Seguendo il web cast “Raf & Alk su C# 4” di dotnetmarche ho scoperto l’introduzione di questa feature nel framework 4.0 con cui mi ero scontrato tempo fa e che mi sembrava quasi scontata. Dalla msdn http://msdn.microsoft.com/it-it/library/ee207183.aspx // Assignment compatibility. string str = "test"; // An object of a more derived type is assigned to an object of a less derived type. object obj = str; // Covariance. IEnumerable<string> strings = new List<string>(); // An object that is instantiated with a more derived type argument // is assigned to an object instantiated with a less derived type argument. // Assignment compatibility...