From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id F2F0F3895FEF; Tue, 15 Nov 2022 14:29:30 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F2F0F3895FEF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1668522570; bh=DxtcAiK79/NK7uPDIVZuL3yyVa9R9T7lpnBZivTTNes=; h=From:To:Subject:Date:From; b=wwkavf685+QjAMnblFFZwENBGTNPn42aSBdGIhWaI6pag+47E/EyeczRMYr4s7BP3 V+4vWxmRb2Zbccykz02f6LQYUAgP3zf/KQWs+/ZoDGPrnGpke5POWZ21bWrjDIH6nW YF4P2KuM/ENlTQX3O1NuffQiZ2ON9lWUFl5SKR8Q= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r13-4060] libstc++: std::formattable concept should not be defined for C++20 X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: ce86d9678b7f3d914133a035fbf8088504d8bad8 X-Git-Newrev: a5d4f38fbe3bf71efd465d5260955bd6675765fd Message-Id: <20221115142930.F2F0F3895FEF@sourceware.org> Date: Tue, 15 Nov 2022 14:29:30 +0000 (GMT) List-Id: https://gcc.gnu.org/g:a5d4f38fbe3bf71efd465d5260955bd6675765fd commit r13-4060-ga5d4f38fbe3bf71efd465d5260955bd6675765fd Author: Jonathan Wakely Date: Tue Nov 15 13:59:51 2022 +0000 libstc++: std::formattable concept should not be defined for C++20 This concept was added by a C++23 proposal, so don't define it for C++20. Split the format/formatter/formatter.cc test into two parts, one that tests the C++20 requirements and one that tests the C++23 concept. libstdc++-v3/ChangeLog: * include/std/format (formattable): Only define for C++23/ * testsuite/std/format/formatter.cc: Moved to... * testsuite/std/format/formatter/requirements.cc: ...here. * testsuite/std/format/formatter/concept.cc: New test. * testsuite/std/format/functions/format.cc: Replace use of std::formattable in C++20. Diff: --- libstdc++-v3/include/std/format | 11 ++++- .../testsuite/std/format/formatter/concept.cc | 46 ++++++++++++++++++ .../{formatter.cc => formatter/requirements.cc} | 54 +++++----------------- .../testsuite/std/format/functions/format.cc | 12 ++++- 4 files changed, 77 insertions(+), 46 deletions(-) diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format index c79c8f2ce31..204a1710aca 100644 --- a/libstdc++-v3/include/std/format +++ b/libstdc++-v3/include/std/format @@ -2181,11 +2181,14 @@ namespace __format } // namespace __format /// @endcond +#if __cplusplus > 202002L // [format.formattable], concept formattable template concept formattable = __format::__formattable_impl, _CharT>; +#endif +#if __cpp_lib_format_ranges /// @cond undocumented namespace __format { @@ -2199,6 +2202,7 @@ namespace __format = conditional_t<__const_formattable_range<_Rg, _CharT>, const _Rg, _Rg>; } // namespace __format /// @endcond +#endif // format_ranges /// An iterator after the last character written, and the number of /// characters that would have been written. @@ -3485,16 +3489,19 @@ namespace __format std::visit_format_arg([this](auto& __arg) { using _Type = remove_reference_t; + using _Formatter = typename _Context::template formatter_type<_Type>; if constexpr (is_same_v<_Type, monostate>) __format::__invalid_arg_id_in_format_string(); else if constexpr (is_same_v<_Type, handle>) __arg.format(this->_M_pc, this->_M_fc); - else + else if constexpr (is_default_constructible_v<_Formatter>) { - typename _Context::template formatter_type<_Type> __f; + _Formatter __f; this->_M_pc.advance_to(__f.parse(this->_M_pc)); this->_M_fc.advance_to(__f.format(__arg, this->_M_fc)); } + else + static_assert(__format::__formattable_with<_Type, _Context>); }, _M_fc.arg(__id)); } }; diff --git a/libstdc++-v3/testsuite/std/format/formatter/concept.cc b/libstdc++-v3/testsuite/std/format/formatter/concept.cc new file mode 100644 index 00000000000..fe56dc44a68 --- /dev/null +++ b/libstdc++-v3/testsuite/std/format/formatter/concept.cc @@ -0,0 +1,46 @@ +// { dg-options "-std=gnu++23" } +// { dg-do compile { target c++23 } } + +#include + +struct S { }; + +template<> struct std::formatter : std::formatter { + template + auto format(S, std::basic_format_context& ctx) const { + return formatter::format("ess", ctx); + } +}; + +struct T { }; + +template<> struct std::formatter : std::formatter { + // This function only accepts std::format_context, not other contexts. + auto format(T, std::format_context& ctx) const { + return formatter::format("tee", ctx); + } +}; + +struct U { }; + +void +test_concept() // [format.formattable] +{ + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( ! std::formattable ); + static_assert( ! std::formattable ); + static_assert( ! std::formattable ); + static_assert( std::formattable ); + static_assert( std::formattable ); + static_assert( ! std::formattable ); // only formats as char + static_assert( ! std::formattable ); // formatter not generic + static_assert( ! std::formattable ); // no formatter +} diff --git a/libstdc++-v3/testsuite/std/format/formatter.cc b/libstdc++-v3/testsuite/std/format/formatter/requirements.cc similarity index 50% rename from libstdc++-v3/testsuite/std/format/formatter.cc rename to libstdc++-v3/testsuite/std/format/formatter/requirements.cc index 64ff2dbfbfd..3bff8bdbd5d 100644 --- a/libstdc++-v3/testsuite/std/format/formatter.cc +++ b/libstdc++-v3/testsuite/std/format/formatter/requirements.cc @@ -4,48 +4,6 @@ #include #include -struct S { }; - -template<> struct std::formatter : std::formatter { - template - auto format(S, std::basic_format_context& ctx) const { - return formatter::format("ess", ctx); - } -}; - -struct T { }; - -template<> struct std::formatter : std::formatter { - // This function only accepts std::format_context, not other contexts. - auto format(T, std::format_context& ctx) const { - return formatter::format("tee", ctx); - } -}; - -struct U { }; - -void -test_concept() // [format.formattable] -{ - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( ! std::formattable ); - static_assert( ! std::formattable ); - static_assert( ! std::formattable ); - static_assert( std::formattable ); - static_assert( std::formattable ); - static_assert( ! std::formattable ); // only formats as char - static_assert( ! std::formattable ); // formatter not generic - static_assert( ! std::formattable ); // no formatter -} - enum color { red, green, blue }; const char* color_names[] = { "red", "green", "blue" }; @@ -62,6 +20,12 @@ test_specializations() // [format.formatter.spec] { std::string s0 = std::format("{}", 42); // OK, library-provided formatter VERIFY( s0 == "42" ); + using Fi = std::format_context::formatter_type; + static_assert( std::is_default_constructible_v ); + static_assert( std::is_copy_constructible_v ); + static_assert( std::is_move_constructible_v ); + static_assert( std::is_copy_assignable_v ); + static_assert( std::is_move_assignable_v ); // std::string s1 = std::format("{}", L"foo"); // error: disabled formatter using Fw = std::format_context::formatter_type; @@ -73,6 +37,12 @@ test_specializations() // [format.formatter.spec] std::string s2 = std::format("{}", red); // OK, user-provided formatter VERIFY( s2 == "red" ); + using Fc = std::format_context::formatter_type; + static_assert( std::is_default_constructible_v ); + static_assert( std::is_copy_constructible_v ); + static_assert( std::is_move_constructible_v ); + static_assert( std::is_copy_assignable_v ); + static_assert( std::is_move_assignable_v ); // std::string s3 = std::format("{}", err{}); // error: disabled formatter using Ferr = std::format_context::formatter_type; diff --git a/libstdc++-v3/testsuite/std/format/functions/format.cc b/libstdc++-v3/testsuite/std/format/functions/format.cc index 165ef41b4b3..c01405eac90 100644 --- a/libstdc++-v3/testsuite/std/format/functions/format.cc +++ b/libstdc++-v3/testsuite/std/format/functions/format.cc @@ -297,17 +297,25 @@ bool format_float() return s == "-0. != +0.500 "; } +#if __cplusplus > 202002L +template +concept formattable = std::formattable; +#else +template +concept formattable = requires (T t, char* p) { std::to_chars(p, p, t); }; +#endif + void test_float128() { #ifdef __SIZEOF_FLOAT128__ - if constexpr (std::formattable<__float128, char>) + if constexpr (formattable<__float128>) VERIFY( format_float<__float128>() ); else std::puts("Cannot format __float128 on this target"); #endif #if __FLT128_DIG__ - if constexpr (std::formattable<_Float128, char>) + if constexpr (formattable<_Float128>) VERIFY( format_float<_Float128>() ); else std::puts("Cannot format _Float128 on this target");