Constant conditions

Reports non-trivial conditions and values that are statically known to be always true, false, null or zero. While sometimes intended, often this is a sign of logical error in the program. Additionally, reports never reachable when branches and some expressions that are statically known to fail always.

Examples:

fun process(x: Int?) {
  val isNull = x == null
  if (!isNull) {
    if (x != null) {} // condition is always true
    require(x!! < 0 && x > 10) // condition is always false
  } else {
    println(x!!) // !! operator will always fail
  }
}
fun process(v: Any) {
  when(v) {
    is CharSequence -> println(v as Int) // cast will always fail
    is String -> println(v) // branch is unreachable
  }
}

Uncheck the "Warn when constant is stored in variable" option to avoid reporting of variables having constant values not in conditions.

New in 2021.3

Inspection options

Option	Type	Default
Warn when constant is stored in variable	Checkbox	true

Inspection Details
Available in:	IntelliJ IDEA 2023.3, Qodana for JVM 2023.3
Plugin:	Kotlin, @snapshot@

Last modified: 13 July 2023