Reposting it here <https://kotlinlang.slack.com/archives/C0B8MA7FA/p1582007328306300>

# codereview

[am]

Reposting it here
https://kotlinlang.slack.com/archives/C0B8MA7FA/p1582007328306300

[dfriehs]

Instead of creating a mutable list and adding elements, i would consider using map :

val newList = studentList.map {
  if (it.id == student.id) it.copy(isFailed = false)
  else it.copy()
}

Should the objects inside themselves be deep-copied, consider either implementing Cloneable or in the case of data classes, call copy.