error[E0277]: the size for values of type `[String]` cannot be known at compilation time --> $DIR/issue-22874.rs:2:11 | LL | rows: [[String]], | ^^^^^^^^^^ doesn't have a size known at compile-time | = help: the trait `Sized` is not implemented for `[String]` = note: slice and array elements must have `Sized` type error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0277`.