error[E0277]: the size for values of type `[u8]` cannot be known at compilation time --> $DIR/wf-array-elem-sized.rs:7:10 | LL | foo: [[u8]], | ^^^^^^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `[u8]` = note: slice and array elements must have `Sized` type error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.