'addAll(map/filter {})' can be replaced with 'mapTo/filterTo'

Reports calls to MutableCollection.addAll/+= where the argument is a call to Iterable.map/filter.

This code allocates an additional List object that can be saved by using mapTo/filterTo.

The quickfixes replaces the call with mapTo/filterTo.

Example:

    coll1.addAll(coll2.map { transform(it) })
    coll1 += coll2.map { transform(it) }

After the quick-fix is applied:

coll2.mapTo(coll1) { transform(it) }

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.

ReplaceAddAllWithMapTo

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: ReplaceAddAllWithMapTo

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 ReplaceAddAllWithMapTo

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

IntelliJ IDEA 2025.3

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.3, Qodana for JVM 2025.3,

Last modified: 03 December 2025