public static bool Is4 <T1, T2, T3, T4, T5, T6, T7, T8>(this IOrType <T1, T2, T3, T4, T5, T6, T7, T8> self, out T4 t4) { if (self.Possibly4() is IIsDefinately <T4> definate) { t4 = definate.Value; return(true); } t4 = default; return(false); }