`inherit mapper`
`method merge_info : 'a -> unit`
`method merge_block_info : 'a -> unit`
`method record_block : block -> unit`
`method def_var : Js_of_ocaml_compiler.Javascript.ident -> unit`
`method def_local : Js_of_ocaml_compiler.Javascript.ident -> unit`
`method use_var : Js_of_ocaml_compiler.Javascript.ident -> unit`
`method state : t`
`method get_count : int Js_of_ocaml_compiler.Javascript.IdentMap.t`
`method get_free : Js_of_ocaml_compiler.Javascript.IdentSet.t`
`method get_def : Js_of_ocaml_compiler.Javascript.IdentSet.t`
`method get_use : Js_of_ocaml_compiler.Javascript.IdentSet.t`