Bugzilla – Full Text Bug Listing
| Summary: | [1.5][compiler] Inconsistency with Sun JDK | ||
|---|---|---|---|
| Product: | [Eclipse Project] JDT | Reporter: | Richard Hyatt <rhyatt> |
| Component: | Core | Assignee: | Philipe Mulet <philippe_mulet> |
| Status: | CLOSED FIXED | QA Contact: | |
| Severity: | normal | ||
| Priority: | P3 | ||
| Version: | 3.1 | ||
| Target Milestone: | 3.1 RC2 | ||
| Hardware: | PC | ||
| OS: | Windows XP | ||
| Whiteboard: | |||
Reproduced in 3.1rc1 Reduced testcase:
public class X {
public static <V, P extends Persistent<V>> P createDataObject(V value) {
return null;
}
public static void testCreateDataObject(Object v) {
Persistent d = createDataObject(v);
}
private interface Persistent<V> {
public V getValueObject();
}
}
Problem comes from inference using expected return type which did not perform substitution of variable (P) upper bound (Persistent<V> --> Persistent<Object>). Added GenericTypeTest#test710. Also, the unchecked warning from javac looks like a bug. Inference should figure P is Persistent<Object>, and this needs no unchecked warning (guessing it infers raw Persistent instead). Fixed Verified for 3.1 RC2 using build N20050607-0010 + JDT/Core HEAD Verified with I20050610-0010 |
The following test code will generate a "Bound Mismatch" error when compiled under 3.1M7: public class Test { public static <V extends ValueObject, P extends Persistent<V>> P createDataObject( V value ) { // create some type of data object given a value object [code ommitted] return (P)null; } public static void testCreateDataObject() { ValueObject v = new AValueObject(); Persistent d = createDataObject( v ); } private interface Persistent<V extends ValueObject> { public V getValueObject(); } private interface ValueObject { } public static class AValueObject implements ValueObject { } public static class ADataObject implements Persistent<AValueObject> { public AValueObject getValueObject() { return new AValueObject(); } } } But when compiled using javac [Sun Java 1.5.03] with -Xlint:all the following warning is issued: Test.java:13: warning: [unchecked] unchecked conversion found : <P>P required: Test.Persistent Persistent d = createDataObject( v ); ^ 1 warning Work-around to this problem is to change the above line to: Persistent<ValueObject> d = createDataObject( v ); but this should not be required since the unchecked base version will assume all implementations of Persistent will extend Persistent<ValueObject>.