// WITH_RUNTIME
// INTENTION_TEXT: "Replace with 'flatMap{}.mapNotNull{}.mapTo(){}'"
// INTENTION_TEXT_2: "Replace with 'asSequence().flatMap{}.mapNotNull{}.mapTo(){}'"
fun foo(list: List<String>, target: MutableList<String>) {
    <caret>list
        .flatMap { it.indices }
        .mapNotNull { bar(it) }
        .mapTo(target) { it.substring(1) }
}

fun bar(p: Int): String? = null