public class ClassA {} public struct GenStruct { int field1; long field2; T field3; } public struct Struct { int field1; long field2; byte field3; } public class Gen { public unsafe int sizeofGenStructT () { return sizeof (Struct); } } public class main { public static unsafe int Main () { Gen ga = new Gen (); if (ga.sizeofGenStructT () != sizeof (Struct)) return 1; return 0; } }