anchor.diff:  
     visitSendSet(SendSet node) {
       openSendNodeWithFields(node, "SendSet");
  -    visitWithPrefix(node.assignmentOperator, "assignmentOperator:");
  +    visitChildNode(node.assignmentOperator, "assignmentOperator");
       closeNode();
     }
   
  
positive.code:         "isPostfix" : "${node.isPostfix}",
          "isIndex" : "${node.isIndex}"
      });
      visitWithPrefix(node.receiver, "receiver:");
      visitWithPrefix(node.selector, "selector:");
      visitWithPrefix(node.argumentsNode, "argumentsNode:");
    }
  
    visitSend(Send node) {
  
negative.code:     visitNodeWithChildren(node, "ScriptTag");
    }
  
    visitChildNode(Node node, String fieldName) {
      if (node === null) return;
      addCurrentIndent();
      sb.add("<$fieldName>\n");
      pushTag(fieldName);
      node.accept(this);
      popTag();
      addCurrentIndent();
      sb.add("</$fieldName>\n");
    }
  
    openSendNodeWithFields(Send node, String type) {
  