Lemma semax_unfold {CS: compspecs} {Espec: OracleKind}: semax Espec = fun Delta P c R => forall (psi: Clight.genv) Delta' (w: nat) (TS: tycontext_sub Delta Delta') (HGG: genv_cenv psi = cenv_cs) (Prog_OK: believe Espec Delta' psi Delta' w) (k: cont) (F: assert), closed_wrt_modvars c F -> rguard Espec psi Delta' (frame_ret_assert R F) k w -> guard Espec psi Delta' (fun rho => F rho * P rho) (Kseq c :: k) w.