Metaprogramming in swift

gistfile1.txt

struct S: Encodable {}

extension Encodable {
    var nnn: Int { return 1 }
}

protocol B {
    static func test<T: Encodable>(_ value: T) -> Int
}

class C: B {
    static func test<T: Encodable>(_ value: T) -> Int {
        print("VALUE IS \(value)")
        return value.nnn
    }
}

func fatality(_ s: S? = nil) -> Int {
    return C.test(s)
}

let s: S? = nil
let result = fatality(s)
print("RESULT: \(result)")