Manually incremented index variable can be replaced with use of 'withIndex()'

Reports for loops with a manually incremented index variable.

for loops with a manually incremented index variable can be simplified with the withIndex() function.

Use withIndex() instead of manual index increment quick-fix can be used to amend the code automatically.

Example:

  fun foo(list: List<String>): Int? {
      var index = 0
      for (s in list) { <== can be simplified
          val x = s.length * index
          index++
          if (x > 0) return x
      }
      return null
  }

After the quick-fix is applied:

  fun foo(list: List<String>): Int? {
      for ((index, s) in list.withIndex()) {
          val x = s.length * index
          if (x > 0) return x
      }
      return null
  }

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

UseWithIndex

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Kotlin | Style issues

Inspection Details
By default bundled with:	IntelliJ IDEA 2024.3, Qodana for JVM 2024.3,
Can be installed with plugin:	Kotlin, 243.26483-IJ

01 April 2025