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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// SPDX-FileCopyrightText: Copyright Contributors to the Kokkos project
#include <Kokkos_DetectionIdiom.hpp>
#include <cstddef>
void test_nonesuch() {
using Kokkos::nonesuch;
static_assert(!std::is_constructible_v<nonesuch>);
static_assert(!std::is_destructible_v<nonesuch>);
static_assert(!std::is_copy_constructible_v<nonesuch>);
static_assert(!std::is_move_constructible_v<nonesuch>);
static_assert(!std::is_aggregate_v<nonesuch>);
}
namespace Example {
// Example from https://en.cppreference.com/w/cpp/experimental/is_detected
template <class T>
using copy_assign_t = decltype(std::declval<T&>() = std::declval<const T&>());
struct Meow {};
struct Purr {
void operator=(const Purr&) = delete;
};
static_assert(Kokkos::is_detected<copy_assign_t, Meow>::value,
"Meow should be copy assignable!");
static_assert(!Kokkos::is_detected<copy_assign_t, Purr>::value,
"Purr should not be copy assignable!");
static_assert(Kokkos::is_detected_exact_v<Meow&, copy_assign_t, Meow>,
"Copy assignment of Meow should return Meow&!");
template <class T>
using diff_t = typename T::difference_type;
template <class Ptr>
using difference_type = Kokkos::detected_or_t<std::ptrdiff_t, diff_t, Ptr>;
struct Woof {
using difference_type = int;
};
struct Bark {};
static_assert(std::is_same_v<difference_type<Woof>, int>,
"Woof's difference_type should be int!");
static_assert(std::is_same_v<difference_type<Bark>, std::ptrdiff_t>,
"Bark's difference_type should be ptrdiff_t!");
} // namespace Example
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