Merge pull request #38330 from rxwei/ad-reflection-test-availability

[AutoDiff] Update availability in differentiable function metadata test.

Author: rxwei

test/AutoDiff/validation-test/function_type_metadata.swift

@@ -61,18 +61,20 @@ if #available(macOS 11.3, iOS 14.5, tvOS 14.5, watchOS 7.4, *) {
   }
 }
 
-FunctionTypeMetadataTests.test("Reflect generic differentiable function type") {
-  func testGeneric<T: Differentiable>(_ type: T.Type) {
-    expectEqual(
-      """
-      @differentiable(reverse) (\(String(reflecting: type))) -> \
-      \(String(reflecting: type))
-      """,
-      String(reflecting: (@differentiable(reverse) (T) -> T).self))
+if #available(macOS 12, iOS 15, tvOS 15, watchOS 8, *) {
+  FunctionTypeMetadataTests.test("Reflect generic differentiable function type") {
+    func testGeneric<T: Differentiable>(_ type: T.Type) {
+      expectEqual(
+        """
+        @differentiable(reverse) (\(String(reflecting: type))) -> \
+        \(String(reflecting: type))
+        """,
+        String(reflecting: (@differentiable(reverse) (T) -> T).self))
+    }
+    testGeneric(Double.self)
+    testGeneric([Float].self)
+    testGeneric(Float?.self)
   }
-  testGeneric(Double.self)
-  testGeneric([Float].self)
-  testGeneric(Float?.self)
 }
 
 runAllTests()