Lint undesirable inference

[som-snytt]

Scala 2 is helpful (under -Xlint)

scala> val xs = mutable.HashMap("a" -> 42L)
val xs: scala.collection.mutable.HashMap[String,Long] = HashMap(a -> 42)

scala> xs.getOrElse("b", 0)
          ^
       warning: a type was inferred to be `AnyVal`; this may indicate a programming error.

but

scala> xs.getOrElse("b", 0)
val res0: Long | Int = 0

scala> xs.getOrElse("b", 0) + 42
-- [E008] Not Found Error: ---------------------------------------------------------------------------------------------
1 |xs.getOrElse("b", 0) + 42
  |^^^^^^^^^^^^^^^^^^^^^^
  |value + is not a member of Long | Int, but could be made available as an extension method.
  |
  |One of the following imports might make progress towards fixing the problem:
  |
  |  import scala.math.Fractional.Implicits.infixFractionalOps
  |  import scala.math.Integral.Implicits.infixIntegralOps
  |  import scala.math.Numeric.Implicits.infixNumericOps
  |
1 error found

I see Discord shows a timestamp when hovering, so it was 6 minutes between a user asking about a type mismatch and following up:

Oh ffs I had to turn the 0 in the getOrElse into a long

This would be a separate discussion, but it has been one day since I complained that REPL (and other tooling) can't render:

HashMap("a" -> 42L)

with distinguishing quotations marks and L suffix.