type t = {
  file : string;
  span : Location.span;
  message : string;
}

exception Error of t

val set_file : string -> unit
val file : unit -> string
val error : Location.span -> ('a, unit, string, 'b) format4 -> 'a
val make : Location.span -> string -> t
val to_string : t -> string
val render : string option -> t -> string