[stdlib] add a storage property to Slab

Author: glessard

stdlib/public/core/Span/Properties/InlineTypeExtensions.swift

@@ -121,3 +121,19 @@ extension SIMD64 {
     }
   }
 }
+
+@available(SwiftStdlib 6.2, *)
+extension Slab where Element: ~Copyable {
+
+  @available(SwiftStdlib 6.2, *)
+  public var storage: Span<Element> {
+    @_alwaysEmitIntoClient
+    @_addressableSelf
+    @lifetime(borrow self)
+    borrowing get {
+      let pointer = _address
+      let span = Span(_unsafeStart: pointer, count: count)
+      return _overrideLifetime(span, borrowing: self)
+    }
+  }
+}

test/stdlib/Span/SlabSpan.swift

@@ -0,0 +1,41 @@
+//===--- SlabSpan.swift ---------------------------------------------------===//
+//
+// 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 the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %target-run-stdlib-swift(-enable-experimental-feature LifetimeDependence -enable-experimental-feature Span -enable-experimental-feature AddressableTypes -enable-experimental-feature ValueGenerics)
+
+// REQUIRES: executable_test
+// REQUIRES: swift_feature_ValueGenerics
+// REQUIRES: swift_feature_AddressableTypes
+// REQUIRES: swift_feature_Span
+// REQUIRES: swift_feature_LifetimeDependence
+
+import StdlibUnittest
+
+var suite = TestSuite("SlabStorageProperty")
+defer { runAllTests() }
+
+suite.test("Slab.storage property")
+.skip(.custom(
+  { if #available(SwiftStdlib 6.1, *) { false } else { true } },
+  reason: "Requires Swift 6.1's standard library"
+))
+.code {
+  guard #available(SwiftStdlib 6.1, *) else { return }
+
+  var s = Slab<5, Int>(repeating: 0)
+  s[3] = .random(in: 0..<1000)
+  let storage = s.storage
+  expectEqual(storage.count, s.count)
+  for i in 0..<s.count {
+    expectEqual(storage[i], s[i])
+  }
+}