Fix PR#6158

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14062 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

testsuite/tests/typing-gadts/pr6158.ml

@@ -0,0 +1,9 @@
+type 'a t = T of 'a
+type 'a s = S of 'a
+
+type (_, _) eq = Refl : ('a, 'a) eq;;
+
+let f : (int s, int t) eq -> unit = function Refl -> ();;
+
+module M (S : sig type 'a t = T of 'a type 'a s = T of 'a end) =
+struct let f : ('a S.s, 'a S.t) eq -> unit = function Refl -> () end;;

testsuite/tests/typing-gadts/pr6158.ml.principal.reference

@@ -0,0 +1,19 @@
+
+#       type 'a t = T of 'a
+type 'a s = S of 'a
+type (_, _) eq = Refl : ('a, 'a) eq
+#   Characters 46-50:
+  let f : (int s, int t) eq -> unit = function Refl -> ();;
+                                               ^^^^
+Error: This pattern matches values of type (int s, int s) eq
+       but a pattern was expected which matches values of type
+         (int s, int t) eq
+       Type int s is not compatible with type int t 
+#     Characters 120-124:
+  struct let f : ('a S.s, 'a S.t) eq -> unit = function Refl -> () end;;
+                                                        ^^^^
+Error: This pattern matches values of type (ex#0 S.s, ex#1 S.t) eq
+       but a pattern was expected which matches values of type
+         (ex#0 S.s, ex#0 S.t) eq
+       The type constructor ex#0 would escape its scope
+# 

testsuite/tests/typing-gadts/pr6158.ml.reference

@@ -0,0 +1,15 @@
+
+#       type 'a t = T of 'a
+type 'a s = S of 'a
+type (_, _) eq = Refl : ('a, 'a) eq
+#   Characters 46-50:
+  let f : (int s, int t) eq -> unit = function Refl -> ();;
+                                               ^^^^
+Error: This pattern matches values of type (int s, int s) eq
+       but a pattern was expected which matches values of type
+         (int s, int t) eq
+       Type int s is not compatible with type int t 
+#     module M :
+  functor (S : sig type 'a t = T of 'a type 'a s = T of 'a end) ->
+    sig val f : (a#0 S.s, a#0 S.t) eq -> unit end
+#