Open Radar

 
Summary:
Swift playground errors with message "Ambiguous reference to member 'subscript'" when trying to decompose an array into an optional tuple `(Element, [Element])?` in a single line ternary statement.

Steps to Reproduce:
1. Create a blank playground.

2. Paste in the following code.

let array = [1, 2, 3, 4, 5]

let decompose: (Int, [Int])? = (array.count > 0) ? .Some(array[0], Array(array[0..<array.count])) : .None

let ambiguous = (array.count > 0) ? .Some(array[0], Array(array[0..<array.count])) : .None


Expected Results:
The resulting type of the ternary statement is unambiguous, so swift should not error with an ambiguous error message.

Actual Results:
The last line of code produces an error: "Ambiguous reference to member 'subscript'"

Version:
Xcode 7.1 beta (7B75) on OS X 10.11 El Capitan

Notes:
I'll attempt to reproduce this bug on the latest Xcode 7.1 beta and update this ticket if anything changes.

Configuration:
Vanilla Xcode install