From 5713834e4b99e4c4c99eef15698a497f091b7dc4 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 7 Feb 2020 11:31:12 +0000 Subject: [PATCH] libstdc++: Enable three-way comparison for iota_view iterators The declaration of operator<=> was disabled due to a typo in the macro. The declaration was also ill-formed when three_way_comparable<_Winc> is not satisfied, which is a defect in the C++20 draft. * include/std/ranges (iota_view::_Iterator): Fix typo in name of __cpp_lib_three_way_comparison macro and use deduced return type for operator<=>. * testsuite/std/ranges/iota/iterator.cc: New test. --- libstdc++-v3/ChangeLog | 7 ++++ libstdc++-v3/include/std/ranges | 4 +-- .../testsuite/std/ranges/iota/iterator.cc | 35 +++++++++++++++++++ 3 files changed, 44 insertions(+), 2 deletions(-) create mode 100644 libstdc++-v3/testsuite/std/ranges/iota/iterator.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index b9c7f436a81..18d02cbfb40 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,10 @@ +2020-02-07 Jonathan Wakely + + * include/std/ranges (iota_view::_Iterator): Fix typo in name of + __cpp_lib_three_way_comparison macro and use deduced return type for + operator<=>. + * testsuite/std/ranges/iota/iterator.cc: New test. + 2020-02-07 Patrick Palka Jonathan Wakely diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 860f7283be5..dc277a74fb6 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -776,8 +776,8 @@ namespace ranges requires totally_ordered<_Winc> { return !(__x < __y); } -#ifdef __cpp_lib_threeway_comparison - friend constexpr compare_three_way_result_t<_Winc> +#ifdef __cpp_lib_three_way_comparison + friend constexpr auto operator<=>(const _Iterator& __x, const _Iterator& __y) requires totally_ordered<_Winc> && three_way_comparable<_Winc> { return __x._M_value <=> __y._M_value; } diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iterator.cc b/libstdc++-v3/testsuite/std/ranges/iota/iterator.cc new file mode 100644 index 00000000000..4d471431eae --- /dev/null +++ b/libstdc++-v3/testsuite/std/ranges/iota/iterator.cc @@ -0,0 +1,35 @@ +// Copyright (C) 2020 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// . + +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } + +#include + +auto i = std::ranges::iota_view{}.begin(); +static_assert( std::three_way_comparable ); + +struct Inc { + Inc& operator++(); + Inc operator++(int); + friend long operator-(Inc, Inc); +}; +static_assert( ! std::three_way_comparable ); + +// Instantiating iterator type must be valid despite !three_way_comparable +auto j = std::ranges::iota_view{}.begin(); +static_assert( ! std::three_way_comparable ); -- 2.30.2