1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <queue>
11 // UNSUPPORTED: c++98, c++03, c++11, c++14
12 // UNSUPPORTED: libcpp-no-deduction-guides
13 
14 
15 // template<class Container>
16 //   queue(Container) -> queue<typename Container::value_type, Container>;
17 //
18 // template<class Container, class Allocator>
19 //   queue(Container, Allocator) -> queue<typename Container::value_type, Container>;
20 
21 
22 #include <queue>
23 #include <list>
24 #include <iterator>
25 #include <cassert>
26 #include <cstddef>
27 #include <climits> // INT_MAX
28 
29 #include "test_macros.h"
30 #include "test_iterators.h"
31 #include "test_allocator.h"
32 
33 struct A {};
34 
35 int main()
36 {
37 
38 //  Test the explicit deduction guides
39     {
40     std::list<int> l{0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
41     std::queue que(l);
42 
43     static_assert(std::is_same_v<decltype(que), std::queue<int, std::list<int>>>, "");
44     assert(que.size() == l.size());
45     assert(que.back() == l.back());
46     }
47 
48     {
49     std::list<long, test_allocator<long>> l{10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
50     std::queue que(l, test_allocator<long>(0,2)); // different allocator
51     static_assert(std::is_same_v<decltype(que)::container_type, std::list<long, test_allocator<long>>>, "");
52     static_assert(std::is_same_v<decltype(que)::value_type, long>, "");
53     assert(que.size() == 10);
54     assert(que.back() == 19);
55 //  I'd like to assert that we've gotten the right allocator in the queue, but
56 //  I don't know how to get at the underlying container.
57     }
58 
59 //  Test the implicit deduction guides
60     {
61 //  We don't expect this one to work - no way to implicitly get value_type
62 //  std::queue que(std::allocator<int>()); // queue (allocator &)
63     }
64 
65     {
66     std::queue<A> source;
67     std::queue que(source); // queue(queue &)
68     static_assert(std::is_same_v<decltype(que)::value_type, A>, "");
69     static_assert(std::is_same_v<decltype(que)::container_type, std::deque<A>>, "");
70     assert(que.size() == 0);
71     }
72 
73     {
74 //  This one is odd - you can pass an allocator in to use, but the allocator
75 //  has to match the type of the one used by the underlying container
76     typedef short T;
77     typedef test_allocator<T> A;
78     typedef std::deque<T, A> C;
79 
80     C c{0,1,2,3};
81     std::queue<T, C> source(c);
82     std::queue que(source, A(2)); // queue(queue &, allocator)
83     static_assert(std::is_same_v<decltype(que)::value_type, T>, "");
84     static_assert(std::is_same_v<decltype(que)::container_type, C>, "");
85     assert(que.size() == 4);
86     assert(que.back() == 3);
87     }
88 
89 }
90