anchor.diff:    @visibleForTesting
     String get plistFile {
       _plistFile ??= _fileSystem.path.join(installPath, 'Contents', 'Info.plist');
  -    return _plistFile;
  -  }
  -  String _plistFile;
  +    return _plistFile!;
  +  }
  +  String? _plistFile;
   
     @override
     String get version {
  
positive.code:       IntelliJValidator._idToTitle.forEach((String id, String title) {
          if (name.startsWith(id)) {
            final String version = name.substring(id.length);
            String installPath;
            try {
              installPath = fileSystem.file(fileSystem.path.join(dir.path, '.home')).readAsStringSync();
            } on FileSystemException {
  
negative.code: /// A windows specific implementation of the intellij validator.
  class IntelliJValidatorOnWindows extends IntelliJValidator {
    IntelliJValidatorOnWindows(String title, this.version, String installPath, this.pluginsPath, {
      required FileSystem fileSystem,
      required UserMessages userMessages,
    }) : super(title, installPath, fileSystem: fileSystem, userMessages: userMessages);
  
    @override
  