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

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.

diff --git a/libstdc++-v3/include/std/optional b/libstdc++-v3/include/std/optional
index 923d45a..785c434 100644 (file)
--- a/libstdc++-v3/include/std/optional
+++ b/libstdc++-v3/include/std/optional
@@ -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

diff --git a/libstdc++-v3/testsuite/20_util/optional/assignment/noexcept.cc b/libstdc++-v3/testsuite/20_util/optional/assignment/noexcept.cc
new file mode 100644 (file)
index 0000000..45592b2
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/optional/assignment/noexcept.cc
@@ -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)) );

diff --git a/libstdc++-v3/testsuite/20_util/optional/cons/noexcept.cc b/libstdc++-v3/testsuite/20_util/optional/cons/noexcept.cc
new file mode 100644 (file)
index 0000000..a529f5d
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/optional/cons/noexcept.cc
@@ -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> );