Name: jl125535 Date: 08/30/2004


FULL PRODUCT VERSION :
java version "1.5.0-beta3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta3-b60)
Java HotSpot(TM) Client VM (build 1.5.0-beta3-b60, mixed mode, sharing)

A DESCRIPTION OF THE PROBLEM :
Javac gets carried away by unused/irrelevant type parameters and starts giving false alarms on concretely-typed _inherited_ members.
In this sample both Bug$A and Bug$B inherit from Vector<String>. So it's a compile-time FACT that the invocation of the method #elements() yields an enumeration of Strings in both cases. So the parameterisation of Bug$B should have no influence on the outcome of that operation.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the sample code provided with "-Xlint:unchecked" on.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
All 3 assignments to Enumeration<String> are type sound so the javac mustn't emit any warnings.
ACTUAL -
  Bug.java:8: warning: [unchecked] unchecked conversion
found : java.util.Enumeration
required: java.util.Enumeration<java.lang.String>
                Enumeration<String> e2 = new B().elements(); // Unchecked conversion?!

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.util.*;

public class Bug {

public static void main(String[] args){
Enumeration<String> e1 = new A().elements();

Enumeration<String> e2 = new B().elements(); // Unchecked conversion?!
Enumeration<String> e3 = new B<Thread>().elements();
}

static class A extends Vector<String> {}

static class B <X> extends Vector<String> {}
}
---------- END SOURCE ----------
(Incident Review ID: 301336)
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