No defaults in enum switch

[matrinox]

I find the exhaustive enum warnings from the compiler super helpful. It ensures that whenever a new enum case is added, every switch statement is updated. But this won't work well with default. Often times the default is there as an easy way to group behaviour for the other cases at the time. I'd like to see this added as a warning

[kevindelord]

+1 we also make sure to never use the default case in our enums :)

[Noobish1]

I'd love this feature also.

[jpsim]

I think this is a good rule to have, but it would be challenging to detect when the variable being switched on is an enum.

[acecilia]

I would love to have this too :)

[valentinradu]

This would be great!

[sammy-SC]

@jpsim

you mentioned that it would be challenging to detect when the variable being switched on is an enum.
In simple case like the one below, shouldn't it be sufficient to see whether the condition next to case is prepended with a dot? In this case .one? I think it should be safe to assume that variable being switched on is an enum if all conditions are prepended with a dot.

enum MyEnum {
  case one, two
}

let myEnum = MyEnum.two

switch myEnum {
  case .one: break
  ↓default: break
}

Please let me know whether you think this could work, I would be happy to implement this rule.