Bad: Kotlin When Expression In

Issue

val finalValue: Array<String> = arrayOf("A", "B", "C", "D")
when (value) {
  in finalValue  -> println("Pass")
  !in finalValue -> println("Not Pass")
}

Error: Kotlin: Type inference failed. The value of the type parameter T should be mentioned in input types (argument types, receiver type or expected type). Try to specify it explicitly.

can you help me to solve this error? thanks

Solution

Assuming that value is of type Char (based on your code in the comment)

You are trying to search a Char in a array of String. To fix this, you either need to change the array to Array<Char> or convert the value to String using toString

val value = 'A'
val finalValue: Array<Char> = arrayOf('A', 'B', 'C', 'D')
when (value) {
  in finalValue  -> println("Pass")
  !in finalValue -> println("Not Pass")
}

or

val value = 'A'
val finalValue: Array<String> = arrayOf("A", "B", "C", "D")
when (value.toString()) {
  in finalValue  -> println("Pass")
  !in finalValue -> println("Not Pass")
}

Answered By - sidgate