* when we shorten [qualifier].
     */
    private fun removeRedundantElements(qualifier: KtElement) {
        typesToShorten.removeAll { it.element.qualifier?.isInsideOf(qualifier) == true }
        qualifiersToShorten.removeAll { it.element.receiverExpression.isInsideOf(qualifier) }
    }

    private fun KtElement.isAlreadyCollected(): Boolean {
        val thisElement = this