An example scaml code to fail `tezos-client typecheck script`

typeerror.ml

open SCaml

type parameter = nat * unit contract * unit

type storage = nat

let main (param: parameter) (storage: storage) =
  let (counter, contr, sigs) = param in
  (*  let counter = counter in *) (* If this line is available then the typecheck will be passed. *)
  if counter <> Nat 1 then failwith "0" else
    let op = Operation.transfer_tokens () (Tz 1.) contr in
    ([op], counter)

The tz code by scaml typeerror.ml.

parameter (pair nat (pair (contract unit) unit)) ;
storage nat ;
code { { /* defs */ } ;
       { /* entry point init */ DUP ; CDR ; DIP { CAR } } ;
       { /* entry point */
         { /* entry main_1152 */
           { /* __v_1175 */
             { /* = __x_1170, = __param_1184, = param_1153, = __v_1185, = __param_1164 */
               { /* var global_param_1163 */ DIG 1 ; DUP ; DUG 2 } } } ;
           { /* __r_1176 */ { /* var __v_1175 */ DUP } ; CDR } ;
           { /* __counter_1172 */
             { /* = counter_1155, = __l_1177 */ { /* var __v_1175 */ DIG 1 ; DUP ; DUG 2 } ; CAR } } ;
           LAMBDA
             (pair nat (contract unit))
             (lambda unit (pair (list operation) nat))
             { { /* fvar __counter_1172 */ DUP ; DIP { CAR } ; CDR } ;
               LAMBDA
                 (pair (contract unit) (pair nat unit))
                 (pair (list operation) nat)
                 { { /* fvar __contr_1173 */ DUP ; DIP { CAR } ; CDR } ;
                   { /* fvar __counter_1172 */ DUP ; DIP { CAR } ; CDR } ;
                   PUSH nat 1 ;
                   { /* var __counter_1172 */ DIG 2 ; DUP ; DUG 3 } ;
                   COMPARE ;
                   NEQ ;
                   IF { PUSH string "0" ; FAILWITH }
                      { { /* var __counter_1172 */ DIG 1 ; DUP ; DUG 2 } ;
                        NIL operation ;
                        { /* = __op_1168, = op_1158, = __v_1169, = __x_1166 */
                          { /* var __contr_1173 */ DIG 4 ; DUP ; DUG 5 } ;
                          PUSH mutez 1000000 ;
                          PUSH unit Unit ;
                          TRANSFER_TOKENS } ;
                        CONS ;
                        PAIR } ;
                   { /* lambda clean up */ DIP { DROP 3 } } } ;
               { /* partial app __contr_1173 */
                 { /* var __contr_1173 */ DIG 1 ; DUP ; DUG 2 } ;
                 APPLY } ;
               { /* partial app __counter_1172 */
                 { /* var __counter_1172 */ DIG 2 ; DUP ; DUG 3 } ;
                 APPLY } ;
               { /* lambda clean up */ DIP { DROP 2 } } } ;
           { /* partial app __counter_1172 */
             { /* var __counter_1172 */ DIG 1 ; DUP ; DUG 2 } ;
             APPLY } ;
           { /* clean __counter_1172 */ DIP { DROP } } ;
           { /* = contr_1156, = __l_1179 */ { /* var __r_1176 */ DIG 1 ; DUP ; DUG 2 } ; CAR } ;
           EXEC ;
           { /* = sigs_1157, = __r_1178 */ { /* var __r_1176 */ DIG 1 ; DUP ; DUG 2 } ; CDR } ;
           EXEC ;
           { /* clean __r_1176 */ DIP { DROP } } ;
           { /* clean __v_1175 */ DIP { DROP } } } } ;
       { /* final clean up */ DIP { DROP 2 } } } ;

The iml by scaml --dump-iml typeerror.ml.

(fun global_param_1163 ->
   (fun storage_1162 ->
      (let __v_1175
         = (global_param_1163 </* = __x_1170 *//* = __param_1184 *//* = param_1153 *//* = __v_1185 *//* = __param_1164 */> : pair nat (pair (contract unit) unit))
       in
       (let __r_1176
          = (snd (__v_1175 : pair nat (pair (contract unit) unit)) : pair (contract unit) unit)
        in
        ((let __counter_1172
            = (fst (__v_1175 : pair nat (pair (contract unit) unit)) </* = counter_1155 *//* = __l_1177 */> : nat)
          in
          (fun __contr_1173 ->
             (fun __sigs_1174 ->
                (if (<> (__counter_1172 : nat) (1 : nat) : bool)
                 then (failwith ("0" : string) : pair (list operation) nat)
                 else (((Operation.transfer_tokens (() : unit) (1000000 : mutez) (__contr_1173 : contract unit) </* = __op_1168 *//* = op_1158 *//* = __v_1169 *//* = __x_1166 */> : operation) :: ([] : list operation) : list operation),
                       (__counter_1172 : nat) : pair (list operation) nat) : pair (list operation) nat) : lambda unit (pair (list operation) nat)) : lambda (contract unit) (lambda unit (pair (list operation) nat))) : lambda (contract unit) (lambda unit (pair (list operation) nat))) 
        (fst (__r_1176 : pair (contract unit) unit) </* = contr_1156 *//* = __l_1179 */> : contract unit) (snd (__r_1176 : pair (contract unit) unit) </* = sigs_1157 *//* = __r_1178 */> : unit) : pair (list operation) nat) : pair (list operation) nat) </* entry main_1152 */> : pair (list operation) nat) : lambda nat (pair (list operation) nat)) : lambda (pair nat (pair (contract unit) unit)) (lambda nat (pair (list operation) nat)))