Abstract data object as collection within data objects not only in Model

[ManukMinasyan]

Hi @rubenvanassche @onursimsek,

I'm encountering an error when trying to implement polymorphic expressions in FilterGroupContentData.

When trying to use FieldExpression or RelationshipExpression within the expressions data collection, I'm getting the following error:

Cannot instantiate abstract class DataLens\Data\Filters\FilterExpression

Here's my current implementation:

abstract class FilterExpression extends Data
{
    public function __construct(
        public string $type,
    ) {}
}

//

class FilterGroupContentData extends Data
{
    public function __construct(
        /*  @var FieldExpression|RelationshipExpression */
        #[DataCollectionOf(FilterExpression::class)]
        public DataCollection $expressions,
    )
    {
    }
}

I attempted to use it inside a data object but haven't been successful. Could you please advise on how to properly integrate a solution that supports polymorphic expressions? I need to handle multiple FilterGroupContentData instances, each containing various expressions of different types (FieldExpression or RelationshipExpression).

Do you have any recommendations for working with abstract classes for this specific use case?

I've created the Cast class that do this thing, is this possible to do same thing by package? https://gist.github.com/ManukMinasyan/d2b367028baab8f5d2c5c6ea80f4c8e8

Thanks for your help!