src/test/ui/issues/issue-17431-1.stderr

   1 error[E0072]: recursive type `Foo` has infinite size
   2   --> $DIR/issue-17431-1.rs:1:1
   3    |
   4 LL | struct Foo { foo: Option<Option<Foo>> }
   5    | ^^^^^^^^^^        ------------------- recursive without indirection
   6    | |
   7    | recursive type has infinite size
   8    |
   9 help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `Foo` representable
  10    |
  11 LL | struct Foo { foo: Option<Box<Option<Foo>>> }
  12    |                          ++++           +
  13
  14 error: aborting due to previous error
  15
  16 For more information about this error, try `rustc --explain E0072`.