[libcxx-commits] [lldb] [libcxx] [libc] [clang] [clang-tools-extra] [libunwind] [compiler-rt] [lld] [flang] [llvm] Reland: [libc++][format] P2637R3: Member visit (std::basic_format_arg) #76449 (PR #79032)
Hristo Hristov via libcxx-commits
libcxx-commits at lists.llvm.org
Wed Jan 24 20:59:25 PST 2024
https://github.com/H-G-Hristov updated https://github.com/llvm/llvm-project/pull/79032
>From e03452fda84a5284420bba1913299b68caabb6cd Mon Sep 17 00:00:00 2001
From: Zingam <zingam at outlook.com>
Date: Mon, 22 Jan 2024 20:35:00 +0200
Subject: [PATCH 1/2] Revert "Revert "[libc++][format] P2637R3: Member `visit`
(`std::basic_format_arg`) (#76449)""
This reverts commit 02f95b77515fe18ed1076b94cbb850ea0cf3c77e.
---
libcxx/docs/ReleaseNotes/18.rst | 1 +
libcxx/docs/Status/Cxx2cPapers.csv | 2 +-
libcxx/docs/Status/FormatIssues.csv | 2 +-
libcxx/include/__config | 6 +
libcxx/include/__format/format_arg.h | 109 +++++-
libcxx/include/__format/format_context.h | 33 +-
libcxx/include/format | 2 +-
.../format.arg/visit.pass.cpp | 333 ++++++++++++++++
.../format.arg/visit.return_type.pass.cpp | 369 ++++++++++++++++++
.../visit_format_arg.deprecated.verify.cpp | 38 ++
.../format.arg/visit_format_arg.pass.cpp | 6 +-
.../format.arguments/format.args/get.pass.cpp | 48 ++-
libcxx/test/support/test_basic_format_arg.h | 20 +-
libcxx/test/support/test_macros.h | 5 +
.../generate_feature_test_macro_components.py | 1 +
15 files changed, 927 insertions(+), 48 deletions(-)
create mode 100644 libcxx/test/std/utilities/format/format.arguments/format.arg/visit.pass.cpp
create mode 100644 libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp
create mode 100644 libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.deprecated.verify.cpp
diff --git a/libcxx/docs/ReleaseNotes/18.rst b/libcxx/docs/ReleaseNotes/18.rst
index fd882bafe19a517..237a63022d55ff5 100644
--- a/libcxx/docs/ReleaseNotes/18.rst
+++ b/libcxx/docs/ReleaseNotes/18.rst
@@ -79,6 +79,7 @@ Implemented Papers
- P1759R6 - Native handles and file streams
- P2868R3 - Remove Deprecated ``std::allocator`` Typedef From C++26
- P2517R1 - Add a conditional ``noexcept`` specification to ``std::apply``
+- P2637R3 - Member ``visit``
- P2447R6 - ``span`` over initializer list
diff --git a/libcxx/docs/Status/Cxx2cPapers.csv b/libcxx/docs/Status/Cxx2cPapers.csv
index f80b1f6b663f045..c45aa3c510072e4 100644
--- a/libcxx/docs/Status/Cxx2cPapers.csv
+++ b/libcxx/docs/Status/Cxx2cPapers.csv
@@ -17,7 +17,7 @@
"`P0792R14 <https://wg21.link/P0792R14>`__","LWG","``function_ref``: a type-erased callable reference","Varna June 2023","","",""
"`P2874R2 <https://wg21.link/P2874R2>`__","LWG","Mandating Annex D Require No More","Varna June 2023","","",""
"`P2757R3 <https://wg21.link/P2757R3>`__","LWG","Type-checking format args","Varna June 2023","","","|format|"
-"`P2637R3 <https://wg21.link/P2637R3>`__","LWG","Member ``visit``","Varna June 2023","|Partial|","18.0",""
+"`P2637R3 <https://wg21.link/P2637R3>`__","LWG","Member ``visit``","Varna June 2023","|Complete|","18.0",""
"`P2641R4 <https://wg21.link/P2641R4>`__","CWG, LWG","Checking if a ``union`` alternative is active","Varna June 2023","","",""
"`P1759R6 <https://wg21.link/P1759R6>`__","LWG","Native handles and file streams","Varna June 2023","|Complete|","18.0",""
"`P2697R1 <https://wg21.link/P2697R1>`__","LWG","Interfacing ``bitset`` with ``string_view``","Varna June 2023","|Complete|","18.0",""
diff --git a/libcxx/docs/Status/FormatIssues.csv b/libcxx/docs/Status/FormatIssues.csv
index 513988d08036ca6..6e58e752191ea5d 100644
--- a/libcxx/docs/Status/FormatIssues.csv
+++ b/libcxx/docs/Status/FormatIssues.csv
@@ -16,7 +16,7 @@ Number,Name,Standard,Assignee,Status,First released version
"`P2693R1 <https://wg21.link/P2693R1>`__","Formatting ``thread::id`` and ``stacktrace``","C++23","Mark de Wever","|In Progress|"
"`P2510R3 <https://wg21.link/P2510R3>`__","Formatting pointers","C++26","Mark de Wever","|Complete|",17.0
"`P2757R3 <https://wg21.link/P2757R3>`__","Type-checking format args","C++26","","",
-"`P2637R3 <https://wg21.link/P2637R3>`__","Member ``visit``","C++26","","",
+"`P2637R3 <https://wg21.link/P2637R3>`__","Member ``visit``","C++26","Hristo Hristov","|Complete|",18.0
"`P2905R2 <https://wg21.link/P2905R2>`__","Runtime format strings","C++26 DR","Mark de Wever","|Complete|",18.0
"`P2918R2 <https://wg21.link/P2918R2>`__","Runtime format strings II","C++26","Mark de Wever","|Complete|",18.0
"`P2909R4 <https://wg21.link/P2909R4>`__","Fix formatting of code units as integers (Dude, where’s my ``char``?)","C++26 DR","Mark de Wever","|Complete|",18.0
diff --git a/libcxx/include/__config b/libcxx/include/__config
index 9a64cdb489119d9..00489d971c296c2 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -995,6 +995,12 @@ typedef __char32_t char32_t;
# define _LIBCPP_DEPRECATED_IN_CXX23
# endif
+# if _LIBCPP_STD_VER >= 26
+# define _LIBCPP_DEPRECATED_IN_CXX26 _LIBCPP_DEPRECATED
+# else
+# define _LIBCPP_DEPRECATED_IN_CXX26
+# endif
+
# if !defined(_LIBCPP_HAS_NO_CHAR8_T)
# define _LIBCPP_DEPRECATED_WITH_CHAR8_T _LIBCPP_DEPRECATED
# else
diff --git a/libcxx/include/__format/format_arg.h b/libcxx/include/__format/format_arg.h
index 10fca15d5a7a94e..02ee3cef7d402b7 100644
--- a/libcxx/include/__format/format_arg.h
+++ b/libcxx/include/__format/format_arg.h
@@ -93,7 +93,7 @@ _LIBCPP_HIDE_FROM_ABI constexpr __arg_t __get_packed_type(uint64_t __types, size
} // namespace __format
-// This function is not user obervable, so it can directly use the non-standard
+// This function is not user observable, so it can directly use the non-standard
// types of the "variant". See __arg_t for more details.
template <class _Visitor, class _Context>
_LIBCPP_HIDE_FROM_ABI decltype(auto) __visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg) {
@@ -144,6 +144,59 @@ _LIBCPP_HIDE_FROM_ABI decltype(auto) __visit_format_arg(_Visitor&& __vis, basic_
__libcpp_unreachable();
}
+# if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
+
+template <class _Rp, class _Visitor, class _Context>
+_LIBCPP_HIDE_FROM_ABI _Rp __visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg) {
+ switch (__arg.__type_) {
+ case __format::__arg_t::__none:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__monostate_);
+ case __format::__arg_t::__boolean:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__boolean_);
+ case __format::__arg_t::__char_type:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__char_type_);
+ case __format::__arg_t::__int:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__int_);
+ case __format::__arg_t::__long_long:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__long_long_);
+ case __format::__arg_t::__i128:
+# ifndef _LIBCPP_HAS_NO_INT128
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__i128_);
+# else
+ __libcpp_unreachable();
+# endif
+ case __format::__arg_t::__unsigned:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__unsigned_);
+ case __format::__arg_t::__unsigned_long_long:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__unsigned_long_long_);
+ case __format::__arg_t::__u128:
+# ifndef _LIBCPP_HAS_NO_INT128
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__u128_);
+# else
+ __libcpp_unreachable();
+# endif
+ case __format::__arg_t::__float:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__float_);
+ case __format::__arg_t::__double:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__double_);
+ case __format::__arg_t::__long_double:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__long_double_);
+ case __format::__arg_t::__const_char_type_ptr:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__const_char_type_ptr_);
+ case __format::__arg_t::__string_view:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__string_view_);
+ case __format::__arg_t::__ptr:
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), __arg.__value_.__ptr_);
+ case __format::__arg_t::__handle:
+ return std::invoke_r<_Rp>(
+ std::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__arg.__value_.__handle_});
+ }
+
+ __libcpp_unreachable();
+}
+
+# endif // _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
+
/// Contains the values used in basic_format_arg.
///
/// This is a separate type so it's possible to store the values and types in
@@ -227,6 +280,52 @@ class _LIBCPP_TEMPLATE_VIS basic_format_arg {
_LIBCPP_HIDE_FROM_ABI explicit operator bool() const noexcept { return __type_ != __format::__arg_t::__none; }
+# if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
+
+ // This function is user facing, so it must wrap the non-standard types of
+ // the "variant" in a handle to stay conforming. See __arg_t for more details.
+ template <class _Visitor>
+ _LIBCPP_HIDE_FROM_ABI decltype(auto) visit(this basic_format_arg __arg, _Visitor&& __vis) {
+ switch (__arg.__type_) {
+# ifndef _LIBCPP_HAS_NO_INT128
+ case __format::__arg_t::__i128: {
+ typename __basic_format_arg_value<_Context>::__handle __h{__arg.__value_.__i128_};
+ return std::invoke(std::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__h});
+ }
+
+ case __format::__arg_t::__u128: {
+ typename __basic_format_arg_value<_Context>::__handle __h{__arg.__value_.__u128_};
+ return std::invoke(std::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__h});
+ }
+# endif
+ default:
+ return std::__visit_format_arg(std::forward<_Visitor>(__vis), __arg);
+ }
+ }
+
+ // This function is user facing, so it must wrap the non-standard types of
+ // the "variant" in a handle to stay conforming. See __arg_t for more details.
+ template <class _Rp, class _Visitor>
+ _LIBCPP_HIDE_FROM_ABI _Rp visit(this basic_format_arg __arg, _Visitor&& __vis) {
+ switch (__arg.__type_) {
+# ifndef _LIBCPP_HAS_NO_INT128
+ case __format::__arg_t::__i128: {
+ typename __basic_format_arg_value<_Context>::__handle __h{__arg.__value_.__i128_};
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__h});
+ }
+
+ case __format::__arg_t::__u128: {
+ typename __basic_format_arg_value<_Context>::__handle __h{__arg.__value_.__u128_};
+ return std::invoke_r<_Rp>(std::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__h});
+ }
+# endif
+ default:
+ return std::__visit_format_arg<_Rp>(std::forward<_Visitor>(__vis), __arg);
+ }
+ }
+
+# endif // _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
+
private:
using char_type = typename _Context::char_type;
@@ -267,7 +366,11 @@ class _LIBCPP_TEMPLATE_VIS basic_format_arg<_Context>::handle {
// This function is user facing, so it must wrap the non-standard types of
// the "variant" in a handle to stay conforming. See __arg_t for more details.
template <class _Visitor, class _Context>
-_LIBCPP_HIDE_FROM_ABI decltype(auto) visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg) {
+# if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
+_LIBCPP_DEPRECATED_IN_CXX26
+# endif
+ _LIBCPP_HIDE_FROM_ABI decltype(auto)
+ visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg) {
switch (__arg.__type_) {
# ifndef _LIBCPP_HAS_NO_INT128
case __format::__arg_t::__i128: {
@@ -279,7 +382,7 @@ _LIBCPP_HIDE_FROM_ABI decltype(auto) visit_format_arg(_Visitor&& __vis, basic_fo
typename __basic_format_arg_value<_Context>::__handle __h{__arg.__value_.__u128_};
return std::invoke(std::forward<_Visitor>(__vis), typename basic_format_arg<_Context>::handle{__h});
}
-# endif
+# endif // _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
default:
return std::__visit_format_arg(std::forward<_Visitor>(__vis), __arg);
}
diff --git a/libcxx/include/__format/format_context.h b/libcxx/include/__format/format_context.h
index 5b252b81f691bc1..0beaa84b028beb7 100644
--- a/libcxx/include/__format/format_context.h
+++ b/libcxx/include/__format/format_context.h
@@ -163,20 +163,25 @@ class _LIBCPP_TEMPLATE_VIS basic_format_context<typename __format::__retarget_bu
# endif
__ctx_(std::addressof(__ctx)),
__arg_([](void* __c, size_t __id) {
- return std::visit_format_arg(
- [&](auto __arg) -> basic_format_arg<basic_format_context> {
- if constexpr (same_as<decltype(__arg), monostate>)
- return {};
- else if constexpr (same_as<decltype(__arg), typename basic_format_arg<_Context>::handle>)
- // At the moment it's not possible for formatting to use a re-targeted handle.
- // TODO FMT add this when support is needed.
- std::__throw_format_error("Re-targeting handle not supported");
- else
- return basic_format_arg<basic_format_context>{
- __format::__determine_arg_t<basic_format_context, decltype(__arg)>(),
- __basic_format_arg_value<basic_format_context>(__arg)};
- },
- static_cast<_Context*>(__c)->arg(__id));
+ auto __visitor = [&](auto __arg) -> basic_format_arg<basic_format_context> {
+ if constexpr (same_as<decltype(__arg), monostate>)
+ return {};
+ else if constexpr (same_as<decltype(__arg), typename basic_format_arg<_Context>::handle>)
+ // At the moment it's not possible for formatting to use a re-targeted handle.
+ // TODO FMT add this when support is needed.
+ std::__throw_format_error("Re-targeting handle not supported");
+ else
+ return basic_format_arg<basic_format_context>{
+ __format::__determine_arg_t<basic_format_context, decltype(__arg)>(),
+ __basic_format_arg_value<basic_format_context>(__arg)};
+ };
+# if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
+ return static_cast<_Context*>(__c)->arg(__id).visit(std::move(__visitor));
+# else
+ _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+ return std::visit_format_arg(std::move(__visitor), static_cast<_Context*>(__c)->arg(__id));
+ _LIBCPP_SUPPRESS_DEPRECATED_POP
+# endif // _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER)
}) {
}
diff --git a/libcxx/include/format b/libcxx/include/format
index ab9b336d0cdabee..64f6ba1d25284aa 100644
--- a/libcxx/include/format
+++ b/libcxx/include/format
@@ -170,7 +170,7 @@ namespace std {
template<class Context> class basic_format_arg;
template<class Visitor, class Context>
- see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
+ see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg); // Deprecated in C++26
// [format.arg.store], class template format-arg-store
template<class Context, class... Args> struct format-arg-store; // exposition only
diff --git a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.pass.cpp b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.pass.cpp
new file mode 100644
index 000000000000000..994ccc70a38daae
--- /dev/null
+++ b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.pass.cpp
@@ -0,0 +1,333 @@
+//===----------------------------------------------------------------------===//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
+// UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
+// The tested functionality needs deducing this.
+// UNSUPPORTED: clang-16 || clang-17
+// XFAIL: apple-clang
+
+// <format>
+
+// class basic_format_arg;
+
+// template<class Visitor>
+// decltype(auto) visit(this basic_format_arg arg, Visitor&& vis); // since C++26
+
+#include <algorithm>
+#include <cassert>
+#include <format>
+#include <type_traits>
+
+#include "constexpr_char_traits.h"
+#include "make_string.h"
+#include "min_allocator.h"
+#include "test_macros.h"
+
+template <class Context, class To, class From>
+void test(From value) {
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ LIBCPP_ASSERT(format_args.__size() == 1);
+ assert(format_args.get(0));
+
+ auto result = format_args.get(0).visit([v = To(value)](auto a) -> To {
+ if constexpr (std::is_same_v<To, decltype(a)>) {
+ assert(v == a);
+ return a;
+ } else {
+ assert(false);
+ return {};
+ }
+ });
+
+ using ct = std::common_type_t<From, To>;
+ assert(static_cast<ct>(result) == static_cast<ct>(value));
+}
+
+// Some types, as an extension, are stored in the variant. The Standard
+// requires them to be observed as a handle.
+template <class Context, class T>
+void test_handle(T value) {
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ LIBCPP_ASSERT(format_args.__size() == 1);
+ assert(format_args.get(0));
+
+ format_args.get(0).visit([](auto a) {
+ assert((std::is_same_v<decltype(a), typename std::basic_format_arg<Context>::handle>));
+ });
+}
+
+// Test specific for string and string_view.
+//
+// Since both result in a string_view there's no need to pass this as a
+// template argument.
+template <class Context, class From>
+void test_string_view(From value) {
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ LIBCPP_ASSERT(format_args.__size() == 1);
+ assert(format_args.get(0));
+
+ using CharT = typename Context::char_type;
+ using To = std::basic_string_view<CharT>;
+ using V = std::basic_string<CharT>;
+
+ auto result = format_args.get(0).visit([v = V(value.begin(), value.end())](auto a) -> To {
+ if constexpr (std::is_same_v<To, decltype(a)>) {
+ assert(v == a);
+ return a;
+ } else {
+ assert(false);
+ return {};
+ }
+ });
+
+ assert(std::equal(value.begin(), value.end(), result.begin(), result.end()));
+}
+
+template <class CharT>
+void test() {
+ using Context = std::basic_format_context<CharT*, CharT>;
+ std::basic_string<CharT> empty;
+ std::basic_string<CharT> str = MAKE_STRING(CharT, "abc");
+
+ // Test boolean types.
+
+ test<Context, bool>(true);
+ test<Context, bool>(false);
+
+ // Test CharT types.
+
+ test<Context, CharT, CharT>('a');
+ test<Context, CharT, CharT>('z');
+ test<Context, CharT, CharT>('0');
+ test<Context, CharT, CharT>('9');
+
+ // Test char types.
+
+ if (std::is_same_v<CharT, char>) {
+ // char to char -> char
+ test<Context, CharT, char>('a');
+ test<Context, CharT, char>('z');
+ test<Context, CharT, char>('0');
+ test<Context, CharT, char>('9');
+ } else {
+ if (std::is_same_v<CharT, wchar_t>) {
+ // char to wchar_t -> wchar_t
+ test<Context, wchar_t, char>('a');
+ test<Context, wchar_t, char>('z');
+ test<Context, wchar_t, char>('0');
+ test<Context, wchar_t, char>('9');
+ } else if (std::is_signed_v<char>) {
+ // char to CharT -> int
+ // This happens when CharT is a char8_t, char16_t, or char32_t and char
+ // is a signed type.
+ // Note if sizeof(CharT) > sizeof(int) this test fails. If there are
+ // platforms where that occurs extra tests need to be added for char32_t
+ // testing it against a long long.
+ test<Context, int, char>('a');
+ test<Context, int, char>('z');
+ test<Context, int, char>('0');
+ test<Context, int, char>('9');
+ } else {
+ // char to CharT -> unsigned
+ // This happens when CharT is a char8_t, char16_t, or char32_t and char
+ // is an unsigned type.
+ // Note if sizeof(CharT) > sizeof(unsigned) this test fails. If there are
+ // platforms where that occurs extra tests need to be added for char32_t
+ // testing it against an unsigned long long.
+ test<Context, unsigned, char>('a');
+ test<Context, unsigned, char>('z');
+ test<Context, unsigned, char>('0');
+ test<Context, unsigned, char>('9');
+ }
+ }
+
+ // Test signed integer types.
+
+ test<Context, int, signed char>(std::numeric_limits<signed char>::min());
+ test<Context, int, signed char>(0);
+ test<Context, int, signed char>(std::numeric_limits<signed char>::max());
+
+ test<Context, int, short>(std::numeric_limits<short>::min());
+ test<Context, int, short>(std::numeric_limits<signed char>::min());
+ test<Context, int, short>(0);
+ test<Context, int, short>(std::numeric_limits<signed char>::max());
+ test<Context, int, short>(std::numeric_limits<short>::max());
+
+ test<Context, int, int>(std::numeric_limits<int>::min());
+ test<Context, int, int>(std::numeric_limits<short>::min());
+ test<Context, int, int>(std::numeric_limits<signed char>::min());
+ test<Context, int, int>(0);
+ test<Context, int, int>(std::numeric_limits<signed char>::max());
+ test<Context, int, int>(std::numeric_limits<short>::max());
+ test<Context, int, int>(std::numeric_limits<int>::max());
+
+ using LongToType = std::conditional_t<sizeof(long) == sizeof(int), int, long long>;
+
+ test<Context, LongToType, long>(std::numeric_limits<long>::min());
+ test<Context, LongToType, long>(std::numeric_limits<int>::min());
+ test<Context, LongToType, long>(std::numeric_limits<short>::min());
+ test<Context, LongToType, long>(std::numeric_limits<signed char>::min());
+ test<Context, LongToType, long>(0);
+ test<Context, LongToType, long>(std::numeric_limits<signed char>::max());
+ test<Context, LongToType, long>(std::numeric_limits<short>::max());
+ test<Context, LongToType, long>(std::numeric_limits<int>::max());
+ test<Context, LongToType, long>(std::numeric_limits<long>::max());
+
+ test<Context, long long, long long>(std::numeric_limits<long long>::min());
+ test<Context, long long, long long>(std::numeric_limits<long>::min());
+ test<Context, long long, long long>(std::numeric_limits<int>::min());
+ test<Context, long long, long long>(std::numeric_limits<short>::min());
+ test<Context, long long, long long>(std::numeric_limits<signed char>::min());
+ test<Context, long long, long long>(0);
+ test<Context, long long, long long>(std::numeric_limits<signed char>::max());
+ test<Context, long long, long long>(std::numeric_limits<short>::max());
+ test<Context, long long, long long>(std::numeric_limits<int>::max());
+ test<Context, long long, long long>(std::numeric_limits<long>::max());
+ test<Context, long long, long long>(std::numeric_limits<long long>::max());
+
+#ifndef TEST_HAS_NO_INT128
+ test_handle<Context, __int128_t>(0);
+#endif // TEST_HAS_NO_INT128
+
+ // Test unsigned integer types.
+
+ test<Context, unsigned, unsigned char>(0);
+ test<Context, unsigned, unsigned char>(std::numeric_limits<unsigned char>::max());
+
+ test<Context, unsigned, unsigned short>(0);
+ test<Context, unsigned, unsigned short>(std::numeric_limits<unsigned char>::max());
+ test<Context, unsigned, unsigned short>(std::numeric_limits<unsigned short>::max());
+
+ test<Context, unsigned, unsigned>(0);
+ test<Context, unsigned, unsigned>(std::numeric_limits<unsigned char>::max());
+ test<Context, unsigned, unsigned>(std::numeric_limits<unsigned short>::max());
+ test<Context, unsigned, unsigned>(std::numeric_limits<unsigned>::max());
+
+ using UnsignedLongToType =
+ std::conditional_t<sizeof(unsigned long) == sizeof(unsigned), unsigned, unsigned long long>;
+
+ test<Context, UnsignedLongToType, unsigned long>(0);
+ test<Context, UnsignedLongToType, unsigned long>(std::numeric_limits<unsigned char>::max());
+ test<Context, UnsignedLongToType, unsigned long>(std::numeric_limits<unsigned short>::max());
+ test<Context, UnsignedLongToType, unsigned long>(std::numeric_limits<unsigned>::max());
+ test<Context, UnsignedLongToType, unsigned long>(std::numeric_limits<unsigned long>::max());
+
+ test<Context, unsigned long long, unsigned long long>(0);
+ test<Context, unsigned long long, unsigned long long>(std::numeric_limits<unsigned char>::max());
+ test<Context, unsigned long long, unsigned long long>(std::numeric_limits<unsigned short>::max());
+ test<Context, unsigned long long, unsigned long long>(std::numeric_limits<unsigned>::max());
+ test<Context, unsigned long long, unsigned long long>(std::numeric_limits<unsigned long>::max());
+ test<Context, unsigned long long, unsigned long long>(std::numeric_limits<unsigned long long>::max());
+
+#ifndef TEST_HAS_NO_INT128
+ test_handle<Context, __uint128_t>(0);
+#endif // TEST_HAS_NO_INT128
+
+ // Test floating point types.
+
+ test<Context, float, float>(-std::numeric_limits<float>::max());
+ test<Context, float, float>(-std::numeric_limits<float>::min());
+ test<Context, float, float>(-0.0);
+ test<Context, float, float>(0.0);
+ test<Context, float, float>(std::numeric_limits<float>::min());
+ test<Context, float, float>(std::numeric_limits<float>::max());
+
+ test<Context, double, double>(-std::numeric_limits<double>::max());
+ test<Context, double, double>(-std::numeric_limits<double>::min());
+ test<Context, double, double>(-0.0);
+ test<Context, double, double>(0.0);
+ test<Context, double, double>(std::numeric_limits<double>::min());
+ test<Context, double, double>(std::numeric_limits<double>::max());
+
+ test<Context, long double, long double>(-std::numeric_limits<long double>::max());
+ test<Context, long double, long double>(-std::numeric_limits<long double>::min());
+ test<Context, long double, long double>(-0.0);
+ test<Context, long double, long double>(0.0);
+ test<Context, long double, long double>(std::numeric_limits<long double>::min());
+ test<Context, long double, long double>(std::numeric_limits<long double>::max());
+
+ // Test const CharT pointer types.
+
+ test<Context, const CharT*, const CharT*>(empty.c_str());
+ test<Context, const CharT*, const CharT*>(str.c_str());
+
+ // Test string_view types.
+
+ {
+ using From = std::basic_string_view<CharT>;
+
+ test_string_view<Context>(From());
+ test_string_view<Context>(From(empty.c_str()));
+ test_string_view<Context>(From(str.c_str()));
+ }
+
+ {
+ using From = std::basic_string_view<CharT, constexpr_char_traits<CharT>>;
+
+ test_string_view<Context>(From());
+ test_string_view<Context>(From(empty.c_str()));
+ test_string_view<Context>(From(str.c_str()));
+ }
+
+ // Test string types.
+
+ {
+ using From = std::basic_string<CharT>;
+
+ test_string_view<Context>(From());
+ test_string_view<Context>(From(empty.c_str()));
+ test_string_view<Context>(From(str.c_str()));
+ }
+
+ {
+ using From = std::basic_string<CharT, constexpr_char_traits<CharT>, std::allocator<CharT>>;
+
+ test_string_view<Context>(From());
+ test_string_view<Context>(From(empty.c_str()));
+ test_string_view<Context>(From(str.c_str()));
+ }
+
+ {
+ using From = std::basic_string<CharT, std::char_traits<CharT>, min_allocator<CharT>>;
+
+ test_string_view<Context>(From());
+ test_string_view<Context>(From(empty.c_str()));
+ test_string_view<Context>(From(str.c_str()));
+ }
+
+ {
+ using From = std::basic_string<CharT, constexpr_char_traits<CharT>, min_allocator<CharT>>;
+
+ test_string_view<Context>(From());
+ test_string_view<Context>(From(empty.c_str()));
+ test_string_view<Context>(From(str.c_str()));
+ }
+
+ // Test pointer types.
+
+ test<Context, const void*>(nullptr);
+ int i = 0;
+ test<Context, const void*>(static_cast<void*>(&i));
+ const int ci = 0;
+ test<Context, const void*>(static_cast<const void*>(&ci));
+}
+
+int main(int, char**) {
+ test<char>();
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+ test<wchar_t>();
+#endif
+
+ return 0;
+}
diff --git a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp
new file mode 100644
index 000000000000000..473278b7b443490
--- /dev/null
+++ b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp
@@ -0,0 +1,369 @@
+//===----------------------------------------------------------------------===//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
+// UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
+// The tested functionality needs deducing this.
+// UNSUPPORTED: clang-16 || clang-17
+// XFAIL: apple-clang
+
+// <format>
+
+// class basic_format_arg;
+
+// template<class R, class Visitor>
+// R visit(this basic_format_arg arg, Visitor&& vis);
+
+#include <algorithm>
+#include <cassert>
+#include <format>
+#include <type_traits>
+
+#include "constexpr_char_traits.h"
+#include "make_string.h"
+#include "min_allocator.h"
+#include "test_macros.h"
+
+// The expected result type shouldn't matter,therefore use a hardcoded value for simplicity.
+using ExpectedResultType = bool;
+constexpr ExpectedResultType visited{true};
+
+template <class ExpectedR>
+ExpectedR make_expected_result() {
+ if constexpr (std::is_same_v<ExpectedR, bool>) {
+ return true;
+ } else if constexpr (std::is_same_v<ExpectedR, long>) {
+ return 192812079084L;
+ } else {
+ return "visited";
+ }
+}
+
+template <class Context, class To, class ExpectedR, class From>
+void test(From value, const ExpectedR& expectedValue) {
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ LIBCPP_ASSERT(format_args.__size() == 1);
+ assert(format_args.get(0));
+
+ // member
+ {
+ std::same_as<ExpectedR> decltype(auto) result =
+ format_args.get(0).template visit<ExpectedR>([v = To(value)](auto a) -> ExpectedR {
+ if constexpr (std::is_same_v<To, decltype(a)>) {
+ assert(v == a);
+ return make_expected_result<ExpectedR>();
+ } else {
+ assert(false);
+ return {};
+ }
+ });
+
+ assert(result == expectedValue);
+ }
+}
+
+// Some types, as an extension, are stored in the variant. The Standard
+// requires them to be observed as a handle.
+template <class Context, class T, class ExpectedR>
+void test_handle(T value, ExpectedR expectedValue) {
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ LIBCPP_ASSERT(format_args.__size() == 1);
+ assert(format_args.get(0));
+
+ std::same_as<ExpectedR> decltype(auto) result = format_args.get(0).template visit<ExpectedR>([](auto a) -> ExpectedR {
+ assert((std::is_same_v<decltype(a), typename std::basic_format_arg<Context>::handle>));
+
+ return make_expected_result<ExpectedR>();
+ });
+
+ assert(result == expectedValue);
+}
+
+// Test specific for string and string_view.
+//
+// Since both result in a string_view there's no need to pass this as a
+// template argument.
+template <class Context, class ExpectedR, class From>
+void test_string_view(From value, ExpectedR expectedValue) {
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ LIBCPP_ASSERT(format_args.__size() == 1);
+ assert(format_args.get(0));
+
+ using CharT = typename Context::char_type;
+ using To = std::basic_string_view<CharT>;
+ using V = std::basic_string<CharT>;
+
+ std::same_as<ExpectedR> decltype(auto) result =
+ format_args.get(0).template visit<ExpectedR>([v = V(value.begin(), value.end())](auto a) -> ExpectedR {
+ if constexpr (std::is_same_v<To, decltype(a)>) {
+ assert(v == a);
+ return make_expected_result<ExpectedR>();
+ } else {
+ assert(false);
+ return {};
+ }
+ });
+
+ assert(result == expectedValue);
+}
+
+template <class CharT>
+void test() {
+ using Context = std::basic_format_context<CharT*, CharT>;
+ std::basic_string<CharT> empty;
+ std::basic_string<CharT> str = MAKE_STRING(CharT, "abc");
+
+ // Test boolean types.
+
+ test<Context, bool, ExpectedResultType>(true, visited);
+ test<Context, bool, ExpectedResultType>(false, visited);
+
+ test<Context, bool, std::string>(true, "visited");
+ test<Context, bool, std::string>(false, "visited");
+
+ test<Context, bool, long>(true, 192812079084L);
+ test<Context, bool, long>(false, 192812079084L);
+
+ // Test CharT types.
+
+ test<Context, CharT, ExpectedResultType, CharT>('a', visited);
+ test<Context, CharT, ExpectedResultType, CharT>('z', visited);
+ test<Context, CharT, ExpectedResultType, CharT>('0', visited);
+ test<Context, CharT, ExpectedResultType, CharT>('9', visited);
+
+ // Test char types.
+
+ if (std::is_same_v<CharT, char>) {
+ // char to char -> char
+ test<Context, CharT, ExpectedResultType, char>('a', visited);
+ test<Context, CharT, ExpectedResultType, char>('z', visited);
+ test<Context, CharT, ExpectedResultType, char>('0', visited);
+ test<Context, CharT, ExpectedResultType, char>('9', visited);
+ } else {
+ if (std::is_same_v<CharT, wchar_t>) {
+ // char to wchar_t -> wchar_t
+ test<Context, wchar_t, ExpectedResultType, char>('a', visited);
+ test<Context, wchar_t, ExpectedResultType, char>('z', visited);
+ test<Context, wchar_t, ExpectedResultType, char>('0', visited);
+ test<Context, wchar_t, ExpectedResultType, char>('9', visited);
+ } else if (std::is_signed_v<char>) {
+ // char to CharT -> int
+ // This happens when CharT is a char8_t, char16_t, or char32_t and char
+ // is a signed type.
+ // Note if sizeof(CharT) > sizeof(int) this test fails. If there are
+ // platforms where that occurs extra tests need to be added for char32_t
+ // testing it against a long long.
+ test<Context, int, ExpectedResultType, char>('a', visited);
+ test<Context, int, ExpectedResultType, char>('z', visited);
+ test<Context, int, ExpectedResultType, char>('0', visited);
+ test<Context, int, ExpectedResultType, char>('9', visited);
+ } else {
+ // char to CharT -> unsigned
+ // This happens when CharT is a char8_t, char16_t, or char32_t and char
+ // is an unsigned type.
+ // Note if sizeof(CharT) > sizeof(unsigned) this test fails. If there are
+ // platforms where that occurs extra tests need to be added for char32_t
+ // testing it against an unsigned long long.
+ test<Context, unsigned, ExpectedResultType, char>('a', visited);
+ test<Context, unsigned, ExpectedResultType, char>('z', visited);
+ test<Context, unsigned, ExpectedResultType, char>('0', visited);
+ test<Context, unsigned, ExpectedResultType, char>('9', visited);
+ }
+ }
+
+ // Test signed integer types.
+
+ test<Context, int, ExpectedResultType, signed char>(std::numeric_limits<signed char>::min(), visited);
+ test<Context, int, ExpectedResultType, signed char>(0, visited);
+ test<Context, int, ExpectedResultType, signed char>(std::numeric_limits<signed char>::max(), visited);
+
+ test<Context, int, ExpectedResultType, short>(std::numeric_limits<short>::min(), visited);
+ test<Context, int, ExpectedResultType, short>(std::numeric_limits<signed char>::min(), visited);
+ test<Context, int, ExpectedResultType, short>(0, visited);
+ test<Context, int, ExpectedResultType, short>(std::numeric_limits<signed char>::max(), visited);
+ test<Context, int, ExpectedResultType, short>(std::numeric_limits<short>::max(), visited);
+
+ test<Context, int, ExpectedResultType, int>(std::numeric_limits<int>::min(), visited);
+ test<Context, int, ExpectedResultType, int>(std::numeric_limits<short>::min(), visited);
+ test<Context, int, ExpectedResultType, int>(std::numeric_limits<signed char>::min(), visited);
+ test<Context, int, ExpectedResultType, int>(0, visited);
+ test<Context, int, ExpectedResultType, int>(std::numeric_limits<signed char>::max(), visited);
+ test<Context, int, ExpectedResultType, int>(std::numeric_limits<short>::max(), visited);
+ test<Context, int, ExpectedResultType, int>(std::numeric_limits<int>::max(), visited);
+
+ using LongToType = std::conditional_t<sizeof(long) == sizeof(int), int, long long>;
+
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<long>::min(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<int>::min(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<short>::min(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<signed char>::min(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(0, visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<signed char>::max(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<short>::max(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<int>::max(), visited);
+ test<Context, LongToType, ExpectedResultType, long>(std::numeric_limits<long>::max(), visited);
+
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<long long>::min(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<long>::min(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<int>::min(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<short>::min(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<signed char>::min(), visited);
+ test<Context, long long, ExpectedResultType, long long>(0, visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<signed char>::max(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<short>::max(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<int>::max(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<long>::max(), visited);
+ test<Context, long long, ExpectedResultType, long long>(std::numeric_limits<long long>::max(), visited);
+
+#ifndef TEST_HAS_NO_INT128
+ test_handle<Context, __int128_t, ExpectedResultType>(0, visited);
+#endif // TEST_HAS_NO_INT128
+
+ // Test unsigned integer types.
+
+ test<Context, unsigned, ExpectedResultType, unsigned char>(0, visited);
+ test<Context, unsigned, ExpectedResultType, unsigned char>(std::numeric_limits<unsigned char>::max(), visited);
+
+ test<Context, unsigned, ExpectedResultType, unsigned short>(0, visited);
+ test<Context, unsigned, ExpectedResultType, unsigned short>(std::numeric_limits<unsigned char>::max(), visited);
+ test<Context, unsigned, ExpectedResultType, unsigned short>(std::numeric_limits<unsigned short>::max(), visited);
+
+ test<Context, unsigned, ExpectedResultType, unsigned>(0, visited);
+ test<Context, unsigned, ExpectedResultType, unsigned>(std::numeric_limits<unsigned char>::max(), visited);
+ test<Context, unsigned, ExpectedResultType, unsigned>(std::numeric_limits<unsigned short>::max(), visited);
+ test<Context, unsigned, ExpectedResultType, unsigned>(std::numeric_limits<unsigned>::max(), visited);
+
+ using UnsignedLongToType =
+ std::conditional_t<sizeof(unsigned long) == sizeof(unsigned), unsigned, unsigned long long>;
+
+ test<Context, UnsignedLongToType, ExpectedResultType, unsigned long>(0, visited);
+ test<Context, UnsignedLongToType, ExpectedResultType, unsigned long>(
+ std::numeric_limits<unsigned char>::max(), visited);
+ test<Context, UnsignedLongToType, ExpectedResultType, unsigned long>(
+ std::numeric_limits<unsigned short>::max(), visited);
+ test<Context, UnsignedLongToType, ExpectedResultType, unsigned long>(std::numeric_limits<unsigned>::max(), visited);
+ test<Context, UnsignedLongToType, ExpectedResultType, unsigned long>(
+ std::numeric_limits<unsigned long>::max(), visited);
+
+ test<Context, unsigned long long, ExpectedResultType, unsigned long long>(0, visited);
+ test<Context, unsigned long long, ExpectedResultType, unsigned long long>(
+ std::numeric_limits<unsigned char>::max(), visited);
+ test<Context, unsigned long long, ExpectedResultType, unsigned long long>(
+ std::numeric_limits<unsigned short>::max(), visited);
+ test<Context, unsigned long long, ExpectedResultType, unsigned long long>(
+ std::numeric_limits<unsigned>::max(), visited);
+ test<Context, unsigned long long, ExpectedResultType, unsigned long long>(
+ std::numeric_limits<unsigned long>::max(), visited);
+ test<Context, unsigned long long, ExpectedResultType, unsigned long long>(
+ std::numeric_limits<unsigned long long>::max(), visited);
+
+#ifndef TEST_HAS_NO_INT128
+ test_handle<Context, __uint128_t, ExpectedResultType>(0, visited);
+#endif // TEST_HAS_NO_INT128
+
+ // Test floating point types.
+
+ test<Context, float, ExpectedResultType, float>(-std::numeric_limits<float>::max(), visited);
+ test<Context, float, ExpectedResultType, float>(-std::numeric_limits<float>::min(), visited);
+ test<Context, float, ExpectedResultType, float>(-0.0, visited);
+ test<Context, float, ExpectedResultType, float>(0.0, visited);
+ test<Context, float, ExpectedResultType, float>(std::numeric_limits<float>::min(), visited);
+ test<Context, float, ExpectedResultType, float>(std::numeric_limits<float>::max(), visited);
+
+ test<Context, double, ExpectedResultType, double>(-std::numeric_limits<double>::max(), visited);
+ test<Context, double, ExpectedResultType, double>(-std::numeric_limits<double>::min(), visited);
+ test<Context, double, ExpectedResultType, double>(-0.0, visited);
+ test<Context, double, ExpectedResultType, double>(0.0, visited);
+ test<Context, double, ExpectedResultType, double>(std::numeric_limits<double>::min(), visited);
+ test<Context, double, ExpectedResultType, double>(std::numeric_limits<double>::max(), visited);
+
+ test<Context, long double, ExpectedResultType, long double>(-std::numeric_limits<long double>::max(), visited);
+ test<Context, long double, ExpectedResultType, long double>(-std::numeric_limits<long double>::min(), visited);
+ test<Context, long double, ExpectedResultType, long double>(-0.0, visited);
+ test<Context, long double, ExpectedResultType, long double>(0.0, visited);
+ test<Context, long double, ExpectedResultType, long double>(std::numeric_limits<long double>::min(), visited);
+ test<Context, long double, ExpectedResultType, long double>(std::numeric_limits<long double>::max(), visited);
+
+ // Test const CharT pointer types.
+
+ test<Context, const CharT*, ExpectedResultType, const CharT*>(empty.c_str(), visited);
+ test<Context, const CharT*, ExpectedResultType, const CharT*>(str.c_str(), visited);
+
+ // Test string_view types.
+
+ {
+ using From = std::basic_string_view<CharT>;
+
+ test_string_view<Context, ExpectedResultType>(From(), visited);
+ test_string_view<Context, ExpectedResultType>(From(empty.c_str()), visited);
+ test_string_view<Context, ExpectedResultType>(From(str.c_str()), visited);
+ }
+ {
+ using From = std::basic_string_view<CharT, constexpr_char_traits<CharT>>;
+
+ test_string_view<Context, ExpectedResultType>(From(), visited);
+ test_string_view<Context, ExpectedResultType>(From(empty.c_str()), visited);
+ test_string_view<Context, ExpectedResultType>(From(str.c_str()), visited);
+ }
+
+ // Test string types.
+
+ {
+ using From = std::basic_string<CharT>;
+
+ test_string_view<Context, ExpectedResultType>(From(), visited);
+ test_string_view<Context, ExpectedResultType>(From(empty.c_str()), visited);
+ test_string_view<Context, ExpectedResultType>(From(str.c_str()), visited);
+ }
+
+ {
+ using From = std::basic_string<CharT, constexpr_char_traits<CharT>, std::allocator<CharT>>;
+
+ test_string_view<Context, ExpectedResultType>(From(), visited);
+ test_string_view<Context, ExpectedResultType>(From(empty.c_str()), visited);
+ test_string_view<Context, ExpectedResultType>(From(str.c_str()), visited);
+ }
+
+ {
+ using From = std::basic_string<CharT, std::char_traits<CharT>, min_allocator<CharT>>;
+
+ test_string_view<Context, ExpectedResultType>(From(), visited);
+ test_string_view<Context, ExpectedResultType>(From(empty.c_str()), visited);
+ test_string_view<Context, ExpectedResultType>(From(str.c_str()), visited);
+ }
+
+ {
+ using From = std::basic_string<CharT, constexpr_char_traits<CharT>, min_allocator<CharT>>;
+
+ test_string_view<Context, ExpectedResultType>(From(), visited);
+ test_string_view<Context, ExpectedResultType>(From(empty.c_str()), visited);
+ test_string_view<Context, ExpectedResultType>(From(str.c_str()), visited);
+ }
+
+ // Test pointer types.
+
+ test<Context, const void*, ExpectedResultType>(nullptr, visited);
+ int i = 0;
+ test<Context, const void*, ExpectedResultType>(static_cast<void*>(&i), visited);
+ const int ci = 0;
+ test<Context, const void*, ExpectedResultType>(static_cast<const void*>(&ci), visited);
+}
+
+int main(int, char**) {
+ test<char>();
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+ test<wchar_t>();
+#endif
+
+ return 0;
+}
diff --git a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.deprecated.verify.cpp b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.deprecated.verify.cpp
new file mode 100644
index 000000000000000..acd9228369e6091
--- /dev/null
+++ b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.deprecated.verify.cpp
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
+// UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
+// UNSUPPORTED: clang-16 || clang-17
+// XFAIL: apple-clang
+
+// <format>
+
+// template<class Visitor, class Context>
+// see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
+
+#include <format>
+#include <tuple>
+
+#include "test_macros.h"
+
+template <typename CharT, class To, class From>
+void test(From value) {
+ using Context = std::basic_format_context<CharT*, CharT>;
+ auto store = std::make_format_args<Context>(value);
+ std::basic_format_args<Context> format_args{store};
+
+ // expected-warning-re at +1 1-2 {{std::basic_format_context{{.*}}' is deprecated}}
+ std::ignore = std::visit_format_arg([]([[maybe_unused]] auto a) -> To { return {}; }, format_args.get(0));
+}
+
+void test() {
+ test<char, bool>('a');
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+ test<wchar_t, bool>('a');
+#endif
+}
diff --git a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.pass.cpp b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.pass.cpp
index 3ddf2d0ff732a76..3497d8935c8d623 100644
--- a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit_format_arg.pass.cpp
@@ -11,7 +11,7 @@
// <format>
// template<class Visitor, class Context>
-// see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
+// see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg); // Deprecated in C++26
#include <algorithm>
#include <format>
@@ -23,6 +23,10 @@
#include "make_string.h"
#include "min_allocator.h"
+#if TEST_STD_VER >= 26 && defined(TEST_HAS_EXPLICIT_THIS_PARAMETER)
+TEST_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated-declarations")
+#endif
+
template <class Context, class To, class From>
void test(From value) {
auto store = std::make_format_args<Context>(value);
diff --git a/libcxx/test/std/utilities/format/format.arguments/format.args/get.pass.cpp b/libcxx/test/std/utilities/format/format.arguments/format.args/get.pass.cpp
index 0f3931adf54dfbe..a5d3703397f4e4a 100644
--- a/libcxx/test/std/utilities/format/format.arguments/format.args/get.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.arguments/format.args/get.pass.cpp
@@ -24,14 +24,17 @@ void test(From value) {
auto store = std::make_format_args<Context>(value);
const std::basic_format_args<Context> format_args{store};
- std::visit_format_arg(
- [v = To(value)](auto a) {
- if constexpr (std::is_same_v<To, decltype(a)>)
- assert(v == a);
- else
- assert(false);
- },
- format_args.get(0));
+ auto visitor = [v = To(value)](auto a) {
+ if constexpr (std::is_same_v<To, decltype(a)>)
+ assert(v == a);
+ else
+ assert(false);
+ };
+#if TEST_STD_VER >= 26 && defined(TEST_HAS_EXPLICIT_THIS_PARAMETER)
+ format_args.get(0).visit(visitor);
+#else
+ std::visit_format_arg(visitor, format_args.get(0));
+#endif
}
// Some types, as an extension, are stored in the variant. The Standard
@@ -41,9 +44,12 @@ void test_handle(T value) {
auto store = std::make_format_args<Context>(value);
std::basic_format_args<Context> format_args{store};
- std::visit_format_arg(
- [](auto a) { assert((std::is_same_v<decltype(a), typename std::basic_format_arg<Context>::handle>)); },
- format_args.get(0));
+ auto visitor = [](auto a) { assert((std::is_same_v<decltype(a), typename std::basic_format_arg<Context>::handle>)); };
+#if TEST_STD_VER >= 26 && defined(TEST_HAS_EXPLICIT_THIS_PARAMETER)
+ format_args.get(0).visit(visitor);
+#else
+ std::visit_format_arg(visitor, format_args.get(0));
+#endif
}
// Test specific for string and string_view.
@@ -58,14 +64,18 @@ void test_string_view(From value) {
using CharT = typename Context::char_type;
using To = std::basic_string_view<CharT>;
using V = std::basic_string<CharT>;
- std::visit_format_arg(
- [v = V(value.begin(), value.end())](auto a) {
- if constexpr (std::is_same_v<To, decltype(a)>)
- assert(v == a);
- else
- assert(false);
- },
- format_args.get(0));
+
+ auto visitor = [v = V(value.begin(), value.end())](auto a) {
+ if constexpr (std::is_same_v<To, decltype(a)>)
+ assert(v == a);
+ else
+ assert(false);
+ };
+#if TEST_STD_VER >= 26 && defined(TEST_HAS_EXPLICIT_THIS_PARAMETER)
+ format_args.get(0).visit(visitor);
+#else
+ std::visit_format_arg(visitor, format_args.get(0));
+#endif
}
template <class CharT>
diff --git a/libcxx/test/support/test_basic_format_arg.h b/libcxx/test/support/test_basic_format_arg.h
index d8547d34b6db436..1ec719a48b6c8ed 100644
--- a/libcxx/test/support/test_basic_format_arg.h
+++ b/libcxx/test/support/test_basic_format_arg.h
@@ -7,18 +7,22 @@
#include <concepts>
#include <format>
+#include <utility>
#include "test_macros.h"
/// Returns whether the basic_format_arg contains a type T with the expected value.
template <class Context, class T>
bool test_basic_format_arg(std::basic_format_arg<Context> arg, T expected) {
- return std::visit_format_arg(
- [expected](auto a) {
- if constexpr (std::same_as<decltype(a), T>)
- return a == expected;
- else
- return false;
- },
- arg);
+ auto visitor = [expected](auto a) {
+ if constexpr (std::same_as<decltype(a), T>)
+ return a == expected;
+ else
+ return false;
+ };
+#if TEST_STD_VER >= 26 && defined(TEST_HAS_EXPLICIT_THIS_PARAMETER)
+ return arg.visit(std::move(visitor));
+#else
+ return std::visit_format_arg(std::move(visitor), arg);
+#endif
}
diff --git a/libcxx/test/support/test_macros.h b/libcxx/test/support/test_macros.h
index fe68e13de6bcbaa..24f69c758f365cc 100644
--- a/libcxx/test/support/test_macros.h
+++ b/libcxx/test/support/test_macros.h
@@ -470,4 +470,9 @@ inline Tp const& DoNotOptimize(Tp const& value) {
# define TEST_IF_AIX(arg_true, arg_false) arg_false
#endif
+// Clang-18 has support for deducing this, but it does not set the FTM.
+#ifdef _LIBCPP_HAS_EXPLICIT_THIS_PARAMETER
+# define TEST_HAS_EXPLICIT_THIS_PARAMETER
+#endif
+
#endif // SUPPORT_TEST_MACROS_HPP
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index b7d95d451f21376..065b70620cd170e 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -467,6 +467,7 @@ def add_version_header(tc):
# "c++20": 202110 Not implemented P2372R3 Fixing locale handling in chrono formatters
"c++20": 202106,
# "c++23": 202207, Not implemented P2419R2 Clarify handling of encodings in localized formatting of chrono types
+ # "c++26": 202306, P2637R3 Member Visit (implemented)
# "c++26": 202311, P2918R2 Runtime format strings II (implemented)
},
# Note these three papers are adopted at the June 2023 meeting and have sequential numbering
>From bd816bb5f141caf7f527ed2ba9c6e0531e5f57de Mon Sep 17 00:00:00 2001
From: Zingam <zingam at outlook.com>
Date: Mon, 22 Jan 2024 20:42:27 +0200
Subject: [PATCH 2/2] Quick fix
---
.../format.arguments/format.arg/visit.return_type.pass.cpp | 3 ---
1 file changed, 3 deletions(-)
diff --git a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp
index 473278b7b443490..b2c40d160454759 100644
--- a/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.arguments/format.arg/visit.return_type.pass.cpp
@@ -131,9 +131,6 @@ void test() {
test<Context, bool, std::string>(true, "visited");
test<Context, bool, std::string>(false, "visited");
- test<Context, bool, long>(true, 192812079084L);
- test<Context, bool, long>(false, 192812079084L);
-
// Test CharT types.
test<Context, CharT, ExpectedResultType, CharT>('a', visited);
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