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
10 
11 // <tuple>
12 
13 // template <class... Types> class tuple;
14 
15 // template <class Alloc>
16 //   explicit(see-below) tuple(allocator_arg_t, const Alloc& a);
17 
18 // NOTE: this constructor does not currently support tags derived from
19 // allocator_arg_t because libc++ has to deduce the parameter as a template
20 // argument. See PR27684 (https://bugs.llvm.org/show_bug.cgi?id=27684)
21 
22 #include <tuple>
23 #include <cassert>
24 
25 #include "test_macros.h"
26 #include "DefaultOnly.h"
27 #include "allocators.h"
28 #include "../alloc_first.h"
29 #include "../alloc_last.h"
30 
31 template <class T = void>
32 struct NonDefaultConstructible {
33   constexpr NonDefaultConstructible() {
34       static_assert(!std::is_same<T, T>::value, "Default Ctor instantiated");
35   }
36 
37   explicit constexpr NonDefaultConstructible(int) {}
38 };
39 
40 
41 struct DerivedFromAllocArgT : std::allocator_arg_t {};
42 
43 int main(int, char**)
44 {
45     {
46         std::tuple<> t(std::allocator_arg, A1<int>());
47     }
48     {
49         std::tuple<int> t(std::allocator_arg, A1<int>());
50         assert(std::get<0>(t) == 0);
51     }
52     {
53         std::tuple<DefaultOnly> t(std::allocator_arg, A1<int>());
54         assert(std::get<0>(t) == DefaultOnly());
55     }
56     {
57         assert(!alloc_first::allocator_constructed);
58         std::tuple<alloc_first> t(std::allocator_arg, A1<int>(5));
59         assert(alloc_first::allocator_constructed);
60         assert(std::get<0>(t) == alloc_first());
61     }
62     {
63         assert(!alloc_last::allocator_constructed);
64         std::tuple<alloc_last> t(std::allocator_arg, A1<int>(5));
65         assert(alloc_last::allocator_constructed);
66         assert(std::get<0>(t) == alloc_last());
67     }
68     {
69         alloc_first::allocator_constructed = false;
70         std::tuple<DefaultOnly, alloc_first> t(std::allocator_arg, A1<int>(5));
71         assert(std::get<0>(t) == DefaultOnly());
72         assert(alloc_first::allocator_constructed);
73         assert(std::get<1>(t) == alloc_first());
74     }
75     {
76         alloc_first::allocator_constructed = false;
77         alloc_last::allocator_constructed = false;
78         std::tuple<DefaultOnly, alloc_first, alloc_last> t(std::allocator_arg,
79                                                            A1<int>(5));
80         assert(std::get<0>(t) == DefaultOnly());
81         assert(alloc_first::allocator_constructed);
82         assert(std::get<1>(t) == alloc_first());
83         assert(alloc_last::allocator_constructed);
84         assert(std::get<2>(t) == alloc_last());
85     }
86     {
87         alloc_first::allocator_constructed = false;
88         alloc_last::allocator_constructed = false;
89         std::tuple<DefaultOnly, alloc_first, alloc_last> t(std::allocator_arg,
90                                                            A2<int>(5));
91         assert(std::get<0>(t) == DefaultOnly());
92         assert(!alloc_first::allocator_constructed);
93         assert(std::get<1>(t) == alloc_first());
94         assert(!alloc_last::allocator_constructed);
95         assert(std::get<2>(t) == alloc_last());
96     }
97     {
98         // Test that the uses-allocator default constructor does not evaluate
99         // its SFINAE when it otherwise shouldn't be selected. Do this by
100         // using 'NonDefaultConstructible' which will cause a compile error
101         // if std::is_default_constructible is evaluated on it.
102         using T = NonDefaultConstructible<>;
103         T v(42);
104         std::tuple<T, T> t(v, v);
105         (void)t;
106         std::tuple<T, T> t2(42, 42);
107         (void)t2;
108     }
109 
110   return 0;
111 }
112