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https://issues.apache.org/jira/browse/TAP5-1493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13014797#comment-13014797
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Howard M. Lewis Ship commented on TAP5-1493:
--------------------------------------------
Well, ASM doesn't think so:
// access flags 0x1
public getBar()Lmypackage/Bar;
L0
LINENUMBER 25 L0
ALOAD 0
GETFIELD mypackage/EditFoo.creation : Lmypackage/Foo;
INVOKEVIRTUAL mypackage/Foo.getBar()Lmypackage/Bar;
ARETURN
MAXSTACK = 1
MAXLOCALS = 1
That looks like a real getBar() method on class Foo that returns type Bar (not
AbstractBar).
> Property expressions on properties that are covariant on a base class use the
> type of the base class property, not the covariant subclass
> -----------------------------------------------------------------------------------------------------------------------------------------
>
> Key: TAP5-1493
> URL: https://issues.apache.org/jira/browse/TAP5-1493
> Project: Tapestry 5
> Issue Type: Bug
> Components: tapestry-core, tapestry-ioc
> Affects Versions: 5.3.0, 5.2.5
> Reporter: Howard M. Lewis Ship
> Priority: Critical
>
> public abstract class AbstractFoo
> {
> public abstract AbstractBar getBar();
> }
> public class Foo extends AbstractFoo
> {
> public Bar getBar();
> }
> Here property bar is covariant; the subclass (Foo) changes the type of the
> return value (from AbstractBar to just Bar). Assuming that Bar is a subclass
> of AbstractBar, that's fine.
> The bug is that in this circumstance, the PropertyConduitSource sees the type
> of
> property "bar" of class Foo as AbstractBar, not Bar.
> Interestingly, a little debugging showed that the getter method for property
> bar was "public AbstractBar Foo.getBar()" ... in other words, much like with
> Generics, covariant return types may be largely
> a fiction of the compiler inserting the necessary casts in place.
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