error[E0208]: [o]
  --> $DIR/variance-object-types.rs:21:1
   |
LL | / struct Foo<'a> { //~ ERROR [o]
LL | |     x: Box<Fn(i32) -> &'a i32 + 'static>
LL | | }
   | |_^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0208`.