anchor.diff:  import 'element.dart' as Our;
   import 'engine.dart';
   
  -
   _openNewScope(scope, k) {
  -
  -
     Map curr = {};
     curr.addAll(scope);
   
  
positive.code:   }
    
    visitClassDeclaration(ClassDeclaration node){
      this.scope["this"] = this.declaredElements[node];
      super.visitClassDeclaration(node);
      this.scope.remove("this");
    }
  
    visitVariableDeclaration(VariableDeclaration node) {
      if (node.initializer != null) node.initializer.accept(this);
      this.scope[node.name.toString()] = this.declaredElements[node];
      if (node.name != null) node.name.accept(this);
    }
    
    visitFunctionDeclaration(FunctionDeclaration node) {
      if (node.name != null) {
        this.scope[node.name.toString()] = this.declaredElements[node];
      }
  
      if (this.declaredElements[node] == null) {
        print('failed for  -- ${node} -- (${node.hashCode})');
        this.declaredElements.keys.forEach((key){
          print('${key} (${key.hashCode})');
          
        });
  
      }
      
      _openNewScope(scope, (_) {
  
negative.code:     }
    }
  
    //Only resolve the prefix.
    //TODO handle library 'as ...' imports.
    visitPrefixedIdentifier(PrefixedIdentifier node) {
  