/**
     * @return How many qualifiers needs to be dropped from [wholeType] to get [nestedType].
     *
     * Example: to get `foo.bar` from `foo.bar.Baz.Inner`, you need to drop 2 qualifiers (`Inner` and `Baz`).
     */
    private fun countQualifiersToDrop(wholeType: KtUserType, nestedType: KtUserType): Int {
        val qualifierIndex = generateSequence(wholeType) { it.qualifier }.indexOf(nestedType)