1 // { dg-options "-std=c++17 -fconcepts" }
2 
3 template<typename T>
Class()4   concept bool Class() { return __is_class(T); }
5 
6 template<typename T>
Union()7   concept bool Union() { return __is_union(T); }
8 
9 // Check non-overlapping specializations
10 template<typename T> struct S1 { static const int value = 0; };
11 template<Class T> struct S1<T> { static const int value = 1; };
12 template<Union T> struct S1<T> { static const int value = 2; };
13 
14 struct S { };
15 union U { };
16 
17 static_assert(S1<int>::value == 0, "");
18 static_assert(S1<S>::value == 1, "");
19 static_assert(S1<U>::value == 2, "");
20 
21 int main() { }
22