exception Test_failure of string
exception User_error of string
exception Internal_error of {
loc : string;
msg : string;
}
val fail_test : string -> 'a
val user_error : string -> 'a
val internal_error : __LOC__:string -> string -> 'a
val assert_false : __LOC__:string -> unit -> 'a
val invalid_arg : __LOC__:string -> string -> 'a