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implemented the proposed resolution for LWG-2762 #2376

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Merged
Stephan T. Lavavej (StephanTLavavej) merged 5 commits into from
Dec 9, 2021
Merged

implemented the proposed resolution for LWG-2762 #2376

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27d7024
implemented the proposed resolution for LWG-2762
OmarSaber98 Dec 4, 2021
6047aad
fully-qualified declval to avoid problems with ADL
OmarSaber98 Dec 4, 2021
49cbf51
added test coverage for optional noexcept deref operator
OmarSaber98 Dec 5, 2021
60f41ec
added test coverage for optional noexcept arrow operator
OmarSaber98 Dec 5, 2021
36d3d17
Remove outdated comments.
StephanTLavavej Dec 7, 2021
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2 changes: 1 addition & 1 deletion stl/inc/memory
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Original file line number Diff line number Diff line change
Expand Up @@ -3242,7 +3242,7 @@ public:
return _Mypair._Get_first();
}

_NODISCARD add_lvalue_reference_t<_Ty> operator*() const noexcept /* strengthened */ {
_NODISCARD add_lvalue_reference_t<_Ty> operator*() const noexcept(noexcept(*_STD declval<pointer>())) {
return *_Mypair._Myval2;
}

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12 changes: 6 additions & 6 deletions stl/inc/optional
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Expand Up @@ -342,38 +342,38 @@ public:
}
}

_NODISCARD constexpr const _Ty* operator->() const {
_NODISCARD constexpr const _Ty* operator->() const noexcept {
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Has_value, "Cannot access value of empty optional");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return _STD addressof(this->_Value);
}
_NODISCARD constexpr _Ty* operator->() {
_NODISCARD constexpr _Ty* operator->() noexcept {
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Has_value, "Cannot access value of empty optional");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return _STD addressof(this->_Value);
}

_NODISCARD constexpr const _Ty& operator*() const& {
_NODISCARD constexpr const _Ty& operator*() const& noexcept {
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Has_value, "Cannot access value of empty optional");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return this->_Value;
}
_NODISCARD constexpr _Ty& operator*() & {
_NODISCARD constexpr _Ty& operator*() & noexcept {
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Has_value, "Cannot access value of empty optional");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return this->_Value;
}
_NODISCARD constexpr _Ty&& operator*() && {
_NODISCARD constexpr _Ty&& operator*() && noexcept {
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Has_value, "Cannot access value of empty optional");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return _STD move(this->_Value);
}
_NODISCARD constexpr const _Ty&& operator*() const&& {
_NODISCARD constexpr const _Ty&& operator*() const&& noexcept {
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(this->_Has_value, "Cannot access value of empty optional");
#endif // _CONTAINER_DEBUG_LEVEL > 0
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54 changes: 6 additions & 48 deletions tests/std/tests/P0220R1_optional/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4776,14 +4776,7 @@ int run_test()
{
optional<X> opt; ((void)opt);
ASSERT_SAME_TYPE(decltype(*opt), X&);
// ASSERT_NOT_NOEXCEPT(*opt);
// TODO: This assertion fails with GCC because it can see that
// (A) operator*() is constexpr, and
// (B) there is no path through the function that throws.
// It's arguable if this is the correct behavior for the noexcept
// operator.
// Regardless this function should still be noexcept(false) because
// it has a narrow contract.
STATIC_ASSERT(noexcept(*opt));
}
{
optional<X> opt(X{});
Expand Down Expand Up @@ -4847,14 +4840,7 @@ int run_test()
{
const optional<X> opt; ((void)opt);
ASSERT_SAME_TYPE(decltype(*opt), X const&);
// ASSERT_NOT_NOEXCEPT(*opt);
// TODO: This assertion fails with GCC because it can see that
// (A) operator*() is constexpr, and
// (B) there is no path through the function that throws.
// It's arguable if this is the correct behavior for the noexcept
// operator.
// Regardless this function should still be noexcept(false) because
// it has a narrow contract.
STATIC_ASSERT(noexcept(*opt));
}
{
constexpr optional<X> opt(X{});
Expand Down Expand Up @@ -4921,14 +4907,7 @@ int run_test()
{
const optional<X> opt; ((void)opt);
ASSERT_SAME_TYPE(decltype(*std::move(opt)), X const &&);
// ASSERT_NOT_NOEXCEPT(*std::move(opt));
// TODO: This assertion fails with GCC because it can see that
// (A) operator*() is constexpr, and
// (B) there is no path through the function that throws.
// It's arguable if this is the correct behavior for the noexcept
// operator.
// Regardless this function should still be noexcept(false) because
// it has a narrow contract.
STATIC_ASSERT(noexcept(*std::move(opt)));
}
{
constexpr optional<X> opt(X{});
Expand Down Expand Up @@ -5002,14 +4981,7 @@ int run_test()
{
optional<X> opt; ((void)opt);
ASSERT_SAME_TYPE(decltype(*std::move(opt)), X&&);
// ASSERT_NOT_NOEXCEPT(*std::move(opt));
// TODO: This assertion fails with GCC because it can see that
// (A) operator*() is constexpr, and
// (B) there is no path through the function that throws.
// It's arguable if this is the correct behavior for the noexcept
// operator.
// Regardless this function should still be noexcept(false) because
// it has a narrow contract.
STATIC_ASSERT(noexcept(*std::move(opt)));
}
{
optional<X> opt(X{});
Expand Down Expand Up @@ -5119,14 +5091,7 @@ int run_test()
{
std::optional<X> opt; ((void)opt);
ASSERT_SAME_TYPE(decltype(opt.operator->()), X*);
// ASSERT_NOT_NOEXCEPT(opt.operator->());
// TODO: This assertion fails with GCC because it can see that
// (A) operator->() is constexpr, and
// (B) there is no path through the function that throws.
// It's arguable if this is the correct behavior for the noexcept
// operator.
// Regardless this function should still be noexcept(false) because
// it has a narrow contract.
STATIC_ASSERT(noexcept(opt.operator->()));
}
{
optional<X> opt(X{});
Expand Down Expand Up @@ -5195,14 +5160,7 @@ int run_test()
{
const std::optional<X> opt; ((void)opt);
ASSERT_SAME_TYPE(decltype(opt.operator->()), X const*);
// ASSERT_NOT_NOEXCEPT(opt.operator->());
// TODO: This assertion fails with GCC because it can see that
// (A) operator->() is constexpr, and
// (B) there is no path through the function that throws.
// It's arguable if this is the correct behavior for the noexcept
// operator.
// Regardless this function should still be noexcept(false) because
// it has a narrow contract.
STATIC_ASSERT(noexcept(opt.operator->()));
}
{
constexpr optional<X> opt(X{});
Expand Down