Merge main into release/6.2

.github/workflows/automerge.yml

@@ -0,0 +1,17 @@
+name: Create PR to merge main into release branch
+# In the first period after branching the release branch, we typically want to include many changes from `main` in the release branch. This workflow automatically creates a PR every Monday to merge main into the release branch.
+# Later in the release cycle we should stop this practice to avoid landing risky changes by disabling this workflow. To do so, disable the workflow as described in https://docs.github.com/en/actions/managing-workflow-runs-and-deployments/managing-workflow-runs/disabling-and-enabling-a-workflow
+on:
+  schedule:
+    - cron: '0 9 * * MON'
+  workflow_dispatch:
+jobs:
+  create_merge_pr:
+    name: Create PR to merge main into release branch
+    uses: swiftlang/github-workflows/.github/workflows/create_automerge_pr.yml@main
+    with:
+      base_branch: release/6.2
+    permissions:
+      contents: write
+      pull-requests: write
+    if: (github.event_name == 'schedule' && github.repository == 'swiftlang/swift-syntax') || (github.event_name != 'schedule')  # Ensure that we don't run this on a schedule in a fork

CodeGeneration/Sources/SyntaxSupport/KeywordSpec.swift

@@ -210,6 +210,7 @@ public enum Keyword: CaseIterable {
   case none
   case nonisolated
   case nonmutating
+  case nonsending
   case objc
   case obsoleted
   case of
@@ -551,6 +552,8 @@ public enum Keyword: CaseIterable {
       return KeywordSpec("nonisolated")
     case .nonmutating:
       return KeywordSpec("nonmutating")
+    case .nonsending:
+      return KeywordSpec("nonsending")
     case .objc:
       return KeywordSpec("objc")
     case .obsoleted:

CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift

@@ -210,6 +210,9 @@ public enum SyntaxNodeKind: String, CaseIterable, IdentifierConvertible, TypeCon
   case multipleTrailingClosureElementList
   case namedOpaqueReturnType
   case nilLiteralExpr
+  case nonisolatedSpecifierArgument
+  case nonisolatedSpecifierArgumentList
+  case nonisolatedTypeSpecifier
   case objCSelectorPiece
   case objCSelectorPieceList
   case operatorDecl

CodeGeneration/Sources/SyntaxSupport/TypeNodes.swift

@@ -676,6 +676,52 @@ public let TYPE_NODES: [Node] = [
     ]
   ),
 
+  Node(
+    kind: .nonisolatedSpecifierArgument,
+    base: .syntax,
+    nameForDiagnostics: nil,
+    documentation: """
+      A single argument that can be added to a nonisolated specifier: 'nonsending'.
+
+      ### Example
+      `data` in `func foo(data: nonisolated(nonsending) () async -> Void) -> X`
+      """,
+    traits: [
+      "Parenthesized"
+    ],
+    children: [
+      Child(
+        name: "leftParen",
+        kind: .token(choices: [.token(.leftParen)])
+      ),
+      Child(
+        name: "nonsendingKeyword",
+        kind: .token(choices: [.keyword(.nonsending)])
+      ),
+      Child(
+        name: "rightParen",
+        kind: .token(choices: [.token(.rightParen)])
+      ),
+    ]
+  ),
+
+  Node(
+    kind: .nonisolatedTypeSpecifier,
+    base: .syntax,
+    nameForDiagnostics: "'nonisolated' specifier",
+    children: [
+      Child(
+        name: "nonisolatedKeyword",
+        kind: .token(choices: [.keyword(.nonisolated)])
+      ),
+      Child(
+        name: "argument",
+        kind: .node(kind: .nonisolatedSpecifierArgument),
+        isOptional: true
+      ),
+    ]
+  ),
+
   Node(
     kind: .simpleTypeSpecifier,
     base: .syntax,
@@ -689,7 +735,6 @@ public let TYPE_NODES: [Node] = [
           .keyword(.__shared),
           .keyword(.__owned),
           .keyword(.isolated),
-          .keyword(.nonisolated),
           .keyword(._const),
           .keyword(.borrowing),
           .keyword(.consuming),
@@ -704,6 +749,6 @@ public let TYPE_NODES: [Node] = [
     kind: .typeSpecifierList,
     base: .syntaxCollection,
     nameForDiagnostics: nil,
-    elementChoices: [.simpleTypeSpecifier, .lifetimeTypeSpecifier]
+    elementChoices: [.simpleTypeSpecifier, .lifetimeTypeSpecifier, .nonisolatedTypeSpecifier]
   ),
 ]

Release Notes/602.md

@@ -12,6 +12,11 @@
   - Pull Request: https://github.com/swiftlang/swift-syntax/pull/2981
   - Migration steps: None required. The new `category` property has optional type, and there is a default implementation that returns `nil`. Types that conform to `DiagnosticMessage` can choose to implement this property and provide a category when appropriate.
 
+- `DiagnosticsFormatter` has a new method, `formattedMessage`, that formats a diagnostic message without any corresponding syntax node.
+  - Description: Some tools want to use the diagnostics formatter to produce diagnostics that don't relate to source code, or for which the source code isn't available. This API allows them to do so while maintaining consistent presentation.
+  - Pull Request: https://github.com/swiftlang/swift-syntax/pull/3059
+  - Migration steps: None required.
+
 - `FixIt.Change` has a new case `replaceText` that performs a textual replacement of a range of text with another string.
   - Description: The other `FixIt.Change` cases provide structured
     modifications to syntax trees, such as replacing specific notes. Some

Sources/SwiftDiagnostics/DiagnosticsFormatter.swift

@@ -360,6 +360,12 @@ public struct DiagnosticsFormatter {
     )
   }
 
+  /// Produce a string that formats the given diagnostic message with any
+  /// source-location information.
+  public func formattedMessage(_ message: some DiagnosticMessage) -> String {
+    diagnosticDecorator.decorateDiagnosticMessage(message)
+  }
+
   /// Produce a string containing "footnotes" for each of the diagnostic
   /// category provided that has associated documentation. Each category
   /// is printed in Markdown link format, e.g.,

Sources/SwiftParser/Attributes.swift

@@ -157,7 +157,7 @@ extension Parser {
       shouldParseArgument = true
     case .customAttribute:
       shouldParseArgument =
-        self.withLookahead { $0.atCustomAttributeArgument() }
+        self.withLookahead { $0.atAttributeOrSpecifierArgument() }
         && self.at(TokenSpec(.leftParen, allowAtStartOfLine: false))
     case .optional:
       shouldParseArgument = self.at(.leftParen)
@@ -1002,7 +1002,7 @@ extension Parser {
 // MARK: Lookahead
 
 extension Parser.Lookahead {
-  mutating func atCustomAttributeArgument() -> Bool {
+  mutating func atAttributeOrSpecifierArgument() -> Bool {
     var lookahead = self.lookahead()
     lookahead.skipSingle()
 
@@ -1036,7 +1036,7 @@ extension Parser.Lookahead {
     }
 
     if self.at(TokenSpec(.leftParen, allowAtStartOfLine: false))
-      && self.withLookahead({ $0.atCustomAttributeArgument() })
+      && self.withLookahead({ $0.atAttributeOrSpecifierArgument() })
     {
       self.skipSingle()
     }

Sources/SwiftParser/Expressions.swift

@@ -381,13 +381,39 @@ extension Parser {
     }
   }
 
+  /// Make sure that we only accept `nonisolated(nonsending)` as a valid type specifier
+  /// in expression context to minimize source compatibility impact.
+  func canParseNonisolatedAsSpecifierInExpressionContext() -> Bool {
+    return withLookahead {
+      guard $0.consume(if: .keyword(.nonisolated)) != nil else {
+        return false
+      }
+
+      if $0.currentToken.isAtStartOfLine {
+        return false
+      }
+
+      guard $0.consume(if: .leftParen) != nil else {
+        return false
+      }
+
+      guard $0.consume(if: TokenSpec(.nonsending, allowAtStartOfLine: false)) != nil else {
+        return false
+      }
+
+      return $0.at(TokenSpec(.rightParen, allowAtStartOfLine: false))
+    }
+  }
+
   /// Parse an expression sequence element.
   mutating func parseSequenceExpressionElement(
     flavor: ExprFlavor,
     pattern: PatternContext = .none
   ) -> RawExprSyntax {
-    // Try to parse '@' sign or 'inout' as an attributed typerepr.
-    if self.at(.atSign, .keyword(.inout)) {
+    // Try to parse '@' sign, 'inout', or 'nonisolated' as an attributed typerepr.
+    if self.at(.atSign, .keyword(.inout))
+      || self.canParseNonisolatedAsSpecifierInExpressionContext()
+    {
       var lookahead = self.lookahead()
       if lookahead.canParseType() {
         let type = self.parseType()

Sources/SwiftParser/Modifiers.swift

@@ -236,7 +236,11 @@ extension Parser {
     let detail: RawDeclModifierDetailSyntax?
     if self.at(.leftParen) {
       let (unexpectedBeforeLeftParen, leftParen) = self.expect(.leftParen)
-      let (unexpectedBeforeDetailToken, detailToken) = self.expect(TokenSpec(.unsafe, remapping: .identifier))
+      let (unexpectedBeforeDetailToken, detailToken) = self.expect(
+        TokenSpec(.unsafe, remapping: .identifier),
+        TokenSpec(.nonsending, remapping: .identifier),
+        default: TokenSpec(.identifier)
+      )
       let (unexpectedBeforeRightParen, rightParen) = self.expect(.rightParen)
       detail = RawDeclModifierDetailSyntax(
         unexpectedBeforeLeftParen,

Sources/SwiftParser/TokenPrecedence.swift

@@ -326,6 +326,7 @@ enum TokenPrecedence: Comparable {
       .module,
       .noasync,
       .none,
+      .nonsending,
       .obsoleted,
       .of,
       .Protocol,