// RUN: %target-swift-frontend -typecheck %s -swift-version 3
// RUN: %target-swift-frontend -typecheck -update-code -primary-file %s -emit-migrated-file-path %t.result -disable-migrator-fixits -swift-version 3
// RUN: diff -u %s.expected %t.result
// RUN: %target-swift-frontend -typecheck %s.expected -swift-version 4

func test1(_: ()) {}
test1(())
test1()
func test2() {}
test2()

enum Result<T> {
	case success(T)
}
func test3(_: Result<()>) {}
test3(.success())

func test4(_: (Int, Int) -> ()) {}
test4({ (x,y) in })
func test5(_: (Int, Int, Int) -> ()) {}
test5({ (x,y,z) in })

func test6(_: ((Int, Int)) -> ()) {}
test6({ (x,y) in })
func test7(_: ((Int, Int, Int)) -> ()) {}
test7({ (x,y,z) in })
test6({ (_ x, _ y) in })
test6({ (_, _) in })
test6({ (x:Int, y:Int) in })
test6({ (_, _) ->() in })

func test8(_: ((Int, Int)) -> Int) {}
test8 { (_, _) -> Int in 2 }
test8 { (x, y) in x }

func isEven(_ x: Int) -> Bool { return x % 2 == 0 }
let items = Array(zip(0..<10, 0..<10))
_ = items.filter { (_, x) in isEven(x) }
_ = items.filter { _ in true }

func toString(indexes: Int?...) -> String {
  let _ = indexes.enumerated().flatMap({ (i: Int, index: Int?) -> String? in
    let _: Int = i
    if index != nil {}
    return ""
  })
  let _ = indexes.reduce(0) { print($0); return $0.0 + ($0.1 ?? 0)}
  let _ = indexes.reduce(0) { (true ? $0 : (1, 2)).0 + ($0.1 ?? 0) }
  let _ = [(1, 2)].contains { $0 != $1 }
  _ = ["Hello", "Foo"].sorted { print($0); return $0.0.count > ($0).1.count }
  _ = ["Hello" : 2].map { ($0, ($1)) }
}

extension Dictionary {
  public mutating func merge(with dictionary: Dictionary) {
    dictionary.forEach { updateValue($1, forKey: $0) }
  }
}

let dictionary: [String: String] = [:]
_ = dictionary.first { (column, value) in true }!.value

func doit(_ x: Int) -> Bool { return x > 0 }
let _: ((String, Int)) -> [String:Bool] = { [$0: doit($1)] }
func returnClosure() -> ((Int, Int)) -> Bool { return {$1 > $0} }