You mean that if you split a file you define another module when you declare it? That is only visible as a module at the level of declaration not beyond. Also

You mean that if you split a file you define another module when you declare it? That is only visible as a module at the level of declaration not beyond. Also note that modules are not per se compile units. Cf. See https://doc.rust-lang.org/rust-by-example/mod/split.html https://doc.rust-lang.org/rust-by-example/mod/split.html Edit: typo.