// CS0425: The constraints for type parameter `T' of method `CA.Foo<T>()' must match the constraints for type parameter `U' of interface method `IA.Foo<U>()'. Consider using an explicit interface implementation instead // Line: 16 interface IA { void Foo<U> (); } class CA { public void Foo<T> () where T : class { } } class CB : CA, IA { public static void Main () { } }