Expression body syntax is preferable here

Reports return expressions (one-liners or when) that can be replaced with expression body syntax.

Expression body syntax is recommended by the style guide.

Convert to expression body quick-fix can be used to amend the code automatically.

Example:

  fun sign(x: Int): Int {
      return when { // <== can be simplified
          x < 0 -> -1
          x > 0 -> 1
          else -> 0
      }
  }

After the quick-fix is applied:

  fun sign(x: Int): Int = when {
      x < 0 -> -1
      x > 0 -> 1
      else -> 0
  }

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.

UseExpressionBody

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

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection UseExpressionBody

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

IntelliJ IDEA 2025.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.2, Qodana for JVM 2025.2,

Last modified: 18 September 2025