Seems to work in Swift 3, although the error is completely bogus. Which Swift were you using?

<stdin>:5:30: error: cannot subscript a value of type 'inout [AnyObject]' (aka 'inout Array<AnyObject>')
    bar = ["key": i < 2 ? foo[i] : nil]
                          ~~~^

Comment by Abdullah Abanmi (JIRA)

The types in ternary operator have to match: ( foo: AnyObject? == bar[string]: AnyObject?)

var foo: [AnyObject?] = []
var bar: [String:AnyObject?] = [:]

for i in 0 ..< 5 {
    foo.append(i as AnyObject?)
    bar = ["key": (i < 2 ? foo[i] : nil)]
}

tested in xcode 8b6 w/ swift 3

Comment by Corey Watson (JIRA)

I'm getting this problem too, though with an error more similar to [SR-2372]. Here's my code that fails with the error: 'Int1' is not convertible to 'Bool'

let indexes: [(row: Int, section: Int)] = [(0, 0), (0, 1), (0, 2)]
let sectionToMatch: Int = 2

let indexOfSectionToMatch = indexes.reduce(nil) { $0?.section == sectionToMatch ? $0 : $1 }

However, when I explicitly specify variable names and a return type, the error disappears and the code compiles fine. Here's my code that works:

let indexes: [(row: Int, section: Int)] = [(0, 0), (0, 1), (0, 2)]
let sectionToMatch: Int = 2

let indexOfSectionToMatch = indexes.reduce(nil) { (index, nextIndex) -> (row: Int, section: Int)? in
    index?.section == sectionToMatch ? index : nextIndex
}

What should happen with this report?