Array property in data class

Reports properties with an Array type in a data class without overridden equals() or hashCode().

Array parameters are compared by reference equality, which is likely an unexpected behavior. It is strongly recommended to override equals() and hashCode() in such cases.

Example:

data class Text(val lines: Array<String>)

The quick-fix generates missing equals() and hashCode() implementations:

  data class Text(val lines: Array<String>) {
      override fun equals(other: Any?): Boolean {
          if (this === other) return true
          if (javaClass != other?.javaClass) return false

          other as Text

          if (!lines.contentEquals(other.lines)) return false

          return true
      }

      override fun hashCode(): Int {
          return lines.contentHashCode()
      }
  }

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.

ArrayInDataClass

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 ArrayInDataClass

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