using System; namespace TestEnum { public enum BooleanEnum : bool { Min = false, Zero = false, One = true, Max = byte.MaxValue } public enum EnumWithNestedClass { #pragma warning disable format // error: nested types are not permitted in C#. public class NestedClass { } , #pragma warning enable format Zero, One } public enum NativeIntEnum : IntPtr { Zero = 0L, One = 1L, FortyTwo = 42L } }