'when' that can be simplified by introducing an argument

Last modified: 03 December 2024

Reports a when expression that can be simplified by introducing a subject argument.

Example:

fun test(obj: Any): String {
    return when {
        obj is String -> "string"
        obj is Int -> "int"
        else -> "unknown"
    }
}

The quick fix introduces a subject argument:

fun test(obj: Any): String {
    return when (obj) {
        is String -> "string"
        is Int -> "int"
        else -> "unknown"
    }
}

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.

IntroduceWhenSubject
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, 243.23126-IJ