From 508eecec8573930f3b520e4f231d359fc8f5927f Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34@live.cn>
Date: Fri, 5 Dec 2025 18:23:20 +0800
Subject: [PATCH 1/2] Disallow specializing `bitset` and `ratio`

---
 stl/inc/bitset | 14 ++++++++++++--
 stl/inc/ratio  |  2 +-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/stl/inc/bitset b/stl/inc/bitset
index 9b8a247a6d1..06d1da21bfc 100644
--- a/stl/inc/bitset
+++ b/stl/inc/bitset
@@ -18,6 +18,12 @@ _STL_DISABLE_CLANG_WARNINGS
 #pragma push_macro("new")
 #undef new
 
+// TRANSITION, non-_Ugly attribute tokens
+#pragma push_macro("msvc")
+#pragma push_macro("no_specializations")
+#undef msvc
+#undef no_specializations
+
 #ifndef _STD_BITSET_TO_STREAM_STACK_RESERVATION
 #define _STD_BITSET_TO_STREAM_STACK_RESERVATION 128
 #endif // !defined(_STD_BITSET_TO_STREAM_STACK_RESERVATION)
@@ -72,8 +78,8 @@ struct _Buffer_for_bitset<_Elem, _Bits, false> {
     _Elem _Buf[(_Bits != 0) ? _Bits : 1];
 };
 
-_EXPORT_STD template <size_t _Bits>
-class bitset { // store fixed-length sequence of Boolean elements
+_EXPORT_STD template <size_t _Bits> // store fixed-length sequence of Boolean elements
+class _NO_SPECIALIZATIONS_CITING("N5014 [namespace.std]/2.1") bitset {
 private:
 #pragma warning(push)
 #pragma warning(disable : 4296) // expression is always true (/Wall)
@@ -687,6 +693,10 @@ struct hash<bitset<_Bits>> {
 };
 _STD_END
 
+// TRANSITION, non-_Ugly attribute tokens
+#pragma pop_macro("no_specializations")
+#pragma pop_macro("msvc")
+
 #pragma pop_macro("new")
 _STL_RESTORE_CLANG_WARNINGS
 #pragma warning(pop)
diff --git a/stl/inc/ratio b/stl/inc/ratio
index 07117b684e5..3a303acb190 100644
--- a/stl/inc/ratio
+++ b/stl/inc/ratio
@@ -70,7 +70,7 @@ _NODISCARD constexpr intmax_t _Gcd(intmax_t _Ax, intmax_t _Bx) noexcept {
 }
 
 _EXPORT_STD template <intmax_t _Nx, intmax_t _Dx = 1>
-struct ratio { // holds the ratio of _Nx to _Dx
+struct _NO_SPECIALIZATIONS_CITING("N5014 [format.arg]/2.1") ratio { // holds the ratio of _Nx to _Dx
     static_assert(_Dx != 0, "zero denominator");
     static_assert(-INTMAX_MAX <= _Nx, "numerator too negative");
     static_assert(-INTMAX_MAX <= _Dx, "denominator too negative");

From 9fbfa895b4b06766a4d163f6e0623533c4508a4a Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@microsoft.com>
Date: Fri, 5 Dec 2025 13:36:33 -0800
Subject: [PATCH 2/2] Fix citation.

---
 stl/inc/ratio | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stl/inc/ratio b/stl/inc/ratio
index 3a303acb190..7d17b36e927 100644
--- a/stl/inc/ratio
+++ b/stl/inc/ratio
@@ -70,7 +70,7 @@ _NODISCARD constexpr intmax_t _Gcd(intmax_t _Ax, intmax_t _Bx) noexcept {
 }
 
 _EXPORT_STD template <intmax_t _Nx, intmax_t _Dx = 1>
-struct _NO_SPECIALIZATIONS_CITING("N5014 [format.arg]/2.1") ratio { // holds the ratio of _Nx to _Dx
+struct _NO_SPECIALIZATIONS_CITING("N5014 [namespace.std]/2.1") ratio { // holds the ratio of _Nx to _Dx
     static_assert(_Dx != 0, "zero denominator");
     static_assert(-INTMAX_MAX <= _Nx, "numerator too negative");
     static_assert(-INTMAX_MAX <= _Dx, "denominator too negative");