Swift Error with Generics [duplicate]

I've come across a problem and I'm struggling to understand why this happens. Whenever I try and pass my custom Swift error object using generics, I get an error when I try to access the localizedDescription property. I have some example code here, which demonstrates the issue:

import Foundation

enum CustomError: Swift.Error {
    case myCustomError

    var localizedDescription: String {
        return "Woop custom error string"
    }
}

func printMyError<T: Swift.Error>(error: T) {
    print(error.localizedDescription)
}

printMyError(error: CustomError.myCustomError) // <-- Fails
print(CustomError.myCustomError.localizedDescription) // <-- Works