Visibility is restricted to a module which isn't an ancestor of the current item.
Erroneous code example:
pub mod Sea {} pub (in crate::Sea) struct Shark; // error! fn main() {}
To fix this error, we need to move the Shark
struct inside the Sea
module:
pub mod Sea { pub (in crate::Sea) struct Shark; // ok! } fn main() {}
Of course, you can do it as long as the module you're referring to is an ancestor:
pub mod Earth { pub mod Sea { pub (in crate::Earth) struct Shark; // ok! } } fn main() {}