Attempting to use deprecated_module; or use deprecated_module::*; fails, but doing use deprecated_module::SpecificItem; compiles with no error. Right now in Diesel I'm actually seeing an even more confusing error:

use of deprecated item 'types::__test_reexports'

Even though there is nothing in the project with that name. However, I'm unable to reproduce that issue outside of Diesel.

Regardless, the following code compiles without warnings, but should warn.

#[deprecated(since = "0.1.0")]
pub mod foo {
    pub use std::option::Option;
}

pub mod bar {
    use foo::Option;
}