diff --git a/tests/lean/run/1089.lean b/tests/lean/run/1089.lean
new file mode 100644
index 0000000000..cede2af532
--- /dev/null
+++ b/tests/lean/run/1089.lean
@@ -0,0 +1,21 @@
+import init.string
+import init.bool
+import system.io
+
+inductive token
+| eof : token
+| plus : token
+| var : string -> token
+
+open token
+open option
+
+def to_token : string → option token
+| [] := none
+| (c :: cs) :=
+  let t : option token := match c with
+    | #"x" := some (var "x")
+    | #"y" := some (var "y")
+    | #"+" := some plus
+    | _ := none
+  end in t