[stdlib] Update stdlib to 4.0 and reorganize compatibility shims (#17580)

* Update stdlib to 4.0 and move all compatibility shims into a dedicated source file

Author: airspeedswift

cmake/modules/SwiftSource.cmake

@@ -257,9 +257,9 @@ function(_compile_swift_files
                             "-Xfrontend" "${GROUP_INFO_JSON_FILE}")
   endif()
 
-  # Force swift 3 compatibility mode for Standard Library.
+  # Force swift 4 compatibility mode for Standard Library.
   if (SWIFTFILE_IS_STDLIB)
-    list(APPEND swift_flags "-swift-version" "3")
+    list(APPEND swift_flags "-swift-version" "4")
   endif()
 
   # Force swift 4 compatibility mode for overlays.

stdlib/private/StdlibUnittest/MinimalTypes.swift

@@ -220,7 +220,7 @@ public var GenericMinimalHashableValue_equalImpl =
     fatalError("GenericMinimalHashableValue_equalImpl is not set yet")
   })
 public var GenericMinimalHashableValue_hashIntoImpl =
-  ResettableValue<(Any, inout Hasher) -> Void>({ _ in
+  ResettableValue<(Any, inout Hasher) -> Void>({ (_,_) in
     fatalError("GenericMinimalHashableValue_hashIntoImpl is not set yet")
   })
 
@@ -276,7 +276,7 @@ public var GenericMinimalHashableClass_equalImpl =
     fatalError("GenericMinimalHashableClass_equalImpl is not set yet")
   })
 public var GenericMinimalHashableClass_hashIntoImpl =
-  ResettableValue<(Any, inout Hasher) -> Void>({ _ in
+  ResettableValue<(Any, inout Hasher) -> Void>({ (_,_) in
     fatalError("GenericMinimalHashableClass_hashIntoImpl is not set yet")
   })
 

stdlib/private/StdlibUnittest/StdlibUnittest.swift

@@ -1775,15 +1775,15 @@ public func _parseDottedVersionTriple(_ s: String) -> (Int, Int, Int) {
 }
 
 func _getOSVersion() -> OSVersion {
-#if os(iOS) && (arch(i386) || arch(x86_64))
+#if os(iOS) && targetEnvironment(simulator)
   // On simulator, the plist file that we try to read turns out to be host's
   // plist file, which indicates OS X.
   //
   // FIXME: how to get the simulator version *without* UIKit?
   return .iOSSimulator
-#elseif os(tvOS) && (arch(i386) || arch(x86_64))
+#elseif os(tvOS) && targetEnvironment(simulator)
   return .tvOSSimulator
-#elseif os(watchOS) && (arch(i386) || arch(x86_64))
+#elseif os(watchOS) && targetEnvironment(simulator)
   return .watchOSSimulator
 #elseif os(Linux)
   return .linux

stdlib/public/SDK/AppKit/AppKit.swift

@@ -13,7 +13,7 @@
 import Foundation
 @_exported import AppKit
 
-extension NSCursor : _DefaultCustomPlaygroundQuickLookable {
+extension NSCursor : __DefaultCustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "NSCursor._defaultCustomPlaygroundQuickLook will be removed in a future Swift version")
   public var _defaultCustomPlaygroundQuickLook: PlaygroundQuickLook {
     return .image(image)
@@ -24,7 +24,7 @@ internal struct _NSViewQuickLookState {
   static var views = Set<NSView>()
 }
 
-extension NSView : _DefaultCustomPlaygroundQuickLookable {
+extension NSView : __DefaultCustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "NSView._defaultCustomPlaygroundQuickLook will be removed in a future Swift version")
   public var _defaultCustomPlaygroundQuickLook: PlaygroundQuickLook {
     // if you set NSView.needsDisplay, you can get yourself in a recursive scenario where the same view

stdlib/public/SDK/CoreGraphics/CoreGraphics.swift

@@ -228,11 +228,13 @@ public extension CGPoint {
   }
 }
 
-extension CGPoint : CustomReflectable, CustomPlaygroundQuickLookable {
+extension CGPoint : CustomReflectable {
   public var customMirror: Mirror {
     return Mirror(self, children: ["x": x, "y": y], displayStyle: .`struct`)
   }
+}
 
+extension CGPoint : _CustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "CGPoint.customPlaygroundQuickLook will be removed in a future Swift version")
   public var customPlaygroundQuickLook: PlaygroundQuickLook {
     return .point(Double(x), Double(y))
@@ -293,14 +295,16 @@ public extension CGSize {
   }
 }
 
-extension CGSize : CustomReflectable, CustomPlaygroundQuickLookable {
+extension CGSize : CustomReflectable {
   public var customMirror: Mirror {
     return Mirror(
       self,
       children: ["width": width, "height": height],
       displayStyle: .`struct`)
   }
+}
 
+extension CGSize : _CustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "CGSize.customPlaygroundQuickLook will be removed in a future Swift version")
   public var customPlaygroundQuickLook: PlaygroundQuickLook {
     return .size(Double(width), Double(height))
@@ -431,14 +435,16 @@ public extension CGRect {
   public var y: CGFloat { return minY }
 }
 
-extension CGRect : CustomReflectable, CustomPlaygroundQuickLookable {
+extension CGRect : CustomReflectable {
   public var customMirror: Mirror {
     return Mirror(
       self,
       children: ["origin": origin, "size": size],
       displayStyle: .`struct`)
   }
+}
 
+extension CGRect : _CustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "CGRect.customPlaygroundQuickLook will be removed in a future Swift version")
   public var customPlaygroundQuickLook: PlaygroundQuickLook {
     return .rectangle(

stdlib/public/SDK/Foundation/Date.swift

@@ -272,7 +272,7 @@ extension NSDate : _HasCustomAnyHashableRepresentation {
     }
 }
 
-extension Date : CustomPlaygroundQuickLookable {
+extension Date : _CustomPlaygroundQuickLookable {
     var summary: String {
         let df = DateFormatter()
         df.dateStyle = .medium

stdlib/public/SDK/Foundation/NSCoder.swift

@@ -172,7 +172,7 @@ extension NSKeyedUnarchiver {
   @available(macOS 10.13, iOS 11.0, watchOS 4.0, tvOS 11.0, *)
   public static func unarchivedObject<DecodedObjectType>(ofClass cls: DecodedObjectType.Type, from data: Data) throws -> DecodedObjectType? where DecodedObjectType : NSCoding, DecodedObjectType : NSObject {
     var error: NSError?
-    let result = __NSKeyedUnarchiverSecureUnarchiveObjectOfClass(cls as! AnyClass, data, &error)
+    let result = __NSKeyedUnarchiverSecureUnarchiveObjectOfClass(cls as AnyClass, data, &error)
     try resolveError(error)
     return result as? DecodedObjectType
   }

stdlib/public/SDK/Foundation/NSDate.swift

@@ -12,7 +12,7 @@
 
 @_exported import Foundation // Clang module
 
-extension NSDate : CustomPlaygroundQuickLookable {
+extension NSDate : _CustomPlaygroundQuickLookable {
   @nonobjc
   var summary: String {
     let df = DateFormatter()

stdlib/public/SDK/Foundation/NSRange.swift

@@ -197,7 +197,7 @@ extension NSRange : CustomReflectable {
     }
 }
 
-extension NSRange : CustomPlaygroundQuickLookable {
+extension NSRange : _CustomPlaygroundQuickLookable {
     @available(*, deprecated, message: "NSRange.customPlaygroundQuickLook will be removed in a future Swift version")
     public var customPlaygroundQuickLook: PlaygroundQuickLook {
         return .range(Int64(location), Int64(length))

stdlib/public/SDK/Foundation/NSString.swift

@@ -107,7 +107,7 @@ extension NSString {
   }
 }
 
-extension NSString : CustomPlaygroundQuickLookable {
+extension NSString : _CustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "NSString.customPlaygroundQuickLook will be removed in a future Swift version")
   public var customPlaygroundQuickLook: PlaygroundQuickLook {
     return .text(self as String)

stdlib/public/SDK/Foundation/NSURL.swift

@@ -12,7 +12,7 @@
 
 @_exported import Foundation // Clang module
 
-extension NSURL : CustomPlaygroundQuickLookable {
+extension NSURL : _CustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "NSURL.customPlaygroundQuickLook will be removed in a future Swift version")
   public var customPlaygroundQuickLook: PlaygroundQuickLook {
     guard let str = absoluteString else { return .text("Unknown URL") }

stdlib/public/SDK/Foundation/URL.swift

@@ -1210,7 +1210,7 @@ extension NSURL : _HasCustomAnyHashableRepresentation {
     }
 }
 
-extension URL : CustomPlaygroundQuickLookable {
+extension URL : _CustomPlaygroundQuickLookable {
     @available(*, deprecated, message: "URL.customPlaygroundQuickLook will be removed in a future Swift version")
     public var customPlaygroundQuickLook: PlaygroundQuickLook {
         return .url(absoluteString)

stdlib/public/SDK/SpriteKit/SpriteKitQuickLooks.swift.gyb

@@ -14,7 +14,7 @@
 
 % for Self in ['SKShapeNode', 'SKSpriteNode', 'SKTextureAtlas', 'SKTexture']:
 
-extension ${Self} : CustomPlaygroundQuickLookable {
+extension ${Self} : _CustomPlaygroundQuickLookable {
   @available(*, deprecated, message: "${Self}.customPlaygroundQuickLook will be removed in a future Swift version")
   public var customPlaygroundQuickLook: PlaygroundQuickLook {
     let data = (self as AnyObject)._copyImageData?() as Data?

stdlib/public/core/Algorithm.swift

@@ -158,6 +158,3 @@ extension EnumeratedSequence: Sequence {
     return Iterator(_base: _base.makeIterator())
   }
 }
-
-@available(*, deprecated: 4.2, renamed: "EnumeratedSequence.Iterator")
-public typealias EnumeratedIterator<T: Sequence> = EnumeratedSequence<T>.Iterator

stdlib/public/core/BidirectionalCollection.swift

@@ -10,15 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-/// A type that provides subscript access to its elements, with bidirectional
-/// index traversal.
-///
-/// In most cases, it's best to ignore this protocol and use the
-/// `BidirectionalCollection` protocol instead, because it has a more complete
-/// interface.
-@available(*, deprecated, message: "it will be removed in Swift 4.0.  Please use 'BidirectionalCollection' instead")
-public typealias BidirectionalIndexable = BidirectionalCollection
-
 /// A collection that supports backward as well as forward traversal.
 ///
 /// Bidirectional collections offer traversal backward from any valid index,

stdlib/public/core/CMakeLists.txt

@@ -73,7 +73,6 @@ set(SWIFTLIB_ESSENTIAL
   Hashing.swift
   HeapBuffer.swift
   ICU.swift
-  ImplicitlyUnwrappedOptional.swift
   Indices.swift
   InputStream.swift
   IntegerParsing.swift
@@ -123,7 +122,6 @@ set(SWIFTLIB_ESSENTIAL
   Sort.swift.gyb
   StaticString.swift
   Stride.swift.gyb
-  StringCharacterView.swift # ORDER DEPENDENCY: Must precede String.swift
   StringHashable.swift  # ORDER DEPENDENCY: Must precede String.swift
   String.swift
   StringBridge.swift
@@ -168,6 +166,7 @@ set(SWIFTLIB_ESSENTIAL
   StringGraphemeBreaking.swift # ORDER DEPENDENCY: Must follow UTF16.swift
   ValidUTF8Buffer.swift
   WriteBackMutableSlice.swift
+  MigrationSupport.swift
   )
 
 # The complete list of sources in the core standard library.  Includes

stdlib/public/core/ClosedRange.swift

@@ -459,16 +459,7 @@ extension ClosedRange {
   }
 }
 
-extension ClosedRange where Bound: Strideable, Bound.Stride : SignedInteger {
-  /// Now that Range is conditionally a collection when Bound: Strideable,
-  /// CountableRange is no longer needed. This is a deprecated initializer
-  /// for any remaining uses of Range(countableRange).
-  @available(*,deprecated: 4.2, 
-    message: "CountableRange is now Range. No need to convert any more.")
-  public init(_ other: ClosedRange<Bound>) {
-    self = other
-  }  
-  
+extension ClosedRange where Bound: Strideable, Bound.Stride : SignedInteger {  
   /// Creates an instance equivalent to the given `Range`.
   ///
   /// - Parameter other: A `Range` to convert to a `ClosedRange` instance.
@@ -495,8 +486,7 @@ extension ClosedRange {
   }
 }
 
-@available(*, deprecated, renamed: "ClosedRange.Index")
-public typealias ClosedRangeIndex<T> = ClosedRange<T>.Index where T: Strideable, T.Stride: SignedInteger
-
+// Note: this is not for compatibility only, it is considered a useful
+// shorthand. TODO: Add documentation
 public typealias CountableClosedRange<Bound: Strideable> = ClosedRange<Bound>
   where Bound.Stride : SignedInteger

stdlib/public/core/Collection.swift

@@ -10,22 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-/// A type that provides subscript access to its elements, with forward
-/// index traversal.
-///
-/// In most cases, it's best to ignore this protocol and use the `Collection`
-/// protocol instead, because it has a more complete interface.
-@available(*, deprecated, message: "it will be removed in Swift 4.0.  Please use 'Collection' instead")
-public typealias IndexableBase = Collection
-
-/// A type that provides subscript access to its elements, with forward index
-/// traversal.
-///
-/// In most cases, it's best to ignore this protocol and use the `Collection`
-/// protocol instead, because it has a more complete interface.
-@available(*, deprecated, message: "it will be removed in Swift 4.0.  Please use 'Collection' instead")
-public typealias Indexable = Collection
-
 /// A type that iterates over a collection using its indices.
 ///
 /// The `IndexingIterator` type is the default iterator for any collection that
@@ -349,6 +333,11 @@ extension IndexingIterator: IteratorProtocol, Sequence {
 /// the number of contained elements, accessing its `count` property is an
 /// O(*n*) operation.
 public protocol Collection: Sequence where SubSequence: Collection {
+  // FIXME: ideally this would be in MigrationSupport.swift, but it needs
+  // to be on the protocol instead of as an extension
+  @available(*, deprecated/*, obsoleted: 5.0*/, message: "all index distances are now of type Int")
+  typealias IndexDistance = Int  
+
   // FIXME(ABI): Associated type inference requires this.
   associatedtype Element
 
@@ -826,9 +815,6 @@ public protocol Collection: Sequence where SubSequence: Collection {
   __consuming func randomElement<T: RandomNumberGenerator>(
     using generator: inout T
   ) -> Element?
-
-  @available(*, deprecated, message: "all index distances are now of type Int")
-  typealias IndexDistance = Int
 }
 
 /// Default implementation for forward collections.
@@ -1803,35 +1789,3 @@ extension Collection {
     return try preprocess()
   }
 }
-
-extension Collection {
-  // FIXME: <rdar://problem/34142121>
-  // This typealias should be removed as it predates the source compatibility
-  // guarantees of Swift 3, but it cannot due to a bug.
-  @available(*, unavailable, renamed: "Iterator")
-  public typealias Generator = Iterator
-
-  @available(swift, deprecated: 3.2, renamed: "Element")
-  public typealias _Element = Element
-
-  @available(*, deprecated, message: "all index distances are now of type Int")
-  public func index<T: BinaryInteger>(_ i: Index, offsetBy n: T) -> Index {
-    return index(i, offsetBy: Int(n))
-  }
-  @available(*, deprecated, message: "all index distances are now of type Int")
-  public func formIndex<T: BinaryInteger>(_ i: inout Index, offsetBy n: T) {
-    return formIndex(&i, offsetBy: Int(n))
-  }
-  @available(*, deprecated, message: "all index distances are now of type Int")
-  public func index<T: BinaryInteger>(_ i: Index, offsetBy n: T, limitedBy limit: Index) -> Index? {
-    return index(i, offsetBy: Int(n), limitedBy: limit)
-  }
-  @available(*, deprecated, message: "all index distances are now of type Int")
-  public func formIndex<T: BinaryInteger>(_ i: inout Index, offsetBy n: T, limitedBy limit: Index) -> Bool {
-    return formIndex(&i, offsetBy: Int(n), limitedBy: limit)
-  }
-  @available(*, deprecated, message: "all index distances are now of type Int")
-  public func distance<T: BinaryInteger>(from start: Index, to end: Index) -> T {
-    return numericCast(distance(from: start, to: end) as Int)
-  }
-}

stdlib/public/core/CollectionOfOne.swift

@@ -170,6 +170,3 @@ extension CollectionOfOne : CustomReflectable {
     return Mirror(self, children: ["element": _element])
   }
 }
-
-@available(*,deprecated: 4.2,renamed: "CollectionOfOne.Iterator")
-public typealias IteratorOverOne<T> = CollectionOfOne<T>.Iterator