fun sourceNamesFrom(entry: File): Sequence<String> =
        when {
            entry.isClassPathArchive -> sourceNamesFromJar(entry)
            entry.isDirectory -> sourceNamesFromDir(entry)
            else -> emptySequence()
        }

    private
    fun sourceNamesFromJar(jar: File): Sequence<String> =
        openJarFile(jar).run {
            entries().asSequence()
                .filter { it.name.isClassFilePath }

                val extension
                    get() = groovyNamedArgumentsToVarargs || javaClassToKotlinClass
            }

            if (!candidateFor.extension) {
                return@flatMap emptySequence<KotlinExtensionFunction>()
            }

            val extensionTypeParameters = function.typeParameters + type.typeParameters

            sequenceOf(
                KotlinExtensionFunction(