1 files changed, 37 insertions, 0 deletions
diff --git a/tests/functor.ur b/tests/functor.ur
new file mode 100644
index 0000000..5adfb59
--- /dev/null
+++ b/tests/functor.ur
@@ -0,0 +1,37 @@
+signature S = sig
+        type t
+        val z : t
+        val s : t -> t
+end
+
+signature T = sig
+        type t
+        val three : t
+end
+
+functor F (M : S) : T where type t = M.t = struct
+        type t = M.t
+        val three = M.s (M.s (M.s M.z))
+end
+
+
+structure O = F (struct
+        type t = int
+        val z = 0
+        val s = fn x : t => x
+end)
+val three : int = O.three
+
+structure S = struct
+        type t = int
+        val z = 0
+        val s = fn x : t => x
+end
+structure SO = F (S)
+val three : int = SO.three
+
+structure SS : S = S
+structure SSO = F (SS)
+val three : SS.t = SSO.three
+
+val main = three