test/std/utilities/meta/meta.rel/is_base_of.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// type_traits

// is_base_of

#include <type_traits>

#include "test_macros.h"

template <class T, class U>
void test_is_base_of()
{
    static_assert((std::is_base_of<T, U>::value), "");
    static_assert((std::is_base_of<const T, U>::value), "");
    static_assert((std::is_base_of<T, const U>::value), "");
    static_assert((std::is_base_of<const T, const U>::value), "");
#if TEST_STD_VER > 14
    static_assert((std::is_base_of_v<T, U>), "");
    static_assert((std::is_base_of_v<const T, U>), "");
    static_assert((std::is_base_of_v<T, const U>), "");
    static_assert((std::is_base_of_v<const T, const U>), "");
#endif
}

template <class T, class U>
void test_is_not_base_of()
{
    static_assert((!std::is_base_of<T, U>::value), "");
}

struct B {};
struct B1 : B {};
struct B2 : B {};
struct D : private B1, private B2 {};
struct I0; // incomplete

int main(int, char**)
{
    test_is_base_of<B, D>();
    test_is_base_of<B1, D>();
    test_is_base_of<B2, D>();
    test_is_base_of<B, B1>();
    test_is_base_of<B, B2>();
    test_is_base_of<B, B>();

    test_is_not_base_of<D, B>();
    test_is_not_base_of<B&, D&>();
    test_is_not_base_of<B[3], D[3]>();
    test_is_not_base_of<int, int>();

//  A scalar is never the base class of anything (including incomplete types)
    test_is_not_base_of<int, B>();
    test_is_not_base_of<int, B1>();
    test_is_not_base_of<int, B2>();
    test_is_not_base_of<int, D>();
    test_is_not_base_of<int, I0>();

//  A scalar never has base classes (including incomplete types)
    test_is_not_base_of<B,  int>();
    test_is_not_base_of<B1, int>();
    test_is_not_base_of<B2, int>();
    test_is_not_base_of<D,  int>();
    test_is_not_base_of<I0, int>();

  return 0;
}