: environ -> pred rmap) P k, tycontext_sub Delta Delta' -> rguard Espec ge Delta' (frame_ret_assert P F) k = rguard Espec ge Delta' (frame_ret_assert (conj_ret_assert P (allp_fun_id Delta)) F) k.