[NFC][libc++][format] Tests formatter requirements.

[Mordante]

Summary

Like done D149543 this validates the other formatter specializations.

[Mordante]

CI fixes.

[ldionne]

LGTM w/ comments and CI.

libcxx/test/std/containers/container.adaptors/container.adaptors.format/types.compile.pass.cpp

19

27–30

I think this comment does not apply to this test.

libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/types.compile.pass.cpp

21–24

libcxx/test/std/utilities/format/types.compile.pass.cpp

55–58

[Mordante]

In D150041#4329887, @ldionne wrote:

LGTM w/ comments and CI.

The CI was green, updating the result on Phab was red. I've applied the fixes to the earlier committed vector<bool>::reference too.

libcxx/test/std/containers/container.adaptors/container.adaptors.format/types.compile.pass.cpp

27–30

I've changed the wording slightly why we don't use the concept here.

libcxx/test/std/containers/container.adaptors/container.adaptors.format/types.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-format
+
+// [container.adaptors.format]/1
+//   For each of queue, priority_queue, and stack, the library provides the
+//   following formatter specialization where adaptor-type is the name of the
+//   template:
+//    template<class charT, class T, formattable<charT> Container, class... U>
+//    struct formatter<adaptor-type<T, Container, U...>, charT>;
+//
+// Note it is unspecified in which header the adaptor formatters reside. In
+// lib++ they are in <format>. However their own headers are still required for
+// the declarations of these types.
+
+// [format.formatter.spec]/4
+//   If the library provides an explicit or partial specialization of
+//   formatter<T, charT>, that specialization is enabled and meets the
+//   Formatter requirements except as noted otherwise.
+//
+// Tests parts of the BasicFormatter requirements. Like the formattable concept
+// it uses the semiregular concept. It test does not use the formattable
+// concept since it is the intention the formatter is available without
+// including the format header.
+
+#include <concepts>
+#include <format>
+#include <queue>
+#include <stack>
+
+#include "test_macros.h"
+
+static_assert(std::semiregular<std::formatter<std::queue<int>, char>>);
+static_assert(std::semiregular<std::formatter<std::priority_queue<int>, char>>);
+static_assert(std::semiregular<std::formatter<std::stack<int>, char>>);
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+static_assert(std::semiregular<std::formatter<std::queue<int>, wchar_t>>);
+static_assert(std::semiregular<std::formatter<std::priority_queue<int>, wchar_t>>);
+static_assert(std::semiregular<std::formatter<std::stack<int>, wchar_t>>);
+#endif // TEST_HAS_NO_WIDE_CHARACTERS

libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.id/types.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-format
+// UNSUPPORTED: no-threads
+
+// <thread>
+
+// template<class charT> struct formatter<thread::id, charT>;
+
+// [format.formatter.spec]/4
+//   If the library provides an explicit or partial specialization of
+//   formatter<T, charT>, that specialization is enabled and meets the
+//   Formatter requirements except as noted otherwise.
+//
+// Tests parts of the BasicFormatter requirements. Like the formattable concept
+// it uses the semiregular concept. It test does not use the formattable
+// concept since it is the intention the formatter is available without
+// including the format header.
+
+// TODO FMT Evaluate what to do with [format.formatter.spec]/2
+// [format.formatter.spec]/2
+//   Each header that declares the template formatter provides the following
+//   enabled specializations:
+// Then there is a list of formatters, but is that really useful?
+// Note this should be discussed in LEWG.
+
+#include <concepts>
+#include <thread>
+
+#include "test_macros.h"
+
+static_assert(std::semiregular<std::formatter<std::thread::id, char>>);
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+static_assert(std::semiregular<std::formatter<std::thread::id, wchar_t>>);
+#endif

libcxx/test/std/utilities/format/types.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-format
+
+// <format>
+
+// C++20
+// ...  provides the following enabled specializations:
+//  The debug-enabled specializations
+//    template<> struct formatter<char, char>;
+//    template<> struct formatter<char, wchar_t>;
+//    template<> struct formatter<wchar_t, wchar_t>;
+//
+//  For each charT, the debug-enabled string type specializations template<>
+//  struct formatter<charT*, charT>;
+//    template<> struct formatter<const charT*, charT>;
+//    template<size_t N> struct formatter<charT[N], charT>;
+//    template<class traits, class Allocator>
+//      struct formatter<basic_string<charT, traits, Allocator>, charT>;
+//    template<class traits>
+//      struct formatter<basic_string_view<charT, traits>, charT>;
+//
+//  For each charT, for each cv-unqualified arithmetic type ArithmeticT other
+//  than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
+//    template<> struct formatter<ArithmeticT, charT>;
+//
+//  For each charT, the pointer type specializations template<> struct
+//  formatter<nullptr_t, charT>;
+//    template<> struct formatter<void*, charT>;
+//    template<> struct formatter<const void*, charT>;
+
+// C++23
+// [format.range.formatter]
+//   template<class T, class charT = char>
+//     requires same_as<remove_cvref_t<T>, T> && formattable<T, charT>
+//   class range_formatter;
+//
+// [format.tuple]/1
+//   For each of pair and tuple, the library provides the following formatter
+//   specialization where pair-or-tuple is the name of the template:
+//   template<class charT, formattable<charT>... Ts>
+//   struct formatter<pair-or-tuple<Ts...>, charT> {
+
+// [format.formatter.spec]/4
+//   If the library provides an explicit or partial specialization of
+//   formatter<T, charT>, that specialization is enabled and meets the
+//   Formatter requirements except as noted otherwise.
+//
+// Tests parts of the BasicFormatter requirements. Like the formattable concept
+// it uses the semiregular concept. It test does not use the formattable
+// concept since it is the intention the formatter is available without
+// including the format header.
+
+#include <concepts>
+#include <format>
+
+#include "test_macros.h"
+
+static_assert(std::semiregular<std::formatter<char, char>>);
+
+static_assert(std::semiregular<std::formatter<char*, char>>);
+static_assert(std::semiregular<std::formatter<const char*, char>>);
+static_assert(std::semiregular<std::formatter<char[1], char>>);
+static_assert(std::semiregular<std::formatter<std::string, char>>);
+static_assert(std::semiregular<std::formatter<std::string_view, char>>);
+
+static_assert(std::semiregular<std::formatter<bool, char>>);
+
+static_assert(std::semiregular<std::formatter<signed char, char>>);
+static_assert(std::semiregular<std::formatter<signed short, char>>);
+static_assert(std::semiregular<std::formatter<signed int, char>>);
+static_assert(std::semiregular<std::formatter<signed long, char>>);
+static_assert(std::semiregular<std::formatter<signed long long, char>>);
+
+static_assert(std::semiregular<std::formatter<unsigned char, char>>);
+static_assert(std::semiregular<std::formatter<unsigned short, char>>);
+static_assert(std::semiregular<std::formatter<unsigned int, char>>);
+static_assert(std::semiregular<std::formatter<unsigned long, char>>);
+static_assert(std::semiregular<std::formatter<unsigned long long, char>>);
+
+static_assert(std::semiregular<std::formatter<float, char>>);
+static_assert(std::semiregular<std::formatter<double, char>>);
+static_assert(std::semiregular<std::formatter<long double, char>>);
+
+static_assert(std::semiregular<std::formatter<nullptr_t, char>>);
+static_assert(std::semiregular<std::formatter<void*, char>>);
+static_assert(std::semiregular<std::formatter<const void*, char>>);
+
+#if TEST_STD_VER > 20
+static_assert(std::semiregular<std::range_formatter<int, char>>);
+static_assert(std::semiregular<std::formatter<std::tuple<int>, char>>);
+static_assert(std::semiregular<std::range_formatter<std::pair<int, int>, char>>);
+#endif
+
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+static_assert(std::semiregular<std::formatter<char, wchar_t>>);
+static_assert(std::semiregular<std::formatter<wchar_t, wchar_t>>);
+
+static_assert(std::semiregular<std::formatter<wchar_t*, wchar_t>>);
+static_assert(std::semiregular<std::formatter<const wchar_t*, wchar_t>>);
+static_assert(std::semiregular<std::formatter<wchar_t[1], wchar_t>>);
+static_assert(std::semiregular<std::formatter<std::wstring, wchar_t>>);
+static_assert(std::semiregular<std::formatter<std::wstring_view, wchar_t>>);
+
+static_assert(std::semiregular<std::formatter<bool, wchar_t>>);
+
+static_assert(std::semiregular<std::formatter<signed char, wchar_t>>);
+static_assert(std::semiregular<std::formatter<signed short, wchar_t>>);
+static_assert(std::semiregular<std::formatter<signed int, wchar_t>>);
+static_assert(std::semiregular<std::formatter<signed long, wchar_t>>);
+static_assert(std::semiregular<std::formatter<signed long long, wchar_t>>);
+
+static_assert(std::semiregular<std::formatter<unsigned char, wchar_t>>);
+static_assert(std::semiregular<std::formatter<unsigned short, wchar_t>>);
+static_assert(std::semiregular<std::formatter<unsigned int, wchar_t>>);
+static_assert(std::semiregular<std::formatter<unsigned long, wchar_t>>);
+static_assert(std::semiregular<std::formatter<unsigned long long, wchar_t>>);
+
+static_assert(std::semiregular<std::formatter<float, wchar_t>>);
+static_assert(std::semiregular<std::formatter<double, wchar_t>>);
+static_assert(std::semiregular<std::formatter<long double, wchar_t>>);
+
+static_assert(std::semiregular<std::formatter<nullptr_t, wchar_t>>);
+static_assert(std::semiregular<std::formatter<void*, wchar_t>>);
+static_assert(std::semiregular<std::formatter<const void*, wchar_t>>);
+
+#  if TEST_STD_VER > 20
+static_assert(std::semiregular<std::range_formatter<int, wchar_t>>);
+static_assert(std::semiregular<std::formatter<std::tuple<int>, wchar_t>>);
+static_assert(std::semiregular<std::range_formatter<std::pair<int, int>, wchar_t>>);
+#  endif
+#endif // TEST_HAS_NO_WIDE_CHARACTERS