1 // RUN: %clang_cc1 -std=c++20 -verify %s
2 // RUN: %clang_cc1 -std=c++20 -verify %s -DDEPENDENT_OR
3 
4 #ifdef DEPENDENT_OR
5 // This causes the || below to be a CXXOperatorCallExpr not a BinaryOperator.
6 struct A {}; bool operator||(A, A);
7 #endif
8 
9 namespace PR45589 {
10   template<typename T> struct X { static constexpr bool value = T::value; }; // expected-error {{cannot be used prior to '::'}}
11   struct False { static constexpr bool value = false; };
12   struct True { static constexpr bool value = true; };
13 
14   template<typename T> concept C = true;
15 
16   template<bool B, typename T> constexpr int test = 0;
17   template<bool B, typename T> requires C<T> constexpr int test<B, T> = 1;
18   template<bool B, typename T> requires (B && C<T>) || (X<T>::value && C<T>) constexpr int test<B, T> = 2; // expected-error {{non-constant expression}} expected-note {{subexpression}} expected-note {{instantiation of}} expected-note {{while substituting}}
19   static_assert(test<true, False> == 2);
20   static_assert(test<true, True> == 2);
21   static_assert(test<true, char> == 2); // satisfaction of second term of || not considered
22   static_assert(test<false, False> == 1);
23   static_assert(test<false, True> == 2); // constraints are partially ordered
24   // FIXME: These diagnostics are excessive.
25   static_assert(test<false, char> == 1); // expected-note 2{{while}} expected-note 2{{during}}
26 }
27 
28 namespace PR52905 {
29 // A mock for std::convertible_to. Not complete support.
30 template <typename _From, typename _To>
31 concept convertible_to = __is_convertible_to(_From, _To); // expected-note {{evaluated to false}}
32 
33 template <typename T>
34 class A {
35 public:
36   using iterator = void **;
37 
38   iterator begin();
39   const iterator begin() const;
40 };
41 
42 template <class T>
43 concept Beginable1 = requires(T t) {
44   { t.begin }
45   ->convertible_to<typename T::iterator>; // expected-note {{not satisfied}}
46 };
47 
48 static_assert(Beginable1<A<int>>); // expected-error {{static_assert failed}}
49                                    // expected-note@-1 {{does not satisfy 'Beginable1'}}
50 
51 template <class T>
52 concept Beginable2 = requires(T t) {
53   { t.begin() }
54   ->convertible_to<typename T::iterator>;
55 };
56 
57 static_assert(Beginable2<A<int>>);
58 } // namespace PR52905
59