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 // UNSUPPORTED: c++03, c++11, c++14, c++17
9
10 // <span>
11
12 // template<class OtherElementType, size_t OtherExtent>
13 // constexpr span(const span<OtherElementType, OtherExtent>& s) noexcept;
14 //
15 // Remarks: This constructor shall not participate in overload resolution unless:
16 // Extent == dynamic_extent || Extent == OtherExtent is true, and
17 // OtherElementType(*)[] is convertible to ElementType(*)[].
18
19
20 #include <span>
21 #include <cassert>
22 #include <string>
23
24 #include "test_macros.h"
25
26 template<class T, std::size_t extent, size_t otherExtent>
createImplicitSpan(std::span<T,otherExtent> s)27 std::span<T, extent> createImplicitSpan(std::span<T, otherExtent> s) {
28 return {s}; // expected-error {{chosen constructor is explicit in copy-initialization}}
29 }
30
checkCV()31 void checkCV ()
32 {
33 // std::span< int> sp;
34 std::span<const int> csp;
35 std::span< volatile int> vsp;
36 std::span<const volatile int> cvsp;
37
38 // std::span< int, 0> sp0;
39 std::span<const int, 0> csp0;
40 std::span< volatile int, 0> vsp0;
41 std::span<const volatile int, 0> cvsp0;
42
43 // Try to remove const and/or volatile (dynamic -> dynamic)
44 {
45 std::span< int> s1{ csp}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
46 std::span< int> s2{ vsp}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
47 std::span< int> s3{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
48
49 std::span<const int> s4{ vsp}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
50 std::span<const int> s5{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
51
52 std::span< volatile int> s6{ csp}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int>'}}
53 std::span< volatile int> s7{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int>'}}
54 }
55
56 // Try to remove const and/or volatile (static -> static)
57 {
58 std::span< int, 0> s1{ csp0}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
59 std::span< int, 0> s2{ vsp0}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
60 std::span< int, 0> s3{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
61
62 std::span<const int, 0> s4{ vsp0}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
63 std::span<const int, 0> s5{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
64
65 std::span< volatile int, 0> s6{ csp0}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
66 std::span< volatile int, 0> s7{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
67 }
68
69 // Try to remove const and/or volatile (static -> dynamic)
70 {
71 std::span< int> s1{ csp0}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
72 std::span< int> s2{ vsp0}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
73 std::span< int> s3{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<int>'}}
74
75 std::span<const int> s4{ vsp0}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
76 std::span<const int> s5{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<const int>'}}
77
78 std::span< volatile int> s6{ csp0}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int>'}}
79 std::span< volatile int> s7{cvsp0}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int>'}}
80 }
81
82 // Try to remove const and/or volatile (static -> static)
83 {
84 std::span< int, 0> s1{ csp}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
85 std::span< int, 0> s2{ vsp}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
86 std::span< int, 0> s3{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<int, 0>'}}
87
88 std::span<const int, 0> s4{ vsp}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
89 std::span<const int, 0> s5{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<const int, 0>'}}
90
91 std::span< volatile int, 0> s6{ csp}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
92 std::span< volatile int, 0> s7{cvsp}; // expected-error {{no matching constructor for initialization of 'std::span<volatile int, 0>'}}
93 }
94 }
95
main(int,char **)96 int main(int, char**)
97 {
98 std::span<int> sp;
99 std::span<int, 0> sp0;
100
101 std::span<float> s1{sp}; // expected-error {{no matching constructor for initialization of 'std::span<float>'}}
102 std::span<float> s2{sp0}; // expected-error {{no matching constructor for initialization of 'std::span<float>'}}
103 std::span<float, 0> s3{sp}; // expected-error {{no matching constructor for initialization of 'std::span<float, 0>'}}
104 std::span<float, 0> s4{sp0}; // expected-error {{no matching constructor for initialization of 'std::span<float, 0>'}}
105
106 checkCV();
107
108 // explicit constructor necessary
109 {
110 createImplicitSpan<int, 1>(sp);
111 }
112
113 return 0;
114 }
115