.mapNotNullTo(mutableSetOf()) { it.nameAsName }
    }

    override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> {
        val callables = index.topLevelPropertyMap[packageFqName].orEmpty() + index.topLevelFunctionMap[packageFqName].orEmpty()
        return callables
            .filter { it.inScope }
            .mapNotNullTo(mutableSetOf()) { it.nameAsName }
    }

    internal val typeAliasMap: MutableMap<FqName, MutableSet<KtTypeAlias>> = mutableMapOf()
    internal val topLevelFunctionMap: MutableMap<FqName, MutableSet<KtNamedFunction>> = mutableMapOf()
    internal val topLevelPropertyMap: MutableMap<FqName, MutableSet<KtProperty>> = mutableMapOf()

    /**
     * Allows quickly finding [KtClassOrObject]s which have a given simple name as a supertype. The map may contain local classes as well.
     */