object Bug extends App {

  val n = Array.fill(1)(0.0)
  n(0) = ???
  
}

results in

error:
while compiling:
during phase: jvm
library version: version 2.10.3
compiler version: version 2.10.3
reconstructed args:

last tree to typer: This(object iw$Bug)
symbol: object iw$Bug in package $line3 (flags: )
symbol definition: class iw$Bug extends App
tpe: type
symbol owners: object iw$Bug -> package $line3
context owners: object iw -> package $line3

== Enclosing template or block ==

Template( // val <local $iw>: , tree.tpe=type
"java.lang.Object" // parents
ValDef(
private
"_"


)
DefDef( // def (): type

""
[]
List(Nil)
// tree.tpe=type
Block( // tree.tpe=Unit
Apply( // def (): Object in class Object, tree.tpe=Object
$read$super."" // def (): Object in class Object, tree.tpe=()Object
Nil
)
()
)
)
)

== Expanded type of tree ==

TypeRef(TypeSymbol(class iw$Bug extends App))

uncaught exception during compilation: java.lang.NegativeArraySizeException
java.lang.NegativeArraySizeException
at scala.tools.asm.Frame.merge(Frame.java:1326)
at scala.tools.asm.MethodWriter.visitMaxs(MethodWriter.java:1353)
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genMethod(GenASM.scala:1565)
at scala.tools.nsc.backend.jvm.GenASM$JPlainBuilder.genClass(GenASM.scala:1398)
at scala.tools.nsc.backend.jvm.GenASM$AsmPhase.run(GenASM.scala:119)
at scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1583)
at scala.tools.nsc.Global$Run.compileUnits(Global.scala:1557)
at scala.tools.nsc.Global$Run.compileSources(Global.scala:1553)
at scala.tools.nsc.interpreter.IMain.compileSourcesKeepingRun(IMain.scala:428)
at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.compileAndSaveRun(IMain.scala:801)
at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.compile(IMain.scala:761)
at scala.tools.nsc.interpreter.IMain$Request.compile$lzycompute(IMain.scala:936)
at scala.tools.nsc.interpreter.IMain$Request.compile(IMain.scala:931)
at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:603)
at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:568)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:756)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:801)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:774)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:801)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:774)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:801)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:774)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:801)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:774)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:801)
at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:774)
at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:801)
at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:713)
at scala.tools.nsc.interpreter.ILoop.processLine$1(ILoop.scala:577)
at scala.tools.nsc.interpreter.ILoop.innerLoop$1(ILoop.scala:584)
at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:587)
at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:878)
at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:833)
at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:833)
at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:833)
at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:83)
at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:96)
at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:105)
at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)

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