[gardening] Remove redundant nil-initialization of optional variable

From the Swift documentation:

"If you define an optional variable without providing a default value,
 the variable is automatically set to nil for you."

Author: practicalswift

CHANGELOG.md

@@ -3663,7 +3663,7 @@ Swift 1.0
   accepts inouts or `nil`:
 
     ```swift
-    var error: NSError? = nil
+    var error: NSError?
     let words = NSString.stringWithContentsOfFile("/usr/share/dict/words",
       encoding: .UTF8StringEncoding,
       error: &error)

benchmark/utils/DriverUtils.swift

@@ -96,7 +96,7 @@ struct TestConfig {
 
   /// After we run the tests, should the harness sleep to allow for utilities
   /// like leaks that require a PID to run on the test harness.
-  var afterRunSleep: Int? = nil
+  var afterRunSleep: Int?
 
   /// The list of tests to run.
   var tests = [Test]()

docs/SequencesAndCollections.rst

@@ -142,7 +142,7 @@ implement a generic `for`\ …\ `in` loop.
         latest = _baseIterator.next() ?? latest
         return latest 
       }
-      public private(set) var latest: I.Element? = nil
+      public private(set) var latest: I.Element?
       private var _baseIterator: I
     }
 

docs/proposals/CPointerInteropLanguageModel.rst

@@ -116,7 +116,7 @@ So if you have a function declared::
 
 You can call it as any of::
 
-  var x: NSBas? = nil
+  var x: NSBas?
   var p: AutoreleasingUnsafeMutablePointer<NSBas?> = nil
   bas(nil)
   bas(p)

stdlib/private/StdlibCollectionUnittest/CheckSequenceType.swift

@@ -1937,8 +1937,8 @@ self.test("\(testNamePrefix)._preprocessingPass/semantics") {
   for test in forEachTests {
     let s = makeWrappedSequence(test.sequence.map(OpaqueValue.init))
     var wasInvoked = false
-    var caughtError: Error? = nil
-    var result: OpaqueValue<Int>? = nil
+    var caughtError: Error?
+    var result: OpaqueValue<Int>?
     do {
       result = try s._preprocessingPass {
         (sequence) -> OpaqueValue<Int> in

stdlib/private/StdlibUnicodeUnittest/Collation.swift

@@ -247,7 +247,7 @@ public struct StringComparisonTest {
   public let collationElements: [UInt64]
   public let loc: SourceLoc
 
-  public var order: Int? = nil
+  public var order: Int?
 
   public init(
     _ string: String,

stdlib/private/StdlibUnittest/StdlibUnittest.swift.gyb

@@ -681,7 +681,7 @@ func _childProcess() {
 }
 
 struct _ParentProcess {
-  internal var _pid: pid_t? = nil
+  internal var _pid: pid_t?
   internal var _childStdin: _FDOutputStream = _FDOutputStream(fd: -1)
   internal var _childStdout: _FDInputStream = _FDInputStream(fd: -1)
   internal var _childStderr: _FDInputStream = _FDInputStream(fd: -1)
@@ -849,7 +849,7 @@ struct _ParentProcess {
 
     // Check if the child has sent us "end" markers for the current test.
     if stdoutEnd && stderrEnd {
-      var status: ProcessTerminationStatus? = nil
+      var status: ProcessTerminationStatus?
       if !testSuite._testByName(testName).canReuseChildProcessAfterTest {
         status = _waitForChild()
         switch status! {
@@ -937,7 +937,7 @@ struct _ParentProcess {
     print("[ RUN      ] \(fullTestName)\(activeXFailsText)")
 
     var expectCrash = false
-    var childTerminationStatus: ProcessTerminationStatus? = nil
+    var childTerminationStatus: ProcessTerminationStatus?
     var crashStdout: [String] = []
     var crashStderr: [String] = []
     if _runTestsInProcess {
@@ -1145,7 +1145,7 @@ public func runAllTests() {
     _childProcess()
   } else {
     var runTestsInProcess: Bool = false
-    var filter: String? = nil
+    var filter: String?
     var args = [String]()
     var i = 0
     i += 1 // Skip the name of the executable.
@@ -1331,10 +1331,10 @@ public final class TestSuite {
     internal final class _Data {
       var _xfail: [TestRunPredicate] = []
       var _skip: [TestRunPredicate] = []
-      var _stdinText: String? = nil
+      var _stdinText: String?
       var _stdinEndsWithEOF: Bool = false
       var _crashOutputMatches: [String] = []
-      var _testLoc: SourceLoc? = nil
+      var _testLoc: SourceLoc?
     }
 
     init(testSuite: TestSuite, name: String, loc: SourceLoc) {
@@ -1507,7 +1507,7 @@ func _getOSVersion() -> OSVersion {
 }
 
 var _runningOSVersion: OSVersion = _getOSVersion()
-var _overrideOSVersion: OSVersion? = nil
+var _overrideOSVersion: OSVersion?
 
 /// Override the OS version for testing.
 public func _setOverrideOSVersion(_ v: OSVersion) {

stdlib/private/StdlibUnittestFoundationExtras/StdlibUnittestFoundationExtras.swift

@@ -13,7 +13,7 @@
 import ObjectiveC
 import Foundation
 
-internal var _temporaryLocaleCurrentLocale: NSLocale? = nil
+internal var _temporaryLocaleCurrentLocale: NSLocale?
 
 extension NSLocale {
   @objc

stdlib/private/SwiftPrivatePthreadExtras/PthreadBarriers.swift

@@ -43,8 +43,8 @@ public var _stdlib_PTHREAD_BARRIER_SERIAL_THREAD: CInt {
 }
 
 public struct _stdlib_pthread_barrier_t {
-  var mutex: UnsafeMutablePointer<pthread_mutex_t>? = nil
-  var cond: UnsafeMutablePointer<pthread_cond_t>? = nil
+  var mutex: UnsafeMutablePointer<pthread_mutex_t>?
+  var cond: UnsafeMutablePointer<pthread_cond_t>?
 
   /// The number of threads to synchronize.
   var count: CUnsignedInt = 0

stdlib/private/SwiftPrivatePthreadExtras/SwiftPrivatePthreadExtras.swift

@@ -95,7 +95,7 @@ public func _stdlib_pthread_join<Result>(
   _ thread: pthread_t,
   _ resultType: Result.Type
 ) -> (CInt, Result?) {
-  var threadResultRawPtr: UnsafeMutableRawPointer? = nil
+  var threadResultRawPtr: UnsafeMutableRawPointer?
   let result = pthread_join(thread, &threadResultRawPtr)
   if result == 0 {
     let threadResultPtr = threadResultRawPtr!.assumingMemoryBound(

stdlib/public/SDK/CryptoTokenKit/CryptoTokenKit.swift

@@ -35,7 +35,7 @@ extension TKSmartCard {
 
   @available(OSX 10.12, *)
   public func withSession<T>(_ body: @escaping () throws -> T) throws -> T {
-    var result: T? = nil
+    var result: T?
     try self.__inSession(executeBlock: {
       (errorPointer: NSErrorPointer) -> Bool in
       do {

stdlib/public/SDK/Dispatch/Data.swift

@@ -72,7 +72,7 @@ public struct DispatchData : RandomAccessCollection, _ObjectiveCBridgeable {
 	public func withUnsafeBytes<Result, ContentType>(
 		body: (UnsafePointer<ContentType>) throws -> Result) rethrows -> Result
 	{
-		var ptr: UnsafeRawPointer? = nil
+		var ptr: UnsafeRawPointer?
 		var size = 0
 		let data = __dispatch_data_create_map(__wrapped, &ptr, &size)
         let contentPtr = ptr!.bindMemory(
@@ -183,7 +183,7 @@ public struct DispatchData : RandomAccessCollection, _ObjectiveCBridgeable {
 		var offset = 0
 		let subdata = __dispatch_data_copy_region(__wrapped, index, &offset)
 
-		var ptr: UnsafeRawPointer? = nil
+		var ptr: UnsafeRawPointer?
 		var size = 0
 		let map = __dispatch_data_create_map(subdata, &ptr, &size)
 		defer { _fixLifetime(map) }
@@ -280,7 +280,7 @@ extension DispatchData {
 	}
 
 	public static func _unconditionallyBridgeFromObjectiveC(_ source: __DispatchData?) -> DispatchData {
-		var result: DispatchData? = nil
+		var result: DispatchData?
 		_forceBridgeFromObjectiveC(source!, result: &result)
 		return result!
 	}

stdlib/public/SDK/Dispatch/Queue.swift

@@ -34,7 +34,7 @@ public extension DispatchQueue {
 		public static let initiallyInactive = Attributes(rawValue: 1<<2)
 
 		fileprivate func _attr() -> __OS_dispatch_queue_attr? {
-			var attr: __OS_dispatch_queue_attr? = nil
+			var attr: __OS_dispatch_queue_attr?
 
 			if self.contains(.concurrent) {
 				attr = _swift_dispatch_queue_concurrent()

stdlib/public/SDK/Foundation/Calendar.swift

@@ -410,7 +410,7 @@ public struct Calendar : Hashable, Equatable, ReferenceConvertible, _MutableBoxi
     /// - parameter date: The specified date.
     /// - returns: `true` if the starting time and duration of a component could be calculated, otherwise `false`.
     public func dateInterval(of component: Component, start: inout Date, interval: inout TimeInterval, for date: Date) -> Bool {
-        var nsDate : NSDate? = nil
+        var nsDate : NSDate?
         var ti : TimeInterval = 0
         if _handle.map({ $0.range(of: Calendar._toCalendarUnit([component]), start: &nsDate, interval: &ti, for: date) }) {
             start = nsDate as! Date
@@ -688,7 +688,7 @@ public struct Calendar : Hashable, Equatable, ReferenceConvertible, _MutableBoxi
     /// - returns: `true` if a date range could be found, and `false` if the date is not in a weekend.
     @available(iOS 8.0, *)
     public func dateIntervalOfWeekend(containing date: Date, start: inout Date, interval: inout TimeInterval) -> Bool {
-        var nsDate : NSDate? = nil
+        var nsDate : NSDate?
         var ti : TimeInterval = 0
         if _handle.map({ $0.range(ofWeekendStart: &nsDate, interval: &ti, containing: date) }) {
             start = nsDate as! Date
@@ -705,7 +705,7 @@ public struct Calendar : Hashable, Equatable, ReferenceConvertible, _MutableBoxi
     /// - returns: A `DateInterval`, or nil if the date is not in a weekend.
     @available(OSX 10.12, iOS 10.0, tvOS 10.0, watchOS 3.0, *)
     public func dateIntervalOfWeekend(containing date: Date) -> DateInterval? {
-        var nsDate : NSDate? = nil
+        var nsDate : NSDate?
         var ti : TimeInterval = 0
         if _handle.map({ $0.range(ofWeekendStart: &nsDate, interval: &ti, containing: date) }) {
             return DateInterval(start: nsDate as! Date, duration: ti)
@@ -729,7 +729,7 @@ public struct Calendar : Hashable, Equatable, ReferenceConvertible, _MutableBoxi
     @available(iOS 8.0, *)
     public func nextWeekend(startingAfter date: Date, start: inout Date, interval: inout TimeInterval, direction: SearchDirection = .forward) -> Bool {
         // The implementation actually overrides previousKeepSmaller and nextKeepSmaller with matchNext, always - but strict still trumps all.
-        var nsDate : NSDate? = nil
+        var nsDate : NSDate?
         var ti : TimeInterval = 0
         if _handle.map({ $0.nextWeekendStart(&nsDate, interval: &ti, options: direction == .backward ? [.searchBackwards] : [], after: date) }) {
             start = nsDate as! Date
@@ -751,7 +751,7 @@ public struct Calendar : Hashable, Equatable, ReferenceConvertible, _MutableBoxi
     @available(OSX 10.12, iOS 10.0, tvOS 10.0, watchOS 3.0, *)
     public func nextWeekend(startingAfter date: Date, direction: SearchDirection = .forward) -> DateInterval? {
         // The implementation actually overrides previousKeepSmaller and nextKeepSmaller with matchNext, always - but strict still trumps all.
-        var nsDate : NSDate? = nil
+        var nsDate : NSDate?
         var ti : TimeInterval = 0
         if _handle.map({ $0.nextWeekendStart(&nsDate, interval: &ti, options: direction == .backward ? [.searchBackwards] : [], after: date) }) {
             /// WARNING: searching backwards is totally broken! 26643365
@@ -1122,7 +1122,7 @@ extension Calendar : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSCalendar?) -> Calendar {
-        var result: Calendar? = nil
+        var result: Calendar?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/Data.swift

@@ -760,7 +760,7 @@ extension Data : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSData?) -> Data {
-        var result: Data? = nil
+        var result: Data?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/Date.swift

@@ -256,7 +256,7 @@ extension Date : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSDate?) -> Date {
-        var result: Date? = nil
+        var result: Date?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/DateComponents.swift

@@ -339,7 +339,7 @@ extension DateComponents : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSDateComponents?) -> DateComponents {
-        var result: DateComponents? = nil
+        var result: DateComponents?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/DateInterval.swift

@@ -214,7 +214,7 @@ extension DateInterval : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSDateInterval?) -> DateInterval {
-        var result: DateInterval? = nil
+        var result: DateInterval?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/Decimal.swift

@@ -454,7 +454,7 @@ extension Decimal : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSDecimalNumber?) -> Decimal {
-        var result: Decimal? = nil
+        var result: Decimal?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/FileManager.swift

@@ -30,7 +30,7 @@ extension FileManager {
 
     @available(*, deprecated, renamed:"replaceItemAt(_:withItemAt:backupItemName:options:)")
     public func replaceItemAtURL(originalItemURL: NSURL, withItemAtURL newItemURL: NSURL, backupItemName: String? = nil, options: FileManager.ItemReplacementOptions = []) throws -> NSURL? {
-        var error: NSError? = nil
+        var error: NSError?
         if let result = NS_Swift_NSFileManager_replaceItemAtURL_withItemAtURL_backupItemName_options(self, originalItemURL, newItemURL, backupItemName, options, &error) {
             return result
         }
@@ -39,7 +39,7 @@ extension FileManager {
 
     @available(OSX 10.6, iOS 4.0, *)
     public func replaceItemAt(_ originalItemURL: URL, withItemAt newItemURL: URL, backupItemName: String? = nil, options: FileManager.ItemReplacementOptions = []) throws -> NSURL? {
-        var error: NSError? = nil
+        var error: NSError?
         if let result = NS_Swift_NSFileManager_replaceItemAtURL_withItemAtURL_backupItemName_options(self, originalItemURL as NSURL, newItemURL as NSURL, backupItemName, options, &error) {
             return result
         }

stdlib/public/SDK/Foundation/Foundation.swift

@@ -1416,7 +1416,7 @@ extension NSCoder {
 
   @nonobjc
   public func decodeObject(of classes: [AnyClass]?, forKey key: String) -> Any? {
-    var classesAsNSObjects: NSSet? = nil
+    var classesAsNSObjects: NSSet?
     if let theClasses = classes {
       classesAsNSObjects = NSSet(array: theClasses.map { $0 as AnyObject })
     }
@@ -1474,8 +1474,8 @@ extension NSCoder {
   @nonobjc
   @available(OSX 10.11, iOS 9.0, *)
   public func decodeTopLevelObject(of classes: [AnyClass]?, forKey key: String) throws -> Any? {
-    var error: NSError? = nil
-    var classesAsNSObjects: NSSet? = nil
+    var error: NSError?
+    var classesAsNSObjects: NSSet?
     if let theClasses = classes {
       classesAsNSObjects = NSSet(array: theClasses.map { $0 as AnyObject })
     }

stdlib/public/SDK/Foundation/IndexSet.swift

@@ -683,7 +683,7 @@ public struct IndexSet : ReferenceConvertible, Equatable, BidirectionalCollectio
     public func filteredIndexSet(in range : Range<Element>, includeInteger: (Element) throws -> Bool) rethrows -> IndexSet {
         let r : NSRange = _toNSRange(range)
         return try _handle.map {
-            var error : Error? = nil
+            var error : Error?
             let result = $0.indexes(in: r, options: [], passingTest: { (i, stop) -> Bool in
                 do {
                     let include = try includeInteger(i)

stdlib/public/SDK/Foundation/Locale.swift

@@ -476,7 +476,7 @@ extension Locale : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSLocale?) -> Locale {
-        var result: Locale? = nil
+        var result: Locale?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/Notification.swift

@@ -121,7 +121,7 @@ extension Notification : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSNotification?) -> Notification {
-        var result: Notification? = nil
+        var result: Notification?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/PersonNameComponents.swift

@@ -130,7 +130,7 @@ extension PersonNameComponents : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSPersonNameComponents?) -> PersonNameComponents {
-        var result: PersonNameComponents? = nil
+        var result: PersonNameComponents?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/TimeZone.swift

@@ -270,7 +270,7 @@ extension TimeZone : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSTimeZone?) -> TimeZone {
-        var result: TimeZone? = nil
+        var result: TimeZone?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }

stdlib/public/SDK/Foundation/URL.swift

@@ -965,7 +965,7 @@ public struct URL : ReferenceConvertible, Equatable {
     ///
     /// This method synchronously checks if the resource's backing store is reachable. Checking reachability is appropriate when making decisions that do not require other immediate operations on the resource, e.g. periodic maintenance of UI state that depends on the existence of a specific document. When performing operations such as opening a file or copying resource properties, it is more efficient to simply try the operation and handle failures. This method is currently applicable only to URLs for file system resources. For other URL types, `false` is returned.
     public func checkResourceIsReachable() throws -> Bool {
-        var error : NSError? = nil
+        var error : NSError?
         let result = _url.checkResourceIsReachableAndReturnError(&error)
         if let e = error {
             throw e
@@ -979,7 +979,7 @@ public struct URL : ReferenceConvertible, Equatable {
     /// This method synchronously checks if the resource's backing store is reachable. Checking reachability is appropriate when making decisions that do not require other immediate operations on the resource, e.g. periodic maintenance of UI state that depends on the existence of a specific document. When performing operations such as opening a file or copying resource properties, it is more efficient to simply try the operation and handle failures. This method is currently applicable only to URLs for file system resources. For other URL types, `false` is returned.
     @available(OSX 10.10, iOS 8.0, *)
     public func checkPromisedItemIsReachable() throws -> Bool {
-        var error : NSError? = nil
+        var error : NSError?
         let result = _url.checkPromisedItemIsReachableAndReturnError(&error)
         if let e = error {
             throw e
@@ -1151,7 +1151,7 @@ extension URL : _ObjectiveCBridgeable {
     }
 
     public static func _unconditionallyBridgeFromObjectiveC(_ source: NSURL?) -> URL {
-        var result: URL? = nil
+        var result: URL?
         _forceBridgeFromObjectiveC(source!, result: &result)
         return result!
     }