On-the-fly settings in REPL

[scabug]

This isn't unreasonable:

$ scala
Welcome to Scala 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_60).
Type in expressions for evaluation. Or try :help.

scala> val x = "hi" ; "$x"
x: String = hi
res0: String = $x

scala> :se -Xlint:missing-interpolator

scala> val x = "hi" ; "$x"
<console>:13: warning: possible missing interpolator: detected interpolated identifier `$x`
        "$x"
        ^
x: String = hi
res1: String = $x

scala> :se -Xlint:-missing-interpolator

scala> val x = "hi" ; "$x"
<console>:13: warning: possible missing interpolator: detected interpolated identifier `$x`
        "$x"
        ^
x: String = hi
res2: String = $x

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-9802?orig=1
Reporter: @som-snytt
Affected Versions: 2.12.0-M4

[som-snytt]

It's even less fly now.

Welcome to Scala 2.13.16 (OpenJDK 64-Bit Server VM, Java 23.0.2).
Type in expressions for evaluation. Or try :help.

scala> val x = "hi"
val x: String = hi

scala> "$x"
val res0: String = $x

scala> :se -Xlint:missing-interpolator

scala> "$x"
val res1: String = $x

scala> :se -Xlint

scala> "$x"
val res2: String = $x

So it's even further out of scope.