return classifiers.filter { it.inScope }
            .mapNotNullTo(mutableSetOf()) { it.nameAsName }
    }

    override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> {
        val callables = index.topLevelPropertyMap[packageFqName].orEmpty() + index.topLevelFunctionMap[packageFqName].orEmpty()
        return callables