1 files changed, 16 insertions, 0 deletions
diff --git a/tests/open_functor.ur b/tests/open_functor.ur
new file mode 100644
index 00000000..36525a05
--- /dev/null
+++ b/tests/open_functor.ur
@@ -0,0 +1,16 @@
+signature S = sig
+        type t
+        val x : t
+end
+
+functor F (M : S) : S where type t = M.t = struct
+        type t = M.t
+        val x = M.x
+end
+
+structure M = F(struct
+        type t = int
+        val x = 0
+end)
+
+open M