Function compose_unit_assets 

pub fn compose_unit_assets(
    name: &str,
    unit_info: &BTreeMap<String, UnitInfo>,
) -> HashMap<String, AssetDecl>

Every asset visible in unit name: its own, plus those of each commons it uses (one level, the same mixin rule compose_unit_symbols applies to types and functions). A local asset wins over an imported one of the same name; two used commons declaring the same name is bynk.uses.name_conflict (phase_uses_name_conflicts), so which of them is kept here is never observable in a program that checks.