类型HalfOpenInterval <T> 不符合协议BooleanType

Question

I have a very simple for loop that is giving me troubles. This code ran without issue in Xcode beta 4, but in beta 5 it is complaining that the half open interval (and the closed interval) don't conform to BooleanType. What has changed, why doesn't this work anymore, or is this a bug?

for let i = 0; i..<cellCount!; ++i {
    //do stuff
}

cellCount is defined as an optional Int property:

private var cellCount: Int?

I have tried storing the cellCount into a non-optional constant but the issue still remains:

let numberOfCells: Int = cellCount!
for let i = 0; i..<numberOfCells; ++i {
    //do stuff
}

I see in the Release Notes a lot has changed with Ranges, but nothing seems to be relevant to this issue.

Answer 1

Ranges are meant to be used in a for in loop:

for i in 0..<cellCount! {
    // do stuff
}

Answer 2

Does this have anything to do with HalfOpenInterval? I thought the struct is Range? If you use HalfOpenInterval in for-in, it will not work. It is not of protocol SequenceType