struct Fish: Hashable, RawRepresentable {

  var rawValue: String

  init?(rawValue: String) {
    self.rawValue = rawValue
  }

  func hash(into hasher: inout Hasher) {
    hasher.combine(1)
  }

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

let f1 = Fish(rawValue: "Cod")!
let f2 = Fish(rawValue: "cod")!

print("\(f1 == f2)") // always true
print("\(Set([f1]) == Set([f2]))") // sometimes true