Provide generic arguments to DocumentReferences in JsonConverter - flutter

Question

I'm using json_serializable's JSONConverter interface to convert Firestore's DocumentReferences into valid JSON objects.
This is the JSON converter class. It tries to be generic:
class DocumentSerializer<T>
implements JsonConverter<DocumentReference<T>, DocumentReference<T>> {
const DocumentSerializer();
#override
DocumentReference<T> fromJson(DocumentReference<T> docRef) => docRef;
#override
DocumentReference<T> toJson(DocumentReference<T> docRef) => docRef;
}
And this is the usage of the annotation:
#JsonSerializable(explicitToJson: true)
class Recipe {
#DocumentSerializer<Recipe>()
final DocumentReference<Recipe> id;
#DocumentSerializer<User>()
final DocumentReference<User> authorId;
final String title;
final String description;
final String imageUrl;
final List<DocumentReference<User>> likes;
final List<String> ingredients;
final List<String> steps;
.
.
.
}
Unfortunately, this does not work. The build runner fails when it reaches the first usage of the annotation, which is the id field. Is there a way to provide generics to DocumentReferences in JsonConverter which can be serialized properly?

Answer 1

I found a workaround; albeit less elegant than what I'm aiming for. Turns out separate JsonConverters need to be created for each DocumentReference type.
For example, if I have an id field of type DocumentReference<Recipe> for the Recipe class , I would need to create the following JSON converter...
class RecipeSerializer
implements
JsonConverter<DocumentReference<Recipe>, DocumentReference<Recipe>> {
const RecipeSerializer();
#override
DocumentReference<Recipe> fromJson(DocumentReference<Recipe> json) => json;
#override
DocumentReference<Recipe> toJson(DocumentReference<Recipe> object) => object;
}
...and use it as such:
#JsonSerializable(explicitToJson: true)
class Recipe {
#RecipeSerializer()
final DocumentReference<Recipe> id;
#UserSerializer() // <- same goes for other types
final DocumentReference<User> authorId;
final String title;
final String description;
final String imageUrl;
final List<DocumentReference<User>> likes;
final List<String> ingredients;
final List<String> steps;
.
.
.
}
A bit more verbose, but I'll take it unless someone comes up with a more efficient answer.