Missing backticks on operator in colon EOL rewrite

[som-snytt]

Compiler version

3.7

Minimized code

def g =
  2
  .+ {
    3
  }

  def receive =
    case ReceiveTimeout =>
      val msg = "Titivate timed out!"
      logBranch.error(msg)
      throw new RuntimeException(msg)

    case Run =>
      gameRepo
        .countSec(_.checkable)
        .foreach: total =>
          lila.mon.round.titivate.total.record(total)
          gameRepo
            .docCursor(Query.checkable)
            .documentSource(100)
            .via(gameRead)
            .via(gameFlow)
            .toMat(LilaStream.sinkCount)(Keep.right)
            .run()
            .addEffect(lila.mon.round.titivate.game.record(_))
            .>> {
              gameRepo
                .countSec(_.checkableOld)
                .dmap(lila.mon.round.titivate.old.record(_))
            }
            .monSuccess(_.round.titivate.time)
            .logFailure(logBranch)
            .addEffectAnyway(scheduleNext())

Output

def g =
  2
  .+ :
    3

  def receive =
    case ReceiveTimeout =>
      val msg = "Titivate timed out!"
      logBranch.error(msg)
      throw new RuntimeException(msg)

    case Run =>
      gameRepo
        .countSec(_.checkable)
        .foreach: total =>
          lila.mon.round.titivate.total.record(total)
          gameRepo
            .docCursor(Query.checkable)
            .documentSource(100)
            .via(gameRead)
            .via(gameFlow)
            .toMat(LilaStream.sinkCount)(Keep.right)
            .run()
            .addEffect(lila.mon.round.titivate.game.record(_))
            .>> :
              gameRepo
                .countSec(_.checkableOld)
                .dmap(lila.mon.round.titivate.old.record(_))
            .monSuccess(_.round.titivate.time)
            .logFailure(logBranch)
            .addEffectAnyway(scheduleNext())

Expectation

Operator >> requires backticks for less-brace syntax.

lichess-org/lila#17036 (comment)

[som-snytt]

Is this the error you saw? All I can say is, "Wha'?"

5 |    i.+ :
  |    ^^^
  |   None of the overloaded alternatives of method + in class Int with types
  |    (x: Double): Double
  |    (x: Float): Float
  |    (x: Long): Long
  |    (x: Int): Int
  |    (x: Char): Int
  |    (x: Short): Int
  |    (x: Byte): Int
  |    (x: String): String
  |   match expected type (27 : Int)

Is there a rule about backticks inverting infix?

Whereby op ids are infix by default (or nature) and must be used that way, except for backticked, and conversely for alnum.

Also, recommend using j, k together more often.

@main def test = println:
  val i = 42
  val j =
    i.+ :
      27
  val k =
    42.+ :
      27
  (j, k)