gistfile1.scala

scala> import example.Lists._
import example.Lists._

scala> sum(List(1,2,3))
scala.NotImplementedError: an implementation is missing
  at scala.Predef$.$qmark$qmark$qmark(Predef.scala:252)
	at example.Lists$.sum(Lists.scala:26)
	at .<init>(<console>:20)
	at .<clinit>(<console>)
	at .<init>(<console>:7)
	at .<clinit>(<console>)
	at $print(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:734)
	at scala.tools.nsc.interpreter.IMain$Request.loadAndRun(IMain.scala:983)
	at scala.tools.nsc.interpreter.IMain.loadAndRunReq$1(IMain.scala:573)
	at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:604)
	at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:568)
	at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:745)
	at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:790)
	at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:702)
	at scala.tools.nsc.interpreter.ILoop.processLine$1(ILoop.scala:566)
	at scala.tools.nsc.interpreter.ILoop.innerLoop$1(ILoop.scala:573)
	at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:576)
	at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:867)
	at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:822)
	at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:822)
	at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
	at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:822)
	at scala.tools.nsc.interpreter.ILoop.main(ILoop.scala:889)
	at xsbt.ConsoleInterface.run(ConsoleInterface.scala:57)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at sbt.compiler.AnalyzingCompiler.call(AnalyzingCompiler.scala:73)
	at sbt.compiler.AnalyzingCompiler.console(AnalyzingCompiler.scala:64)
	at sbt.Console.console0$1(Console.scala:23)
	at sbt.Console$$anonfun$apply$2$$anonfun$apply$1.apply$mcV$sp(Console.scala:24)
	at sbt.TrapExit$.executeMain$1(TrapExit.scala:33)
	at sbt.TrapExit$$anon$1.run(TrapExit.scala:42)