Enable some nice-to-have code formatting rules

.swift-format

@@ -13,6 +13,8 @@
         "NoBlockComments": false,
         "OrderedImports": true,
         "UseLetInEveryBoundCaseVariable": false,
-        "UseSynthesizedInitializer": false
+        "UseSynthesizedInitializer": false,
+        "ReturnVoidInsteadOfEmptyTuple": true,
+        "NoVoidReturnOnFunctionSignature": true,
     }
 }

Sources/CompletionScoring/Text/CandidateBatch.swift

@@ -99,13 +99,13 @@ package struct CandidateBatch: Sendable {
     /// Don't add a method that returns a candidate, the candidates have unsafe pointers back into the batch, and
     /// must not outlive it.
     @inline(__always)
-    func enumerate(body: (Candidate) throws -> ()) rethrows {
+    func enumerate(body: (Candidate) throws -> Void) rethrows {
       for idx in 0..<count {
         try body(candidate(at: idx))
       }
     }
 
-    func enumerate(_ range: Range<Int>, body: (Int, Candidate) throws -> ()) rethrows {
+    func enumerate(_ range: Range<Int>, body: (Int, Candidate) throws -> Void) rethrows {
       precondition(range.lowerBound >= 0)
       precondition(range.upperBound <= count)
       for idx in range {
@@ -224,15 +224,15 @@ package struct CandidateBatch: Sendable {
     append(contentsOf: candidates, contentType: contentType)
   }
 
-  package func enumerate(body: (Candidate) throws -> ()) rethrows {
+  package func enumerate(body: (Candidate) throws -> Void) rethrows {
     try readonlyStorage.enumerate(body: body)
   }
 
-  package func enumerate(body: (Int, Candidate) throws -> ()) rethrows {
+  package func enumerate(body: (Int, Candidate) throws -> Void) rethrows {
     try readonlyStorage.enumerate(0..<count, body: body)
   }
 
-  internal func enumerate(_ range: Range<Int>, body: (Int, Candidate) throws -> ()) rethrows {
+  internal func enumerate(_ range: Range<Int>, body: (Int, Candidate) throws -> Void) rethrows {
     try readonlyStorage.enumerate(range, body: body)
   }
 
@@ -283,7 +283,7 @@ package struct CandidateBatch: Sendable {
     count > 0
   }
 
-  private mutating func mutate(body: (inout UnsafeStorage) -> ()) {
+  private mutating func mutate(body: (inout UnsafeStorage) -> Void) {
     if !isKnownUniquelyReferenced(&__storageBox_useAccessor) {
       __storageBox_useAccessor = __storageBox_useAccessor.copy()
     }
@@ -524,7 +524,7 @@ package struct Candidate {
 // Creates a buffer of `capacity` elements of type `T?`, each initially set to nil.
 ///
 /// After running `initialize`, returns all elements that were set to non-`nil` values.
-private func compactScratchArea<T>(capacity: Int, initialize: (UnsafeMutablePointer<T?>) -> ()) -> [T] {
+private func compactScratchArea<T>(capacity: Int, initialize: (UnsafeMutablePointer<T?>) -> Void) -> [T] {
   let scratchArea = UnsafeMutablePointer<T?>.allocate(capacity: capacity)
   scratchArea.initialize(repeating: nil, count: capacity)
   defer {

Sources/CompletionScoring/Text/Pattern.swift

@@ -752,7 +752,7 @@ extension Pattern {
       self.baseNameLength = baseNameLength ?? byteCount
     }
 
-    func enumerate(body: (Range<Int>) -> ()) {
+    func enumerate(body: (Range<Int>) -> Void) {
       var position = 0
       for token in tokens {
         body(position ..+ token.length)

Sources/CompletionScoring/Utilities/Serialization/BinaryEncoder.swift

@@ -29,7 +29,7 @@ package struct BinaryEncoder {
   ///   - body: a closure accepting a `BinaryEncoder` that you can make `write(_:)` calls against to populate the
   ///   archive.
   /// - Returns: a byte array that can be used with `BinaryDecoder`
-  static func encode(contentVersion: Int, _ body: (inout Self) -> ()) -> [UInt8] {
+  static func encode(contentVersion: Int, _ body: (inout Self) -> Void) -> [UInt8] {
     var encoder = BinaryEncoder(contentVersion: contentVersion)
     body(&encoder)
     return encoder.stream

Sources/CompletionScoring/Utilities/SwiftExtensions.swift

@@ -290,7 +290,7 @@ protocol ContiguousZeroBasedIndexedCollection: Collection where Index == Int {
 }
 
 extension ContiguousZeroBasedIndexedCollection {
-  func slicedConcurrentForEachSliceRange(body: @Sendable (Range<Index>) -> ()) {
+  func slicedConcurrentForEachSliceRange(body: @Sendable (Range<Index>) -> Void) {
     // We want to use `DispatchQueue.concurrentPerform`, but we want to be called only a few times. So that we
     // can amortize per-callback work. We also want to oversubscribe so that we can efficiently use
     // heterogeneous CPUs. If we had 4 efficiency cores, and 4 performance cores, and we dispatched 8 work items
@@ -336,7 +336,7 @@ extension Array {
   ///     }
   ///     ```
   package func unsafeSlicedConcurrentMap<T>(
-    writer: @Sendable (ArraySlice<Element>, _ destination: UnsafeMutablePointer<T>) -> ()
+    writer: @Sendable (ArraySlice<Element>, _ destination: UnsafeMutablePointer<T>) -> Void
   ) -> [T] where Self: Sendable {
     return Array<T>(unsafeUninitializedCapacity: count) { buffer, initializedCount in
       if let bufferBase = buffer.baseAddress {
@@ -353,13 +353,13 @@ extension Array {
   }
 
   /// Concurrent for-each on self, but slice based to allow the body to amortize work across callbacks
-  func slicedConcurrentForEach(body: @Sendable (ArraySlice<Element>) -> ()) where Self: Sendable {
+  func slicedConcurrentForEach(body: @Sendable (ArraySlice<Element>) -> Void) where Self: Sendable {
     slicedConcurrentForEachSliceRange { sliceRange in
       body(self[sliceRange])
     }
   }
 
-  func concurrentForEach(body: @Sendable (Element) -> ()) where Self: Sendable {
+  func concurrentForEach(body: @Sendable (Element) -> Void) where Self: Sendable {
     DispatchQueue.concurrentPerform(iterations: count) { index in
       body(self[index])
     }

Sources/CompletionScoringTestSupport/TestExtensions.swift

@@ -18,7 +18,7 @@ import XCTest
 @inline(never)
 package func drain<T>(_ value: T) {}
 
-func duration(of body: () -> ()) -> TimeInterval {
+func duration(of body: () -> Void) -> TimeInterval {
   let start = ProcessInfo.processInfo.systemUptime
   body()
   return ProcessInfo.processInfo.systemUptime - start
@@ -30,7 +30,7 @@ extension RandomNumberGenerator {
   }
 }
 
-package func withEachPermutation<T>(_ a: T, _ b: T, body: (T, T) -> ()) {
+package func withEachPermutation<T>(_ a: T, _ b: T, body: (T, T) -> Void) {
   body(a, b)
   body(b, a)
 }
@@ -134,7 +134,7 @@ extension XCTestCase {
   /// Run `body()` `iterations`, gathering timing stats, and print them.
   /// In between runs, coax for the machine into an arbitrary but consistent thermal state by either sleeping or doing
   /// pointless work so that results are more comparable run to run, no matter else is happening on the machine.
-  package func gaugeTiming(iterations: Int = 1, testName: String = #function, _ body: () -> ()) {
+  package func gaugeTiming(iterations: Int = 1, testName: String = #function, _ body: () -> Void) {
     let logFD = tryOrFailTest(try Self.openPerformanceLog(), message: "Failed to open performance log")
     var timings = Timings()
     for iteration in 0..<iterations {

Sources/CompletionScoringTestSupport/Timings.swift

@@ -107,7 +107,7 @@ package struct Timings {
 }
 
 extension Optional {
-  mutating func mutateWrappedValue(mutator: (inout Wrapped) -> ()) {
+  mutating func mutateWrappedValue(mutator: (inout Wrapped) -> Void) {
     if var wrapped = self {
       self = nil  // Avoid COW for clients.
       mutator(&wrapped)

Sources/DocCDocumentation/DocCReferenceResolutionService.swift

@@ -45,7 +45,7 @@ final class DocCReferenceResolutionService: DocumentationService, Sendable {
 
   func process(
     _ message: DocumentationServer.Message,
-    completion: @escaping (DocumentationServer.Message) -> ()
+    completion: @escaping (DocumentationServer.Message) -> Void
   ) {
     do {
       let response = try process(message)

Sources/SourceKitD/SourceKitD.swift

@@ -482,7 +482,7 @@ package actor SourceKitD {
 
 /// A sourcekitd notification handler in a class to allow it to be uniquely referenced.
 package protocol SKDNotificationHandler: AnyObject, Sendable {
-  func notification(_: SKDResponse) -> Void
+  func notification(_: SKDResponse)
 }
 
 struct WeakSKDNotificationHandler: Sendable {

Sources/SourceKitLSP/Swift/SwiftLanguageService.swift

@@ -272,7 +272,7 @@ package actor SwiftLanguageService: LanguageService, Sendable {
   }
 
   /// - Important: For testing only
-  package func setReusedNodeCallback(_ callback: (@Sendable (_ node: Syntax) -> ())?) async {
+  package func setReusedNodeCallback(_ callback: (@Sendable (_ node: Syntax) -> Void)?) async {
     await self.syntaxTreeManager.setReusedNodeCallback(callback)
   }
 

Sources/SwiftSourceKitPlugin/Plugin.swift

@@ -85,7 +85,7 @@ final class RequestHandler: Sendable {
       }
     }
 
-    func sourcekitdProducesResult(body: @escaping @Sendable () async -> ()) -> HandleRequestResult {
+    func sourcekitdProducesResult(body: @escaping @Sendable () async -> Void) -> HandleRequestResult {
       requestHandlingQueue.async {
         await body()
       }

Tests/BuildSystemIntegrationTests/CompilationDatabaseTests.swift

@@ -433,7 +433,7 @@ fileprivate var pathSeparator: String {
 
 private func checkCompilationDatabaseBuildSystem(
   _ compdb: String,
-  block: @Sendable (JSONCompilationDatabaseBuildSystem) async throws -> ()
+  block: @Sendable (JSONCompilationDatabaseBuildSystem) async throws -> Void
 ) async throws {
   try await withTestScratchDir { tempDir in
     let configPath = tempDir.appendingPathComponent(JSONCompilationDatabaseBuildSystem.dbName)

Tests/CompletionScoringTests/TopKTests.swift

@@ -36,7 +36,7 @@ class TopKTests: XCTestCase {
   }
 
   func testSelectTopKExhaustively() throws {
-    func allCombinations(count: Int, body: ([Int]) -> ()) {
+    func allCombinations(count: Int, body: ([Int]) -> Void) {
       var array = [Int](repeating: 0, count: count)
       func enumerate(slot: Int) {
         if slot == array.count {

Tests/CompletionScoringTests/XCTestCaseScoringAdditions.swift

@@ -92,7 +92,7 @@ extension XCTestCase {
 }
 
 extension String {
-  func enumeratePrefixes(includeLowercased: Bool, body: (String) -> ()) {
+  func enumeratePrefixes(includeLowercased: Bool, body: (String) -> Void) {
     for length in 1..<count {
       body(String(prefix(length)))
       if includeLowercased {

Tests/SourceKitLSPTests/ExpectedIndexTaskTracker.swift

@@ -142,7 +142,7 @@ actor ExpectedIndexTaskTracker {
     )
   }
 
-  func preparationTaskDidStart(taskDescription: PreparationTaskDescription) -> Void {
+  func preparationTaskDidStart(taskDescription: PreparationTaskDescription) {
     guard let expectedPreparations else {
       return
     }
@@ -160,7 +160,7 @@ actor ExpectedIndexTaskTracker {
     }
   }
 
-  func preparationTaskDidFinish(taskDescription: PreparationTaskDescription) -> Void {
+  func preparationTaskDidFinish(taskDescription: PreparationTaskDescription) {
     guard let expectedPreparations else {
       return
     }
@@ -191,7 +191,7 @@ actor ExpectedIndexTaskTracker {
     }
   }
 
-  func updateIndexStoreTaskDidStart(taskDescription: UpdateIndexStoreTaskDescription) -> Void {
+  func updateIndexStoreTaskDidStart(taskDescription: UpdateIndexStoreTaskDescription) {
     if Task.isCancelled {
       logger.debug(
         """
@@ -212,7 +212,7 @@ actor ExpectedIndexTaskTracker {
     }
   }
 
-  func updateIndexStoreTaskDidFinish(taskDescription: UpdateIndexStoreTaskDescription) -> Void {
+  func updateIndexStoreTaskDidFinish(taskDescription: UpdateIndexStoreTaskDescription) {
     guard let expectedIndexStoreUpdates else {
       return
     }