is it possible to achieve abstract class inheritance?

Hello, I'm attempting to achieve inheritance of an abstract type in parent class with built_value,

```
@BuiltValue(instantiable: false)
abstract class Animal {
String get name;
}

abstract class Dog implements Built, Animal {
@override
String get name;
}

@BuiltValue(instantiable: false)
abstract class Zoo {
bool get value;
Animal get animal;
}

abstract class BigZoo implements Built< BigZoo, BigZoo Builder>, Zoo {

@override
Dog get animal;

@override
bool get value => false;
}

```

The generation produces a not valid override error for the animal property, but none for the boolean property,

`'BigZoo.animal' ('AnimalBuilder Function()') isn't a valid override of 'ZooBuilder.animal' ('AnimalBuilder Function()')`

Is there some other way to achieve this type of inheritance to avoid type checking hell?