如何在Vim中更改制表位后避免缩进错误？

I used to have 8-space tabs in Vim. Then I changed to 4 spaces, but now whenever I add a line to some code I had written before changing to 4 spaces, it gives me an indentation mismatch error even though everything is lining up nicely. Is there any way to avoid this problem?I used to have 8-space tabs in Vim. Then I chan