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
10
11// <span>
12
13// constexpr explicit(extent != dynamic_extent) span(std::initializer_list<value_type> il); // Since C++26
14
15#include <any>
16#include <cassert>
17#include <cstddef>
18#include <initializer_list>
19#include <span>
20#include <type_traits>
21
22#include "test_convertible.h"
23#include "test_macros.h"
24
25#if TEST_STD_VER >= 26
26
27// SFINAE
28
29template <typename T>
30concept ConstElementType = std::is_const_v<typename T::element_type>;
31
32static_assert(ConstElementType<std::span<const int>>);
33static_assert(!ConstElementType<std::span<int>>);
34static_assert(ConstElementType<std::span<const int, 94>>);
35static_assert(!ConstElementType<std::span<int, 94>>);
36
37// Constructor constraings
38
39template <typename I, typename T, std::size_t... N>
40concept HasInitializerListCtr = requires(I il) { std::span<T, N...>{il}; };
41
42static_assert(HasInitializerListCtr<std::initializer_list<const int>, const int>);
43static_assert(!HasInitializerListCtr<std::initializer_list<int>, int>);
44static_assert(HasInitializerListCtr<std::initializer_list<const int>, const int, 94>);
45static_assert(!HasInitializerListCtr<std::initializer_list<int>, int, 94>);
46
47// Constructor conditionally explicit
48
49static_assert(!test_convertible<std::span<const int, 28>, std::initializer_list<int>>(),
50 "This constructor must be explicit");
51static_assert(std::is_constructible_v<std::span<const int, 28>, std::initializer_list<int>>);
52static_assert(test_convertible<std::span<const int>, std::initializer_list<int>>(),
53 "This constructor must not be explicit");
54static_assert(std::is_constructible_v<std::span<const int>, std::initializer_list<int>>);
55
56#endif
57
58struct Sink {
59 constexpr Sink() = default;
60 constexpr Sink(Sink*) {}
61};
62
63constexpr std::size_t count(std::span<const Sink> sp) { return sp.size(); }
64
65template <std::size_t N>
66constexpr std::size_t count_n(std::span<const Sink, N> sp) {
67 return sp.size();
68}
69
70constexpr bool test() {
71#if TEST_STD_VER >= 26
72 // Dynamic extent
73 {
74 Sink a[10];
75
76 assert(count({a}) == 1);
77 assert(count({a, a + 10}) == 2);
78 assert(count({a, a + 1, a + 2}) == 3);
79 assert(count(std::initializer_list<Sink>{a[0], a[1], a[2], a[3]}) == 4);
80 }
81#else
82 {
83 Sink a[10];
84
85 assert(count({a}) == 10);
86 assert(count({a, a + 10}) == 10);
87 assert(count_n<10>({a}) == 10);
88 }
89#endif
90
91 return true;
92}
93
94// Test P2447R4 "Annex C examples"
95
96constexpr int three(std::span<void* const> sp) { return static_cast<int>(sp.size()); }
97
98constexpr int four(std::span<const std::any> sp) { return static_cast<int>(sp.size()); }
99
100bool test_P2447R4_annex_c_examples() {
101 // 1. Overload resolution is affected
102 // --> tested in "initializer_list.verify.cpp"
103
104 // 2. The `initializer_list` ctor has high precedence
105 // --> tested in "initializer_list.verify.cpp"
106
107 // 3. Implicit two-argument construction with a highly convertible value_type
108#if TEST_STD_VER >= 26
109 {
110 void* a[10];
111 assert(three({a, 0}) == 2);
112 }
113 {
114 std::any a[10];
115 assert(four({a, a + 10}) == 2);
116 }
117#else
118 {
119 void* a[10];
120 assert(three({a, 0}) == 0);
121 }
122 {
123 std::any a[10];
124 assert(four({a, a + 10}) == 10);
125 }
126#endif
127
128 return true;
129}
130
131int main(int, char**) {
132 assert(test());
133 static_assert(test());
134
135 assert(test_P2447R4_annex_c_examples());
136
137 return 0;
138}
139

source code of libcxx/test/std/containers/views/views.span/span.cons/initializer_list.pass.cpp