anchor.diff:  
       return new ValidationResult(valid, messages,
         statusInfo: 'on ${osName()}, channel ${version.channel}');
  +  }
  +}
  +
  +class _HostExecutableValidator extends DoctorValidator {
  +  _HostExecutableValidator() : super('Host Executable Compatibility');
  +
  +  bool _genSnapshotRuns(String genSnapshotPath) {
  +    final int kExpectedExitCode = 255;
  +    try {
  +      return processManager.runSync(<String>[genSnapshotPath]).exitCode == kExpectedExitCode;
  +    } catch (error) {
  +      return false;
  +    }
  +  }
  +
  +  @override
  +  Future<ValidationResult> validate() async {
  +    final String genSnapshotPath =
  +      artifacts.getArtifactPath(Artifact.genSnapshot);
  +    final List<ValidationMessage> messages = <ValidationMessage>[];
  +    final bool hostExecutablesRun = _genSnapshotRuns(genSnapshotPath);
  +    final ValidationType valid = hostExecutablesRun ? ValidationType.installed : ValidationType.missing;
  +
  +    if (hostExecutablesRun) {
  +      messages.add(new ValidationMessage('Downloaded executables execute on host'));
  +    } else {
  +      messages.add(new ValidationMessage.error(
  +        'Downloaded executables cannot execute on host. See https://github.com/flutter/flutter/issues/6207 for more information'));
  +    }
  +    return new ValidationResult(valid, messages);
     }
   }
   
  
positive.code:     if (_validators == null) {
        _validators = <DoctorValidator>[];
        _validators.add(new _FlutterValidator());
  
        if (_androidWorkflow.appliesToHostPlatform)
          _validators.add(_androidWorkflow);
  
negative.code: 
  import 'android/android_studio_validator.dart';
  import 'android/android_workflow.dart';
  import 'artifacts.dart';
  import 'base/common.dart';
  import 'base/context.dart';
  import 'base/file_system.dart';
  