error[E0603]: trait `Foo` is private
  --> $DIR/issue-11593.rs:7:24
   |
LL | impl private_trait_xc::Foo for Bar {}
   |                        ^^^ private trait
   |
note: the trait `Foo` is defined here
  --> $DIR/auxiliary/private-trait-xc.rs:1:1
   |
LL | trait Foo {}
   | ^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0603`.