Invalid value for argument to 'attribute' attribute
An attribute was passed either an invalid argument or two mutually exclusive arguments.
The following sample generates CS0591:
using System; using System.Interop; [structlayout(LayoutKind.Union | LayoutKind.Explicit)] // CS0591 // try the following line instead // [structlayout(LayoutKind.Union)] class I { } public class a { public static void Main() { } }