rust/tests/run-coverage/unused_mod.coverage

$DIR/auxiliary/unused_mod_helper.rs:
   LL|       |#[allow(dead_code)]
   LL|      0|pub fn never_called_function() {
   LL|      0|    println!("I am never called");
   LL|      0|}

$DIR/unused_mod.rs:
   LL|       |#[path = "auxiliary/unused_mod_helper.rs"]
   LL|       |mod unused_module;
   LL|       |
   LL|      1|fn main() {
   LL|      1|    println!("hello world!");
   LL|      1|}