Swift 3 warning: Non-optional expression of type 'String' used in a check for optionals

Question

I\'m updating a project to Swift 3 and came across the following warning which I can\'t seem to resolve.

fileprivate var filteredTitlesList: [String] = []

i         


        

Answer 1

Other possibility of this warning is when you're trying to put a statement eg:let keyboardFrame: CGRect = keyboardFrameValue.cgRectValue in conditional statement like if or guard