diff --git a/devtools/get_contracts/get_contracts_alpha.ml b/devtools/get_contracts/get_contracts_alpha.ml
index fbc0f09091c59a02d6e485279749070ab916dcd7..e44c612e3f892aaa3cfb6f9c952bb5ec59457ced 100644
--- a/devtools/get_contracts/get_contracts_alpha.ml
+++ b/devtools/get_contracts/get_contracts_alpha.ml
@@ -257,7 +257,8 @@ module Proto = struct
           List.map (fun g -> function None -> [] | Some v -> g v)
           @@ find_lambda_tys t
       | List_t (t, _) ->
-          List.map (fun g l -> List.flatten @@ List.map g l.elements)
+          List.map (fun g l ->
+              List.flatten @@ List.map g @@ Script_list.to_list l)
           @@ find_lambda_tys t
       | Map_t (_, tv, _) -> find_lambda_tys_map tv
 
diff --git a/src/proto_alpha/lib_benchmark/michelson_samplers.ml b/src/proto_alpha/lib_benchmark/michelson_samplers.ml
index bfcda8b0b58d8b8293657ef633e4fce26b0cefb7..672588f78d607bac3924106c7d5e7a2cc48cc4c3 100644
--- a/src/proto_alpha/lib_benchmark/michelson_samplers.ml
+++ b/src/proto_alpha/lib_benchmark/michelson_samplers.ml
@@ -684,16 +684,15 @@ end)
 
     and generate_list :
         type elt eltc.
-        (elt, eltc) Script_typed_ir.ty -> elt Script_typed_ir.boxed_list sampler
-        =
+        (elt, eltc) Script_typed_ir.ty -> elt Script_list.t sampler =
      fun elt_type ->
       let open M in
-      let* length, elements =
+      let* _, elements =
         Structure_samplers.list
           ~range:P.parameters.list_size
           ~sampler:(value elt_type)
       in
-      return Script_typed_ir.{elements; length}
+      return @@ Script_list.of_list elements
 
     (* Note that we might very well generate sets smaller than the specified range (consider the
        case of a set of type [unit]). *)
diff --git a/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml b/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml
index 3d6bfcdc4027faff3c745c5fcdafebf1bb0661b7..a3a783976aff3e3f97bc892598e3d80e8228ec4f 100644
--- a/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml
+++ b/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml
@@ -3181,7 +3181,8 @@ module Registration_section = struct
           let kbody = halt in
           fun () ->
             let cont =
-              KList_enter_body (kbody, [()], [], Some (list unit), 1, KNil)
+              KList_enter_body
+                (kbody, [()], Script_list.empty, Some (list unit), 1, KNil)
             in
             Ex_stack_and_cont
               {stack = ((), eos); stack_type = unit @$ bot; cont})
@@ -3203,8 +3204,7 @@ module Registration_section = struct
           fun () ->
             let ys = Samplers.Random_value.value (list unit) rng_state in
             let cont =
-              KList_enter_body
-                (kbody, [], ys.elements, Some (list unit), ys.length, KNil)
+              KList_enter_body (kbody, [], ys, Some (list unit), ys.length, KNil)
             in
             Ex_stack_and_cont
               {stack = ((), eos); stack_type = unit @$ bot; cont})
@@ -3225,7 +3225,8 @@ module Registration_section = struct
           let kbody = halt in
           fun () ->
             let cont =
-              KList_enter_body (kbody, [], [], Some (list unit), 1, KNil)
+              KList_enter_body
+                (kbody, [], Script_list.empty, Some (list unit), 1, KNil)
             in
             Ex_stack_and_cont
               {stack = ((), eos); stack_type = unit @$ bot; cont})
@@ -3246,7 +3247,8 @@ module Registration_section = struct
         ~cont_and_stack_sampler:(fun _cfg _rng_state ->
           let kbody = halt in
           let cont =
-            KList_exit_body (kbody, [], [], Some (list unit), 1, KNil)
+            KList_exit_body
+              (kbody, [], Script_list.empty, Some (list unit), 1, KNil)
           in
           fun () ->
             Ex_stack_and_cont
diff --git a/src/proto_alpha/lib_benchmarks_proto/interpreter_workload.ml b/src/proto_alpha/lib_benchmarks_proto/interpreter_workload.ml
index 93d9fae52deefec6148b4d1aa515836e1824bf63..221e1789050ab52ac1478a784226ffddf72766ce 100644
--- a/src/proto_alpha/lib_benchmarks_proto/interpreter_workload.ml
+++ b/src/proto_alpha/lib_benchmarks_proto/interpreter_workload.ml
@@ -1454,7 +1454,7 @@ let extract_control_trace (type bef_top bef aft_top aft)
   | KList_enter_body (_, xs, ys, _, _, _) ->
       Control.list_enter_body
         (Size.of_int (List.length xs))
-        (Size.of_int (List.length ys))
+        (Size.of_int (Script_list.length ys))
   | KList_exit_body (_, _, _, _, _, _) -> Control.list_exit_body
   | KMap_enter_body (_, xs, _, _, _) ->
       Control.map_enter_body (Size.of_int (List.length xs))
diff --git a/src/proto_alpha/lib_benchmarks_proto/ticket_benchmarks.ml b/src/proto_alpha/lib_benchmarks_proto/ticket_benchmarks.ml
index 3a472f44fca2abc8f4fde34eac18035a160672ad..bbe425a30711b4f240877ec7cfcf1dd6b4aaf099 100644
--- a/src/proto_alpha/lib_benchmarks_proto/ticket_benchmarks.ml
+++ b/src/proto_alpha/lib_benchmarks_proto/ticket_benchmarks.ml
@@ -269,16 +269,16 @@ module Collect_tickets_benchmark : Benchmark.S = struct
     let ty =
       match list_t (-1) ticket_ty with Error _ -> assert false | Ok t -> t
     in
-    let length, elements =
+    let _, elements =
       Structure_samplers.list
         ~range:{min = 0; max = config.max_size}
         ~sampler:ticket_sampler
         rng_state
     in
-    let boxed_ticket_list = {elements; length} in
+    let boxed_ticket_list = Script_list.of_list elements in
     Environment.wrap_tzresult
     @@ let* has_tickets, ctxt = Ticket_scanner.type_has_tickets ctxt ty in
-       let workload = {nodes = length} in
+       let workload = {nodes = Script_list.length boxed_ticket_list} in
        let closure () =
          ignore
            (Lwt_main.run
diff --git a/src/proto_alpha/lib_protocol/TEZOS_PROTOCOL b/src/proto_alpha/lib_protocol/TEZOS_PROTOCOL
index 28da979c38740259c5fc24299621c46ea6c68637..83bf16e25dd939c74403a527638a33f6f1458959 100644
--- a/src/proto_alpha/lib_protocol/TEZOS_PROTOCOL
+++ b/src/proto_alpha/lib_protocol/TEZOS_PROTOCOL
@@ -193,6 +193,7 @@
         "Gas_monad",
         "Script_ir_annot",
         "Dependent_bool",
+        "Script_list",
         "Script_typed_ir",
         "Script_comparable",
         "Gas_comparable_input_size",
@@ -204,7 +205,6 @@
         "Michelson_v1_gas_costs_generated",
         "Michelson_v1_gas_costs",
         "Michelson_v1_gas",
-        "Script_list",
         "Script_tc_context",
         "Ticket_token",
         "Ticket_receipt",
diff --git a/src/proto_alpha/lib_protocol/dune b/src/proto_alpha/lib_protocol/dune
index 90310f78555123963e890d46aeb8ffd8d212dc6d..71eca07e7f03153f898fe01d1779bc4645401e43 100644
--- a/src/proto_alpha/lib_protocol/dune
+++ b/src/proto_alpha/lib_protocol/dune
@@ -206,6 +206,7 @@
   Gas_monad
   Script_ir_annot
   Dependent_bool
+  Script_list
   Script_typed_ir
   Script_comparable
   Gas_comparable_input_size
@@ -217,7 +218,6 @@
   Michelson_v1_gas_costs_generated
   Michelson_v1_gas_costs
   Michelson_v1_gas
-  Script_list
   Script_tc_context
   Ticket_token
   Ticket_receipt
@@ -475,6 +475,7 @@
   gas_monad.ml gas_monad.mli
   script_ir_annot.ml script_ir_annot.mli
   dependent_bool.ml dependent_bool.mli
+  script_list.ml script_list.mli
   script_typed_ir.ml script_typed_ir.mli
   script_comparable.ml script_comparable.mli
   gas_comparable_input_size.ml gas_comparable_input_size.mli
@@ -486,7 +487,6 @@
   michelson_v1_gas_costs_generated.ml
   michelson_v1_gas_costs.ml
   michelson_v1_gas.ml michelson_v1_gas.mli
-  script_list.ml script_list.mli
   script_tc_context.ml script_tc_context.mli
   ticket_token.ml ticket_token.mli
   ticket_receipt.ml ticket_receipt.mli
@@ -724,6 +724,7 @@
   gas_monad.ml gas_monad.mli
   script_ir_annot.ml script_ir_annot.mli
   dependent_bool.ml dependent_bool.mli
+  script_list.ml script_list.mli
   script_typed_ir.ml script_typed_ir.mli
   script_comparable.ml script_comparable.mli
   gas_comparable_input_size.ml gas_comparable_input_size.mli
@@ -735,7 +736,6 @@
   michelson_v1_gas_costs_generated.ml
   michelson_v1_gas_costs.ml
   michelson_v1_gas.ml michelson_v1_gas.mli
-  script_list.ml script_list.mli
   script_tc_context.ml script_tc_context.mli
   ticket_token.ml ticket_token.mli
   ticket_receipt.ml ticket_receipt.mli
@@ -978,6 +978,7 @@
   gas_monad.ml gas_monad.mli
   script_ir_annot.ml script_ir_annot.mli
   dependent_bool.ml dependent_bool.mli
+  script_list.ml script_list.mli
   script_typed_ir.ml script_typed_ir.mli
   script_comparable.ml script_comparable.mli
   gas_comparable_input_size.ml gas_comparable_input_size.mli
@@ -989,7 +990,6 @@
   michelson_v1_gas_costs_generated.ml
   michelson_v1_gas_costs.ml
   michelson_v1_gas.ml michelson_v1_gas.mli
-  script_list.ml script_list.mli
   script_tc_context.ml script_tc_context.mli
   ticket_token.ml ticket_token.mli
   ticket_receipt.ml ticket_receipt.mli
diff --git a/src/proto_alpha/lib_protocol/gas_input_size.ml b/src/proto_alpha/lib_protocol/gas_input_size.ml
index 1a35ae6ea9e13d920d3ee52cc4c7952a289a7243..d4105ef06ca12e59af16f76e3ec391e8f3d22500 100644
--- a/src/proto_alpha/lib_protocol/gas_input_size.ml
+++ b/src/proto_alpha/lib_protocol/gas_input_size.ml
@@ -25,8 +25,7 @@
 
 include Gas_comparable_input_size
 
-let list (list : 'a Script_typed_ir.boxed_list) : t =
-  list.Script_typed_ir.length
+let list (list : 'a Script_list.t) : t = list.Script_list.length
 
 let set (set : 'a Script_typed_ir.set) : t =
   let res = Script_int.to_int (Script_set.size set) in
diff --git a/src/proto_alpha/lib_protocol/gas_input_size.mli b/src/proto_alpha/lib_protocol/gas_input_size.mli
index 48961e1a2966ba9fbeb62ff819b1f7b07c170a78..6d3ba74fa43f8c85a26e9bc4c457750fbf5ed753 100644
--- a/src/proto_alpha/lib_protocol/gas_input_size.mli
+++ b/src/proto_alpha/lib_protocol/gas_input_size.mli
@@ -34,7 +34,7 @@ include module type of Gas_comparable_input_size
 
 (* ------------------------------------------------------------------------- *)
 
-val list : 'a Script_typed_ir.boxed_list -> t
+val list : 'a Script_list.t -> t
 
 val set : 'a Script_typed_ir.set -> t
 
diff --git a/src/proto_alpha/lib_protocol/michelson_v1_gas.ml b/src/proto_alpha/lib_protocol/michelson_v1_gas.ml
index d31ddd7e1e5503e3eb6c9d287d0bb6f5dc611cb3..2498a4ab6aa94dcd93acb7ee9c3739213a3419b7 100644
--- a/src/proto_alpha/lib_protocol/michelson_v1_gas.ml
+++ b/src/proto_alpha/lib_protocol/michelson_v1_gas.ml
@@ -78,12 +78,12 @@ module Cost_of = struct
 
     let if_cons = atomic_step_cost cost_N_IIf_cons
 
-    let list_map : 'a Script_typed_ir.boxed_list -> Gas.cost =
+    let list_map : 'a Script_list.t -> Gas.cost =
      fun _ -> atomic_step_cost cost_N_IList_map
 
     let list_size = atomic_step_cost cost_N_IList_size
 
-    let list_iter : 'a Script_typed_ir.boxed_list -> Gas.cost =
+    let list_iter : 'a Script_list.t -> Gas.cost =
      fun _ -> atomic_step_cost cost_N_IList_iter
 
     let empty_set = atomic_step_cost cost_N_IEmpty_set
@@ -308,7 +308,7 @@ module Cost_of = struct
 
     let neq = atomic_step_cost cost_N_INeq
 
-    let pairing_check_bls12_381 (l : 'a Script_typed_ir.boxed_list) =
+    let pairing_check_bls12_381 (l : 'a Script_list.t) =
       atomic_step_cost (cost_N_IPairing_check_bls12_381 l.length)
 
     let comb n = atomic_step_cost (cost_N_IComb n)
@@ -633,7 +633,7 @@ module Cost_of = struct
        list of strings to compute the total allocated cost.
        [concat_string_precheck] corresponds to the meta-gas cost of this computation.
     *)
-    let concat_string_precheck (l : 'a Script_typed_ir.boxed_list) =
+    let concat_string_precheck (l : 'a Script_list.t) =
       (* we set the precheck to be slightly more expensive than cost_N_IList_iter *)
       atomic_step_cost (S.mul (S.safe_int l.length) (S.safe_int 10))
 
diff --git a/src/proto_alpha/lib_protocol/michelson_v1_gas.mli b/src/proto_alpha/lib_protocol/michelson_v1_gas.mli
index d15851a04ad6f176a0c02185fe4983aadf042dfc..bef843924505d937a10d71119110b834917d4eb9 100644
--- a/src/proto_alpha/lib_protocol/michelson_v1_gas.mli
+++ b/src/proto_alpha/lib_protocol/michelson_v1_gas.mli
@@ -70,12 +70,12 @@ module Cost_of : sig
     val if_cons : Gas.cost
 
     (* The argument of this function is ignored when calculating gas cost. *)
-    val list_map : 'a Script_typed_ir.boxed_list -> Gas.cost
+    val list_map : 'a Script_list.t -> Gas.cost
 
     val list_size : Gas.cost
 
     (* The argument of this function is ignored when calculating gas cost. *)
-    val list_iter : 'a Script_typed_ir.boxed_list -> Gas.cost
+    val list_iter : 'a Script_list.t -> Gas.cost
 
     val empty_set : Gas.cost
 
@@ -255,7 +255,7 @@ module Cost_of : sig
 
     val neq : Gas.cost
 
-    val pairing_check_bls12_381 : 'a Script_typed_ir.boxed_list -> Gas.cost
+    val pairing_check_bls12_381 : 'a Script_list.t -> Gas.cost
 
     val comb : int -> Gas.cost
 
@@ -269,7 +269,7 @@ module Cost_of : sig
 
     val compare : 'a Script_typed_ir.comparable_ty -> 'a -> 'a -> Gas.cost
 
-    val concat_string_precheck : 'a Script_typed_ir.boxed_list -> Gas.cost
+    val concat_string_precheck : 'a Script_list.t -> Gas.cost
 
     val concat_string :
       Saturation_repr.may_saturate Saturation_repr.t -> Gas.cost
diff --git a/src/proto_alpha/lib_protocol/script_interpreter.ml b/src/proto_alpha/lib_protocol/script_interpreter.ml
index a0ed820f8f8e774393d9ba7813c363a7fe6040be..76b33e1c92914eb478e870180803cbcdc1d52a82 100644
--- a/src/proto_alpha/lib_protocol/script_interpreter.ml
+++ b/src/proto_alpha/lib_protocol/script_interpreter.ml
@@ -274,7 +274,8 @@ and kmap_enter : type a b c d f i j k. (a, b, c, d, f, i, j, k) kmap_enter_type
 
 and klist_exit : type a b c d e i j. (a, b, c, d, e, i, j) klist_exit_type =
  fun instrument g gas body xs ys ty len ks accu stack ->
-  let ks = instrument @@ KList_enter_body (body, xs, accu :: ys, ty, len, ks) in
+  let ys = Script_list.cons accu ys in
+  let ks = instrument @@ KList_enter_body (body, xs, ys, ty, len, ks) in
   let accu, stack = stack in
   (next [@ocaml.tailcall]) g gas ks accu stack
  [@@inline]
@@ -283,7 +284,7 @@ and klist_enter : type a b c d e f j. (a, b, c, d, e, f, j) klist_enter_type =
  fun instrument g gas body xs ys ty len ks' accu stack ->
   match xs with
   | [] ->
-      let ys = {elements = List.rev ys; length = len} in
+      let ys = Script_list.rev ys in
       (next [@ocaml.tailcall]) g gas ks' ys (accu, stack)
   | x :: xs ->
       let ks = instrument @@ KList_exit_body (body, xs, ys, ty, len, ks') in
@@ -391,7 +392,7 @@ and ilist_map :
     type a b c d e f g h i. (a, b, c, d, e, f, g, h, i) ilist_map_type =
  fun instrument g gas body k ks ty accu stack ->
   let xs = accu.elements in
-  let ys = [] in
+  let ys = Script_list.empty in
   let len = accu.length in
   let ks =
     instrument @@ KList_enter_body (body, xs, ys, ty, len, KCons (k, ks))
@@ -694,8 +695,8 @@ and step : type a s b t r f. (a, s, b, t, r, f) step_type =
           let accu = Script_list.empty in
           (step [@ocaml.tailcall]) g gas k ks accu stack
       | IIf_cons {branch_if_cons; branch_if_nil; k; _} -> (
-          match accu.elements with
-          | [] ->
+          match Script_list.uncons accu with
+          | None ->
               let accu, stack = stack in
               (step [@ocaml.tailcall])
                 g
@@ -704,8 +705,7 @@ and step : type a s b t r f. (a, s, b, t, r, f) step_type =
                 (KCons (k, ks))
                 accu
                 stack
-          | hd :: tl ->
-              let tl = {elements = tl; length = accu.length - 1} in
+          | Some (hd, tl) ->
               (step [@ocaml.tailcall])
                 g
                 gas
@@ -1682,12 +1682,11 @@ and log :
             Script_interpreter_logging.instrument_cont logger sty'
             @@ KCons (k, ks)
       in
-      match accu.elements with
-      | [] ->
+      match Script_list.uncons accu with
+      | None ->
           let accu, stack = stack in
           (step [@ocaml.tailcall]) g gas branch_if_nil k' accu stack
-      | hd :: tl ->
-          let tl = {elements = tl; length = accu.length - 1} in
+      | Some (hd, tl) ->
           (step [@ocaml.tailcall]) g gas branch_if_cons k' hd (tl, stack))
   | IList_map (_, body, ty, k) ->
       let (Item_t (_, sty')) = sty in
diff --git a/src/proto_alpha/lib_protocol/script_interpreter_defs.ml b/src/proto_alpha/lib_protocol/script_interpreter_defs.ml
index 0a87b0a382130b244414f0d7df82fa546bf88427..fc13757c117a4e8c2f92667778de7f96db589851 100644
--- a/src/proto_alpha/lib_protocol/script_interpreter_defs.ml
+++ b/src/proto_alpha/lib_protocol/script_interpreter_defs.ml
@@ -811,10 +811,10 @@ type ('a, 'b, 'c, 'd, 'e, 'i, 'j) klist_exit_type =
   local_gas_counter ->
   ('i, 'a * 'b, 'j, 'a * 'b) kinstr ->
   'i list ->
-  'j list ->
-  ('j boxed_list, 'e) ty option ->
+  'j Script_list.t ->
+  ('j Script_list.t, 'e) ty option ->
   int ->
-  ('j boxed_list, 'a * 'b, 'c, 'd) continuation ->
+  ('j Script_list.t, 'a * 'b, 'c, 'd) continuation ->
   'j ->
   'a * 'b ->
   ('c * 'd * outdated_context * local_gas_counter) tzresult Lwt.t
@@ -825,10 +825,10 @@ type ('a, 'b, 'c, 'd, 'e, 'f, 'j) klist_enter_type =
   local_gas_counter ->
   ('j, 'a * 'c, 'b, 'a * 'c) kinstr ->
   'j list ->
-  'b list ->
-  ('b boxed_list, 'f) ty option ->
+  'b Script_list.t ->
+  ('b Script_list.t, 'f) ty option ->
   int ->
-  ('b boxed_list, 'a * 'c, 'd, 'e) continuation ->
+  ('b Script_list.t, 'a * 'c, 'd, 'e) continuation ->
   'a ->
   'c ->
   ('d * 'e * outdated_context * local_gas_counter) tzresult Lwt.t
@@ -870,10 +870,10 @@ type ('a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i) ilist_map_type =
   outdated_context * step_constants ->
   local_gas_counter ->
   ('e, 'a * 'b, 'f, 'a * 'b) kinstr ->
-  ('f boxed_list, 'a * 'b, 'g, 'h) kinstr ->
+  ('f Script_list.t, 'a * 'b, 'g, 'h) kinstr ->
   ('g, 'h, 'c, 'd) continuation ->
-  ('f boxed_list, 'i) ty option ->
-  'e boxed_list ->
+  ('f Script_list.t, 'i) ty option ->
+  'e Script_list.t ->
   'a * 'b ->
   ('c * 'd * outdated_context * local_gas_counter) tzresult Lwt.t
 
@@ -885,7 +885,7 @@ type ('a, 'b, 'c, 'd, 'e, 'f, 'g, 'cmp) ilist_iter_type =
   ('e, 'cmp) ty option ->
   ('a, 'b, 'f, 'g) kinstr ->
   ('f, 'g, 'c, 'd) continuation ->
-  'e boxed_list ->
+  'e Script_list.t ->
   'a * 'b ->
   ('c * 'd * outdated_context * local_gas_counter) tzresult Lwt.t
 
diff --git a/src/proto_alpha/lib_protocol/script_ir_translator.ml b/src/proto_alpha/lib_protocol/script_ir_translator.ml
index 41453d7ec67e6b181a8241ae6a96cafa3b843149..87051202dad47ee7f3732879ecd30125679b025f 100644
--- a/src/proto_alpha/lib_protocol/script_ir_translator.ml
+++ b/src/proto_alpha/lib_protocol/script_ir_translator.ml
@@ -1117,7 +1117,7 @@ type toplevel = {
 type ('arg, 'storage) code =
   | Code : {
       code :
-        (('arg, 'storage) pair, (operation boxed_list, 'storage) pair) lambda;
+        (('arg, 'storage) pair, (operation Script_list.t, 'storage) pair) lambda;
       arg_type : ('arg, _) ty;
       storage_type : ('storage, _) ty;
       views : view_map;
@@ -5076,7 +5076,7 @@ type 'ty has_lazy_storage =
       'a has_lazy_storage * 'b has_lazy_storage
       -> ('a, 'b) union has_lazy_storage
   | Option_f : 'a has_lazy_storage -> 'a option has_lazy_storage
-  | List_f : 'a has_lazy_storage -> 'a boxed_list has_lazy_storage
+  | List_f : 'a has_lazy_storage -> 'a Script_list.t has_lazy_storage
   | Map_f : 'v has_lazy_storage -> (_, 'v) map has_lazy_storage
 
 (**
@@ -5203,7 +5203,7 @@ let extract_lazy_storage_updates ctxt mode ~temporary ids_to_copy acc ty x =
           (ctxt, Script_list.empty, ids_to_copy, acc)
           l.elements
         >|=? fun (ctxt, l, ids_to_copy, acc) ->
-        let reversed = {length = l.length; elements = List.rev l.elements} in
+        let reversed = Script_list.rev l in
         (ctxt, reversed, ids_to_copy, acc)
     | Map_f has_lazy_storage, Map_t (_, ty, _), map ->
         let (module M) = Script_map.get_module map in
diff --git a/src/proto_alpha/lib_protocol/script_ir_translator.mli b/src/proto_alpha/lib_protocol/script_ir_translator.mli
index 6a65a2e20669aa944f7c1d7f21f32f40342192dc..dd9af56c6fdc32fcb42a625b7a554efac43e19fa 100644
--- a/src/proto_alpha/lib_protocol/script_ir_translator.mli
+++ b/src/proto_alpha/lib_protocol/script_ir_translator.mli
@@ -94,7 +94,7 @@ type ('arg, 'storage) code =
   | Code : {
       code :
         ( ('arg, 'storage) Script_typed_ir.pair,
-          ( Script_typed_ir.operation Script_typed_ir.boxed_list,
+          ( Script_typed_ir.operation Script_list.t,
             'storage )
           Script_typed_ir.pair )
         Script_typed_ir.lambda;
diff --git a/src/proto_alpha/lib_protocol/script_list.ml b/src/proto_alpha/lib_protocol/script_list.ml
index 7e9cbdeb22140b9b7414f692560642afa76c4a00..66d97bdbffbcddb011adcf86e1b5a37824d32818 100644
--- a/src/proto_alpha/lib_protocol/script_list.ml
+++ b/src/proto_alpha/lib_protocol/script_list.ml
@@ -3,6 +3,7 @@
 (* Open Source License                                                       *)
 (* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
 (* Copyright (c) 2020 Metastate AG <hello@metastate.dev>                     *)
+(* Copyright (c) 2021-2022 Nomadic Labs <contact@nomadic-labs.com>           *)
 (*                                                                           *)
 (* Permission is hereby granted, free of charge, to any person obtaining a   *)
 (* copy of this software and associated documentation files (the "Software"),*)
@@ -24,9 +25,23 @@
 (*                                                                           *)
 (*****************************************************************************)
 
-open Script_typed_ir
+type 'elt t = {elements : 'elt list; length : int}
 
-let empty : 'a boxed_list = {elements = []; length = 0}
+let of_list l = {elements = l; length = List.length l} [@@inline always]
 
-let cons : 'a -> 'a boxed_list -> 'a boxed_list =
+let to_list {elements; length = _} = elements [@@inline always]
+
+let empty : 'a t = {elements = []; length = 0}
+
+let cons : 'a -> 'a t -> 'a t =
  fun elt l -> {length = 1 + l.length; elements = elt :: l.elements}
+
+let length {elements = _; length} = length [@@inline always]
+
+let uncons = function
+  | {elements = []; length = _} -> None
+  | {elements = hd :: tl; length} ->
+      Some (hd, {elements = tl; length = length - 1})
+
+let rev {elements; length} = {elements = List.rev elements; length}
+  [@@inline always]
diff --git a/src/proto_alpha/lib_protocol/script_list.mli b/src/proto_alpha/lib_protocol/script_list.mli
index 01a4670df6b47072f6aeed0c62c3dc7f4fc4bae4..dbd19d6467c00a49aa735456286bccb407526f1a 100644
--- a/src/proto_alpha/lib_protocol/script_list.mli
+++ b/src/proto_alpha/lib_protocol/script_list.mli
@@ -3,6 +3,7 @@
 (* Open Source License                                                       *)
 (* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
 (* Copyright (c) 2020 Metastate AG <hello@metastate.dev>                     *)
+(* Copyright (c) 2021-2022 Nomadic Labs <contact@nomadic-labs.com>           *)
 (*                                                                           *)
 (* Permission is hereby granted, free of charge, to any person obtaining a   *)
 (* copy of this software and associated documentation files (the "Software"),*)
@@ -24,8 +25,26 @@
 (*                                                                           *)
 (*****************************************************************************)
 
+type 'elt t = private {elements : 'elt list; length : int}
+
+(** Convert an OCaml list into Michelson list. *)
+val of_list : 'a list -> 'a t
+
+(** Convert a Michelson list to an OCaml list. *)
+val to_list : 'a t -> 'a list
+
+(** [length l] returns the number of elements in [l] as [int]. *)
+val length : 'a t -> int
+
 (** Empty list. *)
-val empty : 'a Script_typed_ir.boxed_list
+val empty : 'a t
 
 (** Prepend an element. *)
-val cons : 'a -> 'a Script_typed_ir.boxed_list -> 'a Script_typed_ir.boxed_list
+val cons : 'a -> 'a t -> 'a t
+
+(** [uncons l] returns [Some (hd, tl)] where [hd :: tl = l] if [l] is
+    not empty or [None] otherwise. *)
+val uncons : 'a t -> ('a * 'a t) option
+
+(** [rev l] returns a list containing all elements of [l] in reversed order. *)
+val rev : 'a t -> 'a t
diff --git a/src/proto_alpha/lib_protocol/script_typed_ir.ml b/src/proto_alpha/lib_protocol/script_typed_ir.ml
index aaded94994b13fd5689cd622de511428eb822b94..3c75ade275fa976d44a0cb3e8980f10fdfe3729a 100644
--- a/src/proto_alpha/lib_protocol/script_typed_ir.ml
+++ b/src/proto_alpha/lib_protocol/script_typed_ir.ml
@@ -418,8 +418,6 @@ type ('key, 'value) big_map_overlay = {
   size : int;
 }
 
-type 'elt boxed_list = {elements : 'elt list; length : int}
-
 type view = {
   input_ty : Script.node;
   output_ty : Script.node;
@@ -531,33 +529,33 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
      -----
   *)
   | ICons_list :
-      Script.location * ('a boxed_list, 's, 'r, 'f) kinstr
-      -> ('a, 'a boxed_list * 's, 'r, 'f) kinstr
+      Script.location * ('a Script_list.t, 's, 'r, 'f) kinstr
+      -> ('a, 'a Script_list.t * 's, 'r, 'f) kinstr
   | INil :
-      Script.location * ('b, _) ty * ('b boxed_list, 'a * 's, 'r, 'f) kinstr
+      Script.location * ('b, _) ty * ('b Script_list.t, 'a * 's, 'r, 'f) kinstr
       -> ('a, 's, 'r, 'f) kinstr
   | IIf_cons : {
       loc : Script.location;
-      branch_if_cons : ('a, 'a boxed_list * ('b * 's), 'c, 't) kinstr;
+      branch_if_cons : ('a, 'a Script_list.t * ('b * 's), 'c, 't) kinstr;
       branch_if_nil : ('b, 's, 'c, 't) kinstr;
       k : ('c, 't, 'r, 'f) kinstr;
     }
-      -> ('a boxed_list, 'b * 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 'b * 's, 'r, 'f) kinstr
   | IList_map :
       Script.location
       * ('a, 'c * 's, 'b, 'c * 's) kinstr
-      * ('b boxed_list, _) ty option
-      * ('b boxed_list, 'c * 's, 'r, 'f) kinstr
-      -> ('a boxed_list, 'c * 's, 'r, 'f) kinstr
+      * ('b Script_list.t, _) ty option
+      * ('b Script_list.t, 'c * 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 'c * 's, 'r, 'f) kinstr
   | IList_iter :
       Script.location
       * ('a, _) ty option
       * ('a, 'b * 's, 'b, 's) kinstr
       * ('b, 's, 'r, 'f) kinstr
-      -> ('a boxed_list, 'b * 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 'b * 's, 'r, 'f) kinstr
   | IList_size :
       Script.location * (n num, 's, 'r, 'f) kinstr
-      -> ('a boxed_list, 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 's, 'r, 'f) kinstr
   (*
     Sets
     ----
@@ -645,7 +643,7 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
   *)
   | IConcat_string :
       Script.location * (Script_string.t, 's, 'r, 'f) kinstr
-      -> (Script_string.t boxed_list, 's, 'r, 'f) kinstr
+      -> (Script_string.t Script_list.t, 's, 'r, 'f) kinstr
   | IConcat_string_pair :
       Script.location * (Script_string.t, 's, 'r, 'f) kinstr
       -> (Script_string.t, Script_string.t * 's, 'r, 'f) kinstr
@@ -661,7 +659,7 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
   *)
   | IConcat_bytes :
       Script.location * (bytes, 's, 'r, 'f) kinstr
-      -> (bytes boxed_list, 's, 'r, 'f) kinstr
+      -> (bytes Script_list.t, 's, 'r, 'f) kinstr
   | IConcat_bytes_pair :
       Script.location * (bytes, 's, 'r, 'f) kinstr
       -> (bytes, bytes * 's, 'r, 'f) kinstr
@@ -1033,7 +1031,11 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
       -> (Script_bls.Fr.t, 's, 'r, 'f) kinstr
   | IPairing_check_bls12_381 :
       Script.location * (bool, 's, 'r, 'f) kinstr
-      -> ((Script_bls.G1.t, Script_bls.G2.t) pair boxed_list, 's, 'r, 'f) kinstr
+      -> ( (Script_bls.G1.t, Script_bls.G2.t) pair Script_list.t,
+           's,
+           'r,
+           'f )
+         kinstr
   | IComb :
       Script.location
       * int
@@ -1174,18 +1176,18 @@ and (_, _, _, _) continuation =
   | KList_enter_body :
       ('a, 'c * 's, 'b, 'c * 's) kinstr
       * 'a list
-      * 'b list
-      * ('b boxed_list, _) ty option
+      * 'b Script_list.t
+      * ('b Script_list.t, _) ty option
       * int
-      * ('b boxed_list, 'c * 's, 'r, 'f) continuation
+      * ('b Script_list.t, 'c * 's, 'r, 'f) continuation
       -> ('c, 's, 'r, 'f) continuation
   | KList_exit_body :
       ('a, 'c * 's, 'b, 'c * 's) kinstr
       * 'a list
-      * 'b list
-      * ('b boxed_list, _) ty option
+      * 'b Script_list.t
+      * ('b Script_list.t, _) ty option
       * int
-      * ('b boxed_list, 'c * 's, 'r, 'f) continuation
+      * ('b Script_list.t, 'c * 's, 'r, 'f) continuation
       -> ('b, 'c * 's, 'r, 'f) continuation
   | KMap_enter_body :
       ('a * 'b, 'd * 's, 'c, 'd * 's) kinstr
@@ -1260,7 +1262,9 @@ and ('ty, 'comparable) ty =
   | Option_t :
       ('v, 'c) ty * 'v option ty_metadata * 'c dbool
       -> ('v option, 'c) ty
-  | List_t : ('v, _) ty * 'v boxed_list ty_metadata -> ('v boxed_list, no) ty
+  | List_t :
+      ('v, _) ty * 'v Script_list.t ty_metadata
+      -> ('v Script_list.t, no) ty
   | Set_t : 'v comparable_ty * 'v set ty_metadata -> ('v set, no) ty
   | Map_t :
       'k comparable_ty * ('v, _) ty * ('k, 'v) map ty_metadata
@@ -1444,7 +1448,7 @@ type ex_ty = Ex_ty : ('a, _) ty -> ex_ty
 type ('arg, 'storage) script =
   | Script : {
       code :
-        (('arg, 'storage) pair, (operation boxed_list, 'storage) pair) lambda;
+        (('arg, 'storage) pair, (operation Script_list.t, 'storage) pair) lambda;
       arg_type : ('arg, _) ty;
       storage : 'storage;
       storage_type : ('storage, _) ty;
diff --git a/src/proto_alpha/lib_protocol/script_typed_ir.mli b/src/proto_alpha/lib_protocol/script_typed_ir.mli
index 5cd6815538db4be844de4854f98aef43ff03c9fb..874cb08556e870eabbb53d4812086fdaf773914e 100644
--- a/src/proto_alpha/lib_protocol/script_typed_ir.mli
+++ b/src/proto_alpha/lib_protocol/script_typed_ir.mli
@@ -29,15 +29,34 @@ open Alpha_context
 open Script_int
 open Dependent_bool
 
+(*
+
+    The step function of the interpreter is parametrized by a bunch of values called the step constants.
+    These values are indeed constants during the call of a smart contract with the notable exception of
+    the IView instruction which modifies `source`, `self`, and `amount` and the KView_exit continuation
+    which restores them.
+    ======================
+
+*)
 type step_constants = {
   source : Contract.t;
+      (** The address calling this contract, as returned by SENDER. *)
   payer : Signature.public_key_hash;
+      (** The address of the implicit account that initiated the chain of contract calls, as returned by SOURCE. *)
   self : Contract_hash.t;
+      (** The address of the contract being executed, as returned by SELF and SELF_ADDRESS.
+     Also used:
+     - as ticketer in TICKET
+     - as caller in VIEW, TRANSFER_TOKENS, and CREATE_CONTRACT *)
   amount : Tez.t;
-  balance : Tez.t;
+      (** The amount of the current transaction, as returned by AMOUNT. *)
+  balance : Tez.t;  (** The balance of the contract as returned by BALANCE. *)
   chain_id : Chain_id.t;
+      (** The chain id of the chain, as returned by CHAIN_ID. *)
   now : Script_timestamp.t;
+      (** The earliest time at which the current block could have been timestamped, as returned by NOW. *)
   level : Script_int.n Script_int.num;
+      (** The level of the current block, as returned by LEVEL. *)
 }
 
 (* Preliminary definitions. *)
@@ -271,8 +290,6 @@ type ('key, 'value) big_map_overlay = {
   size : int;
 }
 
-type 'elt boxed_list = {elements : 'elt list; length : int}
-
 type view = {
   input_ty : Script.node;
   output_ty : Script.node;
@@ -492,33 +509,33 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
      -----
   *)
   | ICons_list :
-      Script.location * ('a boxed_list, 's, 'r, 'f) kinstr
-      -> ('a, 'a boxed_list * 's, 'r, 'f) kinstr
+      Script.location * ('a Script_list.t, 's, 'r, 'f) kinstr
+      -> ('a, 'a Script_list.t * 's, 'r, 'f) kinstr
   | INil :
-      Script.location * ('b, _) ty * ('b boxed_list, 'a * 's, 'r, 'f) kinstr
+      Script.location * ('b, _) ty * ('b Script_list.t, 'a * 's, 'r, 'f) kinstr
       -> ('a, 's, 'r, 'f) kinstr
   | IIf_cons : {
       loc : Script.location;
-      branch_if_cons : ('a, 'a boxed_list * ('b * 's), 'c, 't) kinstr;
+      branch_if_cons : ('a, 'a Script_list.t * ('b * 's), 'c, 't) kinstr;
       branch_if_nil : ('b, 's, 'c, 't) kinstr;
       k : ('c, 't, 'r, 'f) kinstr;
     }
-      -> ('a boxed_list, 'b * 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 'b * 's, 'r, 'f) kinstr
   | IList_map :
       Script.location
       * ('a, 'c * 's, 'b, 'c * 's) kinstr
-      * ('b boxed_list, _) ty option
-      * ('b boxed_list, 'c * 's, 'r, 'f) kinstr
-      -> ('a boxed_list, 'c * 's, 'r, 'f) kinstr
+      * ('b Script_list.t, _) ty option
+      * ('b Script_list.t, 'c * 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 'c * 's, 'r, 'f) kinstr
   | IList_iter :
       Script.location
       * ('a, _) ty option
       * ('a, 'b * 's, 'b, 's) kinstr
       * ('b, 's, 'r, 'f) kinstr
-      -> ('a boxed_list, 'b * 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 'b * 's, 'r, 'f) kinstr
   | IList_size :
       Script.location * (n num, 's, 'r, 'f) kinstr
-      -> ('a boxed_list, 's, 'r, 'f) kinstr
+      -> ('a Script_list.t, 's, 'r, 'f) kinstr
   (*
     Sets
     ----
@@ -606,7 +623,7 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
   *)
   | IConcat_string :
       Script.location * (Script_string.t, 's, 'r, 'f) kinstr
-      -> (Script_string.t boxed_list, 's, 'r, 'f) kinstr
+      -> (Script_string.t Script_list.t, 's, 'r, 'f) kinstr
   | IConcat_string_pair :
       Script.location * (Script_string.t, 's, 'r, 'f) kinstr
       -> (Script_string.t, Script_string.t * 's, 'r, 'f) kinstr
@@ -622,7 +639,7 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
   *)
   | IConcat_bytes :
       Script.location * (bytes, 's, 'r, 'f) kinstr
-      -> (bytes boxed_list, 's, 'r, 'f) kinstr
+      -> (bytes Script_list.t, 's, 'r, 'f) kinstr
   | IConcat_bytes_pair :
       Script.location * (bytes, 's, 'r, 'f) kinstr
       -> (bytes, bytes * 's, 'r, 'f) kinstr
@@ -1030,7 +1047,11 @@ and ('before_top, 'before, 'result_top, 'result) kinstr =
       -> (Script_bls.Fr.t, 's, 'r, 'f) kinstr
   | IPairing_check_bls12_381 :
       Script.location * (bool, 's, 'r, 'f) kinstr
-      -> ((Script_bls.G1.t, Script_bls.G2.t) pair boxed_list, 's, 'r, 'f) kinstr
+      -> ( (Script_bls.G1.t, Script_bls.G2.t) pair Script_list.t,
+           's,
+           'r,
+           'f )
+         kinstr
   | IComb :
       Script.location
       * int
@@ -1237,19 +1258,19 @@ and (_, _, _, _) continuation =
   | KList_enter_body :
       ('a, 'c * 's, 'b, 'c * 's) kinstr
       * 'a list
-      * 'b list
-      * ('b boxed_list, _) ty option
+      * 'b Script_list.t
+      * ('b Script_list.t, _) ty option
       * int
-      * ('b boxed_list, 'c * 's, 'r, 'f) continuation
+      * ('b Script_list.t, 'c * 's, 'r, 'f) continuation
       -> ('c, 's, 'r, 'f) continuation
   (* This continuation represents what is done after each step of a List.map. *)
   | KList_exit_body :
       ('a, 'c * 's, 'b, 'c * 's) kinstr
       * 'a list
-      * 'b list
-      * ('b boxed_list, _) ty option
+      * 'b Script_list.t
+      * ('b Script_list.t, _) ty option
       * int
-      * ('b boxed_list, 'c * 's, 'r, 'f) continuation
+      * ('b Script_list.t, 'c * 's, 'r, 'f) continuation
       -> ('b, 'c * 's, 'r, 'f) continuation
   (* This continuation represents each step of a Map.map. *)
   | KMap_enter_body :
@@ -1357,7 +1378,9 @@ and ('ty, 'comparable) ty =
   | Option_t :
       ('v, 'c) ty * 'v option ty_metadata * 'c dbool
       -> ('v option, 'c) ty
-  | List_t : ('v, _) ty * 'v boxed_list ty_metadata -> ('v boxed_list, no) ty
+  | List_t :
+      ('v, _) ty * 'v Script_list.t ty_metadata
+      -> ('v Script_list.t, no) ty
   | Set_t : 'v comparable_ty * 'v set ty_metadata -> ('v set, no) ty
   | Map_t :
       'k comparable_ty * ('v, _) ty * ('k, 'v) map ty_metadata
@@ -1578,7 +1601,7 @@ and operation = {
 type ('arg, 'storage) script =
   | Script : {
       code :
-        (('arg, 'storage) pair, (operation boxed_list, 'storage) pair) lambda;
+        (('arg, 'storage) pair, (operation Script_list.t, 'storage) pair) lambda;
       arg_type : ('arg, _) ty;
       storage : 'storage;
       storage_type : ('storage, _) ty;
@@ -1684,9 +1707,9 @@ val option_pair_mutez_mutez_t : (Tez.t, Tez.t) pair option comparable_ty
 
 val option_pair_int_nat_t : (z num, n num) pair option comparable_ty
 
-val list_t : Script.location -> ('v, _) ty -> ('v boxed_list, no) ty tzresult
+val list_t : Script.location -> ('v, _) ty -> ('v Script_list.t, no) ty tzresult
 
-val list_operation_t : (operation boxed_list, no) ty
+val list_operation_t : (operation Script_list.t, no) ty
 
 val set_t : Script.location -> 'v comparable_ty -> ('v set, no) ty tzresult
 
diff --git a/src/proto_alpha/lib_protocol/test/helpers/script_list.ml b/src/proto_alpha/lib_protocol/test/helpers/script_list.ml
deleted file mode 100644
index b224d784226bbd2a328edb66d3204cbfccf72c1b..0000000000000000000000000000000000000000
--- a/src/proto_alpha/lib_protocol/test/helpers/script_list.ml
+++ /dev/null
@@ -1,29 +0,0 @@
-(*****************************************************************************)
-(*                                                                           *)
-(* Open Source License                                                       *)
-(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
-(* Copyright (c) 2020 Metastate AG <hello@metastate.dev>                     *)
-(*                                                                           *)
-(* Permission is hereby granted, free of charge, to any person obtaining a   *)
-(* copy of this software and associated documentation files (the "Software"),*)
-(* to deal in the Software without restriction, including without limitation *)
-(* the rights to use, copy, modify, merge, publish, distribute, sublicense,  *)
-(* and/or sell copies of the Software, and to permit persons to whom the     *)
-(* Software is furnished to do so, subject to the following conditions:      *)
-(*                                                                           *)
-(* The above copyright notice and this permission notice shall be included   *)
-(* in all copies or substantial portions of the Software.                    *)
-(*                                                                           *)
-(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
-(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  *)
-(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL   *)
-(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
-(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING   *)
-(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER       *)
-(* DEALINGS IN THE SOFTWARE.                                                 *)
-(*                                                                           *)
-(*****************************************************************************)
-
-open Protocol.Script_typed_ir (* For record fields *)
-
-let of_list xs = {elements = xs; length = List.length xs}
diff --git a/src/proto_alpha/lib_protocol/test/helpers/script_list.mli b/src/proto_alpha/lib_protocol/test/helpers/script_list.mli
deleted file mode 100644
index fecdbe0072c1f130a1524960a95403095e77e758..0000000000000000000000000000000000000000
--- a/src/proto_alpha/lib_protocol/test/helpers/script_list.mli
+++ /dev/null
@@ -1,28 +0,0 @@
-(*****************************************************************************)
-(*                                                                           *)
-(* Open Source License                                                       *)
-(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
-(* Copyright (c) 2020 Metastate AG <hello@metastate.dev>                     *)
-(*                                                                           *)
-(* Permission is hereby granted, free of charge, to any person obtaining a   *)
-(* copy of this software and associated documentation files (the "Software"),*)
-(* to deal in the Software without restriction, including without limitation *)
-(* the rights to use, copy, modify, merge, publish, distribute, sublicense,  *)
-(* and/or sell copies of the Software, and to permit persons to whom the     *)
-(* Software is furnished to do so, subject to the following conditions:      *)
-(*                                                                           *)
-(* The above copyright notice and this permission notice shall be included   *)
-(* in all copies or substantial portions of the Software.                    *)
-(*                                                                           *)
-(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
-(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  *)
-(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL   *)
-(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
-(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING   *)
-(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER       *)
-(* DEALINGS IN THE SOFTWARE.                                                 *)
-(*                                                                           *)
-(*****************************************************************************)
-
-(** Convert a standard list to a Script IR list. *)
-val of_list : 'a list -> 'a Protocol.Script_typed_ir.boxed_list
diff --git a/src/proto_alpha/lib_protocol/test/integration/michelson/test_script_typed_ir_size.ml b/src/proto_alpha/lib_protocol/test/integration/michelson/test_script_typed_ir_size.ml
index 1e0342d85d7be7efac3f20ec649ee21ba7be8105..4f455ac1b9f29c6d12e123a008d7a27b9af297ae 100644
--- a/src/proto_alpha/lib_protocol/test/integration/michelson/test_script_typed_ir_size.ml
+++ b/src/proto_alpha/lib_protocol/test/integration/michelson/test_script_typed_ir_size.ml
@@ -481,7 +481,7 @@ let check_value_size () =
         ======
     *)
     @ (let module P = struct
-         type 'a f = {apply : 'c. ('a boxed_list, 'c) ty -> ex list}
+         type 'a f = {apply : 'c. ('a Script_list.t, 'c) ty -> ex list}
        end in
       let on_list : type a. (a, _) ty -> a P.f -> ex list =
        fun ty f -> f.apply @@ is_ok @@ list_t dummy_loc ty
@@ -492,7 +492,9 @@ let check_value_size () =
           {
             apply =
               (fun ty ->
-                let show fmt l = Format.pp_print_list show_elt fmt l.elements in
+                let show fmt l =
+                  Format.pp_print_list show_elt fmt @@ Script_list.to_list l
+                in
                 exs nsample show ty ": list _");
           }
       in
diff --git a/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_accounting.ml b/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_accounting.ml
index ac711717acdd8a8669efd8e8467f0ca47548b1a9..618766fb1db5f7eaa0d2faf3a628da28a4ac79c5 100644
--- a/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_accounting.ml
+++ b/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_accounting.ml
@@ -431,8 +431,7 @@ let ticket_string_list_type =
   Result.value_f ~default:(fun _ -> assert false)
   @@ Script_typed_ir.list_t (-1) ticket_string_type
 
-let boxed_list elements =
-  {Script_typed_ir.elements; length = List.length elements}
+let boxed_list = Script_list.of_list
 
 let big_map_type ~key_type ~value_type =
   Environment.wrap_tzresult
diff --git a/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_operations_diff.ml b/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_operations_diff.ml
index 81c853bff6c0c482428b0183d081ded3fb328d1d..1612fb26a89daa74da67baacf667305794e3d92f 100644
--- a/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_operations_diff.ml
+++ b/src/proto_alpha/lib_protocol/test/integration/michelson/test_ticket_operations_diff.ml
@@ -408,7 +408,7 @@ let make_ticket (ticketer, contents, amount) =
 
 let make_tickets ts =
   let* elements = List.map_es make_ticket ts in
-  return {elements; length = List.length elements}
+  return @@ Script_list.of_list elements
 
 let transfer_tickets_operation ~incr ~src ~destination tickets =
   let open Lwt_result_syntax in
diff --git a/src/proto_alpha/lib_protocol/ticket_scanner.ml b/src/proto_alpha/lib_protocol/ticket_scanner.ml
index 04075d107f457631896a3dd35a300a82559ac993..3b2106187fc47594ab658709e34cb3d3d4c740b8 100644
--- a/src/proto_alpha/lib_protocol/ticket_scanner.ml
+++ b/src/proto_alpha/lib_protocol/ticket_scanner.ml
@@ -85,7 +85,7 @@ module Ticket_inspection = struct
         'a has_tickets * 'b has_tickets
         -> ('a, 'b) Script_typed_ir.union has_tickets
     | Option_ht : 'a has_tickets -> 'a option has_tickets
-    | List_ht : 'a has_tickets -> 'a Script_typed_ir.boxed_list has_tickets
+    | List_ht : 'a has_tickets -> 'a Script_list.t has_tickets
     | Set_ht : 'k has_tickets -> 'k Script_typed_ir.set has_tickets
     | Map_ht :
         'k has_tickets * 'v has_tickets
@@ -375,7 +375,7 @@ module Ticket_collection = struct
               k
         | None -> (k [@ocaml.tailcall]) ctxt acc)
     | List_ht el_hty, List_t (el_ty, _) ->
-        let {elements; _} = x in
+        let elements = Script_list.to_list x in
         (tickets_of_list [@ocaml.tailcall])
           ctxt
           ~include_lazy