fn unified_workspace_set(&self, workspace_set: &PackageSet<'g>) -> PackageSet<'g> {
        let target_set = self
            .all_cargo_sets()
            .map(|x| x.target_features().to_package_set())
            .reduce(|a, b| a.union(&b))
            .expect("at least one set");
        let host_set = self
            .all_cargo_sets()
            .map(|x| x.host_features().to_package_set())
            .reduce(|a, b| a.union(&b))
            .expect("at least one set");

        target_set.union(&host_set).intersection(workspace_set)
    }
Returns the unified set of workspace dependencies.
tools/determinator/src/determinator.rs