based

0 #pragma once

1

2 #include "based/trait/integral_constant.hpp"

3 #include "based/trait/is/class.hpp"

4

5 namespace based

6 {

7

8 namespace details

9 {

10

11 template<class B>

12 true_type test_ptr_conv(const volatile B*);

13

14 template<class>

15 false_type test_ptr_conv(const volatile void*);

16

17 template<class B, class D>

18 auto test_is_base_of(int)

19 -> decltype(test_ptr_conv<B>(static_cast<D*>(nullptr)));

20

21 template<class, class>

22 auto test_is_base_of(...) -> true_type; // private or ambiguous base

23

24 } // namespace details

25

26 template<class Base, class Derived>

27 struct is_base_of : false_type

28 {

29 };

30

31 template<class Base, class Derived>

32 requires(

33 is_class_v<Base> && is_class_v<Derived>

34 && decltype(details::test_is_base_of<Base, Derived>(0))::value

35 )

36 struct is_base_of<Base, Derived> : true_type

37 {

38 };

39

40 template<class Base, class Derived>

41 constexpr bool is_base_of_v = is_base_of<Base, Derived>::value;

42

43 } // namespace based