Freezed: `package:flutter/material.dart` ruins the generation process.

[azliR]

When I generate the file as usual, it works fine. But when I add package:flutter/material.dart, the generated file has many error with DiagnosticableTreeMixin. This is the generated file

// GENERATED CODE - DO NOT MODIFY BY HAND
// ignore_for_file: deprecated_member_use_from_same_package, use_function_type_syntax_for_parameters, unnecessary_const, avoid_init_to_null, invalid_override_different_default_values_named

part of 'test_issues.dart';

// **************************************************************************
// FreezedGenerator
// **************************************************************************

T _$identity<T>(T value) => value;

class _$AuthFailureTearOff {
  const _$AuthFailureTearOff();

  ServerError serverError() {
    return const ServerError();
  }
}

// ignore: unused_element
const $AuthFailure = _$AuthFailureTearOff();

mixin _$AuthFailure {}

abstract class $AuthFailureCopyWith<$Res> {
  factory $AuthFailureCopyWith(
          AuthFailure value, $Res Function(AuthFailure) then) =
      _$AuthFailureCopyWithImpl<$Res>;
}

class _$AuthFailureCopyWithImpl<$Res> implements $AuthFailureCopyWith<$Res> {
  _$AuthFailureCopyWithImpl(this._value, this._then);

  final AuthFailure _value;
  // ignore: unused_field
  final $Res Function(AuthFailure) _then;
}

abstract class $ServerErrorCopyWith<$Res> {
  factory $ServerErrorCopyWith(
          ServerError value, $Res Function(ServerError) then) =
      _$ServerErrorCopyWithImpl<$Res>;
}

class _$ServerErrorCopyWithImpl<$Res> extends _$AuthFailureCopyWithImpl<$Res>
    implements $ServerErrorCopyWith<$Res> {
  _$ServerErrorCopyWithImpl(
      ServerError _value, $Res Function(ServerError) _then)
      : super(_value, (v) => _then(v as ServerError));

  @override
  ServerError get _value => super._value as ServerError;
}

class _$ServerError with DiagnosticableTreeMixin implements ServerError {
  const _$ServerError();

  @override
  String toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) {
    return 'AuthFailure.serverError()';
  }

  @override
  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
    super.debugFillProperties(properties);
    properties..add(DiagnosticsProperty('type', 'AuthFailure.serverError'));
  }

  @override
  bool operator ==(dynamic other) {
    return identical(this, other) || (other is ServerError);
  }

  @override
  int get hashCode => runtimeType.hashCode;
}

abstract class ServerError implements AuthFailure {
  const factory ServerError() = _$ServerError;
}

I just add the import, nothing else.

[rrousselGit]

Freezed detect that you are using Flutter. As such, it wants you to also import package:flutter/fundations.dart to make your objects dev-tool friendly

[azliR]

Oh right... Thanks... Closed now!