Notation orb_true_b := orb_true_l (only parsing).
(** [false] is neutral for [orb] *)

(* Specifications: *)
Lemma orb_false_r : forall b:bool, b || false = b.
#[global]
Hint Resolve orb_false_r: bool.
Lemma orb_false_l : forall b:bool, false || b = b.
#[global]
Hint Resolve orb_false_l: bool.