Supporting List of non primitive types in toJson about freezed HOT 5 CLOSED

@freezed
@JsonSerializable(explicitToJson: true)
abstract class User with _$User {
  factory User({
    String id,
    String displayName,
    UserLanguage language,
  }) = _User;

  factory User.fromJson(Map<String, dynamic> json) => _$UserFromJson(json);
}

//This method is still created and used by Freezed
User _$UserFromJson(Map<String, dynamic> json) {
  return User();
}
//This method is created by @JsonSerializable
Map<String, dynamic> _$UserToJson(User instance) => <String, dynamic>{};

//This method is created by @JsonSerializable
_$_User _$_$_UserFromJson(Map<String, dynamic> json) {
  return _$_User(
    id: json['id'] as String,
    displayName: json['displayName'] as String,
    language: json['language'] == null
        ? null
        : UserLanguage.fromJson(json['language'] as Map<String, dynamic>),
  );
}
//This method is still created and used by Freezed
Map<String, dynamic> _$_$_UserToJson(_$_User instance) => <String, dynamic>{
      'id': instance.id,
      'displayName': instance.displayName,
      'language': instance.language,
    };

@freezed
abstract class User with _$User {
  factory User({
    String id,
    String displayName,
    UserLanguage language,
  }) = _User;

  @explicitToJson
  factory User.fromJson(Map<String, dynamic> json) => _$UserFromJson(json);
}

// Property passed to JsonSerializable annotation
@JsonSerializable(explicitToJson: true)
class _$_User implements _User {
  _$_User({this.id, this.displayName, this.language});

  factory _$_User.fromJson(Map<String, dynamic> json) =>
      _$_$_UserFromJson(json);

  @override
  final String id;
  @override
  final String displayName;
  @override
  final UserLanguage language;

  @override
  String toString() {
    return 'User(id: $id, displayName: $displayName, language: $language)';
  }