'@Deferred' result is unused

Reports function calls with the Deferred result type if the return value is not used.

If the Deferred return value is not used, the call site would not wait to complete this function.

Example:

  fun calcEverythingAsync() = CompletableDeferred(42)

  fun usage() {
      calcEverythingAsync()
  }

The quick-fix provides a variable with the Deferred initializer:

  fun calcEverythingAsync() = CompletableDeferred(42)

  fun usage() {
      val answer = calcEverythingAsync()
  }

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.

DeferredResultUnused

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

Inspection options

Here you can find the description of settings available for the '@Deferred' result is unused inspection, and the reference of their default values.

Report only function calls from 'kotlinx.coroutines': Default value:
Not selected

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 DeferredResultUnused

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