Local Open Scope logic.

Lemma mpred_semax_post' : forall (R' : environ -> mpred) (Espec : OracleKind)
(Delta : tycontext) (R P : environ -> mpred)
(c : statement),
(forall rho, R' rho |-- R rho) ->
semax Delta P c (normal_ret_assert R') ->
semax Delta P c (normal_ret_assert R).