gistfile1.swift

protocol Value {
}

protocol Smashable {
    typealias V : Value
    func valueBySmashing​OtherValue​(value: V) -> V
}

struct Bar : Value {
}

struct Foo : Value {
    func valueBySmashing​OtherValue​<OtherV : Value>(value: OtherV) -> Bar {
        return Bar()
    }
}