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Fix noexcept and constraints on value_or() and error_or() #3

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Merged
CaptainNeil merged 3 commits into from
Apr 16, 2024
Merged

Fix noexcept and constraints on value_or() and error_or() #3

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d82fcbb
fix: constraints of value_or() and error_or()
X1aomu Apr 16, 2024
79c13d5
test: noexcept on value_or() and error_or()
X1aomu Apr 16, 2024
9e73560
fix: noexcept in C++17
X1aomu Apr 16, 2024
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33 changes: 12 additions & 21 deletions include/zeus/expected.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,9 @@ inline constexpr bool is_copy_assignable_or_void_v = is_void_or_v<T, std::is_cop
template<class T>
inline constexpr bool is_move_assignable_or_void_v = is_void_or_v<T, std::is_move_assignable<T>>;

template<class From, class To>
inline constexpr bool is_nothrow_convertible_v = noexcept(static_cast<To>(std::declval<From>()));

} // namespace expected_detail

template<class E>
Expand Down Expand Up @@ -1681,9 +1684,7 @@ class expected

template<class U>
constexpr T value_or(U &&v) const & //
#if __cplusplus >= 202'002L // doesn't compile with C++17 with MSVC, may be a compiler bug
noexcept(std::is_nothrow_copy_constructible_v<T> && std::is_nothrow_convertible_v<U, T>)
#endif
noexcept(std::is_nothrow_copy_constructible_v<T> && expected_detail::is_nothrow_convertible_v<U, T>)
{
static_assert(std::is_copy_constructible_v<T>, "T must be copy-constructible");
static_assert(std::is_convertible_v<U, T>, "is_convertible_v<U, T> must be true");
Expand All @@ -1698,11 +1699,9 @@ class expected
}
template<class U>
constexpr T value_or(U &&v) && //
#if __cplusplus >= 202'002L // doesn't compile with C++17 with MSVC, may be a compiler bug
noexcept(std::is_nothrow_copy_constructible_v<T> && std::is_nothrow_convertible_v<U, T>)
#endif
noexcept(std::is_nothrow_move_constructible_v<T> && expected_detail::is_nothrow_convertible_v<U, T>)
{
static_assert(std::is_copy_constructible_v<T>, "T must be copy-constructible");
static_assert(std::is_move_constructible_v<T>, "T must be move-constructible");
static_assert(std::is_convertible_v<U, T>, "is_convertible_v<U, T> must be true");
if (this->m_has_val)
{
Expand All @@ -1716,9 +1715,7 @@ class expected

template<class G = E>
constexpr E error_or(G &&v) const & //
#if __cplusplus >= 202'002L // doesn't compile with C++17 with MSVC, may be a compiler bug
noexcept(std::is_nothrow_copy_constructible_v<E> && std::is_nothrow_convertible_v<G, E>)
#endif
noexcept(std::is_nothrow_copy_constructible_v<E> && expected_detail::is_nothrow_convertible_v<G, E>)
{
static_assert(std::is_copy_constructible_v<E>, "E must be copy-constructible");
static_assert(std::is_convertible_v<G, E>, "is_convertible_v<G, E> must be true");
Expand All @@ -1733,11 +1730,9 @@ class expected
}
template<class G = E>
constexpr E error_or(G &&v) && //
#if __cplusplus >= 202'002L // doesn't compile with C++17 with MSVC, may be a compiler bug
noexcept(std::is_nothrow_copy_constructible_v<E> && std::is_nothrow_convertible_v<G, E>)
#endif
noexcept(std::is_nothrow_move_constructible_v<E> && expected_detail::is_nothrow_convertible_v<G, E>)
{
static_assert(std::is_copy_constructible_v<E>, "E must be copy-constructible");
static_assert(std::is_move_constructible_v<E>, "E must be move-constructible");
static_assert(std::is_convertible_v<G, E>, "is_convertible_v<G, E> must be true");
if (this->m_has_val)
{
Expand Down Expand Up @@ -2407,9 +2402,7 @@ class expected<void, E>

template<class G = E>
constexpr E error_or(G &&v) const & //
#if __cplusplus >= 202'002L // doesn't compile with C++17 with MSVC, may be a compiler bug
noexcept(std::is_nothrow_copy_constructible_v<E> && std::is_nothrow_convertible_v<G, E>)
#endif
noexcept(std::is_nothrow_copy_constructible_v<E> && expected_detail::is_nothrow_convertible_v<G, E>)
{
static_assert(std::is_copy_constructible_v<E>, "E must be copy-constructible");
static_assert(std::is_convertible_v<G, E>, "is_convertible_v<G, E> must be true");
Expand All @@ -2424,11 +2417,9 @@ class expected<void, E>
}
template<class G = E>
constexpr E error_or(G &&v) && //
#if __cplusplus >= 202'002L // doesn't compile with C++17 with MSVC, may be a compiler bug
noexcept(std::is_nothrow_copy_constructible_v<E> && std::is_nothrow_convertible_v<G, E>)
#endif
noexcept(std::is_nothrow_move_constructible_v<E> && expected_detail::is_nothrow_convertible_v<G, E>)
{
static_assert(std::is_copy_constructible_v<E>, "E must be copy-constructible");
static_assert(std::is_move_constructible_v<E>, "E must be move-constructible");
static_assert(std::is_convertible_v<G, E>, "is_convertible_v<G, E> must be true");
if (this->m_has_val)
{
Expand Down
1 change: 1 addition & 0 deletions tests/test_expected/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,7 @@ project(test_expected)
set(SOURCES
base_tests.cpp
monadic_tests.cpp
noexcept_tests.cpp
test_expected_main.cpp
)

Expand Down
90 changes: 90 additions & 0 deletions tests/test_expected/noexcept_tests.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,90 @@
#include <catch2/catch_all.hpp>

#include <zeus/expected.hpp>

struct FromType
{
};

enum class NoThrowConvertible
{
Yes,
No,
};

template<NoThrowConvertible N>
struct ToType;

template<>
struct ToType<NoThrowConvertible::Yes>
{
ToType() = default;
ToType(ToType const&) = default;
ToType(ToType&&) = default;

ToType(FromType const&) noexcept {}
};

template<>
struct ToType<NoThrowConvertible::No>
{
ToType() = default;
ToType(ToType const&) = default;
ToType(ToType&&) = default;

ToType(FromType const&) noexcept(false) {}
};

TEST_CASE("value_or() noexcept", "[noexcept, value_or]")
{
{ // noexcept(true)
using T = ToType<NoThrowConvertible::Yes>;
using E = int;
using Expected = zeus::expected<T, E>;
Expected e;
CHECK(noexcept(e.value_or(FromType {})));
}
{ // noexcept(false)
using T = ToType<NoThrowConvertible::No>;
using E = int;
using Expected = zeus::expected<T, E>;
Expected e;
CHECK_FALSE(noexcept(e.value_or(FromType {})));
}
}

TEST_CASE("error_or() noexcept", "[noexcept, error_or]")
{
{ // noexcept(true)
using T = int;
using E = ToType<NoThrowConvertible::Yes>;
using Expected = zeus::expected<T, E>;
Expected e;
CHECK(noexcept(e.error_or(FromType {})));
}
{ // noexcept(false)
using T = int;
using E = ToType<NoThrowConvertible::No>;
using Expected = zeus::expected<T, E>;
Expected e;
CHECK_FALSE(noexcept(e.error_or(FromType {})));
}
}

TEST_CASE("void-T error_or() noexcept", "[noexcept, error_or, void-T]")
{
{ // noexcept(true)
using T = void;
using E = ToType<NoThrowConvertible::Yes>;
using Expected = zeus::expected<T, E>;
Expected e;
CHECK(noexcept(e.error_or(FromType {})));
}
{ // noexcept(false)
using T = void;
using E = ToType<NoThrowConvertible::No>;
using Expected = zeus::expected<T, E>;
Expected e;
CHECK_FALSE(noexcept(e.error_or(FromType {})));
}
}