error[E0055]: reached the recursion limit while auto-dereferencing Foo
  --> $DIR/E0055.rs:21:13
   |
LL |     ref_foo.foo();
   |             ^^^ deref recursion limit reached
   |
   = help: consider adding a `#![recursion_limit="4"]` attribute to your crate

error: aborting due to previous error

For more information about this error, try `rustc --explain E0055`.