Add NoAccessLevelOnExtensionDeclaration rule to swift-format

Author: Matejkob

.swift-format

@@ -9,6 +9,7 @@
     "rules": {
         "AlwaysUseLowerCamelCase": false,
         "AmbiguousTrailingClosureOverload": false,
+	"NoAccessLevelOnExtensionDeclaration": true,
         "NoBlockComments": false,
         "OrderedImports": true,
         "UseLetInEveryBoundCaseVariable": false,

CodeGeneration/Sources/SyntaxSupport/Node.swift

@@ -420,8 +420,8 @@ public struct CollectionNode {
   }
 }
 
-fileprivate extension Child {
-  var kinds: [SyntaxNodeKind] {
+extension Child {
+  fileprivate var kinds: [SyntaxNodeKind] {
     switch kind {
     case .node(let kind):
       return [kind]

CodeGeneration/Sources/SyntaxSupport/String+Extensions.swift

@@ -10,20 +10,20 @@
 //
 //===----------------------------------------------------------------------===//
 
-public extension StringProtocol {
-  var withFirstCharacterLowercased: String {
+extension StringProtocol {
+  public var withFirstCharacterLowercased: String {
     guard first?.isLetter ?? false else {
       return String(first!) + dropFirst().withFirstCharacterLowercased
     }
     return prefix(1).lowercased() + dropFirst()
   }
-  var withFirstCharacterUppercased: String {
+  public var withFirstCharacterUppercased: String {
     guard first?.isLetter ?? false else {
       return String(first!) + dropFirst().withFirstCharacterUppercased
     }
     return prefix(1).uppercased() + dropFirst()
   }
-  var backtickedIfNeeded: String {
+  public var backtickedIfNeeded: String {
     if Keyword.allCases.map(\.spec).contains(where: {
       $0.name == self && ($0.isLexerClassified || $0.name == "Type" || $0.name == "Protocol")
     }) {

CodeGeneration/Sources/SyntaxSupport/Utils.swift

@@ -58,9 +58,9 @@ extension SwiftSyntax.Trivia {
   }
 }
 
-public extension Collection {
+extension Collection {
   /// If the collection contains a single element, return it, otherwise `nil`.
-  var only: Element? {
+  public var only: Element? {
     if !isEmpty && index(after: startIndex) == endIndex {
       return self.first!
     } else {
@@ -69,8 +69,8 @@ public extension Collection {
   }
 }
 
-public extension TokenSyntax {
-  var backtickedIfNeeded: TokenSyntax {
+extension TokenSyntax {
+  public var backtickedIfNeeded: TokenSyntax {
     if Keyword.allCases.map(\.spec).contains(where: {
       $0.name == self.description && ($0.isLexerClassified || $0.name == "Type" || $0.name == "Protocol")
     }) {

CodeGeneration/Sources/Utils/SyntaxBuildableChild.swift

@@ -23,10 +23,10 @@ public enum SyntaxOrTokenNodeKind: Hashable {
 
 /// Extension to the ``Child`` type to provide functionality specific to
 /// SwiftSyntaxBuilder.
-public extension Child {
+extension Child {
   /// The type of this child, represented by a ``SyntaxBuildableType``, which can
   /// be used to create the corresponding `Buildable` and `ExpressibleAs` types.
-  var buildableType: SyntaxBuildableType {
+  public var buildableType: SyntaxBuildableType {
     let buildableKind: SyntaxOrTokenNodeKind
     switch kind {
     case .node(kind: let kind):
@@ -44,7 +44,7 @@ public extension Child {
     )
   }
 
-  var parameterBaseType: TypeSyntax {
+  public var parameterBaseType: TypeSyntax {
     switch kind {
     case .nodeChoices:
       return self.syntaxChoicesType
@@ -53,11 +53,11 @@ public extension Child {
     }
   }
 
-  var parameterType: TypeSyntax {
+  public var parameterType: TypeSyntax {
     return self.buildableType.optionalWrapped(type: parameterBaseType)
   }
 
-  var defaultValue: ExprSyntax? {
+  public var defaultValue: ExprSyntax? {
     if isOptional || isUnexpectedNodes {
       if buildableType.isBaseType && kind.isNodeChoicesEmpty {
         return ExprSyntax("\(buildableType.buildable).none")
@@ -85,7 +85,7 @@ public extension Child {
   /// If the child node has a default value, return an expression of the form
   /// ` = default_value` that can be used as the default value to for a
   /// function parameter. Otherwise, return `nil`.
-  var defaultInitialization: InitializerClauseSyntax? {
+  public var defaultInitialization: InitializerClauseSyntax? {
     if let defaultValue {
       return InitializerClauseSyntax(
         equal: .equalToken(leadingTrivia: .space, trailingTrivia: .space),
@@ -99,7 +99,7 @@ public extension Child {
   /// If this node is a token that can't contain arbitrary text, generate a Swift
   /// `precondition` statement that verifies the variable with name var_name and of type
   /// ``TokenSyntax`` contains one of the supported text options. Otherwise return `nil`.
-  func generateAssertStmtTextChoices(varName: String) -> FunctionCallExprSyntax? {
+  public func generateAssertStmtTextChoices(varName: String) -> FunctionCallExprSyntax? {
     guard case .token(choices: let choices, requiresLeadingSpace: _, requiresTrailingSpace: _) = kind else {
       return nil
     }

CodeGeneration/Sources/Utils/SyntaxBuildableNode.swift

@@ -14,41 +14,41 @@ import SyntaxSupport
 
 /// Extension to the ``Node`` type to provide functionality specific to
 /// SwiftSyntaxBuilder.
-public extension Node {
+extension Node {
   /// The node's syntax kind as ``SyntaxBuildableType``.
-  var type: SyntaxBuildableType {
+  public var type: SyntaxBuildableType {
     SyntaxBuildableType(kind: .node(kind: kind))
   }
 
   /// The node's syntax kind as ``SyntaxBuildableType``.
-  var baseType: SyntaxBuildableType {
+  public var baseType: SyntaxBuildableType {
     if base == .syntaxCollection {
       return SyntaxBuildableType(kind: .node(kind: .syntax))
     } else {
       return SyntaxBuildableType(kind: .node(kind: base))
     }
   }
 
-  static func from(type: SyntaxBuildableType) -> Node {
+  public static func from(type: SyntaxBuildableType) -> Node {
     guard case .node(kind: let kind) = type.kind, let node = SYNTAX_NODE_MAP[kind] else {
       fatalError("Base name \(type) does not have a syntax node")
     }
     return node
   }
 }
 
-public extension LayoutNode {
+extension LayoutNode {
   /// Assuming this node has a single child without a default value, that child.
-  var singleNonDefaultedChild: Child {
+  public var singleNonDefaultedChild: Child {
     let nonDefaultedParams = children.filter { $0.defaultInitialization == nil }
     precondition(nonDefaultedParams.count == 1)
     return nonDefaultedParams[0]
   }
 }
 
-public extension CollectionNode {
+extension CollectionNode {
   /// Assuming this node is a syntax collection, the type of its elements.
-  var collectionElementType: SyntaxBuildableType {
+  public var collectionElementType: SyntaxBuildableType {
     if elementChoices.count > 1 {
       return SyntaxBuildableType(kind: .node(kind: .syntax))
     } else {

CodeGeneration/Sources/generate-swift-syntax/templates/swiftsyntax/RawSyntaxNodesFile.swift

@@ -15,8 +15,8 @@ import SwiftSyntaxBuilder
 import SyntaxSupport
 import Utils
 
-fileprivate extension Node {
-  var childrenChoicesEnums: [(name: TypeSyntax, choices: [(caseName: TokenSyntax, kind: SyntaxNodeKind)])] {
+extension Node {
+  fileprivate var childrenChoicesEnums: [(name: TypeSyntax, choices: [(caseName: TokenSyntax, kind: SyntaxNodeKind)])] {
     let node = self
     if let node = node.layoutNode {
       return node.children.compactMap {
@@ -268,8 +268,8 @@ func rawSyntaxNodesFile(nodesStartingWith: [Character]) -> SourceFileSyntax {
   }
 }
 
-fileprivate extension Child {
-  var rawParameterType: TypeSyntax {
+extension Child {
+  fileprivate var rawParameterType: TypeSyntax {
     let paramType: TypeSyntax
     if case ChildKind.nodeChoices = kind {
       paramType = syntaxChoicesType

CodeGeneration/Tests/ValidateSyntaxNodes/ValidateSyntaxNodes.swift

@@ -48,8 +48,8 @@ fileprivate func assertFailuresMatchXFails(
   assertNoFailures(unmatchedXFails, message: "Unmatched expected failures", file: file, line: line)
 }
 
-fileprivate extension ChildKind {
-  func hasSameType(as other: ChildKind) -> Bool {
+extension ChildKind {
+  fileprivate func hasSameType(as other: ChildKind) -> Bool {
     switch (self, other) {
     case (.node(let kind), .node(kind: let otherKind)):
       return kind == otherKind
@@ -68,7 +68,7 @@ fileprivate extension ChildKind {
     }
   }
 
-  var isCollection: Bool {
+  fileprivate var isCollection: Bool {
     switch self {
     case .node: return false
     case .nodeChoices(let choices): return choices.contains(where: { $0.kind.isCollection })
@@ -78,13 +78,13 @@ fileprivate extension ChildKind {
   }
 }
 
-fileprivate extension Child {
-  func hasSameType(as other: Child) -> Bool {
+extension Child {
+  fileprivate func hasSameType(as other: Child) -> Bool {
     return varOrCaseName.description == other.varOrCaseName.description && kind.hasSameType(as: other.kind)
       && isOptional == other.isOptional
   }
 
-  func isFollowedByColonToken(in node: LayoutNode) -> Bool {
+  fileprivate func isFollowedByColonToken(in node: LayoutNode) -> Bool {
     let childIndex = node.children.firstIndex(where: { $0.varOrCaseName.description == self.varOrCaseName.description })
     guard let childIndex else {
       preconditionFailure("\(self.varOrCaseName) is not a child of \(node.kind.syntaxType)")
@@ -100,13 +100,13 @@ fileprivate extension Child {
   }
 }
 
-fileprivate extension Array where Element: Hashable, Element: Comparable {
+extension Array where Element: Hashable, Element: Comparable {
   /// Returns the element that occurs most frequently in the array.
   ///
   /// If there is a tie, returns the lexicographically first element.
   ///
   /// Returns `nil` if the array is empty.
-  var mostCommon: Element? {
+  fileprivate var mostCommon: Element? {
     var elementCounts: [Element: Int] = [:]
     for element in self {
       elementCounts[element, default: 0] += 1

Examples/Sources/MacroExamples/Implementation/ComplexMacros/ObservableMacro.swift

@@ -13,8 +13,8 @@
 import SwiftSyntax
 import SwiftSyntaxMacros
 
-private extension DeclSyntaxProtocol {
-  var isObservableStoredProperty: Bool {
+extension DeclSyntaxProtocol {
+  fileprivate var isObservableStoredProperty: Bool {
     if let property = self.as(VariableDeclSyntax.self),
       let binding = property.bindings.first,
       let identifier = binding.pattern.as(IdentifierPatternSyntax.self)?.identifier,

Sources/SwiftBasicFormat/BasicFormat.swift

@@ -658,16 +658,16 @@ open class BasicFormat: SyntaxRewriter {
   }
 }
 
-fileprivate extension TokenSyntax {
-  var isStringSegment: Bool {
+extension TokenSyntax {
+  fileprivate var isStringSegment: Bool {
     if case .stringSegment = self.tokenKind {
       return true
     } else {
       return false
     }
   }
 
-  var isStringSegmentWithLastCharacterBeingNewline: Bool {
+  fileprivate var isStringSegmentWithLastCharacterBeingNewline: Bool {
     switch self.tokenKind {
     case .stringSegment(let segment):
       return segment.last?.isNewline ?? false
@@ -677,9 +677,9 @@ fileprivate extension TokenSyntax {
   }
 }
 
-fileprivate extension SyntaxProtocol {
+extension SyntaxProtocol {
   /// Returns this node or the first ancestor that satisfies `condition`.
-  func ancestorOrSelf<T>(mapping map: (Syntax) -> T?) -> T? {
+  fileprivate func ancestorOrSelf<T>(mapping map: (Syntax) -> T?) -> T? {
     var walk: Syntax? = Syntax(self)
     while let unwrappedParent = walk {
       if let mapped = map(unwrappedParent) {

Sources/SwiftBasicFormat/InferIndentation.swift

@@ -124,8 +124,8 @@ private class IndentationInferrer: SyntaxVisitor {
   }
 }
 
-fileprivate extension Array<Int> {
-  var sum: Int {
+extension Array<Int> {
+  fileprivate var sum: Int {
     return self.reduce(0) { return $0 + $1 }
   }
 }

Sources/SwiftBasicFormat/SyntaxProtocol+Formatted.swift

@@ -16,9 +16,9 @@ public import SwiftSyntax
 import SwiftSyntax
 #endif
 
-public extension SyntaxProtocol {
+extension SyntaxProtocol {
   /// Build a syntax node from this `Buildable` and format it with the given format.
-  func formatted(using format: BasicFormat = BasicFormat()) -> Syntax {
+  public func formatted(using format: BasicFormat = BasicFormat()) -> Syntax {
     format.reset()
     return format.rewrite(self)
   }

Sources/SwiftCompilerPlugin/CompilerPlugin.swift

@@ -236,16 +236,16 @@ internal struct PluginHostConnection: MessageConnection {
   }
 }
 
-private extension FileHandle {
-  func _write(contentsOf data: Data) throws {
+extension FileHandle {
+  fileprivate func _write(contentsOf data: Data) throws {
     if #available(macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4, *) {
       return try self.write(contentsOf: data)
     } else {
       return self.write(data)
     }
   }
 
-  func _read(upToCount count: Int) throws -> Data? {
+  fileprivate func _read(upToCount count: Int) throws -> Data? {
     if #available(macOS 10.15.4, iOS 13.4, watchOS 6.2, tvOS 13.4, *) {
       return try self.read(upToCount: count)
     } else {

Sources/SwiftCompilerPluginMessageHandling/CompilerPluginMessageHandler.swift

@@ -182,13 +182,13 @@ struct UnimplementedError: Error, CustomStringConvertible {
 }
 
 /// Default implementation of 'PluginProvider' requirements.
-public extension PluginProvider {
-  var features: [PluginFeature] {
+extension PluginProvider {
+  public var features: [PluginFeature] {
     // No optional features by default.
     return []
   }
 
-  func loadPluginLibrary(libraryPath: String, moduleName: String) throws {
+  public func loadPluginLibrary(libraryPath: String, moduleName: String) throws {
     // This should be unreachable. The host should not call 'loadPluginLibrary'
     // unless the feature is not declared.
     throw UnimplementedError()

Sources/SwiftCompilerPluginMessageHandling/Macros.swift

@@ -184,8 +184,8 @@ extension CompilerPluginMessageHandler {
   }
 }
 
-private extension MacroRole {
-  init(messageMacroRole: PluginMessage.MacroRole) {
+extension MacroRole {
+  fileprivate init(messageMacroRole: PluginMessage.MacroRole) {
     switch messageMacroRole {
     case .expression: self = .expression
     case .declaration: self = .declaration

Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift

@@ -180,9 +180,9 @@ class SourceManager {
   }
 }
 
-fileprivate extension Syntax {
+extension Syntax {
   /// Get a position in the node by ``PositionInSyntaxNode``.
-  func position(at pos: PositionInSyntaxNode) -> AbsolutePosition {
+  fileprivate func position(at pos: PositionInSyntaxNode) -> AbsolutePosition {
     switch pos {
     case .beforeLeadingTrivia:
       return self.position

Sources/SwiftCompilerPluginMessageHandling/PluginMessageCompatibility.swift

@@ -11,8 +11,8 @@
 //===----------------------------------------------------------------------===//
 
 /// Old compiler might send '.declaration' as "freeStandingDeclaration".
-@_spi(PluginMessage) public extension PluginMessage.MacroRole {
-  init(from decoder: Decoder) throws {
+@_spi(PluginMessage) extension PluginMessage.MacroRole {
+  public init(from decoder: Decoder) throws {
     let stringValue = try decoder.singleValueContainer().decode(String.self)
     if let role = Self(rawValue: stringValue) {
       self = role

Sources/SwiftDiagnostics/FixIt.swift

@@ -69,8 +69,8 @@ extension FixIt {
   }
 }
 
-private extension FixIt.Change {
-  var edit: SourceEdit {
+extension FixIt.Change {
+  fileprivate var edit: SourceEdit {
     switch self {
     case .replace(let oldNode, let newNode):
       return SourceEdit(