diff --git a/src/data/CCDeque.ml b/src/data/CCDeque.ml
index 0cd402a4..bbcfaf8f 100644
--- a/src/data/CCDeque.ml
+++ b/src/data/CCDeque.ml
@@ -159,7 +159,8 @@ let add_seq_front q seq = seq (fun x -> push_front q x)
   assert_equal [1;2;3;4;5;6;7] (to_list q);
 *)
 
-let of_seq ?(deque=create ()) seq =
+let of_seq seq =
+  let deque = create () in
   seq (fun x -> push_back deque x);
   deque
 
diff --git a/src/data/CCDeque.mli b/src/data/CCDeque.mli
index 1c702d86..aa3b5cb6 100644
--- a/src/data/CCDeque.mli
+++ b/src/data/CCDeque.mli
@@ -89,7 +89,10 @@ val fold : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'b
 type 'a gen = unit -> 'a option
 type 'a sequence = ('a -> unit) -> unit
 
-val of_seq : ?deque:'a t -> 'a sequence -> 'a t
+val of_seq : 'a sequence -> 'a t
+(** Create a deque from the sequence.
+    @since NEXT_RELEASE optional argument [deque] disappears, use
+      {!add_seq_back} instead *)
 
 val to_seq : 'a t -> 'a sequence