Error occurs while compile in sbt 0.12.X

build.sbt

libraryDependencies := Seq("org.specs2" %% "specs2" % "1.11" % "test") // regardless of libraries


/*
   This build.sbt works well in sbt 0.11.X. 
   But in sbt 0.12.X this build.sbt throws below Exception while compiling
   
> compile

[info] Compiling 1 Scala source to PROJECT_PATH\target\scala-2.9.2\classes...
[trace] Stack trace suppressed: run 'last compile:compile' for the full output.
[error] (compile:compile) scala.tools.nsc.MissingRequirementError: object scala not found.
[error] Total time: 0 s, completed 2012/10/23 12:38:06

> last

...
[debug]         PROJECT_PATH\target\scala-2.9.2\classes
scala.tools.nsc.MissingRequirementError: object scala not found.
        at scala.tools.nsc.symtab.Definitions$definitions$.getModuleOrClass(Definitions.scala:655)
        at scala.tools.nsc.symtab.Definitions$definitions$.getModule(Definitions.scala:605)
        at scala.tools.nsc.symtab.Definitions$definitions$.ScalaPackage(Definitions.scala:145)
        at scala.tools.nsc.symtab.Definitions$definitions$.ScalaPackageClass(Definitions.scala:146)
        at scala.tools.nsc.symtab.Definitions$definitions$.AnyClass(Definitions.scala:176)
        at scala.tools.nsc.symtab.Definitions$definitions$.init(Definitions.scala:814)
        at scala.tools.nsc.Global$Run.<init>(Global.scala:697)
        at xsbt.CachedCompiler0.run(CompilerInterface.scala:87)
        at xsbt.CachedCompiler0.liftedTree1$1(CompilerInterface.scala:72)
        at xsbt.CachedCompiler0.run(CompilerInterface.scala:72)
        at xsbt.CompilerInterface.run(CompilerInterface.scala:26)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at sbt.compiler.AnalyzingCompiler.call(AnalyzingCompiler.scala:73)
        at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:35)
        at sbt.compiler.AnalyzingCompiler.compile(AnalyzingCompiler.scala:29)
        at sbt.compiler.AggressiveCompile$$anonfun$4$$anonfun$compileScala$1$1.apply$mcV$sp(AggressiveCompile.scala:71)
        at sbt.compiler.AggressiveCompile$$anonfun$4$$anonfun$compileScala$1$1.apply(AggressiveCompile.scala:71)
        at sbt.compiler.AggressiveCompile$$anonfun$4$$anonfun$compileScala$1$1.apply(AggressiveCompile.scala:71)
        at sbt.compiler.AggressiveCompile.sbt$compiler$AggressiveCompile$$timed(AggressiveCompile.scala:101)
...
 */