Flutter DART "Try adding an explicit type like 'dynamic', or enable implicit-dynamic in your analysis options file."

Question

I use a Flutter and faces the following warning with analysis_options.yaml.

Missing type arguments for map literal.

Try adding an explicit type like 'dynamic', or enable implicit-dynamic in your analysis options file.

The code is as follows.

 Map<String, dynamic> toJson() => {
        'name': name,
        'isEnabled': isEnabled,
      };

How can I fix this warning?

flutter doctor

C:\src\flutter\bin\flutter.bat doctor --verbose
[√] Flutter (Channel stable, 1.20.4, on Microsoft Windows [Version 10.0.18363.1082], locale ja-JP)
    • Flutter version 1.20.4 at C:\src\flutter
    • Framework revision fba99f6cf9 (5 days ago), 2020-09-14 15:32:52 -0700
    • Engine revision d1bc06f032
    • Dart version 2.9.2

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.1)
    • Android SDK at C:\Users\user\AppData\Local\Android\sdk
    • Platform android-30, build-tools 30.0.1
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
    • All Android licenses accepted.

[√] Android Studio (version 4.0)
    • Android Studio at C:\Program Files\Android\Android Studio
    • Flutter plugin version 48.1.2
    • Dart plugin version 193.7547
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)

Answer 1

Solved with following codes.

Map<String, dynamic> toJson() => <String, dynamic>{
        'name': name,
        'isEnabled': isEnabled,
      };