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// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10
11// <mdspan>
12//
13// Test converting constructor:
14//
15// template<class OtherElementType>
16// constexpr default_accessor(default_accessor<OtherElementType>) noexcept {}
17//
18// Constraints: is_convertible_v<OtherElementType(*)[], element_type(*)[]> is true.
19
20#include <mdspan>
21#include <cassert>
22#include <cstdint>
23#include <type_traits>
24
25#include "test_macros.h"
26
27#include "../MinimalElementType.h"
28
29struct Base {};
30struct Derived : public Base {};
31
32template <class FromT, class ToT>
33constexpr void test_conversion() {
34 std::default_accessor<FromT> acc_from;
35 ASSERT_NOEXCEPT(std::default_accessor<ToT>(acc_from));
36 [[maybe_unused]] std::default_accessor<ToT> acc_to(acc_from);
37}
38
39constexpr bool test() {
40 // default accessor conversion largely behaves like pointer conversion
41 test_conversion<int, int>();
42 test_conversion<int, const int>();
43 test_conversion<const int, const int>();
44 test_conversion<MinimalElementType, MinimalElementType>();
45 test_conversion<MinimalElementType, const MinimalElementType>();
46 test_conversion<const MinimalElementType, const MinimalElementType>();
47
48 // char is convertible to int, but accessors are not
49 static_assert(!std::is_constructible_v<std::default_accessor<int>, std::default_accessor<char>>);
50 // don't allow conversion from const elements to non-const
51 static_assert(!std::is_constructible_v<std::default_accessor<int>, std::default_accessor<const int>>);
52 // MinimalElementType is constructible from int, but accessors should not be convertible
53 static_assert(!std::is_constructible_v<std::default_accessor<MinimalElementType>, std::default_accessor<int>>);
54 // don't allow conversion from const elements to non-const
55 static_assert(!std::is_constructible_v<std::default_accessor<MinimalElementType>,
56 std::default_accessor<const MinimalElementType>>);
57 // don't allow conversion from Base to Derived
58 static_assert(!std::is_constructible_v<std::default_accessor<Derived>, std::default_accessor<Base>>);
59 // don't allow conversion from Derived to Base
60 static_assert(!std::is_constructible_v<std::default_accessor<Base>, std::default_accessor<Derived>>);
61
62 return true;
63}
64
65int main(int, char**) {
66 test();
67 static_assert(test());
68 return 0;
69}
70

source code of libcxx/test/std/containers/views/mdspan/default_accessor/ctor.conversion.pass.cpp