Freezed generator doesn't properly skip special characters in @JsonKey annotation

Minimal reproducing code:

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

part 'worker_history_date.freezed.dart';
part 'worker_history_date.g.dart';

@freezed
abstract class WorkerHistoryDate with _$WorkerHistoryDate {
  const factory WorkerHistoryDate({
    @JsonKey(name: '\u0024numberLong') String numberLong, //\u0024 is $
  }) = _WorkerHistoryDate;
  factory WorkerHistoryDate.fromJson(Map<String, dynamic> json) =>
      _$WorkerHistoryDateFromJson(json);
}

Generated code:

// 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 'worker_history_date.dart';

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

T _$identity<T>(T value) => value;
WorkerHistoryDate _$WorkerHistoryDateFromJson(Map<String, dynamic> json) {
  return _WorkerHistoryDate.fromJson(json);
}

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

  _WorkerHistoryDate call({@JsonKey(name: '$numberLong') String numberLong}) {
    return _WorkerHistoryDate(
      numberLong: numberLong,
    );
  }
}

// ignore: unused_element
const $WorkerHistoryDate = _$WorkerHistoryDateTearOff();

mixin _$WorkerHistoryDate {
  @JsonKey(name: '$numberLong')
  String get numberLong;

  Map<String, dynamic> toJson();
  $WorkerHistoryDateCopyWith<WorkerHistoryDate> get copyWith;
}

abstract class $WorkerHistoryDateCopyWith<$Res> {
  factory $WorkerHistoryDateCopyWith(
          WorkerHistoryDate value, $Res Function(WorkerHistoryDate) then) =
      _$WorkerHistoryDateCopyWithImpl<$Res>;
  $Res call({@JsonKey(name: '$numberLong') String numberLong});
}

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

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

  @override
  $Res call({
    Object numberLong = freezed,
  }) {
    return _then(_value.copyWith(
      numberLong:
          numberLong == freezed ? _value.numberLong : numberLong as String,
    ));
  }
}

abstract class _$WorkerHistoryDateCopyWith<$Res>
    implements $WorkerHistoryDateCopyWith<$Res> {
  factory _$WorkerHistoryDateCopyWith(
          _WorkerHistoryDate value, $Res Function(_WorkerHistoryDate) then) =
      __$WorkerHistoryDateCopyWithImpl<$Res>;
  @override
  $Res call({@JsonKey(name: '$numberLong') String numberLong});
}

class __$WorkerHistoryDateCopyWithImpl<$Res>
    extends _$WorkerHistoryDateCopyWithImpl<$Res>
    implements _$WorkerHistoryDateCopyWith<$Res> {
  __$WorkerHistoryDateCopyWithImpl(
      _WorkerHistoryDate _value, $Res Function(_WorkerHistoryDate) _then)
      : super(_value, (v) => _then(v as _WorkerHistoryDate));

  @override
  _WorkerHistoryDate get _value => super._value as _WorkerHistoryDate;

  @override
  $Res call({
    Object numberLong = freezed,
  }) {
    return _then(_WorkerHistoryDate(
      numberLong:
          numberLong == freezed ? _value.numberLong : numberLong as String,
    ));
  }
}

@JsonSerializable()
class _$_WorkerHistoryDate
    with DiagnosticableTreeMixin
    implements _WorkerHistoryDate {
  const _$_WorkerHistoryDate({@JsonKey(name: '$numberLong') this.numberLong});

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

  @override
  @JsonKey(name: '$numberLong')
  final String numberLong;

  @override
  String toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) {
    return 'WorkerHistoryDate(numberLong: $numberLong)';
  }

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

  @override
  bool operator ==(dynamic other) {
    return identical(this, other) ||
        (other is _WorkerHistoryDate &&
            (identical(other.numberLong, numberLong) ||
                const DeepCollectionEquality()
                    .equals(other.numberLong, numberLong)));
  }

  @override
  int get hashCode =>
      runtimeType.hashCode ^ const DeepCollectionEquality().hash(numberLong);

  @override
  _$WorkerHistoryDateCopyWith<_WorkerHistoryDate> get copyWith =>
      __$WorkerHistoryDateCopyWithImpl<_WorkerHistoryDate>(this, _$identity);

  @override
  Map<String, dynamic> toJson() {
    return _$_$_WorkerHistoryDateToJson(this);
  }
}

abstract class _WorkerHistoryDate implements WorkerHistoryDate {
  const factory _WorkerHistoryDate(
      {@JsonKey(name: '$numberLong') String numberLong}) = _$_WorkerHistoryDate;

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

  @override
  @JsonKey(name: '$numberLong')
  String get numberLong;
  @override
  _$WorkerHistoryDateCopyWith<_WorkerHistoryDate> get copyWith;
}

Analyzer error: const_with_non_constant_argument

Arguments of a constant creation must be constant expressions.

Flutter doctor:

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v1.17.0-3.2.pre, on Mac OS X 10.15.3 19D76, locale en-AE)
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
[✓] Xcode - develop for iOS and macOS (Xcode 11.4.1)
[✓] Chrome - develop for the web
[✓] Android Studio (version 3.6)
[✓] Connected device (2 available)

Running latest 0.10.7 Freezed and 0.7.1 freezed generator

By the way, thanks for this awesome library! Managing API responses with this is a breeze!