[stdlib] add span property to InlineArray

Author: glessard

stdlib/public/core/InlineArray.swift

@@ -43,6 +43,7 @@
 @available(SwiftStdlib 6.2, *)
 @frozen
 @safe
+@_addressableForDependencies
 public struct InlineArray<let count: Int, Element: ~Copyable>: ~Copyable {
   @usableFromInline
   internal let _storage: Builtin.FixedArray<count, Element>
@@ -441,6 +442,26 @@ extension InlineArray where Element: ~Copyable {
   }
 }
 
+//===----------------------------------------------------------------------===//
+// MARK: Span
+//===----------------------------------------------------------------------===//
+
+@available(SwiftStdlib 6.2, *)
+extension InlineArray where Element: ~Copyable {
+
+  @available(SwiftStdlib 6.2, *)
+  public var span: Span<Element> {
+    @lifetime(borrow self)
+    @_addressableSelf
+    @_alwaysEmitIntoClient
+    borrowing get {
+      let pointer = _address
+      let span = unsafe Span(_unsafeStart: pointer, count: count)
+      return unsafe _overrideLifetime(span, borrowing: self)
+    }
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // MARK: - Unsafe APIs
 //===----------------------------------------------------------------------===//

test/stdlib/Span/InlineStorage.swift

@@ -10,9 +10,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-// RUN: %target-run-stdlib-swift
+// RUN: %target-run-stdlib-swift(-enable-experimental-feature ValueGenerics)
 
 // REQUIRES: executable_test
+// REQUIRES: swift_feature_ValueGenerics
 
 import StdlibUnittest
 
@@ -68,3 +69,20 @@ suite.test("CollectionOfOne.span stride test")
   let bytes = span.bytes
   expectEqual(bytes.byteCount, MemoryLayout.size(ofValue: c))
 }
+
+suite.test("InlineArray.span property")
+.skip(.custom(
+  { if #available(SwiftStdlib 6.2, *) { false } else { true } },
+  reason: "Requires Swift 6.2's standard library"
+))
+.code {
+  guard #available(SwiftStdlib 6.2, *) else { return }
+
+  var s = InlineArray<5, Int>(repeating: 0)
+  s[3] = .random(in: 0..<1000)
+  let span = s.span
+  expectEqual(span.count, s.count)
+  for i in s.indices {
+    expectEqual(span[i], s[i])
+  }
+}