Js_of_ocaml_compiler.Duplicateval closure :
Code.program ->
bound_vars:Js_of_ocaml_compiler.Code.Var.Set.t ->
f:Code.Var.t ->
params:Code.Var.t list ->
cont:(int * Code.Var.t list) ->
Code.program * Code.Var.t * Code.Var.t list * (int * Code.Var.t list)