Unused return value of a function with lambda expression body

Reports calls with an unused return value when the called function returns a lambda from an expression body.

If there is = between function header and body block, code from the function will not be evaluated which can lead to incorrect behavior.

Remove = token from function declaration can be used to amend the code automatically.

Example:

  fun printHello() = { println("Hello") }

  fun main() {
      printHello() // This function doesn't print anything
  }

After the quick-fix is applied:

  fun printHello() { println("Hello") }

  fun main() {
      printHello()
  }

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.

UnusedLambdaExpressionBody

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 | Probable bugs

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 UnusedLambdaExpressionBody

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