I have this line:

@State var isModalSheetShown: Bool = false

which gives this error in Xcode 12, Beta 4:

Generic enum 'State' cannot be used as an attribute.

If I prefix State with "@SwiftUI" the error goes away:

@SwiftUI.State var isModalSheetShown: Bool = false

Anybody know why this is? Is it just an oddity of the beta version that should go away when it's fully released? I do have import SwiftUI at the top of the file so I don't think it's caused by a missing import.

Do you have an enum called State anywhere in your code?

Dang, that is impressive intuition! It's not my code per se, but Khanlou's Promise library that I'm using. I searched in there, and sure enough, there's an enum called State. Thanks so much for sleuthing that out!