Merge branch 'master' into RemoveRedundantBufferZeroingNSStringAPI

Author: valeriyvan

CHANGELOG.md

@@ -25,7 +25,75 @@ CHANGELOG
 </details>
 
 Swift 5.3
-----------
+---------
+
+* [SR-7083][]:
+
+  Property observers such as `willSet` and `didSet` are now supported on `lazy` properties:
+
+  ```swift
+  class C {
+    lazy var property: Int = 0 {
+      willSet { print("willSet called!") } // Okay
+      didSet { print("didSet called!") } // Okay
+    }
+  }
+  ```
+
+  Note that the initial value of the property will be forced and made available as the `oldValue` for the `didSet` observer, if the property hasn't been accessed yet.
+  
+  ```swift
+  class C {
+    lazy var property: Int = 0 {
+      didSet { print("Old value: ", oldValue) }
+    }
+  }
+
+  let c = C()
+  c.property = 1 // Prints 'Old value: 0'
+  ```
+
+  This could have side-effects, for example if the lazy property's initializer is doing other work.
+
+* [SR-11700][]:
+
+  Exclusivity violations within code that computes the `default`
+  argument during Dictionary access are now diagnosed.
+
+  ```swift
+  struct Container {
+     static let defaultKey = 0
+
+     var dictionary = [defaultKey:0]
+
+     mutating func incrementValue(at key: Int) {
+       dictionary[key, default: dictionary[Container.defaultKey]!] += 1
+     }
+  }
+  // error: overlapping accesses to 'self.dictionary', but modification requires exclusive access; consider copying to a local variable
+  //     dictionary[key, default: dictionary[Container.defaultKey]!] += 1
+  //     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+  // note: conflicting access is here
+  //     dictionary[key, default: dictionary[Container.defaultKey]!] += 1
+  //                              ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
+  ```
+
+  The exclusivity violation can be avoided by precomputing the `default`
+  argument using a local variable.
+
+  ```swift
+  struct Container {
+    static let defaultKey = 0
+
+    var dictionary = [defaultKey:0]
+
+    mutating func incrementValue(at key: Int) {
+      let defaultValue = dictionary[Container.defaultKey]!
+      dictionary[key, default: defaultValue] += 1
+    }
+  }
+  // No error.
+  ```
 
 * [SE-0268][]:
 
@@ -585,8 +653,6 @@ Swift 5.1
   `Array` and `ContiguousArray` now have `init(unsafeUninitializedCapacity:initializingWith:)`,
   which provides access to the array's uninitialized storage.
 
-**Add new entries to the top of this section, not here!**
-
 Swift 5.0
 ---------
 
@@ -8028,6 +8094,7 @@ Swift 1.0
 [SR-5581]: <https://bugs.swift.org/browse/SR-5581>
 [SR-5719]: <https://bugs.swift.org/browse/SR-5719>
 [SR-6118]: <https://bugs.swift.org/browse/SR-6118>
+[SR-7083]: <https://bugs.swift.org/browse/SR-7083>
 [SR-7139]: <https://bugs.swift.org/browse/SR-7139>
 [SR-7251]: <https://bugs.swift.org/browse/SR-7251>
 [SR-7601]: <https://bugs.swift.org/browse/SR-7601>
@@ -8039,4 +8106,5 @@ Swift 1.0
 [SR-9827]: <https://bugs.swift.org/browse/SR-9827>
 [SR-11298]: <https://bugs.swift.org/browse/SR-11298>
 [SR-11429]: <https://bugs.swift.org/browse/SR-11429>
+[SR-11700]: <https://bugs.swift.org/browse/SR-11700>
 [SR-11841]: <https://bugs.swift.org/browse/SR-11841>

README.md

@@ -338,7 +338,7 @@ See [docs/Testing.md](docs/Testing.md), in particular the section on [lit.py](do
 
 Be sure to look through the [docs](https://github.com/apple/swift/tree/master/docs)
 directory for more information about the compiler. In particular, the documents
-titled [Debugging the Swift Compiler](docs/DebuggingTheCompiler.rst) and
+titled [Debugging the Swift Compiler](docs/DebuggingTheCompiler.md) and
 [Continuous Integration for Swift](docs/ContinuousIntegration.md) are very
 helpful to understand before submitting your first PR.
 

benchmark/CMakeLists.txt

@@ -97,6 +97,8 @@ set(SWIFT_BENCH_MODULES
     single-source/Hash
     single-source/Histogram
     single-source/HTTP2StateMachine
+    single-source/InsertCharacter
+    single-source/IntegerParsing
     single-source/Integrate
     single-source/IterateData
     single-source/Join

benchmark/README.md

@@ -74,6 +74,7 @@ The following build options are available:
 The following build targets are available:
 
 * `swift-benchmark-macosx-x86_64`
+* `swift-benchmark-iphoneos-arm64e`
 * `swift-benchmark-iphoneos-arm64`
 * `swift-benchmark-iphoneos-armv7`
 * `swift-benchmark-appletvos-arm64`

benchmark/utils/main.swift

@@ -85,6 +85,8 @@ import Hanoi
 import Hash
 import Histogram
 import HTTP2StateMachine
+import InsertCharacter
+import IntegerParsing
 import Integrate
 import IterateData
 import Join
@@ -268,6 +270,8 @@ registerBenchmark(Hanoi)
 registerBenchmark(HashTest)
 registerBenchmark(Histogram)
 registerBenchmark(HTTP2StateMachine)
+registerBenchmark(InsertCharacter)
+registerBenchmark(IntegerParsing)
 registerBenchmark(IntegrateTest)
 registerBenchmark(IterateData)
 registerBenchmark(Join)