From a31517cb9ababe3195888eb91e7c1aa821540fc4 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 15 Nov 2019 19:58:27 +0000 Subject: [PATCH] libstdc++: Implement LWG 3149 for std::default_constructible The change approved in Belfast did not actually rename the concept from std::default_constructible to std::default_initializable, even though that was intended. That is expected to be done soon as a separate issue, so I'm implementing that now too. * include/bits/iterator_concepts.h (weakly_incrementable): Adjust. * include/std/concepts (default_constructible): Rename to default_initializable and require default-list-initialization and default-initialization to be valid (LWG 3149). (semiregular): Adjust to new name. * testsuite/std/concepts/concepts.lang/concept.defaultconstructible/ 1.cc: Rename directory to concept.defaultinitializable and adjust to new name. * testsuite/std/concepts/concepts.lang/concept.defaultinitializable/ lwg3149.cc: New test. * testsuite/util/testsuite_iterators.h (test_range): Adjust. From-SVN: r278314 --- libstdc++-v3/ChangeLog | 12 ++++++ libstdc++-v3/include/bits/iterator_concepts.h | 2 +- libstdc++-v3/include/std/concepts | 11 ++++-- .../1.cc | 40 ++++++++++---------- .../concept.defaultinitializable/lwg3149.cc | 43 ++++++++++++++++++++++ libstdc++-v3/testsuite/util/testsuite_iterators.h | 2 +- 6 files changed, 85 insertions(+), 25 deletions(-) rename libstdc++-v3/testsuite/std/concepts/concepts.lang/{concept.defaultconstructible => concept.defaultinitializable}/1.cc (50%) create mode 100644 libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/lwg3149.cc diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index e6094bd..3e4e898 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,5 +1,17 @@ 2019-11-15 Jonathan Wakely + * include/bits/iterator_concepts.h (weakly_incrementable): Adjust. + * include/std/concepts (default_constructible): Rename to + default_initializable and require default-list-initialization and + default-initialization to be valid (LWG 3149). + (semiregular): Adjust to new name. + * testsuite/std/concepts/concepts.lang/concept.defaultconstructible/ + 1.cc: Rename directory to concept.defaultinitializable and adjust to + new name. + * testsuite/std/concepts/concepts.lang/concept.defaultinitializable/ + lwg3149.cc: New test. + * testsuite/util/testsuite_iterators.h (test_range): Adjust. + * src/c++17/fs_path.cc [_GLIBCXX_FILESYSTEM_IS_WINDOWS] (is_disk_designator): New helper function. (path::_Parser::root_path()): Use is_disk_designator. diff --git a/libstdc++-v3/include/bits/iterator_concepts.h b/libstdc++-v3/include/bits/iterator_concepts.h index 90a8bc8..3843ba5 100644 --- a/libstdc++-v3/include/bits/iterator_concepts.h +++ b/libstdc++-v3/include/bits/iterator_concepts.h @@ -506,7 +506,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Requirements on types that can be incremented with ++. template - concept weakly_incrementable = default_constructible<_Iter> + concept weakly_incrementable = default_initializable<_Iter> && movable<_Iter> && requires(_Iter __i) { diff --git a/libstdc++-v3/include/std/concepts b/libstdc++-v3/include/std/concepts index e6d405a..98b3894 100644 --- a/libstdc++-v3/include/std/concepts +++ b/libstdc++-v3/include/std/concepts @@ -138,9 +138,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION concept constructible_from = destructible<_Tp> && is_constructible_v<_Tp, _Args...>; - /// [concept.defaultconstructible], concept default_constructible + /// [concept.defaultinitializable], concept default_initializable template - concept default_constructible = constructible_from<_Tp>; + concept default_initializable = constructible_from<_Tp> + && requires + { + _Tp{}; + (void) ::new _Tp; + }; /// [concept.moveconstructible], concept move_constructible template @@ -249,7 +254,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION && assignable_from<_Tp&, const _Tp&>; template - concept semiregular = copyable<_Tp> && default_constructible<_Tp>; + concept semiregular = copyable<_Tp> && default_initializable<_Tp>; // [concepts.compare], comparison concepts diff --git a/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultconstructible/1.cc b/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/1.cc similarity index 50% rename from libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultconstructible/1.cc rename to libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/1.cc index 56a4844..ed69e5c 100644 --- a/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultconstructible/1.cc +++ b/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/1.cc @@ -20,28 +20,28 @@ #include -static_assert( !std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( !std::default_constructible ); -static_assert( !std::default_constructible ); -static_assert( !std::default_constructible ); -static_assert( !std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( !std::default_constructible ); -static_assert( std::default_constructible ); -static_assert( !std::default_constructible ); +static_assert( !std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( !std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( !std::default_initializable ); +static_assert( std::default_initializable ); +static_assert( !std::default_initializable ); enum E { }; -static_assert( std::default_constructible ); +static_assert( std::default_initializable ); enum class CE { }; -static_assert( std::default_constructible ); +static_assert( std::default_initializable ); struct A { }; -static_assert( std::default_constructible ); +static_assert( std::default_initializable ); union B { }; static_assert( std::constructible_from ); @@ -50,7 +50,7 @@ struct C C(void* = nullptr) { } ~C() noexcept(false) { } }; -static_assert( !std::default_constructible ); +static_assert( !std::default_initializable ); class D { @@ -60,4 +60,4 @@ public: private: ~D() { } }; -static_assert( !std::default_constructible ); +static_assert( !std::default_initializable ); diff --git a/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/lwg3149.cc b/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/lwg3149.cc new file mode 100644 index 0000000..024601b --- /dev/null +++ b/libstdc++-v3/testsuite/std/concepts/concepts.lang/concept.defaultinitializable/lwg3149.cc @@ -0,0 +1,43 @@ +// Copyright (C) 2019 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 + +// Default-initialization of const T is only valid for class types that are +// const-default-constructible. +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +struct A { int i; }; +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +struct B { int i; long l; }; +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +struct C : A { }; +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); +struct D { A a; }; +static_assert( !std::default_initializable ); +static_assert( !std::default_initializable ); + +struct S0 { explicit S0() = default; }; +struct S1 { S0 x; }; // Note: aggregate +// S1{} would be ill-formed, due to copy-list-initialization of S1::x from {} +static_assert( !std::default_initializable ); diff --git a/libstdc++-v3/testsuite/util/testsuite_iterators.h b/libstdc++-v3/testsuite/util/testsuite_iterators.h index 4c5e9a3..13993a4 100644 --- a/libstdc++-v3/testsuite/util/testsuite_iterators.h +++ b/libstdc++-v3/testsuite/util/testsuite_iterators.h @@ -682,7 +682,7 @@ namespace __gnu_test auto get_iterator(T* p) { - if constexpr (std::default_constructible>) + if constexpr (std::default_initializable>) return Iter(p, &bounds); else return iterator(p, &bounds); -- 2.7.4