[SwiftParser] Allow nonisolated to accept nonsending modifier

Author: xedin

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:

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,

Sources/SwiftSyntax/generated/Keyword.swift

@@ -261,8 +261,8 @@ final class DeclarationTests: ParserTestCase {
       """,
       diagnostics: [
         DiagnosticSpec(
-          message: "expected 'unsafe' in modifier",
-          fixIts: ["replace 'safe' with 'unsafe'"]
+          message: "expected identifier in modifier",
+          fixIts: ["replace 'safe' with identifier"]
         )
       ],
       fixedSource: """
@@ -271,7 +271,36 @@ final class DeclarationTests: ParserTestCase {
         struct A {
           nonisolated(unsafe) let b = 0
           nonisolated(unsafe) var c: Int { 0 }
-          nonisolated(unsafe) let d = 0
+          nonisolated(<#identifier#>) let d = 0
+        }
+        """
+    )
+  }
+
+  func testNonisolatedNonSendingParsing() {
+    assertParse(
+      """
+      nonisolated(nonsending) let a = 0
+
+      struct A {
+        nonisolated(nonsending) let b = 0
+        nonisolated(nonsending) var c: Int { 0 }
+        nonisolated(1️⃣sending) let d = 0
+      }
+      """,
+      diagnostics: [
+        DiagnosticSpec(
+          message: "expected identifier in modifier",
+          fixIts: ["replace 'sending' with identifier"]
+        )
+      ],
+      fixedSource: """
+        nonisolated(nonsending) let a = 0
+
+        struct A {
+          nonisolated(nonsending) let b = 0
+          nonisolated(nonsending) var c: Int { 0 }
+          nonisolated(<#identifier#>) let d = 0
         }
         """
     )