From 269e8130b77065452698ab97e5da77d132d00276 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Wed, 5 Feb 2020 10:35:19 +0000 Subject: [PATCH] libstdc++: Remove workarounds for constraints on alias templates The G++ bug has been fixed for a couple of months so we can remove these workarounds that define alias templates in terms of constrained class templates. We can just apply constraints directly to alias templates as specified in the C++20 working draft. * include/bits/iterator_concepts.h (iter_reference_t) (iter_rvalue_reference_t, iter_common_reference_t, indirect_result_t): Remove workarounds for PR c++/67704. * testsuite/24_iterators/aliases.cc: New test. --- libstdc++-v3/ChangeLog | 7 ++ libstdc++-v3/include/bits/iterator_concepts.h | 67 +++---------------- .../testsuite/24_iterators/aliases.cc | 61 +++++++++++++++++ 3 files changed, 79 insertions(+), 56 deletions(-) create mode 100644 libstdc++-v3/testsuite/24_iterators/aliases.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index b54f1f694e4..76a6e2b542d 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,10 @@ +2020-02-05 Jonathan Wakely + + * include/bits/iterator_concepts.h (iter_reference_t) + (iter_rvalue_reference_t, iter_common_reference_t, indirect_result_t): + Remove workarounds for PR c++/67704. + * testsuite/24_iterators/aliases.cc: New test. + 2020-02-05 Patrick Palka * include/bits/stl_iterator.h (move_iterator::move_iterator): Move __i diff --git a/libstdc++-v3/include/bits/iterator_concepts.h b/libstdc++-v3/include/bits/iterator_concepts.h index bf581597229..d9b8958d0a7 100644 --- a/libstdc++-v3/include/bits/iterator_concepts.h +++ b/libstdc++-v3/include/bits/iterator_concepts.h @@ -70,17 +70,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { { *__t } -> __can_reference; }; - - // FIXME: needed due to PR c++/67704 - template<__detail::__dereferenceable _Tp> - struct __iter_ref - { - using type = decltype(*std::declval<_Tp&>()); - }; } // namespace __detail - template - using iter_reference_t = typename __detail::__iter_ref<_Tp>::type; + template<__detail::__dereferenceable _Tp> + using iter_reference_t = decltype(*std::declval<_Tp&>()); namespace ranges { @@ -127,26 +120,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION } // inline namespace __cust } // namespace ranges - namespace __detail - { - // FIXME: needed due to PR c++/67704 - template<__detail::__dereferenceable _Tp> - struct __iter_rvalue_ref - { }; - - template<__detail::__dereferenceable _Tp> - requires requires(_Tp& __t) - { - { ranges::iter_move(__t) } -> __detail::__can_reference; - } - struct __iter_rvalue_ref<_Tp> - { using type = decltype(ranges::iter_move(std::declval<_Tp&>())); }; - - } // namespace __detail - - template + template<__detail::__dereferenceable _Tp> + requires requires(_Tp& __t) + { { ranges::iter_move(__t) } -> __detail::__can_reference; } using iter_rvalue_reference_t - = typename __detail::__iter_rvalue_ref<_Tp>::type; + = decltype(ranges::iter_move(std::declval<_Tp&>())); template struct incrementable_traits { }; @@ -467,18 +445,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION && common_reference_with&&, const iter_value_t<_In>&>; - namespace __detail - { - // FIXME: needed due to PR c++/67704 - template - struct __iter_common_ref - : common_reference, iter_value_t<_Tp>&> - { }; - } // namespace __detail - - template + template using iter_common_reference_t - = typename __detail::__iter_common_ref<_Tp>::type; + = common_reference_t, iter_value_t<_Tp>&>; /// Requirements for writing a value into an iterator's referenced object. template @@ -663,24 +632,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION && strict_weak_order<_Fn&, iter_common_reference_t<_I1>, iter_common_reference_t<_I2>>; - namespace __detail - { - // FIXME: needed due to PR c++/67704 - template - struct __indirect_result - { }; - - template - requires (readable<_Is> && ...) - && invocable<_Fn, iter_reference_t<_Is>...> - struct __indirect_result<_Fn, _Is...> - : invoke_result<_Fn, iter_reference_t<_Is>...> - { }; - } // namespace __detail - template - using indirect_result_t = typename - __detail::__indirect_result<_Fn, _Is...>::type; + requires (readable<_Is> && ...) + && invocable<_Fn, iter_reference_t<_Is>...> + using indirect_result_t = invoke_result_t<_Fn, iter_reference_t<_Is>...>; /// [projected], projected template _Proj> diff --git a/libstdc++-v3/testsuite/24_iterators/aliases.cc b/libstdc++-v3/testsuite/24_iterators/aliases.cc new file mode 100644 index 00000000000..29bb56ec0d3 --- /dev/null +++ b/libstdc++-v3/testsuite/24_iterators/aliases.cc @@ -0,0 +1,61 @@ +// 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 + +template +struct Dereferenceable { T operator*(); }; + +template + concept has_iter_reference + = requires { typename std::iter_reference_t; }; + +template + concept is_iter_reference_for + = has_iter_reference && std::same_as>; + +static_assert(!has_iter_reference>); +static_assert(is_iter_reference_for>); +static_assert(is_iter_reference_for>); +static_assert(is_iter_reference_for>); +static_assert(is_iter_reference_for); +static_assert(is_iter_reference_for); + +template + concept has_iter_rvalue_reference + = requires { typename std::iter_rvalue_reference_t; }; + +template + concept is_iter_rvalue_reference_for + = has_iter_rvalue_reference + && std::same_as>; + +static_assert(!has_iter_rvalue_reference>); +static_assert(is_iter_rvalue_reference_for>); +static_assert(is_iter_rvalue_reference_for>); +static_assert(is_iter_rvalue_reference_for>); +static_assert(is_iter_rvalue_reference_for); +static_assert(is_iter_rvalue_reference_for); + +// These functions should be found by ADL. std::move is not applied to result. +long iter_move(Dereferenceable); +long& iter_move(Dereferenceable); +static_assert(is_iter_rvalue_reference_for>); +static_assert(is_iter_rvalue_reference_for>);