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

   1 //===----------------------------------------------------------------------===//
   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
   9 // type_traits
  10
  11 // is_base_of
  12
  13 #include <type_traits>
  14
  15 #include "test_macros.h"
  16
  17 template <class T, class U>
  18 void test_is_base_of()
  19 {
  20     static_assert((std::is_base_of<T, U>::value), "");
  21     static_assert((std::is_base_of<const T, U>::value), "");
  22     static_assert((std::is_base_of<T, const U>::value), "");
  23     static_assert((std::is_base_of<const T, const U>::value), "");
  24 #if TEST_STD_VER > 14
  25     static_assert((std::is_base_of_v<T, U>), "");
  26     static_assert((std::is_base_of_v<const T, U>), "");
  27     static_assert((std::is_base_of_v<T, const U>), "");
  28     static_assert((std::is_base_of_v<const T, const U>), "");
  29 #endif
  30 }
  31
  32 template <class T, class U>
  33 void test_is_not_base_of()
  34 {
  35     static_assert((!std::is_base_of<T, U>::value), "");
  36 }
  37
  38 struct B {};
  39 struct B1 : B {};
  40 struct B2 : B {};
  41 struct D : private B1, private B2 {};
  42 struct I0; // incomplete
  43
  44 int main(int, char**)
  45 {
  46     test_is_base_of<B, D>();
  47     test_is_base_of<B1, D>();
  48     test_is_base_of<B2, D>();
  49     test_is_base_of<B, B1>();
  50     test_is_base_of<B, B2>();
  51     test_is_base_of<B, B>();
  52
  53     test_is_not_base_of<D, B>();
  54     test_is_not_base_of<B&, D&>();
  55     test_is_not_base_of<B[3], D[3]>();
  56     test_is_not_base_of<int, int>();
  57
  58 //  A scalar is never the base class of anything (including incomplete types)
  59     test_is_not_base_of<int, B>();
  60     test_is_not_base_of<int, B1>();
  61     test_is_not_base_of<int, B2>();
  62     test_is_not_base_of<int, D>();
  63     test_is_not_base_of<int, I0>();
  64
  65 //  A scalar never has base classes (including incomplete types)
  66     test_is_not_base_of<B,  int>();
  67     test_is_not_base_of<B1, int>();
  68     test_is_not_base_of<B2, int>();
  69     test_is_not_base_of<D,  int>();
  70     test_is_not_base_of<I0, int>();
  71
  72   return 0;
  73 }