Not-null assertion can be replaced with 'error()'

Reports not-null assertion (!!) calls that can be replaced with the elvis operator and error(...).

A not-null assertion can lead to an unexpected NPE (NullPointerException). Replacing it with ?: error(...) makes the failure explicit and supports whole-file inspection cleanup.

Example:

fun test(number: Int?) {
    val x = number!!
}

fun test(number: Int?) {
    val x = number ?: error("Expression 'number' must not be null")
}

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.

DoubleBang

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 ID: DoubleBang

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 DoubleBang

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

IntelliJ IDEA 2026.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2026.2, Qodana for JVM 2026.2,

Last modified: 30 June 2026