冻结 package flutter 在代码生成中抛出不可为空的错误

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

Answer 1

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