override fun getPossibleCallableNames(): Set<Name> = withValidityAssertion {
        imports.flatMapTo(hashSetOf()) { listOfNotNull(it.callableName, it.aliasName) }
    }

    override fun getPossibleClassifierNames(): Set<Name> = withValidityAssertion {
        imports.flatMapTo((hashSetOf())) { listOfNotNull(it.relativeClassName?.shortName(), it.aliasName) }
    }

    // todo cache?
    override fun getPossibleCallableNames(): Set<Name> = withValidityAssertion {
        imports.flatMapTo(hashSetOf()) { import: Import ->
            if (import.relativeClassName == null) { // top level callable
                DeclarationsInPackageProvider.getTopLevelCallableNamesInPackageProvider(import.packageFqName, analysisSession)

    val outputClassFilename
        get() = "$outputClassName.class"
}


class PackagePatterns(givenPrefixes: Set<String>) {

    private
    val prefixes: MutableSet<String> = hashSetOf()

    private
    val names: MutableSet<String> = hashSetOf()

    init {
        givenPrefixes.map { it.replace('.', '/') }.forEach { internalName ->
            names.add(internalName)
            prefixes.add("$internalName/")
        }

        val unresolvedNames = mutableSetOf<Name>()

        fun saveReferencedItem(importableName: FqName, referencedByName: Name) {
            usedImports.getOrPut(importableName) { hashSetOf() } += referencedByName
        }

        firFile.accept(object : FirVisitorVoid() {
            override fun visitElement(element: FirElement) {
                element.acceptChildren(this)
            }