Separating multiple if conditions with commas in Swift

Question

We already know multiple optional bindings can be used in a single if/guard statement by separating them with commas, but not with && e.g.

Answer 1

When pattern matching a associated value in a switch, it matters when using a , or &&. One compiles, the other won't (Swift 5.1). This compiles (&&):

enum SomeEnum {
    case integer(Int)
}

func process(someEnum: SomeEnum) {
    switch someEnum {
    // Compiles
    case .integer(let integer) where integer > 10 && integer < 10:
        print("hi")
    default:
        fatalError()
    }
}

This won't (,):

enum SomeEnum {
    case integer(Int)
}

func process(someEnum: SomeEnum) {
    switch someEnum {
    // Compiles
    case .integer(let integer) where integer > 10, integer < 10:
        print("hi")
    default:
        fatalError()
    }
}