Compiler crashes instead of reporting an error

[Georgi Jojgov]

Hi,

The code below crashes the 2.11.8 compiler instead of producing a type mismatch error message (see attachments):

object Crasher {
  trait Handler {
    def onPush(): Unit
    def onUpstreamFinish() : Unit
  }

  def setHandler(handler: Handler): Unit = {}

  setHandler(new Handler {
    override def onPush(): Unit = {
      // changing 100L to 100 avoids the crash
      (0 until 100L) foreach {_ => ()}
    }


    @throws(classOf[Exception])
    def onUpstreamFinish(): Unit = {}
  })
}

The top of error stack trace is:

java.lang.NullPointerException
 at scala.tools.nsc.typechecker.Typers$Typer.typedAnnotation(Typers.scala:3669)
 at scala.tools.nsc.typechecker.Namers$Namer$$anonfun$23$$anonfun$apply$17$$anonfun$apply$18.apply(Namers.scala:1504)
 at scala.tools.nsc.typechecker.Namers$Namer$$anonfun$23$$anonfun$apply$17$$anonfun$apply$18.apply(Namers.scala:1504)
 at scala.reflect.internal.SymbolTable.enteringPhase(SymbolTable.scala:235)
 at scala.tools.nsc.typechecker.Namers$Namer$$anonfun$23$$anonfun$apply$17.apply(Namers.scala:1504)
 at scala.tools.nsc.typechecker.Namers$Namer$$anonfun$23$$anonfun$apply$17.apply(Namers.scala:1504)
 at scala.reflect.internal.AnnotationInfos$LazyAnnotationInfo.forcedInfo$lzycompute(AnnotationInfos.scala:212)
 at scala.reflect.internal.AnnotationInfos$LazyAnnotationInfo.forcedInfo(AnnotationInfos.scala:212)
 at scala.reflect.internal.AnnotationInfos$LazyAnnotationInfo.completeInfo(AnnotationInfos.scala:225)
 at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$typedDefDef$2.apply(Typers.scala:2185)
 at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$typedDefDef$2.apply(Typers.scala:2185)
 at scala.collection.immutable.List.map(List.scala:273)
 at scala.tools.nsc.typechecker.Typers$Typer.typedDefDef(Typers.scala:2185)
 at scala.tools.nsc.typechecker.Typers$Typer.typedMemberDef$1(Typers.scala:5308)
 at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5359)
 at scala.tools.nsc.typechecker.Typers$Typer.runTyper$1(Typers.scala:5396)
 at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedInternal(Typers.scala:5423)
 at scala.tools.nsc.typechecker.Typers$Typer.body$2(Typers.scala:5370)
 at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5374)
 at scala.tools.nsc.typechecker.Typers$Typer.typedByValueExpr(Typers.scala:5452)
 at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedStat$1(Typers.scala:3047)
 at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$65.apply(Typers.scala:3151)
 at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$65.apply(Typers.scala:3151)

The expected compile error is exposed for example by commenting out the @throws annotation:

[error] <....>/Crasher.scala:12: type mismatch;
[error]  found   : Long(100L)
[error]  required: Int
[error]       (0 until 100L) foreach {_ => ()}
[error]                ^
[error] one error found

Removing the error by changing 

(0 until 100L) foreach {_ => ()}

to

(0 until 100) foreach {_ => ()}

results in successful compile.

Is this a known issue or should I file a bug?

Georgi

[Seth Tisue]

The 2.12.0 compiler doesn’t crash on this, so I wouldn’t bother opening a JIRA ticket on it.