Hint Resolve synt_wp_monotonic: hoare.

(** * Completeness  The proof of completeness proceeds by induction over [prog] syntax.  Please, notice that coq performs this proof almost alone. The only hint given here is the invariant. *)
Lemma wp_complete: forall prog post, prog{=post=} |= (synt_wp prog post).
Hint Resolve wp_complete wp_sound: hoare.