diff --git a/examples/user_types/Makefile b/examples/user_types/Makefile
index 607a20a97e9bcdab4a3951690e38322c5d650af7..757301e818275ec4ae55c10514b825483b2ce0b8 100644
--- a/examples/user_types/Makefile
+++ b/examples/user_types/Makefile
@@ -3,3 +3,4 @@ all:
 clean:
 
 distclean:
+	rm -rf gen