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99dee823 | 1 | // Copyright (C) 2016-2021 Free Software Foundation, Inc. |
7663cae2 JW |
2 | // |
3 | // This file is part of the GNU ISO C++ Library. This library is free | |
4 | // software; you can redistribute it and/or modify it under the | |
5 | // terms of the GNU General Public License as published by the | |
6 | // Free Software Foundation; either version 3, or (at your option) | |
7 | // any later version. | |
8 | ||
9 | // This library is distributed in the hope that it will be useful, | |
10 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | // GNU General Public License for more details. | |
13 | ||
14 | // You should have received a copy of the GNU General Public License along | |
15 | // with this library; see the file COPYING3. If not see | |
16 | // <http://www.gnu.org/licenses/>. | |
17 | ||
18 | // { dg-do compile { target c++11 } } | |
19 | ||
20 | #include <memory> | |
21 | ||
22 | template<typename T, typename Args, typename = void> | |
23 | struct resettable | |
24 | : std::false_type | |
25 | { }; | |
26 | ||
27 | template<typename... T> struct type_list { }; | |
28 | ||
29 | template<typename T, typename... Args> | |
30 | using reset_result | |
31 | = decltype(std::shared_ptr<T>{}.reset(std::declval<Args>()...)); | |
32 | ||
33 | template<typename T, typename... Args> | |
34 | struct resettable<T, type_list<Args...>, reset_result<T, Args...>> | |
35 | : std::true_type | |
36 | { }; | |
37 | ||
38 | template<typename T, typename... Args> | |
39 | constexpr bool can_reset() | |
40 | { return resettable<T, type_list<Args...>>::value; } | |
41 | ||
42 | template<typename T> | |
43 | struct Deleter { | |
44 | void operator()(T*) const; | |
45 | }; | |
46 | ||
47 | template<typename T> | |
48 | using Alloc = std::allocator<T>; | |
49 | ||
50 | struct Base { }; | |
51 | struct Derived : Base { }; | |
52 | ||
53 | // Positive cases: | |
54 | ||
55 | static_assert( can_reset<const void, void*>(), | |
56 | "void* convertible to const void*"); | |
57 | static_assert( can_reset<const int, int*>(), | |
58 | "int* convertible to const int*"); | |
59 | static_assert( can_reset<Base, Derived*>(), | |
60 | "Derived* convertible to Base*"); | |
61 | static_assert( can_reset<const Base, Derived*>(), | |
62 | "Derived* convertible to const Base*"); | |
63 | ||
64 | // Negative cases: | |
65 | ||
66 | static_assert( !can_reset<int, void*>(), | |
67 | "void* not convertible to int*"); | |
68 | static_assert( !can_reset<int, void*, Deleter<int>>(), | |
69 | "void* not convertible to int*"); | |
70 | static_assert( !can_reset<int, void*, Deleter<int>, Alloc<int>>(), | |
71 | "void* not convertible to int*"); | |
72 | ||
73 | static_assert( !can_reset<int, const int*>(), | |
74 | "const int* not convertible to int*"); | |
75 | static_assert( !can_reset<int, const int*, Deleter<int>>(), | |
76 | "const int* not convertible to int*"); | |
77 | static_assert( !can_reset<int, const int*, Deleter<int>, Alloc<int>>(), | |
78 | "const int* not convertible to int*"); | |
79 | ||
80 | static_assert( !can_reset<int, long*>(), | |
81 | "long* not convertible to int*"); | |
82 | static_assert( !can_reset<int, long*, Deleter<int>>(), | |
83 | "long* not convertible to int*"); | |
84 | static_assert( !can_reset<int, long*, Deleter<int>, Alloc<int>>(), | |
85 | "long* not convertible to int*"); | |
86 | ||
87 | static_assert( !can_reset<Derived, Base*>(), | |
88 | "Base* not convertible to Derived*"); | |
89 | static_assert( !can_reset<Derived, Base*, Deleter<int>>(), | |
90 | "Base* not convertible to Derived*"); | |
91 | static_assert( !can_reset<Derived, Base*, Deleter<int>, Alloc<int>>(), | |
92 | "Base* not convertible to Derived*"); |