Aladdin - Scala Bugtracking
[#301] project: compiler priority: high category: bug
submitter assigned to status date submitted
Matthias Martin fixed 2004-03-02 15:34:50.0
subject Typechecker doesn't detect some unimplemented methods
code 
class A {
  def foo: Object = new Object;
}
abstract class B extends A {
  override def foo: String;
  val x: String = foo;
}
object C extends A with B with Application;
what happened 
The program compiles even though the abstract
foo method of class B is not implemented in
object C. Consequently, we get a runtime error
when C is executed:

Exception in thread "main" java.lang.AbstractMethodError: C$.foo()Ljava/lang/String;
        at C$.mixin$B$class$init$(T.scala:6)
        at C$.(T.scala:8)
        at C$.(T.scala)
        at C.main(T.scala)
what expected The compiler should reject the object definition C.
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Changes of this bug report
Martin  edited on  2004-04-16 17:04:27.0