error[E0072]: recursive type `List` has infinite size --> $DIR/recursive-enum.rs:1:1 | LL | enum List { Cons(T, List), Nil } | ^^^^^^^^^^^^ ------- recursive without indirection | help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to break the cycle | LL | enum List { Cons(T, Box>), Nil } | ++++ + error: aborting due to previous error For more information about this error, try `rustc --explain E0072`.