diff --git a/test/dictionary.ml b/test/dictionary.ml
new file mode 100644
index 0000000000000000000000000000000000000000..9886c416f3713fc11273eba7d049d11604493790
--- /dev/null
+++ b/test/dictionary.ml
@@ -0,0 +1,9 @@
+type ('a, 'b) dictionary =
+  | Empty
+  | NonEmpty of 'a * 'b * ('a, 'b) dictionary
+[@@deriving visitors { variety = "map"; polymorphic = ["'b"] }]
+
+type ('a, 'b) dictionary2 =
+  | Empty
+  | NonEmpty of 'a * 'b * ('a, 'b) dictionary2
+[@@deriving visitors { name = "map2"; variety = "map"; polymorphic = ["'b"; "'env"] }]
diff --git a/test/misc.mllib b/test/misc.mllib
index 2b0c5e9e719aa819bdd54c258bf2c5185ff42721..30e6ddb4e7e45d0b99768d31d6eca6fce4d288fb 100644
--- a/test/misc.mllib
+++ b/test/misc.mllib
@@ -1,3 +1,4 @@
+dictionary
 fold
 mapReduce
 map_from_fold