add test for polymorphic variants

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@11296 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

testsuite/tests/typing-gadts/test.ml

@@ -454,3 +454,16 @@ let f : type a b. (a M.t * a, b M.t * b) eq -> (a, b) eq =
 let f : type a b. (a * a M.t, b * b M.t) eq -> (a, b) eq =
   function Eq -> Eq (* ok *)
 ;;
+
+(* Applications of polymorphic variants *)
+
+type _ t =
+  | V1 : [`A | `B] t
+  | V2 : [`C | `D] t
+
+let f : type a. a t -> a = function
+  | V1 -> `A
+  | V2 -> `C
+;;
+
+f V1;;

testsuite/tests/typing-gadts/test.ml.principal.reference

@@ -276,4 +276,7 @@ Error: This expression has type (a, a) eq
        but an expression was expected of type (a, b) eq
 #       val f : ('a M.t * 'a, 'b M.t * 'b) eq -> ('a, 'b) eq = <fun>
 #       val f : ('a * 'a M.t, 'b * 'b M.t) eq -> ('a, 'b) eq = <fun>
+#                     type 'a t = V1 : [ `A | `B ] t | V2 : [ `C | `D ] t
+val f : 'a t -> 'a = <fun>
+#   - : [ `A | `B ] = `A
 # 

testsuite/tests/typing-gadts/test.ml.reference

@@ -263,4 +263,7 @@ Error: This expression has type (a, a) eq
        but an expression was expected of type (a, b) eq
 #       val f : ('a M.t * 'a, 'b M.t * 'b) eq -> ('a, 'b) eq = <fun>
 #       val f : ('a * 'a M.t, 'b * 'b M.t) eq -> ('a, 'b) eq = <fun>
+#                     type 'a t = V1 : [ `A | `B ] t | V2 : [ `C | `D ] t
+val f : 'a t -> 'a = <fun>
+#   - : [ `A | `B ] = `A
 #