// CS0266: Cannot implicitly convert type `System.Collections.Generic.IEnumerable<T>' to `System.Collections.Generic.IEnumerable<U>'. An explicit conversion exists (are you missing a cast?) // Line: 12 using System; using System.Collections.Generic; public class Test { static void Bla<T, U> () where T : U { IEnumerable<T> ita = null; IEnumerable<U> itu = ita; } }