Cannot convert value of type '() -> Void' to expected argument type '(() -> Void)?'

Question

I am trying to fix my finale error whilst trying to convert to Swift 3, however I am unsure why I am getting the error

Cannot convert value of type '() -> Void' to expected argument type '(() -> Void)?'

For

 CATransaction.setCompletionBlock(completion)

Complete Function

fileprivate func deleteRowsAtIndexPaths(_ indexPaths: [IndexPath], withRowAnimation animation: UITableViewRowAnimation, duration: TimeInterval, completion:() -> Void) {
    CATransaction.begin()
    CATransaction.setCompletionBlock(completion) //Error
    UIView.animate(withDuration: duration) { () -> Void in
        self.deleteRows(at: indexPaths, with: animation)
    }
    CATransaction.commit()
}

Does anybody know why I am getting this and how I can resolve the error ?

Are you sure that the message says "cover" and not "convert"? — molbdnilo
@molbdnilo Oops my bad, it does say convert, must of misspelled and then spell check corrected to cover. — A.Roe
Possible duplicate of Cannot assign value of type '() -> Void' to type '(() -> Void)!' — Hamish

OOPer OOPer · Accepted Answer · 2016-09-06T13:18:35

Please check the latest reference when you find something odd in migrating your code to Swift 3.

Declaration

class func setCompletionBlock(_ block: (@escaping () -> Void)?)

Try changing this part of your method header completion:() -> Void to this:

completion: @escaping () -> Void

Cannot convert value of type '() -> Void' to expected argument type '(() -> Void)?'

1 Answers

Declaration