1 // { dg-options "-std=c++17 -fconcepts" }
6 return requires (T t) { t.mf(); };
12 return C<typename T::ca1_type>();
18 return CA1<T>() && requires () { typename T::ca2_type; };
24 return CA2<T>() && requires () { typename T::ca3_type; };
30 return requires () { typename T::cb1_type; };
36 return CB1<T>() && requires () { typename T::cb2_type; };
42 return CB2<T>() && requires () { typename T::cb3_type; };
46 struct MC { void mf(); };
47 static_assert(C<MC>(), "");
50 struct MA1 { using ca1_type = MC; };
51 struct MA2 : MA1 { using ca2_type = int; };
52 struct MA3 : MA2 { using ca3_type = int; };
53 static_assert(CA1<MA1>(), "");
54 static_assert(CA2<MA2>(), "");
55 static_assert(CA3<MA3>(), "");
57 struct MB1 { using cb1_type = int; };
58 struct MB2 : MB1 { using cb2_type = int; };
59 struct MB3 : MB2 { using cb3_type = int; };
60 static_assert(CB1<MB1>(), "");
61 static_assert(CB2<MB2>(), "");
62 static_assert(CB3<MB3>(), "");
65 template<typename T1, typename T2>
68 template<CA1 T1, CB1 T2>
69 struct S<T1, T2> // Specialization #1
71 static constexpr int value = 1;
74 template<CA1 T1, CB2 T2>
76 struct S<T1, T2> // Specialization #2
78 static constexpr int value = 2;
81 template<CA2 T1, CB3 T2>
83 struct S<T1, T2> // Specialization #3
85 static constexpr int value = 3;
98 static_assert(S<MA1,MB1>::value == 1, "");
99 static_assert(S<MA1,MB2>::value == 2, "");
100 static_assert(S<MA1,MB3>::value == 2, "");
101 static_assert(S<MA2,MB1>::value == 1, "");
102 static_assert(S<MA2,MB2>::value == 1, "");
103 static_assert(S<MA2,MB3>::value == 3, "");
104 static_assert(S<MA3,MB1>::value == 1, "");
105 static_assert(S<MA3,MB2>::value == 1, "");
106 static_assert(S<MA3,MB3>::value == 1, "");