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(* Various tests. Some of these are included elsewhere in this directory. *)
signature S =
sig
type s
type t
sharing type s = t
end;
signature S =
sig
type s
datatype t = C
sharing type s = t
end;
signature S =
sig
structure T:
sig
datatype t = X of int
end
datatype s = Y of bool;
sharing type s = T.t
end;
(* The following is legal in ML97 but not in ML90. *)
functor F(
structure S:
sig
eqtype s
datatype t = C of int -> int
sharing type s = t
end) =
struct
val x:S.s = S.C(fn i => i+1)
val y = x = x
end;
(* But of course this must fail. *)
(*structure Z =
F(structure S = struct datatype t = C of int -> int type s = t end);*)
(* The following is legal because sharing between an eqtype and
a type makes the type into an eqatype. *)
functor F(structure S:
sig
eqtype s
type t
val x: t
sharing type s = t
end) =
struct
val q = S.x = S.x
end;
(* This was previously rejected but is actually legal. *)
signature S =
sig
datatype t = C
end where type t = bool;
(* I don't know whether this is legal or not. *)
signature S =
sig
eqtype t
end where type t = int;
(* This is legal. *)
signature S =
sig
type t
type u
sharing type t = u
end where type u = int;
(* This is legal. A and C share so their types share. *)
functor F(
structure A: sig type t val x: t end
structure B: sig end
structure C: sig type t end
sharing A = B = C
) =
struct
val q = A.x : C.t
end;
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