From a4bf12cacabd18b236b1b700721b3c5cb83ba1e0 Mon Sep 17 00:00:00 2001
From: Casey Carter <Casey@Carter.net>
Date: Mon, 13 Mar 2023 13:35:49 -0700
Subject: [PATCH] Weakly_unwrappable should use _Allow_inheriting_unwrap_v

... so as not to require `_Prevent_inheriting_unwrap`. The intent of the unwrapping design is that `_Prevent_inheriting_unwrap` is optional.
---
 stl/inc/xutility | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/stl/inc/xutility b/stl/inc/xutility
index d4b5112f2de..51cdd466fe8 100644
--- a/stl/inc/xutility
+++ b/stl/inc/xutility
@@ -2287,9 +2287,8 @@ namespace ranges {
     using sentinel_t = decltype(_RANGES end(_STD declval<_Rng&>()));
 
     template <class _Wrapped>
-    concept _Weakly_unwrappable =
-        same_as<typename remove_cvref_t<_Wrapped>::_Prevent_inheriting_unwrap, remove_cvref_t<_Wrapped>>
-        && requires(_Wrapped&& _Wr) { _STD forward<_Wrapped>(_Wr)._Unwrapped(); };
+    concept _Weakly_unwrappable = _Allow_inheriting_unwrap_v<remove_cvref_t<_Wrapped>>
+                               && requires(_Wrapped&& _Wr) { _STD forward<_Wrapped>(_Wr)._Unwrapped(); };
 
     template <class _Sent>
     concept _Weakly_unwrappable_sentinel = _Weakly_unwrappable<const remove_reference_t<_Sent>&>;