From 34a9c14e787ef602479fe6ff3780594ebe762c37 Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34@live.cn>
Date: Mon, 15 Jan 2024 09:52:13 +0800
Subject: [PATCH 1/3] Make `is_nothrow_convertible` a class template and
 ADL-proof

---
 stl/inc/type_traits                           |  4 +--
 .../test.compile.pass.cpp                     | 25 +++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/stl/inc/type_traits b/stl/inc/type_traits
index 3071d59197..d1a88f9c28 100644
--- a/stl/inc/type_traits
+++ b/stl/inc/type_traits
@@ -1764,7 +1764,7 @@ constexpr auto invoke(_Callable&& _Obj, _Ty1&& _Arg1, _Types2&&... _Args2) noexc
 #pragma warning(disable : 4365) // '%s': conversion from '%s' to '%s', signed/unsigned mismatch (/Wall)
 
 template <class _From, class _To, bool = is_convertible_v<_From, _To>, bool = is_void_v<_To>>
-_INLINE_VAR constexpr bool _Is_nothrow_convertible_v = noexcept(_Fake_copy_init<_To>(_STD declval<_From>()));
+_INLINE_VAR constexpr bool _Is_nothrow_convertible_v = noexcept(_STD _Fake_copy_init<_To>(_STD declval<_From>()));
 
 #pragma warning(pop)
 
@@ -1784,7 +1784,7 @@ _EXPORT_STD template <class _From, class _To>
 inline constexpr bool is_nothrow_convertible_v = _Is_nothrow_convertible_v<_From, _To>;
 
 _EXPORT_STD template <class _From, class _To>
-using is_nothrow_convertible = _Is_nothrow_convertible<_From, _To>;
+struct is_nothrow_convertible : bool_constant<_Is_nothrow_convertible_v<_From, _To>> {};
 #endif // _HAS_CXX20
 
 template <class _From, class _To, class = void>
diff --git a/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp b/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
index 041abc2d4a..15f6eaca21 100644
--- a/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
+++ b/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
@@ -105,5 +105,30 @@ STATIC_ASSERT(is_nothrow_convertible_v<int[1], int*>);
 STATIC_ASSERT(!is_nothrow_convertible_v<int[], int[]>);
 STATIC_ASSERT(!is_nothrow_convertible_v<int[], int[1]>);
 
+// Also test GH-4317 <type_traits>: some traits are an aliases and fail when used with parameter pack
+
+template <class... Ts>
+using aliased_is_nothrow_convertible = is_nothrow_convertible<Ts...>;
+
+template <class T, template <class...> class Tmpl>
+constexpr bool is_specialization_of_v = false;
+template <class... Ts, template <class...> class Tmpl>
+constexpr bool is_specialization_of_v<Tmpl<Ts...>, Tmpl> = true;
+
+STATIC_ASSERT(is_specialization_of_v<is_nothrow_convertible<void, void>, is_nothrow_convertible>);
+STATIC_ASSERT(!is_specialization_of_v<aliased_is_nothrow_convertible<void, void>, aliased_is_nothrow_convertible>);
+
+// Also test that is_nothrow_convertible/is_nothrow_convertible_v are ADL-proof
+
+template <class T>
+struct holder {
+    T t;
+};
+
+struct incomplete;
+
+STATIC_ASSERT(is_nothrow_convertible<holder<incomplete>*, holder<incomplete>*>::value);
+STATIC_ASSERT(is_nothrow_convertible_v<holder<incomplete>*, holder<incomplete>*>);
+
 // VSO_0105317_expression_sfinae and VSO_0000000_type_traits provide
 // additional coverage of this machinery

From 4b2cbb55e4063a1155b819ec64e4348e0ea5ca0c Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34@live.cn>
Date: Mon, 15 Jan 2024 10:32:52 +0800
Subject: [PATCH 2/3] Skip `_M_CEE` for tests for incomplete types

---
 .../tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp  | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp b/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
index 15f6eaca21..a86418ae4d 100644
--- a/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
+++ b/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
@@ -118,6 +118,7 @@ constexpr bool is_specialization_of_v<Tmpl<Ts...>, Tmpl> = true;
 STATIC_ASSERT(is_specialization_of_v<is_nothrow_convertible<void, void>, is_nothrow_convertible>);
 STATIC_ASSERT(!is_specialization_of_v<aliased_is_nothrow_convertible<void, void>, aliased_is_nothrow_convertible>);
 
+#ifndef _M_CEE // TRANSITION, VSO-1659496
 // Also test that is_nothrow_convertible/is_nothrow_convertible_v are ADL-proof
 
 template <class T>
@@ -129,6 +130,7 @@ struct incomplete;
 
 STATIC_ASSERT(is_nothrow_convertible<holder<incomplete>*, holder<incomplete>*>::value);
 STATIC_ASSERT(is_nothrow_convertible_v<holder<incomplete>*, holder<incomplete>*>);
+#endif // _M_CEE
 
 // VSO_0105317_expression_sfinae and VSO_0000000_type_traits provide
 // additional coverage of this machinery

From e50a400846a443ec4c98a54647c251757567274c Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Tue, 16 Jan 2024 12:02:59 -0800
Subject: [PATCH 3/3] Fix grammar mistake in bug title.

---
 .../tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp b/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
index a86418ae4d..06dfe28844 100644
--- a/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
+++ b/tests/std/tests/P0758R1_is_nothrow_convertible/test.compile.pass.cpp
@@ -105,7 +105,7 @@ STATIC_ASSERT(is_nothrow_convertible_v<int[1], int*>);
 STATIC_ASSERT(!is_nothrow_convertible_v<int[], int[]>);
 STATIC_ASSERT(!is_nothrow_convertible_v<int[], int[1]>);
 
-// Also test GH-4317 <type_traits>: some traits are an aliases and fail when used with parameter pack
+// Also test GH-4317 <type_traits>: some traits are aliases and fail when used with parameter packs
 
 template <class... Ts>
 using aliased_is_nothrow_convertible = is_nothrow_convertible<Ts...>;