diff --git a/vlib/v/tests/options/option_fn_voidptr_test.v b/vlib/v/tests/options/option_fn_voidptr_test.v
index 7508a45c9c..34cb910329 100644
--- a/vlib/v/tests/options/option_fn_voidptr_test.v
+++ b/vlib/v/tests/options/option_fn_voidptr_test.v
@@ -1,9 +1,9 @@
 struct Foo {
 mut:
-	func ?fn (voidptr) bool = unsafe { nil }
+	func ?fn (voidptr) ?bool = unsafe { nil }
 }
 
-fn callback(foo &Foo) bool {
+fn callback(foo &Foo) ?bool {
 	return foo.func? == callback
 }
 
@@ -13,11 +13,11 @@ fn test_main() {
 	}
 	assert t.func? == callback
 	call_fn := t.func?
-	assert call_fn(&t)
+	assert call_fn(&t)?
 
 	mut a := Foo{}
 	a.func = callback
 	assert a.func? == callback
 	call_fn2 := a.func?
-	assert call_fn2(&a)
+	assert call_fn2(&a)?
 }