IntelliJ IDE gives incorrect warning: "Condition 'list.size > 0' is always false"

IncorrectConditionIsAlwaysFalse.kt

package bugs

import kotlin.random.Random.Default.nextBoolean

object IncorrectConditionIsAlwaysFalse {

    private fun conditionA() = nextBoolean()
    private fun conditionB() = nextBoolean()

    data class Action(val list: List<Int>)

    fun buildAction(): Action? {
        val list = mutableListOf<Int>().apply {
            if (conditionA()) {
                add(123)
            }
            if (conditionB()) {
                add(456)
            }
        }
        // The IntelliJ IDE will give this warning: "Condition 'list.size > 0' is always false"
        return if (list.size > 0) {
            Action(list)
        }
        else null
    }

}