1//===-- declval utility -----------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H
9#define LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H
10
11#include "src/__support/CPP/type_traits/add_rvalue_reference.h"
12#include "src/__support/CPP/type_traits/always_false.h"
13#include "src/__support/macros/config.h"
14
15namespace LIBC_NAMESPACE_DECL {
16namespace cpp {
17
18// declval
19template <typename T> cpp::add_rvalue_reference_t<T> declval() {
20 static_assert(cpp::always_false<T>,
21 "declval not allowed in an evaluated context");
22}
23
24} // namespace cpp
25} // namespace LIBC_NAMESPACE_DECL
26
27#endif // LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H
28