如果ruby on rails脚本中有多个错误，它如何知道哪一个显示？

I often write some code, then get an error, change it, and see a different error. Does this mean that the first error is fixed and that I only have a new error because of what I just changed? or just that this new error is more "pressing" than the first? How can I find out?I often write some code, then get an error, cha