Adjust availability and inlinability of span projections (#1400)

* Remove re-definitions of `_overrideLifetime()`

- These have now propagated to become public in all the relevant sources of the stdlib.

* Update availability of `Span` projections

* Adjust availability of `Span` tests

* Make adjustments to mitigate the ABI break

* Remove the “FoundationSpan” availability name.

* Remove availabilities older than the test deployment target

* Availability and symbol adjustments
- adjust visionOS availability

Author: glessard

CMakeLists.txt

@@ -94,7 +94,6 @@ list(APPEND CMAKE_MODULE_PATH ${SwiftFoundation_SOURCE_DIR}/cmake/modules)
 
 # Availability Macros (only applies to FoundationEssentials and FoundationInternationalization)
 set(_SwiftFoundation_BaseAvailability "macOS 15, iOS 18, tvOS 18, watchOS 11")
-set(_SwiftFoundation_macOS26Availability "macOS 26, iOS 26, tvOS 26, watchOS 26")
 set(_SwiftFoundation_FutureAvailability "macOS 10000, iOS 10000, tvOS 10000, watchOS 10000")
 
 # All versions to define for each availability name
@@ -106,13 +105,11 @@ list(APPEND _SwiftFoundation_versions
 
 # Each availability name to define
 list(APPEND _SwiftFoundation_availability_names
-    "FoundationPreview"
-    "FoundationSpan")
+    "FoundationPreview")
 
 # The aligned availability for each name (in the same order)
 list(APPEND _SwiftFoundation_availability_releases
-    ${_SwiftFoundation_BaseAvailability}
-    ${_SwiftFoundation_macOS26Availability})
+    ${_SwiftFoundation_BaseAvailability})
 
 foreach(version ${_SwiftFoundation_versions})
     foreach(name release IN ZIP_LISTS _SwiftFoundation_availability_names _SwiftFoundation_availability_releases)

Package.swift

@@ -8,7 +8,6 @@ import CompilerPluginSupport
 
 let availabilityTags: [_Availability] = [
     _Availability("FoundationPreview"), // Default FoundationPreview availability
-    _Availability("FoundationSpan", availability: .macOS26), // Availability of Span types
 ]
 let versionNumbers = ["6.0.2", "6.1", "6.2"]
 

Sources/FoundationEssentials/Data/Data.swift

@@ -2203,7 +2203,8 @@ public struct Data : Equatable, Hashable, RandomAccessCollection, MutableCollect
         return try _representation.withUnsafeBytes(body)
     }
 
-    @available(FoundationSpan 6.2, *)
+    @available(macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.1, *)
+    @_alwaysEmitIntoClient
     public var bytes: RawSpan {
         @lifetime(borrow self)
         borrowing get {
@@ -2230,7 +2231,8 @@ public struct Data : Equatable, Hashable, RandomAccessCollection, MutableCollect
         }
     }
 
-    @available(FoundationSpan 6.2, *)
+    @available(macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.1, *)
+    @_alwaysEmitIntoClient
     public var span: Span<UInt8> {
         @lifetime(borrow self)
         borrowing get {
@@ -2239,7 +2241,8 @@ public struct Data : Equatable, Hashable, RandomAccessCollection, MutableCollect
         }
     }
 
-    @available(FoundationSpan 6.2, *)
+    @available(macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.1, *)
+    @_alwaysEmitIntoClient
     public var mutableBytes: MutableRawSpan {
         @lifetime(&self)
         mutating get {
@@ -2266,7 +2269,8 @@ public struct Data : Equatable, Hashable, RandomAccessCollection, MutableCollect
         }
     }
 
-    @available(FoundationSpan 6.2, *)
+    @available(macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.1, *)
+    @_alwaysEmitIntoClient
     public var mutableSpan: MutableSpan<UInt8> {
         @lifetime(&self)
         mutating get {
@@ -2970,53 +2974,3 @@ extension Data : Codable {
         }
     }
 }
-
-// TODO: remove once _overrideLifetime is public in the standard library
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` with a lifetime dependency on the caller's
-/// borrow scope of the `source` argument.
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(borrow source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, borrowing source: borrowing U
-) -> T {
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
-/// a value identical to `dependent` that inherits all lifetime dependencies from
-/// the `source` argument.
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(copy source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T, copying source: borrowing U
-) -> T {
-  dependent
-}
-
-/// Unsafely discard any lifetime dependency on the `dependent` argument.
-/// Return a value identical to `dependent` with a lifetime dependency
-/// on the caller's exclusive borrow scope of the `source` argument.
-@unsafe
-@_unsafeNonescapableResult
-@_alwaysEmitIntoClient
-@_transparent
-@lifetime(&source)
-internal func _overrideLifetime<
-  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
->(
-  _ dependent: consuming T,
-  mutating source: inout U
-) -> T {
-  dependent
-}

Tests/FoundationEssentialsTests/DataTests.swift

@@ -1645,8 +1645,8 @@ private final class DataTests {
         #endif
     }
 
-    @available(FoundationSpan 6.2, *)
-    @Test func inlineDataSpan() throws {
+    @Test
+    func inlineDataSpan() throws {
         var source = Data()
         var span = source.span
         var isEmpty = span.isEmpty
@@ -1661,16 +1661,16 @@ private final class DataTests {
         #expect(firstElement == 1)
     }
 
-    @available(FoundationSpan 6.2, *)
-    @Test func inlineSliceDataSpan() throws {
+    @Test
+    func inlineSliceDataSpan() throws {
         let source = Data(0 ... .max)
         let span = source.span
         #expect(span.count == source.count)
         #expect(span[span.indices.last!] == .max)
     }
 
-    @available(FoundationSpan 6.2, *)
-    @Test func inlineDataMutableSpan() throws {
+    @Test
+    func inlineDataMutableSpan() throws {
 #if !canImport(Darwin) || FOUNDATION_FRAMEWORK
         var source = Data()
         var span = source.mutableSpan
@@ -1693,8 +1693,8 @@ private final class DataTests {
 #endif
     }
 
-    @available(FoundationSpan 6.2, *)
-    @Test func inlineSliceDataMutableSpan() throws {
+    @Test
+    func inlineSliceDataMutableSpan() throws {
 #if !canImport(Darwin) || FOUNDATION_FRAMEWORK
         var source = Data(0..<100)
         let count = source.count
@@ -1707,8 +1707,8 @@ private final class DataTests {
 #endif
     }
 
-    @available(FoundationSpan 6.2, *)
-    @Test func inlineDataMutableRawSpan() throws {
+    @Test
+    func inlineDataMutableRawSpan() throws {
         var source = Data()
         var span = source.mutableBytes
         var isEmpty = span.isEmpty
@@ -1728,8 +1728,8 @@ private final class DataTests {
         #expect(source[i] == v)
     }
 
-    @available(FoundationSpan 6.2, *)
-    @Test func inlineSliceDataMutableRawSpan() throws {
+    @Test
+    func inlineSliceDataMutableRawSpan() throws {
         var source = Data(0..<100)
         let count = source.count
         var span = source.mutableBytes
@@ -2386,7 +2386,6 @@ extension DataTests {
 @Suite("Large Data Tests", .serialized)
 struct LargeDataTests {
     @Test
-    @available(FoundationSpan 6.2, *)
     func largeSliceDataSpan() throws {
 #if _pointerBitWidth(_64)
         let count = Int(Int32.max)
@@ -2404,7 +2403,6 @@ struct LargeDataTests {
     }
 
     @Test
-    @available(FoundationSpan 6.2, *)
     func largeSliceDataMutableSpan() throws {
 #if _pointerBitWidth(_64)
         var count = Int(Int32.max)
@@ -2428,7 +2426,6 @@ struct LargeDataTests {
     }
 
     @Test
-    @available(FoundationSpan 6.2, *)
     func largeSliceDataMutableRawSpan() throws {
 #if _pointerBitWidth(_64)
         var count = Int(Int32.max)