From d26c8416fc1215ce5c343566055a6fca7f1f6336 Mon Sep 17 00:00:00 2001
From: Casey Carter <cacarter@microsoft.com>
Date: Tue, 13 Apr 2021 08:15:29 -0700
Subject: [PATCH] Push _Rewrap_iterator up into <xutility>

Fixes #1830
---
 stl/inc/algorithm                                  | 14 --------------
 stl/inc/xutility                                   | 14 ++++++++++++++
 .../P0896R4_ranges_alg_uninitialized_copy/test.cpp | 13 ++++++++++++-
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/stl/inc/algorithm b/stl/inc/algorithm
index e128b93569c..a748bbb800d 100644
--- a/stl/inc/algorithm
+++ b/stl/inc/algorithm
@@ -215,20 +215,6 @@ namespace ranges {
         }
     }
 
-    // FUNCTION TEMPLATE _Rewrap_iterator
-    template <forward_range _Rng, class _It>
-    _NODISCARD constexpr iterator_t<_Rng> _Rewrap_iterator(_Rng&& _Range, _It&& _Val) {
-        _STL_INTERNAL_STATIC_ASSERT(is_same_v<remove_cvref_t<_It>, _Unwrapped_t<iterator_t<_Rng>>>);
-
-        if constexpr (is_same_v<remove_cvref_t<_It>, iterator_t<_Rng>>) {
-            return _STD forward<_It>(_Val);
-        } else {
-            auto _Result = _RANGES begin(_Range);
-            _Result._Seek_to(_STD forward<_It>(_Val));
-            return _Result;
-        }
-    }
-
     // FUNCTION TEMPLATE _Get_final_iterator_unwrapped
     template <forward_iterator _Wrapped, sentinel_for<_Wrapped> _Se>
     _NODISCARD constexpr auto _Get_final_iterator_unwrapped(const _Unwrapped_t<_Wrapped>& _UFirst, _Se&& _Last) {
diff --git a/stl/inc/xutility b/stl/inc/xutility
index 728c332e48e..2e17ebc0b5a 100644
--- a/stl/inc/xutility
+++ b/stl/inc/xutility
@@ -4766,6 +4766,20 @@ _NODISCARD bool equal(_ExPo&& _Exec, const _FwdIt1 _First1, const _FwdIt1 _Last1
 
 #ifdef __cpp_lib_concepts
 namespace ranges {
+    // FUNCTION TEMPLATE _Rewrap_iterator
+    template <forward_range _Rng, class _It>
+    _NODISCARD constexpr iterator_t<_Rng> _Rewrap_iterator(_Rng&& _Range, _It&& _Val) {
+        _STL_INTERNAL_STATIC_ASSERT(is_same_v<remove_cvref_t<_It>, _Unwrapped_t<iterator_t<_Rng>>>);
+
+        if constexpr (is_same_v<remove_cvref_t<_It>, iterator_t<_Rng>>) {
+            return _STD forward<_It>(_Val);
+        } else {
+            auto _Result = _RANGES begin(_Range);
+            _Result._Seek_to(_STD forward<_It>(_Val));
+            return _Result;
+        }
+    }
+
     // CONCEPT _Convertible_from
     template <class _To, class _From>
     concept _Convertible_from = convertible_to<_From, _To>;
diff --git a/tests/std/tests/P0896R4_ranges_alg_uninitialized_copy/test.cpp b/tests/std/tests/P0896R4_ranges_alg_uninitialized_copy/test.cpp
index 0199745aa45..331bda6932f 100644
--- a/tests/std/tests/P0896R4_ranges_alg_uninitialized_copy/test.cpp
+++ b/tests/std/tests/P0896R4_ranges_alg_uninitialized_copy/test.cpp
@@ -1,11 +1,22 @@
 // Copyright (c) Microsoft Corporation.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
+#include <memory>
+
+// Regression test for GH-1830, in which ranges::uninitialized_copy used
+// _Rewrap_iterator which was defined in <algorithm> (now in <xutility>).
+
+void unused_function() {
+    const int src[] = {11, 22, 33, 44, 55};
+    int dst[5];
+
+    std::ranges::uninitialized_copy(src, dst);
+}
+
 #include <algorithm>
 #include <cassert>
 #include <concepts>
 #include <cstdlib>
-#include <memory>
 #include <ranges>
 #include <span>
 #include <utility>