Drop remaining Swift 6.1 compiler support.

This PR drops the remaining bits in the package that build with the Swift 6.1
compiler. Swift 6.2 has been released and our main branch no longer supports
Swift 6.1 toolchains (and hasn't for a while now.)

Author: grynspan

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 6.1
+// swift-tools-version: 6.2
 
 //
 // This source file is part of the Swift.org open source project
@@ -164,7 +164,7 @@ let package = Package(
         "Testing",
       ],
       path: "Tests/_MemorySafeTestingTests",
-      swiftSettings: .packageSettings + .strictMemorySafety
+      swiftSettings: .packageSettings + .strictMemorySafety()
     ),
 
     .macro(
@@ -369,17 +369,6 @@ extension Array where Element == PackageDescription.SwiftSetting {
       // proposal via Swift Evolution.
       .enableExperimentalFeature("SymbolLinkageMarkers"),
 
-      // This setting is no longer needed when building with a 6.2 or later
-      // toolchain now that SE-0458 has been accepted and implemented, but it is
-      // needed in order to preserve support for building with 6.1 development
-      // snapshot toolchains. (Production 6.1 toolchains can build the testing
-      // library even without this setting since this experimental feature is
-      // _suppressible_.) This setting can be removed once the minimum supported
-      // toolchain for building the testing library is ≥ 6.2. It is not needed
-      // in the CMake settings since that is expected to build using a
-      // new-enough toolchain.
-      .enableExperimentalFeature("AllowUnsafeAttribute"),
-
       .enableUpcomingFeature("InferIsolatedConformances"),
 
       // When building as a package, the macro plugin always builds as an
@@ -436,18 +425,6 @@ 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 {
-#if compiler(>=6.2)
-    // FIXME: Adopt official `.strictMemorySafety()` condition once the minimum
-    // supported toolchain is 6.2.
-    [.unsafeFlags(["-strict-memory-safety"])]
-#else
-    []
-#endif
-  }
 }
 
 extension Array where Element == PackageDescription.CXXSetting {

Sources/Testing/ExitTests/ExitTest.swift

@@ -349,10 +349,7 @@ extension ExitTest {
   ///
   /// - Warning: This function is used to implement the
   ///   `#expect(processExitsWith:)` macro. Do not use it directly.
-#if compiler(>=6.2)
-  @safe
-#endif
-  public static func __store<each T>(
+  @safe public static func __store<each T>(
     _ id: (UInt64, UInt64, UInt64, UInt64),
     _ body: @escaping @Sendable (repeat each T) async throws -> Void,
     into outValue: UnsafeMutableRawPointer,
@@ -394,10 +391,7 @@ extension ExitTest {
   ///
   /// - Warning: This function is used to implement the
   ///   `#expect(processExitsWith:)` macro. Do not use it directly.
-#if compiler(>=6.2)
-  @safe
-#endif
-  public static func __store<T>(
+  @safe public static func __store<T>(
     _ id: (UInt64, UInt64, UInt64, UInt64),
     _ body: T,
     into outValue: UnsafeMutableRawPointer,

Sources/Testing/Expectations/Expectation+Macro.swift

@@ -131,7 +131,6 @@ public macro require<T>(
 
 // MARK: - Matching errors by type
 
-#if compiler(>=6.2)
 /// Check that an expression always throws an error of a given type.
 ///
 /// - Parameters:
@@ -197,7 +196,6 @@ public macro expect<E, R>(
   sourceLocation: SourceLocation = #_sourceLocation,
   performing expression: () throws -> R
 ) -> E? = #externalMacro(module: "TestingMacros", type: "ExpectMacro") where E: Error
-#endif
 
 /// Check that an expression always throws an error of a given type.
 ///
@@ -263,7 +261,6 @@ public macro expect<E, R>(
   performing expression: () async throws -> R
 ) -> E? = #externalMacro(module: "TestingMacros", type: "ExpectMacro") where E: Error
 
-#if compiler(>=6.2)
 /// Check that an expression always throws an error of a given type, and throw
 /// an error if it does not.
 ///
@@ -313,7 +310,6 @@ public macro require<E, R>(
   sourceLocation: SourceLocation = #_sourceLocation,
   performing expression: () throws -> R
 ) -> E = #externalMacro(module: "TestingMacros", type: "RequireThrowsMacro") where E: Error
-#endif
 
 /// Check that an expression always throws an error of a given type, and throw
 /// an error if it does not.
@@ -363,7 +359,6 @@ public macro require<E, R>(
   performing expression: () async throws -> R
 ) -> E = #externalMacro(module: "TestingMacros", type: "RequireThrowsMacro") where E: Error
 
-#if compiler(>=6.2)
 /// Check that an expression never throws an error, and throw an error if it
 /// does.
 ///
@@ -383,7 +378,6 @@ public macro require<R>(
   sourceLocation: SourceLocation = #_sourceLocation,
   performing expression: () throws -> R
 ) = #externalMacro(module: "TestingMacros", type: "RequireThrowsNeverMacro")
-#endif
 
 /// Check that an expression never throws an error, and throw an error if it
 /// does.
@@ -407,7 +401,6 @@ public macro require<R>(
 
 // MARK: - Matching instances of equatable errors
 
-#if compiler(>=6.2)
 /// Check that an expression always throws a specific error.
 ///
 /// - Parameters:
@@ -449,7 +442,6 @@ public macro expect<E, R>(
   sourceLocation: SourceLocation = #_sourceLocation,
   performing expression: () throws -> R
 ) -> E? = #externalMacro(module: "TestingMacros", type: "ExpectMacro") where E: Error & Equatable
-#endif
 
 /// Check that an expression always throws a specific error.
 ///
@@ -491,7 +483,6 @@ public macro expect<E, R>(
   performing expression: () async throws -> R
 ) -> E? = #externalMacro(module: "TestingMacros", type: "ExpectMacro") where E: Error & Equatable
 
-#if compiler(>=6.2)
 /// Check that an expression always throws a specific error, and throw an error
 /// if it does not.
 ///
@@ -537,7 +528,6 @@ public macro require<E, R>(
   sourceLocation: SourceLocation = #_sourceLocation,
   performing expression: () throws -> R
 ) -> E = #externalMacro(module: "TestingMacros", type: "RequireMacro") where E: Error & Equatable
-#endif
 
 /// Check that an expression always throws a specific error, and throw an error
 /// if it does not.
@@ -585,7 +575,6 @@ public macro require<E, R>(
 
 // MARK: - Arbitrary error matching
 
-#if compiler(>=6.2)
 /// Check that an expression always throws an error matching some condition.
 ///
 /// - Parameters:
@@ -649,7 +638,6 @@ public macro expect<R>(
   performing expression: () throws -> R,
   throws errorMatcher: (any Error) throws -> Bool
 ) -> (any Error)? = #externalMacro(module: "TestingMacros", type: "ExpectMacro")
-#endif
 
 /// Check that an expression always throws an error matching some condition.
 ///
@@ -713,7 +701,6 @@ public macro expect<R>(
   throws errorMatcher: (any Error) async throws -> Bool
 ) -> (any Error)? = #externalMacro(module: "TestingMacros", type: "ExpectMacro")
 
-#if compiler(>=6.2)
 /// Check that an expression always throws an error matching some condition, and
 /// throw an error if it does not.
 ///
@@ -784,7 +771,6 @@ public macro require<R>(
   performing expression: () throws -> R,
   throws errorMatcher: (any Error) throws -> Bool
 ) -> any Error = #externalMacro(module: "TestingMacros", type: "RequireMacro")
-#endif
 
 /// Check that an expression always throws an error matching some condition, and
 /// throw an error if it does not.

Sources/Testing/Parameterization/TypeInfo.swift

@@ -405,23 +405,6 @@ extension TypeInfo: Hashable {
   }
 }
 
-#if compiler(<6.2)
-// MARK: - ObjectIdentifier support
-
-extension ObjectIdentifier {
-  /// Initialize an instance of this type from a type reference.
-  ///
-  /// - Parameters:
-  ///   - type: The type to initialize this instance from.
-  ///
-  /// - Bug: The standard library should support this conversion.
-  ///   ([134276458](rdar://134276458), [134415960](rdar://134415960))
-  fileprivate init(_ type: any ~Copyable.Type) {
-    self.init(unsafeBitCast(type, to: Any.Type.self))
-  }
-}
-#endif
-
 // MARK: - Codable
 
 extension TypeInfo: Codable {

Sources/Testing/Test+Discovery.swift

@@ -39,10 +39,7 @@ extension Test {
   ///
   /// - Warning: This function is used to implement the `@Test` macro. Do not
   ///   use it directly.
-#if compiler(>=6.2)
-  @safe
-#endif
-  public static func __store(
+  @safe public static func __store(
     _ generator: @escaping @Sendable () async -> Test,
     into outValue: UnsafeMutableRawPointer,
     asTypeAt typeAddress: UnsafeRawPointer

Sources/TestingMacros/ConditionMacro.swift

@@ -498,11 +498,10 @@ extension ExitTestConditionMacro {
       var recordDecl: DeclSyntax?
 #if !SWT_NO_LEGACY_TEST_DISCOVERY
       let legacyEnumName = context.makeUniqueName("__🟡$")
-      let unsafeKeyword: TokenSyntax? = isUnsafeKeywordSupported ? .keyword(.unsafe, trailingTrivia: .space) : nil
       recordDecl = """
       enum \(legacyEnumName): Testing.__TestContentRecordContainer {
         nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          \(unsafeKeyword)\(enumName).testContentRecord
+          unsafe \(enumName).testContentRecord
         }
       }
       """

Sources/TestingMacros/SuiteDeclarationMacro.swift

@@ -169,13 +169,12 @@ public struct SuiteDeclarationMacro: MemberMacro, PeerMacro, Sendable {
 #if !SWT_NO_LEGACY_TEST_DISCOVERY
     // Emit a type that contains a reference to the test content record.
     let enumName = context.makeUniqueName("__🟡$")
-    let unsafeKeyword: TokenSyntax? = isUnsafeKeywordSupported ? .keyword(.unsafe, trailingTrivia: .space) : nil
     result.append(
       """
       @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 {
-          \(unsafeKeyword)\(testContentRecordName)
+          unsafe \(testContentRecordName)
         }
       }
       """

Sources/TestingMacros/Support/EffectfulExpressionHandling.swift

@@ -130,17 +130,6 @@ extension BidirectionalCollection<Syntax> {
 
 // MARK: - Inserting effect keywords/thunks
 
-/// Whether or not the `unsafe` expression keyword is supported.
-var isUnsafeKeywordSupported: Bool {
-  // The 'unsafe' keyword was introduced in 6.2 as part of SE-0458. Older
-  // toolchains are not aware of it.
-#if compiler(>=6.2)
-  true
-#else
-  false
-#endif
-}
-
 /// Make a function call expression to an effectful thunk function provided by
 /// the testing library.
 ///
@@ -184,8 +173,7 @@ func applyEffectfulKeywords(_ effectfulKeywords: Set<Keyword>, to expr: some Exp
 
   let needAwait = effectfulKeywords.contains(.await) && !expr.is(AwaitExprSyntax.self)
   let needTry = effectfulKeywords.contains(.try) && !expr.is(TryExprSyntax.self)
-
-  let needUnsafe = isUnsafeKeywordSupported && effectfulKeywords.contains(.unsafe) && !expr.is(UnsafeExprSyntax.self)
+  let needUnsafe = effectfulKeywords.contains(.unsafe) && !expr.is(UnsafeExprSyntax.self)
 
   // First, add thunk function calls.
   if insertThunkCalls {

Sources/TestingMacros/Support/TestContentGeneration.swift

@@ -63,13 +63,12 @@ func makeTestContentRecordDecl(named name: TokenSyntax, in typeName: TypeSyntax?
     IntegerLiteralExprSyntax(context, radix: .binary)
   }
 
-  let unsafeKeyword: TokenSyntax? = isUnsafeKeywordSupported ? .keyword(.unsafe, trailingTrivia: .space) : nil
   var result: DeclSyntax = """
   @available(*, deprecated, message: "This property is an implementation detail of the testing library. Do not use it directly.")
   private nonisolated \(staticKeyword(for: typeName)) let \(name): Testing.__TestContentRecord = (
     \(kindExpr), \(kind.commentRepresentation)
     0,
-    \(unsafeKeyword)\(accessorName),
+    unsafe \(accessorName),
     \(contextExpr),
     0
   )

Sources/TestingMacros/TestDeclarationMacro.swift

@@ -496,13 +496,12 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
 #if !SWT_NO_LEGACY_TEST_DISCOVERY
     // Emit a type that contains a reference to the test content record.
     let enumName = context.makeUniqueName(thunking: functionDecl, withPrefix: "__🟡$")
-    let unsafeKeyword: TokenSyntax? = isUnsafeKeywordSupported ? .keyword(.unsafe, trailingTrivia: .space) : nil
     result.append(
       """
       @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 {
-          \(unsafeKeyword)\(testContentRecordName)
+          unsafe \(testContentRecordName)
         }
       }
       """