Aladdin - Scala Bugtracking
[#267] project: compiler priority: high category: bug
submitter assigned to status date submitted
Martin Philippe fixed 2004-01-05 12:50:18.0
subject assertin error in maxeboxing
code 
package expAbstractData;

/** A base class consisting of
 *   - a root trait (i.e. abstract class) `Exp' with an `eval' function
 *   - an abstract type `exp' bounded by `Exp'
 *   - a concrete instance class `Num' of `Exp' for numeric literals
 */
trait Base {
  type exp <: Exp;

  trait Exp {
    def eval: int
  }
  class Num(v: int): exp extends Exp {
    val value = v;
    def eval = value
  }
}

object testBase extends Base with Executable {
  type exp = Exp;
  val term = new Num(2);
  System.out.println(term.eval);
}

/** Data extension: An extension of `Base' with `Plus' expressions
 */
trait BasePlus extends Base {
  class Plus(l: exp, r: exp): exp extends Exp {
    val left = l;
    val right = r;
    def eval = left.eval + right.eval
  }
}

/** Operation extension: An extension of `Base' with 'show' methods.
 */
trait Show extends Base {
  type exp <: Exp1;

  trait Exp1 extends Exp {
    def show: String;
  }
  class Num1(v: int): exp extends Num(v) with Exp1 {
    def show = value.toString();
  }
}

/** Operation extension: An extension of `BasePlus' with 'show' methods.
 */
trait ShowPlus extends BasePlus with Show {
  class Plus1(l: exp, r: exp): exp extends Plus(l, r) with Exp1 {
    def show = left.show + " + " + right.show
  }
}
what happened 
Exception in thread "main" java.lang.AssertionError: 
unit        : /home/odersky/scala/test/pos/abstract-data.scala
clasz       : expAbstractData.ShowPlus.Plus1$class
member      : expAbstractData.ShowPlus.Plus1$class.show
owner       : expAbstractData.ShowPlus.Plus1$class.show
tree        : Plus1$class.this.right().show
tree.pos    : 53:41
tree.symbol : expAbstractData.Show.Exp1.show
tree.type   : ()String
	at scalac.checkers.TreeChecker.selection(TreeChecker.java:413)
	at scalac.checkers.TreeChecker.function(TreeChecker.java:367)
	at scalac.checkers.TreeChecker.expression(TreeChecker.java:292)
	at scalac.checkers.TreeChecker.vapply(TreeChecker.java:351)
	at scalac.checkers.TreeChecker.expression(TreeChecker.java:284)
	at scalac.checkers.TreeChecker.member(TreeChecker.java:176)
	at scalac.checkers.TreeChecker.member(TreeChecker.java:143)
	at scalac.checkers.TreeChecker.template(TreeChecker.java:111)
	at scalac.checkers.TreeChecker.member(TreeChecker.java:155)
	at scalac.checkers.TreeChecker.member(TreeChecker.java:143)
	at scalac.checkers.TreeChecker.template(TreeChecker.java:111)
	at scalac.checkers.TreeChecker.template(TreeChecker.java:91)
	at scalac.checkers.TreeChecker.template(TreeChecker.java:121)
	at scalac.checkers.TreeChecker.template(TreeChecker.java:91)
	at scalac.checkers.TreeChecker.check(TreeChecker.java:81)
	at scalac.transformer.MakeBoxingExplicitPhase.apply(MakeBoxingExplicitPhase.java:46)
	at scalac.Global.compile(Global.java:306)
	at scalac.Global.compile(Global.java:278)
	at scala.tools.scalac.Main$.main(sources/scala/tools/scalac/Main.scala:33)
	at scala.tools.scalac.Main.main(sources/scala/tools/scalac/Main.scala)
what expected succesful compilation
[back to overview]
Changes of this bug report
Martin  edited on  2004-01-05 17:39:49.0
Philippe  edited on  2004-01-07 18:45:04.0

Fixed by new version of ExplicitOuterPhase.