28 lines · c
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-exception6//7//===----------------------------------------------------------------------===//8#ifndef LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H9#define LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H10 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// declval19template <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 cpp25} // namespace LIBC_NAMESPACE_DECL26 27#endif // LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H28