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 // <functional>
10 
11 // class function<R(ArgTypes...)>
12 
13 // template<class F> function(F);
14 
15 // Allow incomplete argument types in the __is_callable check
16 
17 #include <functional>
18 #include <cassert>
19 
20 #include "test_macros.h"
21 
22 struct X{
23     typedef std::function<void(X&)> callback_type;
24     virtual ~X() {}
25 private:
26     callback_type _cb;
27 };
28 
29 struct IncompleteReturnType {
30   std::function<IncompleteReturnType ()> fn;
31 };
32 
33 
34 int called = 0;
35 IncompleteReturnType test_fn() {
36   ++called;
37   IncompleteReturnType I;
38   return I;
39 }
40 
41 // See llvm.org/PR34298
42 void test_pr34298()
43 {
44   static_assert(std::is_copy_constructible<IncompleteReturnType>::value, "");
45   static_assert(std::is_copy_assignable<IncompleteReturnType>::value, "");
46   {
47     IncompleteReturnType X;
48     X.fn = test_fn;
49     const IncompleteReturnType& CX = X;
50     IncompleteReturnType X2 = CX;
51     assert(X2.fn);
52     assert(called == 0);
53     X2.fn();
54     assert(called == 1);
55   }
56   {
57     IncompleteReturnType Empty;
58     IncompleteReturnType X2 = Empty;
59     assert(!X2.fn);
60   }
61 }
62 
63 int main(int, char**) {
64   test_pr34298();
65 
66   return 0;
67 }
68