error[E0277]: the size for values of type `[{integer}]` cannot be known at compilation time --> $DIR/issue-17651.rs:5:9 | LL | (|| Box::new(*(&[0][..])))(); | ^^^^^^^^ doesn't have a size known at compile-time | = help: the trait `std::marker::Sized` is not implemented for `[{integer}]` = note: to learn more, visit = note: required by `std::boxed::Box::::new` error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.