Mark templates users shouldn't specialize with no_specializations attributes

stl/inc/__msvc_chrono.hpp

@@ -25,13 +25,20 @@ _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
+
 _STD_BEGIN
 namespace chrono {
     _EXPORT_STD template <class _Rep>
     struct treat_as_floating_point : is_floating_point<_Rep> {}; // tests for floating-point type
 
     _EXPORT_STD template <class _Rep>
-    constexpr bool treat_as_floating_point_v = treat_as_floating_point<_Rep>::value;
+    _NO_SPECIALIZATIONS_OF_VARIABLE_TEMPLATES constexpr bool treat_as_floating_point_v =
+        treat_as_floating_point<_Rep>::value;
 
     _EXPORT_STD template <class _Rep>
     struct duration_values { // gets arithmetic properties of a type
@@ -53,7 +60,7 @@ namespace chrono {
 
 #if _HAS_CXX20
     _EXPORT_STD template <class _Clock>
-    constexpr bool is_clock_v = requires {
+    _NO_SPECIALIZATIONS_OF_VARIABLE_TEMPLATES constexpr bool is_clock_v = requires {
         typename _Clock::rep;
         typename _Clock::period;
         typename _Clock::duration;
@@ -62,7 +69,7 @@ namespace chrono {
         _Clock::now();
     };
     _EXPORT_STD template <class _Clock>
-    struct is_clock : bool_constant<is_clock_v<_Clock>> {};
+    struct _NO_SPECIALIZATIONS_CITING("N5014 [time.traits.is.clock]/2") is_clock : bool_constant<is_clock_v<_Clock>> {};
 
     template <class _Clock>
     constexpr bool _Is_clock_v = is_clock_v<_Clock>;
@@ -688,6 +695,10 @@ namespace chrono {
 } // namespace chrono
 _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)

stl/inc/__msvc_formatter.hpp

@@ -58,6 +58,12 @@ _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
+
 _STD_BEGIN
 #if _HAS_CXX23
 #define _FMT_P2286_BEGIN inline namespace __p2286 {
@@ -90,7 +96,7 @@ enum class _Basic_format_arg_type : uint8_t {
 static_assert(static_cast<int>(_Basic_format_arg_type::_Custom_type) < 16, "must fit in 4-bit bitfield");
 
 #if _HAS_CXX23
-_EXPORT_STD template <class _Ty>
+_EXPORT_STD template <class _Ty> // specializations allowed by N5014 [format.formatter.locking]/1
 constexpr bool enable_nonlocking_formatter_optimization = false;
 
 _NODISCARD consteval bool _Is_debug_enabled_fmt_type(_Basic_format_arg_type _Ty) {
@@ -126,7 +132,7 @@ struct _Dynamic_format_specs : _Basic_format_specs<_CharT> {
 [[noreturn]] inline void _Throw_format_error(const char* _Message);
 
 _EXPORT_STD template <class _CharT>
-class basic_format_parse_context;
+class _NO_SPECIALIZATIONS_CITING("N5014 [format.parse.ctx]/2") basic_format_parse_context;
 
 template <class _CharT>
 concept _Format_supported_charT = _Is_any_of_v<_CharT, char, wchar_t>;
@@ -328,7 +334,7 @@ struct _Invalid_format_kind {
 };
 
 _EXPORT_STD template <class _Ty>
-constexpr _Invalid_format_kind<_Ty> format_kind;
+constexpr _Invalid_format_kind<_Ty> format_kind; // specializations allowed by N5014 [format.range.fmtkind]/3
 
 template <class _Ty>
 constexpr bool _Is_two_tuple = false;
@@ -442,6 +448,10 @@ struct _Fill_align_and_width_formatter {
 #endif // _HAS_CXX23
 _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)

stl/inc/__msvc_iter_core.hpp

@@ -16,6 +16,12 @@ _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
+
 _STD_BEGIN
 template <class _Ty, class _Alloc, class = void>
 struct _Has_allocator_type : false_type {}; // tests for suitable _Ty::allocator_type
@@ -34,7 +40,7 @@ _EXPORT_STD template <class _Ty, class _Alloc>
 struct uses_allocator : _Has_allocator_type<_Ty, _Alloc>::type {};
 
 _EXPORT_STD template <class _Ty, class _Alloc>
-constexpr bool uses_allocator_v = uses_allocator<_Ty, _Alloc>::value;
+_NO_SPECIALIZATIONS_OF_VARIABLE_TEMPLATES constexpr bool uses_allocator_v = uses_allocator<_Ty, _Alloc>::value;
 
 // from <iterator>
 _EXPORT_STD struct input_iterator_tag {};
@@ -406,7 +412,7 @@ concept input_or_output_iterator = requires(_It __i) {
 _EXPORT_STD template <class _Se, class _It>
 concept sentinel_for = semiregular<_Se> && input_or_output_iterator<_It> && _Weakly_equality_comparable_with<_Se, _It>;
 
-_EXPORT_STD template <class _Se, class _It>
+_EXPORT_STD template <class _Se, class _It> // specializations allowed by N5014 [iterator.concept.sizedsentinel]/3
 constexpr bool disable_sized_sentinel_for = false;
 
 _EXPORT_STD template <class _Se, class _It>
@@ -542,6 +548,10 @@ struct _Meta_find_unique_index_<_List<_First, _Rest...>, _Ty> {
 };
 _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)

stl/inc/__msvc_ranges_tuple_formatter.hpp

@@ -61,6 +61,12 @@ _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
+
 _STD_BEGIN
 _EXPORT_STD template <class, class>
 class vector;
@@ -93,7 +99,7 @@ template <class _CharT>
 class _Compile_time_parse_context;
 
 _EXPORT_STD template <class _CharT>
-class basic_format_parse_context {
+class _NO_SPECIALIZATIONS_CITING("N5014 [format.parse.ctx]/2") basic_format_parse_context {
 public:
     using char_type      = _CharT;
     using const_iterator = basic_string_view<_CharT>::const_iterator;
@@ -229,7 +235,7 @@ struct _Format_handler;
 _FMT_P2286_END
 
 _EXPORT_STD template <class _Context>
-class basic_format_arg {
+class _NO_SPECIALIZATIONS_CITING("N5014 [format.arg]/2") basic_format_arg {
 public:
     using _CharType = _Context::char_type;
 
@@ -674,7 +680,7 @@ class _Lazy_locale {
 
 _EXPORT_STD template <class _Out, class _CharT>
     requires output_iterator<_Out, const _CharT&>
-class basic_format_context {
+class _NO_SPECIALIZATIONS_CITING("N5014 [format.context]/2") basic_format_context {
 private:
     _Out _OutputIt;
     basic_format_args<basic_format_context> _Args;
@@ -1256,6 +1262,10 @@ struct formatter<tuple<_Types...>, _CharT> : _Tuple_formatter_base<tuple<_Types.
 #endif // _HAS_CXX23
 _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)

stl/inc/compare

@@ -20,6 +20,12 @@ _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
+
 _STD_BEGIN
 void _Literal_zero_is_expected();
 
@@ -321,7 +327,7 @@ using compare_three_way_result_t =
     decltype(_STD declval<const remove_reference_t<_Ty1>&>() <=> _STD declval<const remove_reference_t<_Ty2>&>());
 
 _EXPORT_STD template <class _Ty1, class _Ty2 = _Ty1>
-struct compare_three_way_result {};
+struct _NO_SPECIALIZATIONS_CITING("N5014 [cmp.result]/1") compare_three_way_result {};
 
 template <class _Ty1, class _Ty2>
     requires requires { typename compare_three_way_result_t<_Ty1, _Ty2>; }
@@ -841,6 +847,10 @@ inline namespace _Cpos {
 }
 _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)

stl/inc/coroutine

@@ -32,6 +32,12 @@ _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
+
 _STD_BEGIN
 
 template <class _Ret, class = void>
@@ -46,7 +52,7 @@ _EXPORT_STD template <class _Ret, class...>
 struct coroutine_traits : _Coroutine_traits<_Ret> {};
 
 _EXPORT_STD template <class = void>
-struct coroutine_handle;
+struct _NO_SPECIALIZATIONS_CITING("N5014 [coroutine.handle.general]/2") coroutine_handle;
 
 template <>
 struct coroutine_handle<void> {
@@ -93,7 +99,7 @@ private:
 };
 
 _EXPORT_STD template <class _CoroPromise>
-struct coroutine_handle {
+struct _NO_SPECIALIZATIONS_CITING("N5014 [coroutine.handle.general]/2") coroutine_handle {
     constexpr coroutine_handle() noexcept = default;
     constexpr coroutine_handle(nullptr_t) noexcept {}
 
@@ -255,6 +261,10 @@ _EXPORT_STD struct suspend_always {
 
 _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)

stl/inc/functional

@@ -28,6 +28,12 @@ _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
+
 _STD_BEGIN
 // plus, minus, and multiplies are defined in <xutility>
 
@@ -301,13 +307,13 @@ _STL_RESTORE_DEPRECATED_WARNING
 
 #if _HAS_AUTO_PTR_ETC
 _EXPORT_STD template <class _Arg, class _Result>
-struct unary_function { // base class for unary functions
+struct _NO_SPECIALIZATIONS_CITING("N4140 [depr.base]/1") unary_function { // base class for unary functions
     using argument_type = _Arg;
     using result_type   = _Result;
 };
 
 _EXPORT_STD template <class _Arg1, class _Arg2, class _Result>
-struct binary_function { // base class for binary functions
+struct _NO_SPECIALIZATIONS_CITING("N4140 [depr.base]/1") binary_function { // base class for binary functions
     using first_argument_type  = _Arg1;
     using second_argument_type = _Arg2;
     using result_type          = _Result;
@@ -2008,7 +2014,7 @@ template <class _Tx>
 struct is_placeholder<const volatile _Tx> : is_placeholder<_Tx>::type {}; // ignore cv-qualifiers
 
 _EXPORT_STD template <class _Ty>
-constexpr int is_placeholder_v = is_placeholder<_Ty>::value;
+_NO_SPECIALIZATIONS_OF_VARIABLE_TEMPLATES constexpr int is_placeholder_v = is_placeholder<_Ty>::value;
 
 template <class _Ret, class _Fx, class... _Types>
 class _Binder;
@@ -2029,7 +2035,7 @@ template <class _Tx>
 struct is_bind_expression<const volatile _Tx> : is_bind_expression<_Tx>::type {}; // ignore cv-qualifiers
 
 _EXPORT_STD template <class _Ty>
-constexpr bool is_bind_expression_v = is_bind_expression<_Ty>::value;
+_NO_SPECIALIZATIONS_OF_VARIABLE_TEMPLATES constexpr bool is_bind_expression_v = is_bind_expression<_Ty>::value;
 
 template <class _Cv_TiD, bool = _Is_specialization_v<remove_cv_t<_Cv_TiD>, reference_wrapper>,
     bool = is_bind_expression_v<_Cv_TiD>, int = is_placeholder_v<_Cv_TiD>>
@@ -3160,6 +3166,10 @@ namespace _DEPRECATE_TR1_NAMESPACE tr1 {
 
 _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)

stl/inc/generator

@@ -27,7 +27,11 @@ _STL_DISABLE_CLANG_WARNINGS
 #undef new
 
 // TRANSITION, non-_Ugly attribute tokens
+#pragma push_macro("msvc")
+#pragma push_macro("no_specializations")
 #pragma push_macro("empty_bases")
+#undef msvc
+#undef no_specializations
 #undef empty_bases
 
 _STD_BEGIN
@@ -40,7 +44,7 @@ template <class _Alloc>
 constexpr bool _Stateless_allocator = default_initializable<_Alloc> && allocator_traits<_Alloc>::is_always_equal::value;
 
 _EXPORT_STD template <class _Rty, class _Vty = void, class _Alloc = void>
-class generator;
+class _NO_SPECIALIZATIONS_CITING("N5014 [coro.generator.class]/4") generator;
 
 namespace _Gen_detail {
     template <class _Alloc>
@@ -518,7 +522,8 @@ namespace _Gen_detail {
 } // namespace _Gen_detail
 
 _EXPORT_STD template <class _Rty, class _Vty, class _Alloc>
-class generator : public _RANGES view_interface<generator<_Rty, _Vty, _Alloc>> {
+class _NO_SPECIALIZATIONS_CITING("N5014 [coro.generator.class]/4") generator
+    : public _RANGES view_interface<generator<_Rty, _Vty, _Alloc>> {
 private:
     static_assert(_Gen_detail::_Valid_allocator<_Alloc>,
         "generator allocators must use raw pointers (N4988 [coro.generator.class]/1.1)");
@@ -603,6 +608,8 @@ _STD_END
 
 // TRANSITION, non-_Ugly attribute tokens
 #pragma pop_macro("empty_bases")
+#pragma pop_macro("no_specializations")
+#pragma pop_macro("msvc")
 
 #pragma pop_macro("new")
 _STL_RESTORE_CLANG_WARNINGS

stl/inc/initializer_list

@@ -16,9 +16,15 @@ _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
+
 _STD_BEGIN
 _EXPORT_STD template <class _Elem>
-class initializer_list {
+class _NO_SPECIALIZATIONS_CITING("N5014 [initializer.list.syn]/2") initializer_list {
 public:
     using value_type      = _Elem;
     using reference       = const _Elem&;
@@ -60,6 +66,11 @@ _NODISCARD constexpr const _Elem* end(initializer_list<_Elem> _Ilist) noexcept {
     return _Ilist.end();
 }
 _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)