Aladdin - Scala Bugtracking
[#873] project: compiler priority: high category: bug
submitter assigned to status date submitted
Burak Martin fixed 2007-01-05 18:54:41.0
subject 1st year 2007 bug: lub and subtype not in sync
code 
abstract class Foo {

  val x:Option[List[String]]
  val y:List[Int]

  (0:Any) match {
    case 1 => x
    case 2 => y
  }
}
what happened 
lamppc31:/localhome/buraq/svn/scala> ./build/quick/bin/scalac -d /tmp /tmp/broken.scala
failed with type mismatch;
 found   : scala.List[scala.Int]
 required: scala.Iterable[scala.Any]{<none>; <none>; <none>; <none>} on: temp0.==(2).&&({
  exit(Foo.this.y());
  true
})
what expected silent compile. priority is high, because lub seems pretty important!
This is what broke the build earlier today, synthetic methods generated matching code similar to the above. I include the debugging output, just for fun. 
lub of List(scala.Option[scala.List[java.lang.String]],scala.List[scala.dbc.statement.Expression])
 is scala.Iterable[scala.ScalaObject]{<none>; <none>; <none>; <none>}
src/dbc/scala/dbc/statement/InsertionData.scala:28 error: type mismatch;
 found   : scala.Option[scala.List[java.lang.String]]
 required: scala.Iterable[scala.ScalaObject]{<none>; <none>; <none>; <none>}
  case class Constructor (
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Changes of this bug report
Burak  edited on  2007-01-05 18:55:56.0
renamed the subject. the trouble is maybe not lub, but that lub and the subtype relation do not agree.
Martin  edited on  2007-01-05 19:27:21.0
Should be fixed now.