Freezed package flutter throwing non-nullable error in code generation

Question

I am starting a project and decided to use the new version version of **Freezed** for my models, but when I run flutter *pub run build_runner build* to generate my code I get the following error:
>The parameter 'placeFormattedAddress' of 'Address' is non-nullbale but is neither required nor marked with @Default
> I am importing the **Meta** package and also including the *@required* annotation; the funny thing is that when I change the parameters from named to positional (without the curly braces, it works well).
Here is the code ¿Could anybody please point me what is wrong?
**Here is the class**

import 'package:freezed_annotation/freezed_annotation.dart';
import 'package:flutter/foundation.dart';

part 'address.freezed.dart';
part 'address.g.dart';

@freezed
class Address with _$Address {
   const factory Address({
         @required String placeFormattedAddress, @required String placeName, @required String 
         placeId,@required double latitude, @required double longitude,}) = _Address;

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

Here is my pubspec.yaml

publish_to: 'none'

version: 1.0.0+1

environment:
  sdk: ">=2.12.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  
  freezed_annotation: ^0.14.1
  json_serializable: ^4.1.0
  flutter_hooks: ^0.16.0
  hooks_riverpod: ^0.13.1

dev_dependencies:
  flutter_test:
    sdk: flutter
  lint: ^1.0.0
  build_runner:
  freezed: ^0.14.1+2

Solution

I finally found the answer; with null-safe dart the @ is no longer needed to mark a required parameter; so instead of @required, now the syntax is only required

When null safe code is called from legacy code the required keyword is treated exactly like the @required annotation: failure to supply the argument will cause an analyzer hint.

https://dart.dev/null-safety/faq