Infinite recursive call in Swift 2.0

eq.swift

protocol Eq {
    typealias A = Self
    func equalsTo(a: A) -> Bool
    func notEqualsTo(a: A) -> Bool
}

extension Eq {
    func equalsTo(a: A) -> Bool { return !self.notEqualsTo(a) }
    func notEqualsTo(a: A) -> Bool { return self.equalsTo(a) }
}

extension Int : Eq {
    func equalsTo(a: Int) -> Bool { return self == a }
}

let x = 1

// infinite recursive call happens and crashes on Xcode Version 7.0 beta 4 (7A165t)
print("x \(x.notEqualsTo(1))")