class B { def ::(a: List[Int]): Unit = { a match { case x::xs => case _ => } } } object Test { def testSuccess1( x: Any ) = { val stable = 2 x match { case Some( `stable` ) => case _ => } } val bar = 3 def testSuccess2( x: Any ) = { x match { case Some( `bar` ) => case _ => } } def testFail1( x: Any ) = { var syncID = 0 x match { case Some( `syncID` ) => case _ => } } var foo = 0 def testFail2( x: Any ) = { x match { case Some( `foo` ) => case _ => } } }