diff --git a/aqua/examples/option.aqua b/aqua/examples/option.aqua
index dfc0462..8b178c8 100644
--- a/aqua/examples/option.aqua
+++ b/aqua/examples/option.aqua
@@ -4,6 +4,10 @@ service SomeS("test2"):
     getStr: ?string -> ?string
     getStr1: -> ?string
     getStr2: string -> string
+    checkU32(u: ?u32)
+
+func checkU32AndU8(a: ?u8):
+    SomeS.checkU32(a)
 
 func useOptional(opt: ?string) -> string:
     res <- SomeS.getStr(opt)