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|
(* TEST
* expect
*)
let partition_map f xs =
let rec part left right = function
| [] -> List.rev left, List.rev right
| x::xs ->
match f x with
| `Left v -> part (v::left) right xs
| `Right v -> part left (v::right) xs
in
part [] [] xs
;;
let f xs : (int list * int list) = partition_map (fun x -> if x then `Left ()
else `Right ()) xs
;;
[%%expect{|
val partition_map :
('a -> [< `Left of 'b | `Right of 'c ]) -> 'a list -> 'b list * 'c list =
<fun>
Lines 12-13, characters 35-18:
12 | ...................................partition_map (fun x -> if x then `Left ()
13 | else `Right ()) xs
Error: This expression has type unit list * unit list
but an expression was expected of type int list * int list
Type unit is not compatible with type int
|}]
module M : sig
type t = [
| `A of int
| `B of [ `BA | `BB of unit list ]
| `C of unit ]
val a : t -> t
end = struct
type t = [
| `A of int
| `B of [ `BA | `BB of unit list ]
| `C of unit ]
let a b =
let f = function
| Ok x -> x
| Error _ -> `C ()
in
f (match b with
| `A pc ->
begin match pc with
| 1 -> Ok (`B `BA)
| _ -> Ok (`B (`BB [1;2;3]))
end
| _ -> assert false)
end
;;
[%%expect{|
Lines 8-27, characters 6-3:
8 | ......struct
9 | type t = [
10 | | `A of int
11 | | `B of [ `BA | `BB of unit list ]
12 | | `C of unit ]
...
24 | end
25 | | _ -> assert false)
26 |
27 | end
Error: Signature mismatch:
Modules do not match:
sig
type t =
[ `A of int | `B of [ `BA | `BB of unit list ] | `C of unit ]
val a :
[> `A of int ] ->
[> `B of [> `BA | `BB of int list ] | `C of unit ]
end
is not included in
sig
type t =
[ `A of int | `B of [ `BA | `BB of unit list ] | `C of unit ]
val a : t -> t
end
Values do not match:
val a :
[> `A of int ] ->
[> `B of [> `BA | `BB of int list ] | `C of unit ]
is not included in
val a : t -> t
The type
[ `A of int | `B of [ `BA | `BB of unit list ] | `C of unit ] ->
[> `B of [> `BA | `BB of int list ] | `C of unit ]
is not compatible with the type t -> t
Type [> `B of [> `BA | `BB of int list ] | `C of unit ]
is not compatible with type
t = [ `A of int | `B of [ `BA | `BB of unit list ] | `C of unit ]
Types for tag `BB are incompatible
|}]
|
