error[E0277]: the size for values of type `[std::boxed::Box]` cannot be known at compilation time --> $DIR/issue-35988.rs:12:7 | LL | V([Box]), | ^^^^^^^^ doesn't have a size known at compile-time | = help: the trait `std::marker::Sized` is not implemented for `[std::boxed::Box]` = note: to learn more, visit = note: no field of an enum variant may have a dynamically sized type error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.