Quite odd behaviour, isn't it?
var error: Error?
_ = error!.localizedDescription // ✅
_ = error.debugDescription // ✅
_ = error.localizedDescription // 🛑 Value of optional type '(any Error)?' must be unwrapped to refer to member 'localizedDescription' of wrapped base type 'any Error'
_ = error!.debugDescription // 🛑 Value of type 'any Error' has no member 'debugDescription'