public static bool Is8 <T1, T2, T3, T4, T5, T6, T7, T8>(this IOrType <T1, T2, T3, T4, T5, T6, T7, T8> self, out T8 t8) { if (self.Possibly8() is IIsDefinately <T8> definate) { t8 = definate.Value; return(true); } t8 = default; return(false); }