anchor.diff:          String sdkPath;
           // may be "xcodebuild/ReleaseIA32/dart" with "dart-sdk" sibling
           {
  -          sdkPath = pathos.join(pathos.dirname(exec), "dart-sdk");
  +          sdkPath = new Path(exec).directoryPath.append("dart-sdk").toNativePath();
             if (new Directory(sdkPath).existsSync()) {
               _properties[name] = sdkPath;
               return sdkPath;
             }
           }
           // probably be "dart-sdk/bin/dart"
  -        sdkPath = pathos.dirname(pathos.dirname(exec));
  +        sdkPath = new Path(exec).directoryPath.directoryPath.toString();
           _properties[name] = sdkPath;
           return sdkPath;
         }
  
positive.code: library java.io;
  
  import "dart:io";
  import 'package:path/path.dart' as pathos;
  
  class JavaSystemIO {
    static Map<String, String> _properties = new Map();
  
negative.code:     if (parent == null) return null;
      return new JavaFile(parent);
    }
    String getAbsolutePath() => _path.canonicalize().toNativePath();
    String getCanonicalPath() => _path.canonicalize().toNativePath();
    JavaFile getAbsoluteFile() => new JavaFile(getAbsolutePath());
    JavaFile getCanonicalFile() => new JavaFile(getCanonicalPath());
    bool exists() {
  