title: How can I pass self reference to object in dart
body: <p>I have a class Field and has a copy() method, I want to pass self reference to new object but Dart editor seem not allow. How can I pass self reference to new object like java?</p>
  
  <pre><code>class Field 
     Field copy() {
         return new Field(this); 
     }    
  }
  </code></pre>