In addition to the copyWith method of each case-modddel, the super-sealed class has a copyWith method too. However, this method only includes shared properties that have the same type across all case-modddels.

For example : Let's say we have a Weather MultiValueObject union :

// @Modddel (... , sharedProps: [ SharedProp('int', 'temperature') ])
// class ... {

factory Weather.sunny({
  required int temperature,
}) // { ... }

factory Weather.rainy({
  required int temperature,
  required double rainIntensity,
}) // { ... }

In this example, temperature is a shared property of type int, and it has the same type int in both case-modddels. So it can be used in the super-sealed class's copyWith method :

final otherWeather = weather.copyWith(temperature: 12);

The original plan was that the super-sealed class's copyWith method would include all shared properties, even when their types in the case-modddels is different. However, this could not be done due to a limitation in the Dart language related to inheritence.