Open Radar

 
Summary:
For example, this is a folded declaration:

func timestamp(_ timeZoneHour: Int = 0, ...}

And so is this:

@discardableResult func YamsAssertEqual(_ lhs: Any?, _ rhs: Any?, ...}

The curly braces aren’t balanced.

Xcode 8’s code folding avoided this issue by never folding a declaration, even if it was declared on multiple lines. It only ever folded the body.

Steps to Reproduce:
Fold the following function:

func timestamp(_ timeZoneHour: Int = 0,
               _ year: Int? = nil,
               _ month: Int? = nil,
               _ day: Int? = nil,
               _ hour: Int? = nil,
               _ minute: Int? = nil,
               _ second: Int? = nil,
               _ fraction: Double? = nil ) -> Date {
    let calendar = Calendar(identifier: .gregorian)
    let timeZone = TimeZone(secondsFromGMT: timeZoneHour * 60 * 60)
    #if os(Linux)
        let NSEC_PER_SEC = 1000000000
    #endif
    let nanosecond = fraction.map { Int($0 * Double(NSEC_PER_SEC)) }
    let datecomponents = DateComponents(calendar: calendar, timeZone: timeZone,
                          year: year, month: month, day: day,
                          hour: hour, minute: minute, second: second, nanosecond: nanosecond)
    // Using `DateComponents.date` causes crash on Linux
    guard let date = NSCalendar(identifier: .gregorian)?.date(from: datecomponents) else {
        fatalError("Never happen this")
    }
    return date
}

Expected Results:
The folded result should be one of the following:

func timestamp(_ timeZoneHour: Int = 0, ...) {...}

Or:

func timestamp(_ timeZoneHour: Int = 0,
               _ year: Int? = nil,
               _ month: Int? = nil,
               _ day: Int? = nil,
               _ hour: Int? = nil,
               _ minute: Int? = nil,
               _ second: Int? = nil,
               _ fraction: Double? = nil ) -> Date {...}

Actual Results:
The folded result is the following:

func timestamp(_ timeZoneHour: Int = 0, ...}

Version:
Xcode 9 beta 5 (9M202q)

Notes:
See attached gif of folding in action.