Hive generated file Error - "control-flow-collections" experiment is not enabled - Flutter/Dart

Question

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'dbmodel.dart';

// **************************************************************************
// TypeAdapterGenerator
// **************************************************************************

class CacheAdapter extends TypeAdapter<Cache> {
  @override
  final typeId = 4;

  @override
  Cache read(BinaryReader reader) {
    var numOfFields = reader.readByte();
    var fields = <int, dynamic>{
      for (var i = 0; i < numOfFields; i++) reader.readByte(): reader.read(),
    };
    return Cache(
      isDarkMode: fields[0] as bool,
    );
  }

  @override
  void write(BinaryWriter writer, Cache obj) {
    writer
      ..writeByte(1)
      ..writeByte(0)
      ..write(obj.isDarkMode);
  }
}

There is an error in the for loop of the Hive generated file, where it says that the "control-flow-collections" experiment is not enabled.

for (var i = 0; i < numOfFields; i++) reader.readByte(): reader.read(),

Can anyone help me with it?

Solution

I found a solution, run the following command in the root folder of your flutter app(not flutter SDK):

flutter analyze

And you will see multiple warning, saying that there is no experiment defined for "control-flow-collections", the problem is that the SDK defined in the pubspec.yaml of your Flutter App folder contains

environment:
  sdk: ">=2.1.0 <3.0.0"

There is not supported experiment before the 2.3.0 version so you have to change the version to:

environment:
  sdk: ">=2.3.0 <3.0.0"

then run:

flutter pub get

in the root of your flutter app and rerun, "flutter analyze", and the issue goes away.