diff --git a/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml b/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml
index 4335935509a9f3e390246ba7fdd5d0c3319ee89f..6ae814811e9d54330f6464ab12ba3d1bd1cdb7ec 100644
--- a/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml
+++ b/src/proto_alpha/lib_benchmarks_proto/interpreter_benchmarks.ml
@@ -850,9 +850,8 @@ module Registration_section = struct
       else
         match comb_acc with
         | Ex_value {value; ty} ->
-            make_comb
-              (comb_width - 1)
-              (Ex_value {value = ((), value); ty = pair unit ty})
+            let ty = pair unit ty in
+            make_comb (comb_width - 1) (Ex_value {value = ((), value); ty})
 
     let () =
       let unpair n =
@@ -937,25 +936,25 @@ module Registration_section = struct
     let () =
       simple_benchmark
         ~name:Interpreter_workload.N_ICons_pair
-        ~kinstr:(ICons_pair (kinfo_unitunit, halt (pair unit unit @$ bot)))
+        ~kinstr:(ICons_pair (kinfo_unitunit, halt (cpair unit unit @$ bot)))
         ()
 
     let () =
       simple_benchmark
         ~name:Interpreter_workload.N_ICar
-        ~kinstr:(ICar (kinfo (pair unit unit @$ bot), halt_unit))
+        ~kinstr:(ICar (kinfo (cpair unit unit @$ bot), halt_unit))
         ()
 
     let () =
       simple_benchmark
         ~name:Interpreter_workload.N_ICdr
-        ~kinstr:(ICdr (kinfo (pair unit unit @$ bot), halt_unit))
+        ~kinstr:(ICdr (kinfo (cpair unit unit @$ bot), halt_unit))
         ()
 
     let () =
       simple_benchmark
         ~name:Interpreter_workload.N_IUnpair
-        ~kinstr:(IUnpair (kinfo (pair unit unit @$ bot), halt_unitunit))
+        ~kinstr:(IUnpair (kinfo (cpair unit unit @$ bot), halt_unitunit))
         ()
   end
 
@@ -1018,13 +1017,13 @@ module Registration_section = struct
     let () =
       simple_benchmark
         ~name:Interpreter_workload.N_ILeft
-        ~kinstr:(ICons_left (kinfo_unit, halt (union unit unit @$ bot)))
+        ~kinstr:(ICons_left (kinfo_unit, halt (cunion unit unit @$ bot)))
         ()
 
     let () =
       simple_benchmark
         ~name:Interpreter_workload.N_IRight
-        ~kinstr:(ICons_right (kinfo_unit, halt (union unit unit @$ bot)))
+        ~kinstr:(ICons_right (kinfo_unit, halt (cunion unit unit @$ bot)))
         ()
 
     let () =
@@ -1033,7 +1032,7 @@ module Registration_section = struct
         ~kinstr:
           (IIf_left
              {
-               kinfo = kinfo (union unit unit @$ bot);
+               kinfo = kinfo (cunion unit unit @$ bot);
                branch_if_left = halt_unit;
                branch_if_right = halt_unit;
                k = halt_unit;
@@ -1255,14 +1254,14 @@ module Registration_section = struct
     let map_map_code =
       IMap_map
         ( kinfo (map int_cmp unit @$ unit @$ bot),
-          ICdr (kinfo (pair int unit @$ unit @$ bot), halt_unitunit),
+          ICdr (kinfo (cpair int unit @$ unit @$ bot), halt_unitunit),
           halt (map int_cmp unit @$ unit @$ bot) )
      *)
 
     let map_map_code =
       IMap_map
         ( kinfo (map int_cmp unit @$ unit @$ bot),
-          IFailwith (kinfo (pair int unit @$ unit @$ bot), 0, pair int unit),
+          IFailwith (kinfo (cpair int unit @$ unit @$ bot), 0, cpair int unit),
           halt (map int_cmp unit @$ unit @$ bot) )
 
     let () =
@@ -1283,7 +1282,7 @@ module Registration_section = struct
     let kmap_iter_code =
       IMap_iter
         ( kinfo (map int_cmp unit @$ unit @$ bot),
-          IDrop (kinfo (pair int unit @$ unit @$ bot), halt_unit),
+          IDrop (kinfo (cpair int unit @$ unit @$ bot), halt_unit),
           halt_unit )
 
     let () =
@@ -1746,7 +1745,7 @@ module Registration_section = struct
         ~kinstr:
           (IEdiv_teznat
              ( kinfo (mutez @$ nat @$ bot),
-               halt (option (pair mutez mutez) @$ bot) ))
+               halt (option (cpair mutez mutez) @$ bot) ))
         ~stack_sampler:(fun cfg rng_state ->
           let (_, samplers) = make_default_samplers cfg.sampler in
           fun () ->
@@ -1761,7 +1760,7 @@ module Registration_section = struct
         ~kinstr:
           (IEdiv_tez
              ( kinfo (mutez @$ mutez @$ bot),
-               halt (option (pair nat mutez) @$ bot) ))
+               halt (option (cpair nat mutez) @$ bot) ))
         ()
   end
 
@@ -1871,7 +1870,7 @@ module Registration_section = struct
         ~intercept_stack:(zero, (zero, eos))
         ~kinstr:
           (IEdiv_int
-             (kinfo (int @$ int @$ bot), halt (option (pair int nat) @$ bot)))
+             (kinfo (int @$ int @$ bot), halt (option (cpair int nat) @$ bot)))
         ()
 
     let () =
@@ -1880,7 +1879,7 @@ module Registration_section = struct
         ~intercept_stack:(zero_n, (zero, eos))
         ~kinstr:
           (IEdiv_nat
-             (kinfo (nat @$ int @$ bot), halt (option (pair int nat) @$ bot)))
+             (kinfo (nat @$ int @$ bot), halt (option (cpair int nat) @$ bot)))
         ()
 
     let () =
@@ -1984,10 +1983,11 @@ module Registration_section = struct
         ICons_right ->
         IHalt
        *)
-      let cons_r = ICons_right (kinfo_unit, halt (union unit unit @$ bot)) in
+      let cons_r = ICons_right (kinfo_unit, halt (cunion unit unit @$ bot)) in
       simple_benchmark
         ~name:Interpreter_workload.N_ILoop_left
-        ~kinstr:(ILoop_left (kinfo (union unit unit @$ bot), cons_r, halt_unit))
+        ~kinstr:
+          (ILoop_left (kinfo (cunion unit unit @$ bot), cons_r, halt_unit))
         ()
 
     let () =
@@ -2035,9 +2035,9 @@ module Registration_section = struct
         let descr =
           {
             kloc = 0;
-            kbef = pair unit unit @$ bot;
+            kbef = cpair unit unit @$ bot;
             kaft = unit @$ bot;
-            kinstr = ICdr (kinfo (pair unit unit @$ bot), halt_unit);
+            kinstr = ICdr (kinfo (cpair unit unit @$ bot), halt_unit);
           }
         in
         Lam (descr, Micheline.Int (0, Z.zero))
@@ -2046,7 +2046,7 @@ module Registration_section = struct
         ~name:Interpreter_workload.N_IApply
         ~kinstr:
           (IApply
-             ( kinfo (unit @$ lambda (pair unit unit) unit @$ bot),
+             ( kinfo (unit @$ lambda (cpair unit unit) unit @$ bot),
                unit,
                halt (lambda unit unit @$ bot) ))
         ~stack_sampler:(fun _cfg _rng_state () -> ((), (code, eos)))
@@ -2178,20 +2178,20 @@ module Registration_section = struct
     let () =
       let lambda =
         let open Script_typed_ir in
+        let pair_list_operation_unit = pair (list operation) unit in
         let descr =
           {
             kloc = 0;
-            kbef = pair unit unit @$ bot;
-            kaft = pair (list operation) unit @$ bot;
+            kbef = cpair unit unit @$ bot;
+            kaft = pair_list_operation_unit @$ bot;
             kinstr =
               ICdr
-                ( kinfo (pair unit unit @$ bot),
+                ( kinfo (cpair unit unit @$ bot),
                   INil
                     ( kinfo (unit @$ bot),
                       ICons_pair
                         ( kinfo (list operation @$ unit @$ bot),
-                          IHalt (kinfo (pair (list operation) unit @$ bot)) ) )
-                );
+                          IHalt (kinfo (pair_list_operation_unit @$ bot)) ) ) );
           }
         in
         Lam (descr, Micheline.Int (0, Z.zero))
@@ -2462,9 +2462,10 @@ module Registration_section = struct
         let kinstr =
           let spl_state = sapling_state memo_size in
           let spl_tx = sapling_transaction memo_size in
+          let pair_int_spl_state = pair int spl_state in
           ISapling_verify_update
             ( kinfo (spl_tx @$ spl_state @$ bot),
-              halt (option (pair int spl_state) @$ bot) )
+              halt (option pair_int_spl_state @$ bot) )
 
         let prepare_sapling_execution_environment sapling_forge_rng_seed
             sapling_transition =
@@ -2666,12 +2667,12 @@ module Registration_section = struct
         ()
 
     let () =
+      let pair_bls12_381_g1_g2 = pair bls12_381_g1 bls12_381_g2 in
       simple_benchmark
         ~name:Interpreter_workload.N_IPairing_check_bls12_381
         ~kinstr:
           (IPairing_check_bls12_381
-             ( kinfo (list (pair bls12_381_g1 bls12_381_g2) @$ bot),
-               halt (bool @$ bot) ))
+             (kinfo (list pair_bls12_381_g1_g2 @$ bot), halt (bool @$ bot)))
         ()
   end
 
@@ -2689,13 +2690,16 @@ module Registration_section = struct
         ~kinstr:
           (IRead_ticket
              ( kinfo (ticket unit_cmp @$ bot),
-               halt (pair address (pair unit nat) @$ ticket unit_cmp @$ bot) ))
+               halt (cpair address (cpair unit nat) @$ ticket unit_cmp @$ bot)
+             ))
         ()
 
     let split_ticket_instr =
+      let ticket_unit = ticket unit_cmp in
+      let pair_ticket_unit_ticket_unit = pair ticket_unit ticket_unit in
       ISplit_ticket
-        ( kinfo (ticket unit_cmp @$ pair nat nat @$ bot),
-          halt (option (pair (ticket unit_cmp) (ticket unit_cmp)) @$ bot) )
+        ( kinfo (ticket_unit @$ cpair nat nat @$ bot),
+          halt (option pair_ticket_unit_ticket_unit @$ bot) )
 
     let () =
       let zero = Alpha_context.Script_int.zero_n in
@@ -2739,10 +2743,12 @@ module Registration_section = struct
         ()
 
     let join_tickets_instr =
+      let ticket_str = ticket string_cmp in
+      let pair_ticket_str_ticket_str = pair ticket_str ticket_str in
       IJoin_tickets
-        ( kinfo (pair (ticket string_cmp) (ticket string_cmp) @$ bot),
+        ( kinfo (pair_ticket_str_ticket_str @$ bot),
           string_cmp,
-          halt (option (ticket string_cmp) @$ bot) )
+          halt (option ticket_str @$ bot) )
 
     let () =
       benchmark
@@ -2792,7 +2798,7 @@ module Registration_section = struct
       IOpen_chest
         ( kinfo
             (Michelson_types.chest_key @$ Michelson_types.chest @$ nat @$ bot),
-          halt (union bytes bool @$ bot) )
+          halt (cunion bytes bool @$ bot) )
 
     let resulting_stack chest chest_key time =
       let chest = Script_timelock.make_chest chest in
@@ -2941,7 +2947,7 @@ module Registration_section = struct
         ~cont_and_stack_sampler:(fun _cfg _rng_state ->
           let cont =
             KLoop_in_left
-              (ICons_right (kinfo_unit, halt (union unit unit @$ bot)), KNil)
+              (ICons_right (kinfo_unit, halt (cunion unit unit @$ bot)), KNil)
           in
           let stack = (R (), eos) in
           fun () -> Ex_stack_and_cont {stack; cont})
@@ -3072,7 +3078,7 @@ module Registration_section = struct
         ()
 
     let map_enter_body_code =
-      let kbody = ICdr (kinfo (pair int unit @$ unit @$ bot), halt_unitunit) in
+      let kbody = ICdr (kinfo (cpair int unit @$ unit @$ bot), halt_unitunit) in
       fun accu -> KMap_enter_body (kbody, accu, Script_map.empty int_cmp, KNil)
 
     let () =
@@ -3122,7 +3128,7 @@ module Registration_section = struct
         ~name:Interpreter_workload.N_KMap_exit_body
         ~cont_and_stack_sampler:(fun cfg rng_state ->
           let kbody =
-            ICdr (kinfo (pair int unit @$ unit @$ bot), halt_unitunit)
+            ICdr (kinfo (cpair int unit @$ unit @$ bot), halt_unitunit)
           in
           fun () ->
             let (key, map) = Maps.generate_map_and_key_in_map cfg rng_state in
diff --git a/src/proto_alpha/lib_benchmarks_proto/michelson_types.ml b/src/proto_alpha/lib_benchmarks_proto/michelson_types.ml
index 0e659cc97c91f52514d1680aa606280f7180da2d..48cc403e04292faf276482658d26e874b9c50792 100644
--- a/src/proto_alpha/lib_benchmarks_proto/michelson_types.ml
+++ b/src/proto_alpha/lib_benchmarks_proto/michelson_types.ml
@@ -96,10 +96,18 @@ let set k = match set_t (-1) k with Error _ -> assert false | Ok t -> t
 let pair k1 k2 =
   match pair_t (-1) k1 k2 with Error _ -> assert false | Ok t -> t
 
+(* (will become) comparable pair type constructor *)
+let cpair k1 k2 =
+  match pair_t (-1) k1 k2 with Error _ -> assert false | Ok t -> t
+
 (* union type constructor*)
 let union k1 k2 =
   match union_t (-1) k1 k2 with Error _ -> assert false | Ok t -> t
 
+(* (will become) comparable union type constructor *)
+let cunion k1 k2 =
+  match union_t (-1) k1 k2 with Error _ -> assert false | Ok t -> t
+
 let lambda x y =
   match lambda_t (-1) x y with Error _ -> assert false | Ok t -> t