In the attached project, when you want to compile the file, you will get "Error in Scala compiler", and when you see the log, you will see:

java.lang.Error
at scala.tools.nsc.symtab.SymbolTable.abort(SymbolTable.scala:35)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:737)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$typedApply$1$1.apply(Typers.scala:3355)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$typedApply$1$1.apply(Typers.scala:3355)
at scala.tools.nsc.typechecker.Typers$Typer.silent(Typers.scala:624)
at scala.tools.nsc.typechecker.Typers$Typer.typedApply$1(Typers.scala:3355)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:4106)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.transformedOrTyped(Typers.scala:4430)
at scala.tools.nsc.typechecker.Typers$Typer.typedValDef(Typers.scala:1567)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3918)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.typedStat$1(Typers.scala:2100)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.collection.immutable.List.loop$1(List.scala:148)
at scala.collection.immutable.List.mapConserve(List.scala:164)
at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer.typedBlock(Typers.scala:1919)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3953)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.typedStat$1(Typers.scala:2100)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.collection.immutable.List.loop$1(List.scala:148)
at scala.collection.immutable.List.mapConserve(List.scala:164)
at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer.typedBlock(Typers.scala:1919)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3953)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.typedBlock(Typers.scala:1920)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3953)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.transformedOrTyped(Typers.scala:4430)
at scala.tools.nsc.typechecker.Typers$Typer.typedDefDef(Typers.scala:1760)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3921)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.typedStat$1(Typers.scala:2100)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.collection.immutable.List.loop$1(List.scala:148)
at scala.collection.immutable.List.mapConserve(List.scala:164)
at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer.typedTemplate(Typers.scala:1512)
at scala.tools.nsc.typechecker.Typers$Typer.typedClassDef(Typers.scala:1278)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3912)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.typedStat$1(Typers.scala:2100)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$24.apply(Typers.scala:2184)
at scala.collection.immutable.List.loop$1(List.scala:148)
at scala.collection.immutable.List.mapConserve(List.scala:164)
at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:2184)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3908)
at scala.tools.nsc.transform.Erasure$Eraser.typed1(Erasure.scala:731)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4273)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4333)
at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anonfun$transform$1.apply(Erasure.scala:1182)
at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anonfun$transform$1.apply(Erasure.scala:1177)
at scala.tools.nsc.symtab.SymbolTable.atPhase(SymbolTable.scala:95)
at scala.tools.nsc.transform.Erasure$ErasureTransformer.transform(Erasure.scala:1177)
at scala.tools.nsc.ast.Trees$Transformer.transformUnit(Trees.scala:892)
at scala.tools.nsc.transform.Transform$Phase.apply(Transform.scala:30)
at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:329)
at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:297)
at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:297)
at scala.collection.Iterator$class.foreach(Iterator.scala:772)
at scala.collection.mutable.ListBuffer$$anon$1.foreach(ListBuffer.scala:318)
at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:297)
at scala.tools.nsc.Global$Run.compileSources(Global.scala:953)
at scala.tools.nsc.Global$Run.compile(Global.scala:1041)
at xsbt.CachedCompiler0.run(CompilerInterface.scala:112)
at xsbt.CachedCompiler0.liftedTree1$1(CompilerInterface.scala:86)
at xsbt.CachedCompiler0.run(CompilerInterface.scala:86)
at xsbt.CompilerInterface.run(CompilerInterface.scala:26)
at sun.reflect.GeneratedMethodAccessor26.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sbt.compiler.AnalyzingCompiler.call(AnalyzingCompiler.scala:74)
at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:36)
at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:30)
at sbt.compiler.AggressiveCompile$$anonfun$5$$anonfun$compileScala$1$1.apply$mcV$sp(AggressiveCompile.scala:72)
at sbt.compiler.AggressiveCompile$$anonfun$5$$anonfun$compileScala$1$1.apply(AggressiveCompile.scala:72)
at sbt.compiler.AggressiveCompile$$anonfun$5$$anonfun$compileScala$1$1.apply(AggressiveCompile.scala:72)
at sbt.compiler.AggressiveCompile.sbt$compiler$AggressiveCompile$$timed(AggressiveCompile.scala:129)
at sbt.compiler.AggressiveCompile$$anonfun$5.compileScala$1(AggressiveCompile.scala:71)
at sbt.compiler.AggressiveCompile$$anonfun$5.apply(AggressiveCompile.scala:112)
at sbt.compiler.AggressiveCompile$$anonfun$5.apply(AggressiveCompile.scala:60)
at sbt.inc.IncrementalCompile$$anonfun$doCompile$1.apply(Compile.scala:24)
at sbt.inc.IncrementalCompile$$anonfun$doCompile$1.apply(Compile.scala:22)
at sbt.inc.Incremental$.cycle(Incremental.scala:39)
at sbt.inc.Incremental$.compile(Incremental.scala:26)
at sbt.inc.IncrementalCompile$.apply(Compile.scala:20)
at sbt.compiler.AggressiveCompile.compile2(AggressiveCompile.scala:120)
at sbt.compiler.AggressiveCompile.compile1(AggressiveCompile.scala:44)
at sbt.compiler.AggressiveCompile.apply(AggressiveCompile.scala:31)
at sbt.compiler.IC$.compile(IncrementalCompiler.scala:20)
at scala.tools.eclipse.buildmanager.sbtintegration.EclipseSbtBuildManager.runCompiler(EclipseSbtBuildManager.scala:125)
at scala.tools.eclipse.buildmanager.sbtintegration.EclipseSbtBuildManager.update(EclipseSbtBuildManager.scala:117)
at scala.tools.eclipse.buildmanager.sbtintegration.EclipseSbtBuildManager.build(EclipseSbtBuildManager.scala:170)
at scala.tools.eclipse.ScalaProject.build(ScalaProject.scala:597)
at scala.tools.eclipse.ScalaBuilder.build(ScalaBuilder.scala:114)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:728)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:239)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:292)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:295)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:351)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:374)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:143)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:241)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
which seems useless.
Whenever you activate IDE-log, you will see this error:
2012-08-20 12:43:58,878 DEBUG [Worker-25] - System.out - exception when typing qual$1.slurpString$default$1
2012-08-20 12:43:58,878 DEBUG [Worker-25] - System.out - class file needed by Resource is missing.
The problem is adding scala-arm_2.9.1.jar to resources. Because it is needed by Path class.
But this problem should be reported in a cleaner way.