failure to resolve import

[alsam]

cat main.rs

//extern crate collections;

pub mod sub;

fn main() {
}

cat sub.rs

cat sub.rs

extern crate collections;

use collections::TreeMap;

rustc main.rs 
sub.rs:4:5: 4:16 error: unresolved import. maybe a missing `extern crate collections`?
sub.rs:4 use collections::TreeMap;
             ^~~~~~~~~~~
sub.rs:4:5: 4:25 error: failed to resolve import `collections::TreeMap`
sub.rs:4 use collections::TreeMap;
             ^~~~~~~~~~~~~~~~~~~~
error: aborting due to 2 previous errors

Looks like a bug for me because there is explicit extern crate collections; in sub.rs
If uncomment //extern crate collections; in main.rs that is at top level the code will compile ok:

rustc main.rs 
sub.rs:4:5: 4:25 warning: unused import, #[warn(unused_imports)] on by default
sub.rs:4 use collections::TreeMap;
             ^~~~~~~~~~~~~~~~~~~~

[alexcrichton]

Closing, this is intended behavior. Use statements have crate-relative paths, not module-relative paths (like other paths in the module). The manual has more information about this.

[alsam]

Ok, thanks for clarification.