Use Builtin.addressOfRawLayout

Author: Azoy

stdlib/public/Synchronization/Cell.swift

@@ -28,7 +28,11 @@ internal struct _Cell<Value: ~Copyable>: ~Copyable {
   @_alwaysEmitIntoClient
   @_transparent
   var rawAddress: Builtin.RawPointer {
-    Builtin.unprotectedAddressOfBorrow(self)
+#if $BuiltinAddressOfRawLayout
+    Builtin.addressOfRawLayout(self)
+#else
+    fatalError()
+#endif
   }
 
   @available(SwiftStdlib 6.0, *)

stdlib/public/Synchronization/Mutex/Mutex.swift

@@ -36,10 +36,10 @@
 @_staticExclusiveOnly
 public struct Mutex<Value: ~Copyable>: ~Copyable {
   @usableFromInline
-  let value: _Cell<Value>
+  let handle = _MutexHandle()
 
   @usableFromInline
-  let handle = _MutexHandle()
+  let value: _Cell<Value>
 
   /// Initializes a value of this mutex with the given initial state.
   ///