Error code E0583

A file wasn't found for an out-of-line module.

Erroneous code example:

mod file_that_doesnt_exist; // error: file not found for module

fn main() {}

Please be sure that a file corresponding to the module exists. If you want to use a module named file_that_doesnt_exist, you need to have a file named or file_that_doesnt_exist/ in the same directory.