Method1(亲测有效):
target -> Build Settings -> 搜索weak -> 切换WeakReferences in Manual Retain Release的值为No (No->Yes->No)
Method2:
进入Preferences…-> Text Editing
![20201102181028131.png](https://upload-images.jianshu.io/upload_images/3579083-16820eaea8fb9f1f.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
Method3:
退出Xcode,重启电脑,前往文件夹~/Library/Caches/com.apple.dt.Xcode并删除,并删除DerivedData,重新运行Xcode