Mocking content of module in different file does not work since rustc 1.30.0-nightly (63d51e89a 2018-09-28)

[CodeSandwich]

#[mockable]
mod module;

Doesn't make content of module mockable since rustc 1.30.0-nightly (63d51e89a 2018-09-28). The necessary functionality was removed from rustc, it may or may not be restored: https://github.com/rust-lang/rust/issues/54727.