As can be seen on https://go.dev/play/p/82i2tTP60Q- time.Time cannot be easily handled with D-Bus. This in itself is not a problem. It would be good to provide a more accurate error message: panic(fmt.Errorf("cannot compute signature of empty struct %T", t). This is especially important if the time.Time type is buried deep inside other types.