Conforming types may be used in switch statements and as the element of a Set.

Hashable.swift

extension <# extendedType #> : Hashable {  
  var hashValue: Int { return <# hashValue #> }
}

func ==(lhs: <# extendedType #>, rhs: <# extendedType #>) -> Bool {  
  return <# comparator #>
}