error[E0277]: the size for values of type `str` cannot be known at compilation time --> $DIR/issue-14366.rs:12:14 | LL | let _x = "test" as &::std::any::Any; | ^^^^^^ doesn't have a size known at compile-time | = help: the trait `std::marker::Sized` is not implemented for `str` = note: to learn more, visit = note: required for the cast to the object type `dyn std::any::Any` error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.