anchor.diff:    FieldElement(FieldDeclaration this.ast,VariableDeclaration this.varDecl, ClassElement classDecl): super(classDecl); 
   }
   
  -
  +/**
  + * Instances of a class`MethodElement` is a our abstract representation of methods
  + **/
   class MethodElement extends ClassMember with Block implements Element {
     MethodDeclaration ast;
     
  
positive.code:   void addMethod(MethodElement method) => methods.add(method);
  }
  
  class VariableElement implements Element {
    List<SimpleIdentifier> references = <SimpleIdentifier>[];
    
  
negative.code:   void addFunction(FunctionElement func) => functions.add(func);
  }
  
  /** 
   * Instance of a `ClassElement` is our abstract representation of the class.
   **/
  class ClassElement implements Element{
    List<FieldElement> fields = <FieldElement>[];
    List<MethodElement> methods = <MethodElement>[];
  