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libstdc++: Add noexcept to std::optional initialization (PR 96036)

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libstdc++-v3/ChangeLog:

	PR libstdc++/96036
	* include/std/optional (optional): Add noexcept-specifier to
	every constructor, assignment operator, emplace function and
	dereference operator.
	* testsuite/20_util/optional/assignment/noexcept.cc: New test.
	* testsuite/20_util/optional/cons/noexcept.cc: New test.
This commit is contained in:
Jonathan Wakely 2020-07-06 21:54:12 +01:00
parent e88218fd5a
commit 8992cd1892
3 changed files with 170 additions and 6 deletions
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31
libstdc++-v3/include/std/optional
View File

@ -698,6 +698,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
is_convertible<_Up&&, _Tp>> = true>
constexpr
optional(_Up&& __t)
noexcept(is_nothrow_constructible_v<_Tp, _Up>)
: _Base(std::in_place, std::forward<_Up>(__t)) { }
template<typename _Up = _Tp,
@ -706,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<is_convertible<_Up&&, _Tp>>> = false>
explicit constexpr
optional(_Up&& __t)
noexcept(is_nothrow_constructible_v<_Tp, _Up>)
: _Base(std::in_place, std::forward<_Up>(__t)) { }
template<typename _Up,
@ -715,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<__converts_from_optional<_Tp, _Up>>> = true>
constexpr
optional(const optional<_Up>& __t)
noexcept(is_nothrow_constructible_v<_Tp, const _Up&>)
{
if (__t)
emplace(*__t);
@ -727,6 +730,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<__converts_from_optional<_Tp, _Up>>> = false>
explicit constexpr
optional(const optional<_Up>& __t)
noexcept(is_nothrow_constructible_v<_Tp, const _Up&>)
{
if (__t)
emplace(*__t);
@ -739,6 +743,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<__converts_from_optional<_Tp, _Up>>> = true>
constexpr
optional(optional<_Up>&& __t)
noexcept(is_nothrow_constructible_v<_Tp, _Up>)
{
if (__t)
emplace(std::move(*__t));
@ -751,6 +756,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<__converts_from_optional<_Tp, _Up>>> = false>
explicit constexpr
optional(optional<_Up>&& __t)
noexcept(is_nothrow_constructible_v<_Tp, _Up>)
{
if (__t)
emplace(std::move(*__t));
@ -760,6 +766,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Requires<is_constructible<_Tp, _Args&&...>> = false>
explicit constexpr
optional(in_place_t, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
: _Base(std::in_place, std::forward<_Args>(__args)...) { }
template<typename _Up, typename... _Args,
@ -768,8 +775,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Args&&...>> = false>
explicit constexpr
optional(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&,
_Args...>)
: _Base(std::in_place, __il, std::forward<_Args>(__args)...) { }
// Assignment operators.
optional&
operator=(nullopt_t) noexcept
@ -786,6 +796,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
is_assignable<_Tp&, _Up>>,
optional&>
operator=(_Up&& __u)
noexcept(__and_v<is_nothrow_constructible<_Tp, _Up>,
is_nothrow_assignable<_Tp&, _Up>>)
{
if (this->_M_is_engaged())
this->_M_get() = std::forward<_Up>(__u);
@ -803,6 +815,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<__assigns_from_optional<_Tp, _Up>>>,
optional&>
operator=(const optional<_Up>& __u)
noexcept(__and_v<is_nothrow_constructible<_Tp, const _Up&>,
is_nothrow_assignable<_Tp&, const _Up&>>)
{
if (__u)
{
@ -826,6 +840,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__not_<__assigns_from_optional<_Tp, _Up>>>,
optional&>
operator=(optional<_Up>&& __u)
noexcept(__and_v<is_nothrow_constructible<_Tp, _Up>,
is_nothrow_assignable<_Tp&, _Up>>)
{
if (__u)
{
@ -845,6 +861,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename... _Args>
enable_if_t<is_constructible_v<_Tp, _Args&&...>, _Tp&>
emplace(_Args&&... __args)
noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
{
this->_M_reset();
this->_M_construct(std::forward<_Args>(__args)...);
@ -855,6 +872,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&,
_Args&&...>, _Tp&>
emplace(initializer_list<_Up> __il, _Args&&... __args)
noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&,
_Args...>)
{
this->_M_reset();
this->_M_construct(__il, std::forward<_Args>(__args)...);
@ -887,27 +906,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Observers.
constexpr const _Tp*
operator->() const
operator->() const noexcept
{ return std::__addressof(this->_M_get()); }
constexpr _Tp*
operator->()
operator->() noexcept
{ return std::__addressof(this->_M_get()); }
constexpr const _Tp&
operator*() const&
operator*() const& noexcept
{ return this->_M_get(); }
constexpr _Tp&
operator*()&
operator*()& noexcept
{ return this->_M_get(); }
constexpr _Tp&&
operator*()&&
operator*()&& noexcept
{ return std::move(this->_M_get()); }
constexpr const _Tp&&
operator*() const&&
operator*() const&& noexcept
{ return std::move(this->_M_get()); }
constexpr explicit operator bool() const noexcept

81
libstdc++-v3/testsuite/20_util/optional/assignment/noexcept.cc Normal file
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@ -0,0 +1,81 @@
// 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
// <http://www.gnu.org/licenses/>.
// { dg-do compile { target c++17 } }
#include <optional>
template<bool B>
struct X
{
X() noexcept(B);
X(const X&) noexcept(B);
X& operator=(const X&) noexcept(B);
X(int) noexcept(B);
X& operator=(int) noexcept(false);
X(void*) noexcept(true);
X& operator=(void*) noexcept(B);
X(const X<!B>&) noexcept(B);
X& operator=(const X<!B>&) noexcept(B);
X(std::initializer_list<int>, int) noexcept(B);
};
using std::is_nothrow_assignable_v;
using Xyes = X<true>;
using Xno = X<false>;
using Oyes = std::optional<Xyes>;
using Ono = std::optional<Xno>;
static_assert( is_nothrow_assignable_v<Oyes, std::nullopt_t> );
static_assert( is_nothrow_assignable_v<Oyes, const Xyes&> );
static_assert( is_nothrow_assignable_v<Oyes, Xyes> );
static_assert( ! is_nothrow_assignable_v<Oyes, int> );
static_assert( is_nothrow_assignable_v<Oyes, void*> );
static_assert( is_nothrow_assignable_v<Oyes, const Ono&> );
static_assert( is_nothrow_assignable_v<Oyes, Ono> );
static_assert( is_nothrow_assignable_v<Ono, std::nullopt_t> );
static_assert( ! is_nothrow_assignable_v<Ono, const Xno&> );
static_assert( ! is_nothrow_assignable_v<Ono, Xno> );
static_assert( ! is_nothrow_assignable_v<Ono, int> );
static_assert( ! is_nothrow_assignable_v<Ono, void*> );
static_assert( ! is_nothrow_assignable_v<Ono, const Xyes&> );
static_assert( ! is_nothrow_assignable_v<Ono, Xyes> );
Xyes xyes;
Xno xno;
Oyes oyes;
Ono ono;
static_assert( noexcept(oyes.emplace()) );
static_assert( noexcept(oyes.emplace(xyes)) );
static_assert( noexcept(oyes.emplace(1)) );
static_assert( noexcept(oyes.emplace(nullptr)) );
static_assert( noexcept(oyes.emplace(xno)) );
static_assert( noexcept(oyes.emplace({1,2,3}, 1)) );
static_assert( ! noexcept(ono.emplace()) );
static_assert( ! noexcept(ono.emplace(xno)) );
static_assert( ! noexcept(ono.emplace(1)) );
static_assert( noexcept(ono.emplace(nullptr)) );
static_assert( ! noexcept(ono.emplace(xyes)) );
static_assert( ! noexcept(ono.emplace({1,2,3}, 1)) );

64
libstdc++-v3/testsuite/20_util/optional/cons/noexcept.cc Normal file
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@ -0,0 +1,64 @@
// 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
// <http://www.gnu.org/licenses/>.
// { dg-do compile { target c++17 } }
#include <optional>
template<bool B>
struct X
{
X() noexcept(B);
X(const X&) noexcept(B);
X(int) noexcept(B);
X(std::initializer_list<int>, int) noexcept(B);
X(const X<!B>&) noexcept(B);
X& operator=(const X&) noexcept(false);
};
using std::is_nothrow_constructible_v;
using std::in_place_t;
using Xyes = X<true>;
using Xno = X<false>;
using Oyes = std::optional<Xyes>;
using Ono = std::optional<Xno>;
static_assert( is_nothrow_constructible_v<Oyes> );
static_assert( is_nothrow_constructible_v<Oyes, std::nullopt_t> );
static_assert( is_nothrow_constructible_v<Oyes, const Xyes&> );
static_assert( is_nothrow_constructible_v<Oyes, Xyes> );
static_assert( is_nothrow_constructible_v<Oyes, in_place_t, short> );
static_assert( is_nothrow_constructible_v<Oyes, in_place_t,
std::initializer_list<int>,
long> );
static_assert( is_nothrow_constructible_v<Oyes, const Ono&> );
static_assert( is_nothrow_constructible_v<Oyes, Ono> );
static_assert( is_nothrow_constructible_v<Ono> );
static_assert( is_nothrow_constructible_v<Ono, std::nullopt_t> );
static_assert( ! is_nothrow_constructible_v<Ono, const Xno&> );
static_assert( ! is_nothrow_constructible_v<Ono, Xno> );
static_assert( ! is_nothrow_constructible_v<Ono, in_place_t, short> );
static_assert( ! is_nothrow_constructible_v<Ono, in_place_t,
std::initializer_list<int>,
long> );
static_assert( ! is_nothrow_constructible_v<Ono, const Xyes&> );
static_assert( ! is_nothrow_constructible_v<Ono, Xyes> );