1 error[E0072]: recursive type `Foo` has infinite size
2 --> $DIR/issue-17431-7.rs:1:1
4 LL | enum Foo { Voo(Option<Option<Foo>>) }
5 | ^^^^^^^^ --- recursive without indirection
7 help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to break the cycle
9 LL | enum Foo { Voo(Option<Option<Box<Foo>>>) }
12 error: aborting due to previous error
14 For more information about this error, try `rustc --explain E0072`.