Functions that use Deferred as return type should have a name with the Async suffix. Otherwise, it's recommended to mark a function as suspend and unwrap Deferred inside it.

Example:

  fun calcEverything(): Deferred<Int> {
      return CompletableDeferred(42)
  }

After the quick-fix that adds the Async suffix applied:

  fun calcEverythingAsync(): Deferred<Int> {
      return CompletableDeferred(42)
  }

After the quick-fix that converts the function into a suspend one applied:

  suspend fun calcEverything(): Int {
      return CompletableDeferred(42).await()
  }