From 244bf110428646f38d77ae08f07e3802781bb665 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Fri, 20 Oct 2023 14:40:22 -0700
Subject: [PATCH 1/5] Add a Standard mode check to `<__msvc_print.hpp>`.

---
 stl/inc/__msvc_print.hpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/stl/inc/__msvc_print.hpp b/stl/inc/__msvc_print.hpp
index 5de74a0f268..79f5171d160 100644
--- a/stl/inc/__msvc_print.hpp
+++ b/stl/inc/__msvc_print.hpp
@@ -8,6 +8,11 @@
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
 
+#ifndef __cpp_lib_concepts
+#error The contents of <format> are available only with C++20 or later, and the contents of <print> \
+are available only with C++23 or later. (Also, you should not include this internal header.)
+#endif // ^^^ !defined(__cpp_lib_concepts) ^^^
+
 #include <cstdio>
 #include <xfilesystem_abi.h>
 

From 4c24a200018da97d43a655ea4adc6fe7b323c66f Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Fri, 20 Oct 2023 14:40:44 -0700
Subject: [PATCH 2/5] Move Standard mode checks in `<xmeow.h>` as early as
 possible.

`<xcharconv_tables.h>` was already doing this.
---
 stl/inc/xcharconv.h            | 8 ++++----
 stl/inc/xcharconv_ryu.h        | 8 ++++----
 stl/inc/xcharconv_ryu_tables.h | 4 ++--
 stl/inc/xnode_handle.h         | 3 ++-
 4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/stl/inc/xcharconv.h b/stl/inc/xcharconv.h
index cf352799eae..07f6c2f8752 100644
--- a/stl/inc/xcharconv.h
+++ b/stl/inc/xcharconv.h
@@ -8,14 +8,14 @@
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
 
-#include <cstdint>
-#include <type_traits>
-#include <xerrc.h>
-
 #if !_HAS_CXX17
 #error The contents of <charconv> are only available with C++17. (Also, you should not include this internal header.)
 #endif // !_HAS_CXX17
 
+#include <cstdint>
+#include <type_traits>
+#include <xerrc.h>
+
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)
 #pragma warning(disable : _STL_DISABLED_WARNINGS)
diff --git a/stl/inc/xcharconv_ryu.h b/stl/inc/xcharconv_ryu.h
index fc29a3d4858..343a09226b7 100644
--- a/stl/inc/xcharconv_ryu.h
+++ b/stl/inc/xcharconv_ryu.h
@@ -37,6 +37,10 @@
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
 
+#if !_HAS_CXX17
+#error The contents of <charconv> are only available with C++17. (Also, you should not include this internal header.)
+#endif // !_HAS_CXX17
+
 #include <cstring>
 #include <type_traits>
 #include <utility>
@@ -54,10 +58,6 @@
 #include _STL_INTRIN_HEADER // for _umul128() and __shiftright128()
 #endif // ^^^ intrinsics available ^^^
 
-#if !_HAS_CXX17
-#error The contents of <charconv> are only available with C++17. (Also, you should not include this internal header.)
-#endif // !_HAS_CXX17
-
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)
 #pragma warning(disable : _STL_DISABLED_WARNINGS)
diff --git a/stl/inc/xcharconv_ryu_tables.h b/stl/inc/xcharconv_ryu_tables.h
index ef01dd9e581..a8d4e5a7b4e 100644
--- a/stl/inc/xcharconv_ryu_tables.h
+++ b/stl/inc/xcharconv_ryu_tables.h
@@ -37,12 +37,12 @@
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
 
-#include <cstdint>
-
 #if !_HAS_CXX17
 #error The contents of <charconv> are only available with C++17. (Also, you should not include this internal header.)
 #endif // !_HAS_CXX17
 
+#include <cstdint>
+
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)
 #pragma warning(disable : _STL_DISABLED_WARNINGS)
diff --git a/stl/inc/xnode_handle.h b/stl/inc/xnode_handle.h
index f7f685b259e..2462a506e53 100644
--- a/stl/inc/xnode_handle.h
+++ b/stl/inc/xnode_handle.h
@@ -7,12 +7,13 @@
 #define _XNODE_HANDLE_H
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
-#include <xmemory>
 
 #if !_HAS_CXX17
 #error Node handles are only available with C++17. (Also, you should not include this internal header.)
 #endif // _HAS_CXX17
 
+#include <xmemory>
+
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)
 #pragma warning(disable : _STL_DISABLED_WARNINGS)

From dffa3d6821739a6ac8a3fe0b7bbfb03fb53028f6 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Fri, 20 Oct 2023 16:12:11 -0700
Subject: [PATCH 3/5] `<ostream>` should have guarded its includes with
 `__cpp_lib_print` instead of `_HAS_CXX23`.

---
 stl/inc/ostream | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/stl/inc/ostream b/stl/inc/ostream
index 1a679cf019b..de3b0a0feef 100644
--- a/stl/inc/ostream
+++ b/stl/inc/ostream
@@ -9,11 +9,11 @@
 #if _STL_COMPILER_PREPROCESSOR
 #include <ios>
 
-#if _HAS_CXX23
+#ifdef __cpp_lib_print
 #include <__msvc_filebuf.hpp>
 #include <__msvc_print.hpp>
 #include <format>
-#endif // _HAS_CXX23
+#endif // ^^^ defined(__cpp_lib_print) ^^^
 
 #pragma pack(push, _CRT_PACKING)
 #pragma warning(push, _STL_WARNING_LEVEL)

From c4ceaf0bf255d28513c337a8eedc548b4d2b1f85 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Fri, 20 Oct 2023 16:58:13 -0700
Subject: [PATCH 4/5] Update how GH_001411_core_headers tests __msvc_print.hpp.

---
 tests/std/tests/GH_001411_core_headers/test.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/std/tests/GH_001411_core_headers/test.cpp b/tests/std/tests/GH_001411_core_headers/test.cpp
index a3cbc49e9bf..1bf1d87f6c6 100644
--- a/tests/std/tests/GH_001411_core_headers/test.cpp
+++ b/tests/std/tests/GH_001411_core_headers/test.cpp
@@ -19,9 +19,9 @@
 #include <xfilesystem_abi.h>
 #endif // _HAS_CXX17
 
-#if _HAS_CXX23
+#ifdef __cpp_lib_concepts
 #include <__msvc_print.hpp>
-#endif // _HAS_CXX23
+#endif // ^^^ defined(__cpp_lib_concepts) ^^^
 
 // <__msvc_bit_utils.hpp> is included by <bit> and <limits>
 // <__msvc_iter_core.hpp> is included by <tuple>

From 40e37b5b7afd594a9a6c0cf96ab68cd9bf35ef3d Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Tue, 24 Oct 2023 13:09:41 -0700
Subject: [PATCH 5/5] Mention `<format>` in a comment and only `<print>` in the
 error.

---
 stl/inc/__msvc_print.hpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/stl/inc/__msvc_print.hpp b/stl/inc/__msvc_print.hpp
index 79f5171d160..b1b3a249dfb 100644
--- a/stl/inc/__msvc_print.hpp
+++ b/stl/inc/__msvc_print.hpp
@@ -8,9 +8,8 @@
 #include <yvals_core.h>
 #if _STL_COMPILER_PREPROCESSOR
 
-#ifndef __cpp_lib_concepts
-#error The contents of <format> are available only with C++20 or later, and the contents of <print> \
-are available only with C++23 or later. (Also, you should not include this internal header.)
+#ifndef __cpp_lib_concepts // note: <format> includes this header in C++20 mode
+#error The contents of <print> are available only with C++23. (Also, you should not include this internal header.)
 #endif // ^^^ !defined(__cpp_lib_concepts) ^^^
 
 #include <cstdio>