// CS0452: The type `int' must be a reference type in order to use it as type parameter `T' in the generic type or method `Foo.Test<T>(ref T)' // Line: 14 public class Foo { public static void Test<T> (ref T t) where T : class { } } public class C { public static void Main () { int i = 0; Foo.Test<int> (ref i); } }