use swc_config::merge::Merge; #[derive(Merge)] struct Fields { a: Option<()>, } #[test] fn test_fields() { let mut fields = Fields { a: None }; fields.merge(Fields { a: Some(()) }); assert_eq!(fields.a, Some(())); } #[derive(Merge)] struct Tuple(Option<()>); #[test] fn test_tuple() { let mut tuple = Tuple(None); tuple.merge(Tuple(Some(()))); assert_eq!(tuple.0, Some(())); }