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libstdc++: Fix constraints on std::optional comparisons [PR 96269]
The relational operators for std::optional were using the wrong types in the declval expressions used to constrain them. Instead of using const lvalues they were using non-const rvalues, which meant that a type might satisfy the constraints but then give an error when the function body was instantiated. libstdc++-v3/ChangeLog: PR libstdc++/96269 * include/std/optional (operator==, operator!=, operator<) (operator>, operator<=, operator>=): Fix types used in SFINAE constraints. * testsuite/20_util/optional/relops/96269.cc: New test.
This commit is contained in:
Jonathan Wakely
parent
10508db867
commit
cdd2d448d8
@ -1002,11 +1002,41 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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using __optional_relop_t =
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enable_if_t<is_convertible<_Tp, bool>::value, bool>;
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template<typename _Tp, typename _Up>
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using __optional_eq_t = __optional_relop_t<
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decltype(std::declval<const _Tp&>() == std::declval<const _Up&>())
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>;
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template<typename _Tp, typename _Up>
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using __optional_ne_t = __optional_relop_t<
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decltype(std::declval<const _Tp&>() != std::declval<const _Up&>())
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>;
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template<typename _Tp, typename _Up>
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using __optional_lt_t = __optional_relop_t<
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decltype(std::declval<const _Tp&>() < std::declval<const _Up&>())
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>;
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template<typename _Tp, typename _Up>
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using __optional_gt_t = __optional_relop_t<
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decltype(std::declval<const _Tp&>() > std::declval<const _Up&>())
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>;
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template<typename _Tp, typename _Up>
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using __optional_le_t = __optional_relop_t<
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decltype(std::declval<const _Tp&>() <= std::declval<const _Up&>())
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>;
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template<typename _Tp, typename _Up>
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using __optional_ge_t = __optional_relop_t<
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decltype(std::declval<const _Tp&>() >= std::declval<const _Up&>())
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>;
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// Comparisons between optional values.
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template<typename _Tp, typename _Up>
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constexpr auto
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operator==(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() == declval<_Up>())>
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-> __optional_eq_t<_Tp, _Up>
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{
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return static_cast<bool>(__lhs) == static_cast<bool>(__rhs)
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&& (!__lhs || *__lhs == *__rhs);
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@ -1015,7 +1045,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Up>
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constexpr auto
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operator!=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() != declval<_Up>())>
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-> __optional_ne_t<_Tp, _Up>
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{
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return static_cast<bool>(__lhs) != static_cast<bool>(__rhs)
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|| (static_cast<bool>(__lhs) && *__lhs != *__rhs);
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@ -1024,7 +1054,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Up>
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constexpr auto
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operator<(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() < declval<_Up>())>
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-> __optional_lt_t<_Tp, _Up>
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{
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return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs);
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}
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@ -1032,7 +1062,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Up>
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constexpr auto
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operator>(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() > declval<_Up>())>
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-> __optional_gt_t<_Tp, _Up>
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{
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return static_cast<bool>(__lhs) && (!__rhs || *__lhs > *__rhs);
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}
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@ -1040,7 +1070,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Up>
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constexpr auto
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operator<=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Up>())>
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-> __optional_le_t<_Tp, _Up>
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{
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return !__lhs || (static_cast<bool>(__rhs) && *__lhs <= *__rhs);
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}
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@ -1048,7 +1078,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Up>
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constexpr auto
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operator>=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Up>())>
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-> __optional_ge_t<_Tp, _Up>
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{
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return !__rhs || (static_cast<bool>(__lhs) && *__lhs >= *__rhs);
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}
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@ -1134,73 +1164,73 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, typename _Up>
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constexpr auto
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operator==(const optional<_Tp>& __lhs, const _Up& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() == declval<_Up>())>
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-> __optional_eq_t<_Tp, _Up>
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{ return __lhs && *__lhs == __rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator==(const _Up& __lhs, const optional<_Tp>& __rhs)
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-> __optional_relop_t<decltype(declval<_Up>() == declval<_Tp>())>
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-> __optional_eq_t<_Up, _Tp>
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{ return __rhs && __lhs == *__rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator!=(const optional<_Tp>& __lhs, const _Up& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() != declval<_Up>())>
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-> __optional_ne_t<_Tp, _Up>
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{ return !__lhs || *__lhs != __rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator!=(const _Up& __lhs, const optional<_Tp>& __rhs)
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-> __optional_relop_t<decltype(declval<_Up>() != declval<_Tp>())>
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-> __optional_ne_t<_Up, _Tp>
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{ return !__rhs || __lhs != *__rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator<(const optional<_Tp>& __lhs, const _Up& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() < declval<_Up>())>
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-> __optional_lt_t<_Tp, _Up>
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{ return !__lhs || *__lhs < __rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator<(const _Up& __lhs, const optional<_Tp>& __rhs)
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-> __optional_relop_t<decltype(declval<_Up>() < declval<_Tp>())>
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-> __optional_lt_t<_Up, _Tp>
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{ return __rhs && __lhs < *__rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator>(const optional<_Tp>& __lhs, const _Up& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() > declval<_Up>())>
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-> __optional_gt_t<_Tp, _Up>
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{ return __lhs && *__lhs > __rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator>(const _Up& __lhs, const optional<_Tp>& __rhs)
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-> __optional_relop_t<decltype(declval<_Up>() > declval<_Tp>())>
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-> __optional_gt_t<_Up, _Tp>
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{ return !__rhs || __lhs > *__rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator<=(const optional<_Tp>& __lhs, const _Up& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Up>())>
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-> __optional_le_t<_Tp, _Up>
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{ return !__lhs || *__lhs <= __rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator<=(const _Up& __lhs, const optional<_Tp>& __rhs)
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-> __optional_relop_t<decltype(declval<_Up>() <= declval<_Tp>())>
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-> __optional_le_t<_Up, _Tp>
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{ return __rhs && __lhs <= *__rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator>=(const optional<_Tp>& __lhs, const _Up& __rhs)
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-> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Up>())>
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-> __optional_ge_t<_Tp, _Up>
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{ return __lhs && *__lhs >= __rhs; }
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template<typename _Tp, typename _Up>
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constexpr auto
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operator>=(const _Up& __lhs, const optional<_Tp>& __rhs)
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-> __optional_relop_t<decltype(declval<_Up>() >= declval<_Tp>())>
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-> __optional_ge_t<_Up, _Tp>
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{ return !__rhs || __lhs >= *__rhs; }
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#ifdef __cpp_lib_three_way_comparison
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76
libstdc++-v3/testsuite/20_util/optional/relops/96269.cc
Normal file
76
libstdc++-v3/testsuite/20_util/optional/relops/96269.cc
Normal file
@ -0,0 +1,76 @@
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// Copyright (C) 2020 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// { dg-options "-std=gnu++2a" }
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// { dg-do compile { target c++2a } }
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#include <optional>
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struct X
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{
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template <typename T>
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bool operator==(const T&) /* not const */ { return false; }
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template <typename T>
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bool operator!=(const T&) /* not const */ { return false; }
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template <typename T>
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bool operator<(const T&) /* not const */ { return false; }
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template <typename T>
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bool operator>(const T&) /* not const */ { return false; }
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template <typename T>
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bool operator<=(const T&) /* not const */ { return false; }
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template <typename T>
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bool operator>=(const T&) /* not const */ { return false; }
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};
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void test01()
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{
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// PR 96269 optional comparison with nullopt fails
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std::optional<X> x;
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bool eq [[maybe_unused]] = std::nullopt == x;
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bool ne [[maybe_unused]] = std::nullopt != x;
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bool lt [[maybe_unused]] = std::nullopt < x;
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bool gt [[maybe_unused]] = std::nullopt > x;
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bool le [[maybe_unused]] = std::nullopt <= x;
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bool ge [[maybe_unused]] = std::nullopt >= x;
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}
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template<typename T>
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concept optional_lt_cmp
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= requires(std::optional<T> o, T t) { { o < t } -> std::same_as<bool>; };
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template<typename T>
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concept optional_gt_cmp
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= requires(std::optional<T> o, T t) { { o > t } -> std::same_as<bool>; };
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template<typename T>
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concept optional_le_cmp
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= requires(std::optional<T> o, T t) { { o <= t } -> std::same_as<bool>; };
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template<typename T>
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concept optional_ge_cmp
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= requires(std::optional<T> o, T t) { { o >= t } -> std::same_as<bool>; };
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static_assert( ! optional_lt_cmp<X> );
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static_assert( ! optional_gt_cmp<X> );
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static_assert( ! optional_le_cmp<X> );
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static_assert( ! optional_ge_cmp<X> );
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