IDEA with Kotlin plugin freeze

Player.kt

package example

class DataChannel {
    fun registerObserver(dataChannelObserver: DataChannelObserver?) {}
}

interface DataChannelObserver {
    fun onStateChange()
}

class Player
{
    suspend fun startAsync(dataChannel: DataChannel) {
        dataChannel.registerObserver(object : DataChannelObserver {
            override fun onStateChange() {
                println("onStateChange: $") // place cursor after $ and type {
            }
        })
        println("Observer registered: ${dataChannel.toString()}") // .toString() here is intentional
    }
}