Shapeless' narrow method crashes the compiler 2.12.x (only in REPL)

[n4to4]

Scala version: 2.12.2 and 2.12.1

Shapeless' 42.narrow seems to crash the compiler only in REPL.
It seems fine when running in a program with sbt run.

build.sbt:

scalaVersion := "2.12.2"

libraryDependencies ++= Seq("com.chuusai" %% "shapeless" % "2.3.2")

How to reproduce:

$ sbt
sbt> console
[info] Starting scala interpreter...
[info]
Welcome to Scala 2.12.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_60).
Type in expressions for evaluation. Or try :help.

scala> import shapeless.syntax.singleton._
import shapeless.syntax.singleton._

scala> 42.narrow
scala.reflect.internal.Types$TypeError: assignment to non variable
        at scala.tools.nsc.typechecker.Contexts$ThrowingReporter.handleError(Contexts.scala:1402)
        at scala.tools.nsc.typechecker.Contexts$ContextReporter.issue(Contexts.scala:1254)
        at scala.tools.nsc.typechecker.Contexts$Context.issue(Contexts.scala:576)
        at scala.tools.nsc.typechecker.ContextErrors$ErrorUtils$.issueTypeError(ContextErrors.scala:106)
        at scala.tools.nsc.typechecker.ContextErrors$ErrorUtils$.issueNormalTypeError(ContextErrors.scala:99)
        at scala.tools.nsc.typechecker.ContextErrors$TyperContextErrors$TyperErrorGen$.AssignmentError(ContextErrors.scala:323)
        at scala.tools.nsc.typechecker.Typers$Typer.fail$2(Typers.scala:4338)
        at scala.tools.nsc.typechecker.Typers$Typer.typedAssign$1(Typers.scala:4341)
        at scala.tools.nsc.typechecker.Typers$Typer.typedOutsidePatternMode$1(Typers.scala:5491)
        at scala.tools.nsc.typechecker.Typers$Typer.typedInAnyMode$1(Typers.scala:5520)
        at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5527)
        at scala.tools.nsc.typechecker.Typers$Typer.runTyper$1(Typers.scala:5563)
        at scala.tools.nsc.typechecker.Typers$Typer.typedInternal(Typers.scala:5593)
        at scala.tools.nsc.typechecker.Typers$Typer.body$2(Typers.scala:5537)
        at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5541)
        at scala.tools.nsc.typechecker.Typers$Typer.typedByValueExpr(Typers.scala:5624)
[...]
        at sbt.Console$$anonfun$apply$2$$anonfun$apply$1.apply(Console.scala:23)
        at sbt.Console$$anonfun$apply$2$$anonfun$apply$1.apply(Console.scala:23)
        at sbt.Logger$$anon$4.apply(Logger.scala:84)
        at sbt.TrapExit$App.run(TrapExit.scala:248)
        at java.lang.Thread.run(Thread.java:745)

That entry seems to have slain the compiler.  Shall I replay
your session? I can re-run each line except the last one.

[xuwei-k]

milessabin/shapeless#674

[som-snytt]

It's the same result with 23.narrow.

It trips up on a lazy val that is not ordinarily visible.

// currently lazy
//<stable> <accessor> lazy val $result: Int(23) = $line6.$read.$iw.$iw.$iw.$iw.res2;

package narrowly

import shapeless.syntax.singleton._

object Main extends App {
  lazy val x = 23.narrow
}

Mr Fields comments, "Lazy vals do not receive constant types (anymore)."

[lihaoyi]

Notably, this seems to work in Ammonite

$ amm
Loading...
Welcome to the Ammonite Repl 1.0.0-RC6
(Scala 2.12.2 Java 1.8.0_112)
If you like Ammonite, please support our development at www.patreon.com/lihaoyi
@ import $ivy.`com.chuusai::shapeless:2.3.2`
import $ivy.$
@  import shapeless.syntax.singleton._
import shapeless.syntax.singleton._
@ 42.narrow
res2: 42 = 42

Not sure what we're doing differently; Ammonite compiles these things in pretty simple object wrappers, but I thought the Scala REPL did too

[SethTisue]

let's consolidate at #10768