Aladdin - Scala Bugtracking
[#281] project: compiler priority: medium category: bug
submitter assigned to status date submitted
Burak Iulian fixed 2004-01-22 11:18:10.0
subject missing accessors for protected fields of Java superclass
code 
import org.apache.tools.ant.taskdefs.Javac; // put ant.jar in classpath

// Javac has a protected field 
//      compileList:Array[java.io.File]    !!

class A extends Javac {

 def bar( i:int ) = {
   for( val j <- List.range( 0, 42 )) {
      Console.println( compileList )
    }
  }
}

object Test {
  def main( args:Array[String] ) = {
    new A().bar( 4 )
  }
}
what happened 
/tmp/bugFu> scalac -classpath ${CLASSPATH}:/home/linuxsoft/apps/ant/lib/ant.jar ScalaFU.scala
/tmp/bugFu> java -classpath ${CLASSPATH}:/home/linuxsoft/apps/ant/lib/ant.jar Test
Exception in thread "main" java.lang.IllegalAccessError: tried to access field org.apache.tools.ant.taskdefs.Jav\
ac.compileList from class A$$anon$0
	at A$$anon$0.apply(ScalaFU.scala:10)
	at A$$anon$0.apply(ScalaFU.scala:9)
	at scala.List$class.foreach(sources/scala/List.scala:381)
	at A$class.bar(ScalaFU.scala:9)
	at Test$.main(ScalaFU.scala:17)
	at Test.main(ScalaFU.scala)
what expected normal execution (42 times output "[java.io.File@iii").

The problem is that the body of the file becomes anonymous class that has no right to access protected fields of the superclass (here Javac.compileList).

[back to overview]
Changes of this bug report
Michel  edited on  2004-02-03 13:50:49.0
Here is a simplified example: 
class A extends java.util.Hashtable {
  class B { def f = rehash() }
}

object Main {
  def main(args: Array[String]): Unit = {
    val a = new A;
    val b = new a.B;
    b.f
  }
}
The problem is that B accesses a protected method of the super-class of its outer class, namely A. ExplicitOuter should find all the instances of such calls and provide forwarding methods to be used by its enclosing classes. In this example, A should be augmented with a forwarding rehash method, and method f would simply use it instead of rehash itself.
Michel  edited on  2004-02-03 15:59:36.0
Assigned to Philippe (I thought I had done it before, but apparently not).
Philippe  edited on  2004-04-02 15:44:12.0
Added creation of access methods for hidden methods/fields accessed from inner classes in ExplicitOuter.
Gilles  edited on  2005-12-15 14:50:05.0
This bug is open again for NSC!
Lex  edited on  2006-03-28 14:12:28.0
This problem still occurs as of scalac 2.1.0.
Nikolay  edited on  2006-09-13 09:01:29.0
Reassigned from Philippe to Martin
Martin  edited on  2006-10-26 16:49:43.0
Reassigned to Iulian (this bug is really being pushed around!)
Iulian  edited on  2006-10-26 18:31:43.0