diff --git a/src/data/CCFun_vec.ml b/src/data/CCFun_vec.ml
index 29af2859..65947ee9 100644
--- a/src/data/CCFun_vec.ml
+++ b/src/data/CCFun_vec.ml
@@ -236,10 +236,10 @@ let pop_ i (m:'a t) : 'a * 'a t =
 
 let pop_exn (v:'a t) : 'a * 'a t =
   if v.size=0 then failwith "Fun_vec.pop_exn";
-  pop_ v.size v
+  pop_ (v.size-1) v
 
 let pop (v:'a t) : ('a * 'a t) option =
-  if v.size=0 then None else Some (pop_ v.size v)
+  if v.size=0 then None else Some (pop_ (v.size-1) v)
 
 let iteri ~f (m : 'a t) : unit =
   (* basically, a 32-way BFS traversal.
diff --git a/src/data/CCFun_vec.mli b/src/data/CCFun_vec.mli
index bff63d96..6d4a55f6 100644
--- a/src/data/CCFun_vec.mli
+++ b/src/data/CCFun_vec.mli
@@ -72,6 +72,10 @@ val get_exn : int -> 'a t -> 'a
 val pop_exn : 'a t -> 'a * 'a t
 (** Pop last element. *)
 
+val pop : 'a t -> ('a * 'a t) option
+(** Pop last element.
+    @since NEXT_RELEASE *)
+
 val iter : f:('a -> unit) -> 'a t -> unit
 
 val iteri : f:(int -> 'a -> unit) -> 'a t -> unit