Redundant 'Unit'

Reports redundant Unit expressions.

Unit in Kotlin can be used as the return type of functions that do not return anything meaningful. The Unit type has only one possible value, which is the Unit object.

Examples:

  fun redundantA(): Unit {
      return Unit // redundant, 'Unit' is returned by default and matches the expected return type
  }

  fun requiredA(condition: Boolean): Any {
      if (condition) return "hello"
      return Unit // explicit 'Unit' is required since the expected type is 'Any'
  }

  fun redundantB(condition: Boolean): Any = if (condition) {
      fun ancillary(): Int = 1
      println("${ancillary()}")
      Unit // redundant since the last expression is already of type 'Unit'
  } else {
      println("else")
  }

  fun requiredB(condition: Boolean): Any = if (condition) {
      1024
      Unit // required, otherwise '1024' (Int) would be the return value
  } else {
      println("else")
  }

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.

RedundantUnitExpression

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 | Redundant constructs

Availability

By default bundled with: IntelliJ IDEA 2024.1, Qodana for JVM 2024.1,
Can be installed with plugin: Kotlin, 241.18072-IJ

Last modified: 18 June 2024