Open Radar

 
UPDATE 6/10/2014: Marked as duplicate of 17183596

Forced unwrapping of a dictionary or array cannot add/modify/remove elements from the dictionary or array without assigning the unwrapped value to a variable or constant.

Example:

Every single access after the ! below has a compile time "could not find member" error.

var optionalDict: Dictionary<String, String>? = Dictionary<String, String>()
optionalDict!.removeValueForKey("test")
optionalDict!.removeAll(keepCapacity: true)
optionalDict!.updateValue("test", forKey: "test")

var optionalArray: Int[]? = Int[]()
optionalArray!.removeAtIndex(2)
optionalArray!.append(4)

However, all of the methods work if the unwrapped values are assigned to another variable or constant, like this:

var dict = optionalDict!
dict.removeValueForKey("test")
dict.removeAll(keepCapacity: true)
dict.updateValue("test", forKey: "test")

var arr = optionalArray!
arr.removeAtIndex(2)
arr.append(4)

Steps to Reproduce:
1. Install Xcode
2. Open a new playground
3. Try the example code from the description

Expected Results:
Be able to unwrap and use an optional array or dictionary

Actual Results:
Cannot unwrap and use an optional array or dictionary without first assigning the unwrapped value to another variable or constant