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|
(* TEST
* expect
*)
type s = [`A | `B] and sub = [`B];;
type +'a t = T : [< `Conj of 'a & sub | `Other of string] -> 'a t;; (* ok *)
let f (T (`Other msg) : s t) = print_string msg;;
let _ = f (T (`Conj `B) :> s t);; (* warn *)
[%%expect{|
type s = [ `A | `B ]
and sub = [ `B ]
type +'a t = T : [< `Conj of 'a & sub | `Other of string ] -> 'a t
Line _, characters 6-47:
Warning 8: this pattern-matching is not exhaustive.
Here is an example of a case that is not matched:
T (`Conj _)
val f : s t -> unit = <fun>
Exception: Match_failure ("", 4, 6).
|}];;
module M : sig
type s
type t = T : [< `Conj of int & s | `Other of string] -> t
val x : t
end = struct
type s = int
type t = T : [< `Conj of int | `Other of string] -> t
let x = T (`Conj 42)
end;;
let () = M.(match x with T (`Other msg) -> print_string msg);; (* warn *)
[%%expect{|
module M :
sig
type s
type t = T : [< `Conj of int & s | `Other of string ] -> t
val x : t
end
Line _, characters 12-59:
Warning 8: this pattern-matching is not exhaustive.
Here is an example of a case that is not matched:
T (`Conj _)
Exception: Match_failure ("", 11, 12).
|}];;
module M : sig
type s
type elim =
{ ex : 'a . ([<`Conj of int & s | `Other of string] as 'a) -> unit }
val e : elim -> unit
end = struct
type s = int
type elim =
{ ex : 'a . (([<`Conj of int | `Other of string] as 'a) -> unit) }
let e { ex } = ex (`Conj 42 : [`Conj of int])
end;;
let () = M.(e { ex = fun (`Other msg) -> print_string msg });; (* warn *)
[%%expect{|
module M :
sig
type s
type elim = {
ex : 'a. ([< `Conj of int & s | `Other of string ] as 'a) -> unit;
}
val e : elim -> unit
end
Line _, characters 21-57:
Warning 8: this pattern-matching is not exhaustive.
Here is an example of a case that is not matched:
`Conj _
Exception: Match_failure ("", 13, 21).
|}];;
|
