Function unit_sources_for 

pub fn unit_sources_for<'a>(
    unit_sources: &'a HashMap<String, Vec<PathBuf>>,
    view: Option<&DependencyView>,
    written: &str,
) -> Option<&'a Vec<PathBuf>>

The project-relative source paths of the unit a uses/consumes target names, from an analysed round’s unit_sources — what go-to-definition opens. A dependency unit is keyed by its canonical name, so money.currency is looked up through view when it isn’t a key itself.