diff --git a/plugins/qcheck-stm/test/all_warnings.mli b/plugins/qcheck-stm/test/all_warnings.mli
index d9da486f..6eade310 100644
--- a/plugins/qcheck-stm/test/all_warnings.mli
+++ b/plugins/qcheck-stm/test/all_warnings.mli
@@ -7,7 +7,7 @@ type s
 
 val make : int -> 'a -> 'a t
 (*@ t = make i a
-    ensures t.contents = List.init i (fun x -> a) *)
+    ensures t.contents = List.init i (fun _ -> a) *)
 
 val constant : unit
 (*@ constant
diff --git a/plugins/qcheck-stm/test/hashtbl.mli b/plugins/qcheck-stm/test/hashtbl.mli
index 506ff7e6..8b10a514 100644
--- a/plugins/qcheck-stm/test/hashtbl.mli
+++ b/plugins/qcheck-stm/test/hashtbl.mli
@@ -28,22 +28,22 @@ val add : ('a, 'b) t -> 'a -> 'b -> unit
 val find : ('a, 'b) t -> 'a -> 'b
 (*@ b = find h a
     raises Not_found -> forall x. not (List.mem (a, x) h.contents)
-    raises Not_found -> not (List.mem a (List.map (fun x -> fst x) h.contents))
+    raises Not_found -> not (List.mem a (List.map fst h.contents))
     ensures List.mem (a, b) h.contents *)
 
 val find_opt : ('a, 'b) t -> 'a -> 'b option
 (*@ o = find_opt h a
     ensures match o with
-      | None -> not (List.mem a (List.map (fun x -> fst x) h.contents))
+      | None -> not (List.mem a (List.map fst h.contents))
       | Some b -> List.mem (a, b) h.contents *)
 
 val find_all : ('a, 'b) t -> 'a -> 'b list
 (*@ bs = find_all h a
-    ensures bs = Sequence.filter_map (fun x -> if fst x = a then Some (snd x) else None)  h.contents *)
+    ensures bs = Sequence.filter_map (fun (x, y) -> if x = a then Some y else None) h.contents *)
 
 val mem : ('a, 'b) t -> 'a -> bool
 (*@ b = mem h a
-    ensures b = List.mem a (List.map (fun x -> fst x) h.contents) *)
+    ensures b = List.mem a (List.map fst h.contents) *)
 
 (*@ function rec remove_first (x: 'a) (xs : ('a * 'b) list) : ('a * 'b) list =
       match xs with
@@ -65,9 +65,9 @@ val filter_map_inplace : ('a -> 'b -> 'b option) -> ('a, 'b) t -> unit
 (*@ filter_map_inplace f h
     modifies h
     ensures h.contents = Sequence.filter_map
-                            (fun x -> match f (fst x) (snd x) with
-                                       | None -> None
-                                       | Some b' -> Some (fst x, b'))
+                            (fun (x,y) -> match f x y with
+                                          | None -> None
+                                          | Some b' -> Some (x, b'))
                             (old h.contents) *)
 
 val fold : ('a -> 'b -> 'c -> 'c) -> ('a, 'b) t -> 'c -> 'c
diff --git a/plugins/qcheck-stm/test/hashtbl_stm_tests.expected.ml b/plugins/qcheck-stm/test/hashtbl_stm_tests.expected.ml
index 7d0d291f..b94dfdeb 100644
--- a/plugins/qcheck-stm/test/hashtbl_stm_tests.expected.ml
+++ b/plugins/qcheck-stm/test/hashtbl_stm_tests.expected.ml
@@ -105,7 +105,7 @@ module Spec =
                not
                  (Ortac_runtime.Gospelstdlib.List.mem a_3
                     (Ortac_runtime.Gospelstdlib.List.map
-                       (fun x_1 -> Ortac_runtime.Gospelstdlib.fst x_1)
+                       Ortac_runtime.Gospelstdlib.fst
                        (Lazy.force new_state__007_).contents))
            | _ -> false)
       | (Find_opt a_4, Res ((Option (Int), _), o)) ->
@@ -115,7 +115,7 @@ module Spec =
                  not
                    (Ortac_runtime.Gospelstdlib.List.mem a_4
                       (Ortac_runtime.Gospelstdlib.List.map
-                         (fun x_2 -> Ortac_runtime.Gospelstdlib.fst x_2)
+                         Ortac_runtime.Gospelstdlib.fst
                          (Lazy.force new_state__007_).contents))
                then true
                else false
@@ -129,17 +129,14 @@ module Spec =
       | (Find_all a_5, Res ((List (Int), _), bs)) ->
           (Ortac_runtime.Gospelstdlib.List.to_seq bs) =
             (Ortac_runtime.Gospelstdlib.Sequence.filter_map
-               (fun x_3 ->
-                  if (Ortac_runtime.Gospelstdlib.fst x_3) = a_5
-                  then Some (Ortac_runtime.Gospelstdlib.snd x_3)
-                  else None)
+               (fun (x_1, y) -> if x_1 = a_5 then Some y else None)
                (Ortac_runtime.Gospelstdlib.List.to_seq
                   (Lazy.force new_state__007_).contents))
       | (Mem a_6, Res ((Bool, _), b_6)) ->
           (b_6 = true) =
             (Ortac_runtime.Gospelstdlib.List.mem a_6
                (Ortac_runtime.Gospelstdlib.List.map
-                  (fun x_4 -> Ortac_runtime.Gospelstdlib.fst x_4)
+                  Ortac_runtime.Gospelstdlib.fst
                   (Lazy.force new_state__007_).contents))
       | (Remove a_7, Res ((Unit, _), _)) -> true
       | (Replace (a_8, b_3), Res ((Unit, _), _)) -> true