gistfile1.swift

protocol Value: Equatable {
}

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

struct Foo : Value, Smashable {
	typealias T = Bar
	func valueBySmashing​OtherValue​(value: Bar) -> Bar {
		return Bar()
	}
}

func == (lhs: Foo, rhs: Foo) -> Bool {
	return true
}

struct Bar: Value {
}

func == (lhs: Bar, rhs: Bar)  -> Bool {
	return true
}