Acknowledge unsafe API usages in code expanded from testing library macros

Package.swift

@@ -127,9 +127,18 @@ let package = Package(
         "Testing",
         "_Testing_CoreGraphics",
         "_Testing_Foundation",
+        "MemorySafeTestingTests",
       ],
       swiftSettings: .packageSettings
     ),
+    .target(
+      name: "MemorySafeTestingTests",
+      dependencies: [
+        "Testing",
+      ],
+      path: "Tests/_MemorySafeTestingTests",
+      swiftSettings: .packageSettings + .strictMemorySafety
+    ),
 
     .macro(
       name: "TestingMacros",
@@ -355,6 +364,14 @@ extension Array where Element == PackageDescription.SwiftSetting {
 
     return result
   }
+
+  /// Settings necessary to enable Strict Memory Safety, introduced in
+  /// [SE-0458: Opt-in Strict Memory Safety Checking](https://github.com/swiftlang/swift-evolution/blob/main/proposals/0458-strict-memory-safety.md#swiftpm-integration).
+  static var strictMemorySafety: Self {
+    // FIXME: Adopt official `.strictMemorySafety()` condition once the minimum
+    // supported toolchain is 6.2.
+    [.unsafeFlags(["-strict-memory-safety"])]
+  }
 }
 
 extension Array where Element == PackageDescription.CXXSetting {

Sources/TestingMacros/ConditionMacro.swift

@@ -499,7 +499,7 @@ extension ExitTestConditionMacro {
       recordDecl = """
       enum \(legacyEnumName): Testing.__TestContentRecordContainer {
         nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          \(enumName).testContentRecord
+          unsafe \(enumName).testContentRecord
         }
       }
       """
@@ -510,7 +510,7 @@ extension ExitTestConditionMacro {
         @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
         enum \(enumName) {
           private nonisolated static let accessor: Testing.__TestContentRecordAccessor = { outValue, type, hint, _ in
-            Testing.ExitTest.__store(
+            unsafe Testing.ExitTest.__store(
               \(idExpr),
               \(bodyThunkName),
               into: outValue,

Sources/TestingMacros/SuiteDeclarationMacro.swift

@@ -150,7 +150,7 @@ public struct SuiteDeclarationMacro: MemberMacro, PeerMacro, Sendable {
       """
       @available(*, deprecated, message: "This property is an implementation detail of the testing library. Do not use it directly.")
       private nonisolated static let \(accessorName): Testing.__TestContentRecordAccessor = { outValue, type, _, _ in
-        Testing.Test.__store(\(generatorName), into: outValue, asTypeAt: type)
+        unsafe Testing.Test.__store(\(generatorName), into: outValue, asTypeAt: type)
       }
       """
     )
@@ -174,7 +174,7 @@ public struct SuiteDeclarationMacro: MemberMacro, PeerMacro, Sendable {
       @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
       enum \(enumName): Testing.__TestContentRecordContainer {
         nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          \(testContentRecordName)
+          unsafe \(testContentRecordName)
         }
       }
       """

Sources/TestingMacros/Support/TestContentGeneration.swift

@@ -68,7 +68,7 @@ func makeTestContentRecordDecl(named name: TokenSyntax, in typeName: TypeSyntax?
   private nonisolated \(staticKeyword(for: typeName)) let \(name): Testing.__TestContentRecord = (
     \(kindExpr), \(kind.commentRepresentation)
     0,
-    \(accessorName),
+    unsafe \(accessorName),
     \(contextExpr),
     0
   )

Sources/TestingMacros/TestDeclarationMacro.swift

@@ -475,7 +475,7 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
       """
       @available(*, deprecated, message: "This property is an implementation detail of the testing library. Do not use it directly.")
       private \(staticKeyword(for: typeName)) nonisolated let \(accessorName): Testing.__TestContentRecordAccessor = { outValue, type, _, _ in
-        Testing.Test.__store(\(generatorName), into: outValue, asTypeAt: type)
+        unsafe Testing.Test.__store(\(generatorName), into: outValue, asTypeAt: type)
       }
       """
     )
@@ -499,7 +499,7 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
       @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
       enum \(enumName): Testing.__TestContentRecordContainer {
         nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          \(testContentRecordName)
+          unsafe \(testContentRecordName)
         }
       }
       """

Tests/_MemorySafeTestingTests/MemorySafeTestDecls.swift

@@ -0,0 +1,27 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+@testable import Testing
+
+#if !hasFeature(StrictMemorySafety)
+#error("This file requires strict memory safety to be enabled")
+#endif
+
+@Test(.hidden)
+func exampleTestFunction() {}
+
+@Suite(.hidden)
+struct ExampleSuite {
+  @Test func example() {}
+}
+
+func exampleExitTest() async {
+  await #expect(processExitsWith: .success) {}
+}