diff --git a/theories/list.v b/theories/list.v
index 84c0b177cb2c9b5f04622c052b64f2ac48dacf7e..6e0bac82ae30832c2582a686ab64310422c5be2d 100644
--- a/theories/list.v
+++ b/theories/list.v
@@ -34,6 +34,9 @@ Notation "x ≢ₚ y":= (¬x ≡ₚ y) (at level 70, no associativity) : C_scope
Notation "( x ≢ₚ)" := (λ y, x ≢ₚ y) (only parsing) : C_scope.
Notation "(≢ₚ x )" := (λ y, y ≢ₚ x) (only parsing) : C_scope.
+Instance maybe_cons {A} : Maybe2 (@cons A) := λ l,
+ match l with x :: l => Some (x,l) | _ => None end.
+
(** * Definitions *)
(** Setoid equality lifted to lists *)
Inductive list_equiv `{Equiv A} : Equiv (list A) :=