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🐛 Fix CX_WRAP for empty types #253

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Merged
bdeane-intel merged 1 commit into from
Jul 14, 2025
Merged

🐛 Fix CX_WRAP for empty types #253

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56 changes: 29 additions & 27 deletions include/stdx/utility.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -260,23 +260,25 @@ template <typename T> constexpr auto is_ct_v<T const> = is_ct_v<T>;

#if __cplusplus >= 202002L

#define CT_WRAP(X) \
#define CT_WRAP(...) \
[&](auto f) { \
if constexpr (::stdx::is_ct_v<decltype(f())>) { \
return f(); \
} else if constexpr (requires { \
::stdx::ct<[&]() constexpr { return X; }()>; \
::stdx::ct<[&]() constexpr { \
return __VA_ARGS__; \
}()>; \
}) { \
return ::stdx::ct<[&]() constexpr { return X; }()>(); \
return ::stdx::ct<[&]() constexpr { return __VA_ARGS__; }()>(); \
} else { \
return f(); \
} \
}([&] { return X; })
}([&] { return __VA_ARGS__; })

#ifdef __clang__
#define CX_DETECT(X) \
#define CX_DETECT(...) \
std::is_empty_v<decltype([&] { \
return (X) + ::stdx::cxv_detail::type_val{}; \
return (__VA_ARGS__) + ::stdx::cxv_detail::type_val{}; \
})>
#else
namespace stdx {
Expand All @@ -285,42 +287,42 @@ template <auto> constexpr auto cx_detect0() {}
constexpr auto cx_detect1(auto) { return 0; }
} // namespace v1
} // namespace stdx
#define CX_DETECT(X) \
#define CX_DETECT(...) \
requires { \
::stdx::cx_detect0<::stdx::cx_detect1( \
(X) + ::stdx::cxv_detail::type_val{})>; \
(__VA_ARGS__) + ::stdx::cxv_detail::type_val{})>; \
}
#endif

#define CX_WRAP(X) \
[&](auto f) { \
#define CX_WRAP(...) \
[&]([[maybe_unused]] auto f) { \
STDX_PRAGMA(diagnostic push) \
STDX_PRAGMA(diagnostic ignored "-Wold-style-cast") \
if constexpr (::stdx::is_cx_value_v< \
std::invoke_result_t<decltype(f)>> or \
std::is_empty_v<std::invoke_result_t<decltype(f)>>) { \
if constexpr (decltype(::stdx::cxv_detail::is_type< \
::stdx::cxv_detail::from_any( \
__VA_ARGS__)>())::value) { \
return ::stdx::overload{ \
::stdx::cxv_detail::cx_base{}, [&] { \
return ::stdx::type_identity< \
decltype(::stdx::cxv_detail::type_of< \
::stdx::cxv_detail::from_any( \
__VA_ARGS__)>())>{}; \
}}; \
} else if constexpr (::stdx::is_cx_value_v< \
std::invoke_result_t<decltype(f)>> or \
std::is_empty_v< \
std::invoke_result_t<decltype(f)>>) { \
return f(); \
} else if constexpr (CX_DETECT(X)) { \
if constexpr (decltype(::stdx::cxv_detail::is_type< \
::stdx::cxv_detail::from_any( \
X)>())::value) { \
return ::stdx::overload{ \
::stdx::cxv_detail::cx_base{}, [&] { \
return ::stdx::type_identity< \
decltype(::stdx::cxv_detail::type_of< \
::stdx::cxv_detail::from_any(X)>())>{}; \
}}; \
} else { \
return ::stdx::overload{::stdx::cxv_detail::cx_base{}, f}; \
} \
} else if constexpr (CX_DETECT(__VA_ARGS__)) { \
return ::stdx::overload{::stdx::cxv_detail::cx_base{}, f}; \
} else { \
return f(); \
} \
STDX_PRAGMA(diagnostic pop) \
}([&] { \
STDX_PRAGMA(diagnostic push) \
STDX_PRAGMA(diagnostic ignored "-Wold-style-cast") \
return (X) + ::stdx::cxv_detail::type_val{}; \
return (__VA_ARGS__) + ::stdx::cxv_detail::type_val{}; \
STDX_PRAGMA(diagnostic pop) \
})

Expand Down
7 changes: 7 additions & 0 deletions test/utility.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -364,6 +364,13 @@ TEST_CASE("CX_WRAP type argument", "[utility]") {
std::is_same_v<decltype(CX_WRAP(int)()), stdx::type_identity<int>>);
}

TEST_CASE("CX_WRAP empty type argument", "[utility]") {
using X = std::integral_constant<int, 17>;
STATIC_REQUIRE(stdx::is_cx_value_v<decltype(CX_WRAP(X))>);
STATIC_REQUIRE(
std::is_same_v<decltype(CX_WRAP(X)()), stdx::type_identity<X>>);
}

TEST_CASE("CX_WRAP integral_constant arg", "[utility]") {
auto x = std::integral_constant<int, 17>{};
STATIC_REQUIRE(std::is_same_v<decltype(CX_WRAP(x)), decltype(x)>);
Expand Down