inout-vs-UnsafeMutablePointer.swift

// 这两个方法有冲突（调用时无法区分），除非其中一个去掉IndexPath后的问号

/// 不能有默认参数 nil，因为inout不能操作常量
func shouldChange(indexPath: inout IndexPath?) -> Bool {
    indexPath = IndexPath(item: 0, section: 1)
    return true
}

/// 可以有默认参数 nil，
func shouldChange(indexPath: UnsafeMutablePointer<IndexPath?>? = nil) -> Bool {
    indexPath?.pointee = IndexPath(item: 0, section: 0)
    return false
}

var ip: IndexPath?
let should = shouldChange(indexPath: &ip)
if let i = ip {
    print(i, should)
}