error[E0603]: module `b` is private --> $DIR/private-trait.rs:8:9 | LL | impl a::b::Hidden for S {} | ^ ------ trait `Hidden` is not publicly re-exported | | | private module | note: the module `b` is defined here --> $DIR/private-trait.rs:2:5 | LL | mod b { | ^^^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0603`.