1 // { dg-options "-std=c++17 -fconcepts" } 2 3 template<typename T> Concept()4concept bool Concept() { 5 return requires () { 6 typename T::member_type1; 7 typename T::member_type2; 8 }; 9 } 10 11 struct model { 12 using member_type1 = int; 13 using member_type2 = int; 14 }; 15 16 template<Concept C> 17 struct S {}; 18 19 S<model> s; 20