For blog post about sealed classes, when expressions and custom detekt rule Raw

NonExhaustiveWhen.kt

override fun visitLambdaExpression(lambdaExpression: KtLambdaExpression) {
    super.visitLambdaExpression(lambdaExpression)

    val whenExpressions = lambdaExpression.bodyExpression?.statements
      ?.filterIsInstance<KtWhenExpression>()

    if (whenExpressions?.isNotEmpty() == true) {
      report(
        CodeSmell(
          issue, Entity.from(lambdaExpression), MESSAGE
        )
      )
    }
  }