Cannot infer contextual base in reference to member 'wifi'

[kundancodelab]

DispatchQueue.main.async {
self.reachability.whenReachable = { reachability in
if reachability.connection == .wifi {
print("Reachable via WiFi")
} else {
print("Reachable via Cellular")
}
}
self.reachability.whenUnreachable = { _ in
print("Not reachable")
}

        do {
            try self.reachability.startNotifier()
        } catch {
            print("Unable to start notifier")
        }
    }
    getting  3 syntex error assist. 
    whenReachability Cannot infer type of closure parameter 'reachability' without a type annotation  
   Why is this happening with one particular project when I go run this project all I see three red flags . What is happening here?