for IntelliJ IDEA Scala plugin bug https://youtrack.jetbrains.com/issue/SCL-8267

test.sc

import scala.language.implicitConversions

case class SomethingElse(value: String)

implicit class ToSomethingElse(val value: String) {
  def toSomethingElse = SomethingElse("###" + value)
}

val list = Option(List(Option("test"), None, Option("Another")))

val maybeList = list.map {
  for {
    maybeValue <- _
    mayBeSomethingElse = maybeValue.map(_.toSomethingElse)
    if (mayBeSomethingElse.isDefined)
  } yield mayBeSomethingElse.get
}

println(maybeList)

Test.scala

import scala.language.implicitConversions

object Test extends App {

  case class SomethingElse(value: String)

  implicit class ToSomethingElse(val value: String) {
    def toSomethingElse = SomethingElse("###" + value)
  }

  val list = Option(List(Option("test"), None, Option("Another")))

  val maybeList = list.map {
    for {
      maybeValue <- _
      mayBeSomethingElse = maybeValue.map(_.toSomethingElse)
      if (mayBeSomethingElse.isDefined)
    } yield mayBeSomethingElse.get
  }

  println(maybeList)
  
}