Swift 3.0 optimizations crash (fixed in Xcode 8.1 beta 3)

optimizationCrash.swift

///
/// This code crashes with Swift 3.0 with optimizations enabled
/// Run with:
/// $ swift -O optimizationCrash.swift
///
extension Dictionary {
    // init(pairs: [(Key, Value)]?) { // With `(Key, Value)` this doesn't crash
    init(pairs: [Element]?) { // With `Element` this crashes with -0
        self.init()
    }
}

let elements: [(Int, Int)] = [(1, 1)]
dump(Dictionary(pairs: elements))

optimizationCrash2.swift

extension Dictionary {
    init(_ pairs: [(Key, Value)]?) {
        self.init()
        for (k, v) in pairs ?? [] {
            self[k] = v
        }
    }
}

let dictionary: [String: Int] = ["hi": 1]
let array: [(String, Int)] = dictionary.filter { _ in return true } // Crashes using filter
// var array = [(String, Int)]() // Doesn't crash if you use a for loop
// for (key, value) in dictionary {
//     array.append((key, value))
// }
dump(Dictionary(array))