Extract method fail with NoSuchElementException

class Foo {

  def foo = {
    2
  }
  
  def bar = {
    List(1,2,3).mkString(",") // <- set the cursor inside the expression, and try to extract method
  }
}

Try extract method, the following exception is logged in the Eclipse Error Log view

java.util.NoSuchElementException
	at scala.collection.LinearSeqOptimized$class.last(LinearSeqOptimized.scala:135)
	at scala.collection.immutable.List.last(List.scala:76)
	at scala.tools.refactoring.transformation.TreeFactory$class.mkDefDef(TreeFactory.scala:123)
	at scala.tools.refactoring.MultiStageRefactoring.mkDefDef(MultiStageRefactoring.scala:14)
	at scala.tools.refactoring.implementations.ExtractMethod.perform(ExtractMethod.scala:46)
	at scala.tools.refactoring.implementations.ExtractMethod.perform(ExtractMethod.scala:16)
	at scala.tools.eclipse.refactoring.ScalaIdeRefactoring$$anonfun$5$$anonfun$apply$7.apply(ScalaIdeRefactoring.scala:158)
	at scala.tools.eclipse.refactoring.ScalaIdeRefactoring$$anonfun$5$$anonfun$apply$7.apply(ScalaIdeRefactoring.scala:157)
	at scala.tools.nsc.util.InterruptReq.liftedTree1$1(InterruptReq.scala:20)
	at scala.tools.nsc.util.InterruptReq.execute(InterruptReq.scala:19)
	at scala.tools.nsc.interactive.Global.pollForWork(Global.scala:330)
	at scala.tools.nsc.interactive.PresentationCompilerThread.run(PresentationCompilerThread.scala:22)

Leave a comment

on 2012-07-01 09:25 *

By Mirco Dotta

Oh, I see why it's happening. It expects a valid region to be selected, while I thought the region could have been inferred.

on 2012-07-02 02:53 *

By Mirko Stocker

Status changed from New to Accepted

I've added a better check that doesn't allow the refactoring if the selection is not good enough, but I'm leaving this ticket open to fix it properly. There are other things I don't like about extract method, like that it always creates a private "sibling" method, so I plan to write an improved version sometime.

on 2012-07-03 05:54 *

By Mirco Dotta

Coolio. Thanks!

on 2015-03-13 19:06 *

By Simon Schäfer

Assigned to changed from Mirko Stocker to -none-

Ticket assignment reverted due to inactivity.