Open Radar

 
Summary:
I wrote a Swift method:

func scheduleLocalNotificationForArrivalTime(arrivalTime: Int, routeName: String, stopName: String, fromViewController viewController: UIViewController) {}

In my test bundle, I tried to exercise this function by calling it with the following:

scheduleLocalNotificationForArrivalTime(4, "Black Route", "Branscomb Quad", nil)

When I tried to build this, I got the attached error. It took me around a half hour to realize it was because I hadn't declared the viewController parameter as an optional. I couldn't understand why this wouldn't compile; the argument list seemed exactly as I defined it and exactly as I was calling it. 

Xcode could provide a much more helpful error message, like "cannot pass nil value into non-optional parameter". That would have allowed me to instantly realize what the problem was.

Steps to Reproduce:
1. Write method with no optional parameters
2. Call the method, and try to pass nil into one of the parameters
3. See attached error

Expected Results:
A helpful error message when I try to pass nil into a non-optional parameter

Actual Results:
A very vague error message when I try to pass nil into a non-optional parameter

Version:
Xcode 6.3.1, OS X 10.10.3