forked from mirror/libcxx
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
47 lines
1.8 KiB
C++
47 lines
1.8 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// UNSUPPORTED: c++98, c++03, c++11, c++14
|
|
|
|
// template <class T> constexpr add_const<T>& as_const(T& t) noexcept; // C++17
|
|
// template <class T> add_const<T>& as_const(const T&&) = delete; // C++17
|
|
|
|
#include <utility>
|
|
#include <cassert>
|
|
|
|
struct S {int i;};
|
|
bool operator==(const S& x, const S& y) { return x.i == y.i; }
|
|
bool operator==(const volatile S& x, const volatile S& y) { return x.i == y.i; }
|
|
|
|
template<typename T>
|
|
void test(T& t)
|
|
{
|
|
static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const (t))>::type>::value, "");
|
|
static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const< T>(t))>::type>::value, "");
|
|
static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const<const T>(t))>::type>::value, "");
|
|
static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const<volatile T>(t))>::type>::value, "");
|
|
static_assert(std::is_const<typename std::remove_reference<decltype(std::as_const<const volatile T>(t))>::type>::value, "");
|
|
|
|
assert(std::as_const(t) == t);
|
|
assert(std::as_const< T>(t) == t);
|
|
assert(std::as_const<const T>(t) == t);
|
|
assert(std::as_const<volatile T>(t) == t);
|
|
assert(std::as_const<const volatile T>(t) == t);
|
|
}
|
|
|
|
int main()
|
|
{
|
|
int i = 3;
|
|
double d = 4.0;
|
|
S s{2};
|
|
test(i);
|
|
test(d);
|
|
test(s);
|
|
}
|