[Foundation] UUID: Modernize hashing

Author: lorentey

Darwin/Foundation-swiftoverlay-Tests/TestUUID.swift

@@ -85,9 +85,28 @@ class TestUUID : TestUUIDSuper {
     }
 
     func test_hash() {
-        let ref = NSUUID()
-        let val = UUID(uuidString: ref.uuidString)!
-        expectEqual(ref.hashValue, val.hashValue, "Hashes of references and values should be identical")
+        let values: [UUID] = [
+            // This list takes a UUID and tweaks every byte while
+            // leaving the version/variant intact.
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a63baa1c-b4f5-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53caa1c-b4f5-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53bab1c-b4f5-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53baa1d-b4f5-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b5f5-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f6-48db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-49db-9467-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48dc-9467-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9567-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9468-9786b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9886b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9787b76b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9786b86b256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9786b76c256c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9786b76b266c")!,
+            UUID(uuidString: "a53baa1c-b4f5-48db-9467-9786b76b256d")!,
+        ]
+        checkHashable(values, equalityOracle: { $0 == $1 })
     }
 
     func test_AnyHashableContainingUUID() {

Darwin/Foundation-swiftoverlay/UUID.swift

@@ -74,14 +74,12 @@ public struct UUID : ReferenceConvertible, Hashable, Equatable, CustomStringConv
         }
     }
 
-    public var hashValue: Int {
-        return withUnsafePointer(to: uuid) {
-              $0.withMemoryRebound(to: UInt8.self, capacity: 16) {
-                  return Int(bitPattern: CFHashBytes(UnsafeMutablePointer(mutating: $0), CFIndex(MemoryLayout<uuid_t>.size)))
-              }
+    public func hash(into hasher: inout Hasher) {
+        withUnsafeBytes(of: uuid) { buffer in
+            hasher.combine(bytes: buffer)
         }
     }
-    
+
     public var description: String {
         return uuidString
     }