# Error code E0578

A module cannot be found and therefore, the visibility cannot be determined.

Erroneous code example:

    foo!();

    pub (in ::Sea) struct Shark; // error!

    fn main() {}

Because of the call to the `foo` macro, the compiler guesses that the missing module could be inside it and fails because the macro definition cannot be found.

To fix this error, please be sure that the module is in scope:

    pub mod Sea {
        pub (in crate::Sea) struct Shark;
    }

    fn main() {}