[libcxx-commits] [libcxx] [libc++] Add tombstone traits and use them in optional (PR #98498)

[Louis Dionne via libcxx-commits]

================
@@ -0,0 +1,288 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___TYPE_TRAITS_DISENGAGED_TRAITS_H
----------------
ldionne wrote:

```suggestion
#ifndef _LIBCPP___MEMORY_TOMBSTONE_TRAITS_H
```

https://github.com/llvm/llvm-project/pull/98498