Please explain generic types deserialization

Generated code:
```dart
Response _$ResponseFromJson(
Map json,
T Function(Object json) fromJsonT,
) {
return Response()
..status = json['status'] as int
..value = fromJsonT(json['value']);
}
```
Seems like it is not fully automated for any types. It claims to provide Function for concrete types parsing.
My try:
```dart
@JsonSerializable(createToJson: false, genericArgumentFactories: true)
class Response {
final T data;
final Status status;

Response({this.data, this.status});

factory Response.fromJson(Map json) => _$ResponseFromJson(json, (jsonObject) {
switch (jsonObject) {
case User:
return User.fromJson(jsonObject) as T;
case Profile:
return Profile.fromJson(jsonObject) as T;
case StartChangeClientPhoneResponseBody:
return StartChangeClientPhoneResponseBody.fromJson(jsonObject) as T;
// primitive types, bool, etc.
default:
return jsonObject;
}
});
}
```
It throws runtime exception:
`Dart Unhandled Exception: type '_InternalLinkedHashMap' is not a subtype of type 'Profile'`

Documentation says nothing on how to handle it properly.