Determine if Any.Type is Optional

Question

I’m trying to determine if a given type t (Any.Type) is an optional type, I’m using this test

t is Optional.Type
         


        

Answer 1

Assuming that what you are trying to do is something like this:

let anyType: Any.Type = Optional.self
anyType is Optional.Type // false

Sadly swift currently (as of Swift 2) does not support covariance nor contravariance and type checks directly against Optional.Type cannot be done:

// Argument for generic parameter 'Wrapped' could not be inferred
anyType is Optional.Type // Causes error

An alternative is to make Optional extend an specific protocol, and check for that type:

protocol OptionalProtocol {}

extension Optional : OptionalProtocol {}

let anyType: Any.Type = Optional.self
anyType is OptionalProtocol.Type // true