error[E0277]: the size for values of type `(dyn AbstractRenderer + 'static)` cannot be known at compilation time --> $DIR/issue-18107.rs:14:5 | LL | AbstractRenderer | ^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time | = help: the trait `std::marker::Sized` is not implemented for `(dyn AbstractRenderer + 'static)` = note: to learn more, visit = note: the return type of a function must have a statically known size error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.