iosswiftxcodeoption-typeunwrap

Error to use a shorter spelling to unwrap a value

in Swift documentation at https://docs.swift.org/swift-book/GuidedTour/GuidedTour.html, there are examples about usage of optionals and unwrapping them. When I try the examples on my Macbook, I got an error as; "Variable binding in a condition requires an initializer".

Defining the variables part in document:

let nickname: String? = nil
let fullName: String = "John Appleseed"
let informalGreeting = "Hi \(nickname ?? fullName)"

Explanation and example parts which throws the error written above:

You can use a shorter spelling to unwrap a value, using the same name for that unwrapped value.

if let nickname {
    print("Hey, \(nickname)")
}

Why I cannot use if let nickname and if it throws error, why it is written in the documentation?

Solution

  • The shorthand syntax for optional unwrapping with if let, guard let and while let was introduced in swift 5.7. I believe u are using an older version of swift.

    Check this to find out which version of swift u are using.

    For more details read the section Language updates -> Quality of life improvements.