Code generator build successfully but with 0 outputs and 0 actions

[SinoAHpx]

Versions

Content of my pubspec.yaml:

name: hello_world
dependencies:
  build_runner: ^2.1.8
  characters: ^1.2.0
  json_annotation: ^4.4.0
  json_serializable: ^6.1.5
environment:
    sdk: '>=2.16.0 <3.0.0'

Verbose

I've executed build_runner clean previously, and here's what I see when I run dart run build_runner build --verbose

$ dart run build_runner build --verbose
[INFO] Entrypoint:Generating build script...
[INFO] Entrypoint:Generating build script completed, took 393ms

[INFO] Bootstrap:Precompiling build script......
[INFO] Bootstrap:Precompiling build script... completed, took 6.1s

[FINE] Bootstrap:Core package locations file does not exist
[INFO] BuildDefinition:Initializing inputs
[INFO] BuildDefinition:Building new asset graph...
[INFO] BuildDefinition:Building new asset graph completed, took 737ms

[INFO] BuildDefinition:Checking for unexpected pre-existing outputs....
[INFO] BuildDefinition:Checking for unexpected pre-existing outputs. completed, took 1ms

[INFO] Build:Running build...
[INFO] Build:Running build completed, took 7ms

[INFO] Build:Caching finalized dependency graph...
[INFO] Build:Caching finalized dependency graph completed, took 30ms

[INFO] Build:Succeeded after 47ms with 0 outputs (0 actions)

Project structure

I want to generate example.g.dart for the file example.dart, and here is the content of example.dart (I completely copied it from https://pub.dev/packages/json_serializable)

import 'package:json_annotation/json_annotation.dart';

part 'example.g.dart';

@JsonSerializable()
class Person {
  final String firstName, lastName;
  final DateTime? dateOfBirth;

  Person({required this.firstName, required this.lastName, this.dateOfBirth});

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

  Map<String, dynamic> toJson() => _$PersonToJson(this);
}

I created this project by using IntelliJ IDEA with Dart plugin installed, and selected the temple named Console Application, but apparently this template doesn't work properly. So I created another new project by using the command dart create -t console-full another_dart_app, added JsonSerializable annotation for expected class and run the build_runner build again, I don't know why but it works.