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Build Identifier: 20100917-0705 The following source code compiles well on Helios (JDK 1.6) but not on Indigo (same computer). There are 3 classes in my project. The error is : The method doSomething(Class<? extends Task<Input>>) in the type BogusClass<T>.ExecutionContext is not applicable for the arguments (Class<BogusClass.ExecutionContext.SubTask>) BogusClass.java If the class BogusClass is not generic anymore, the bug disappears (removing the <T extends AnInterface>). ---- package indigo.compile.bug; public interface AnInterface { } ---- package indigo.compile.bug; public abstract class Task<Input> { public Task() { super(); } } ---- package indigo.compile.bug; public class BogusClass<T extends AnInterface> { public class ExecutionContext { public class SubTask extends Task<String> { } public <Input> void doSomething( Class<? extends Task<Input>> method) { } public void start() { doSomething(SubTask.class); } } public BogusClass() { super(); } } ---- Reproducible: Always Steps to Reproduce: 1. create the 3 classes in a project and compile 2. 3.
Created attachment 199559 [details] source code to reproduce the bug
(In reply to comment #0) > Build Identifier: 20100917-0705 This is a Helios build (probably (3.6.1). The example code compiles fine for me when using Indigo (3.7).
It's my mistake, the build id is 20110615-0604. The previous one was the build id of the helios instance on which the code compiles well.
Created attachment 199564 [details] source code to reproduce the bug
The previsous attachement was also the bad version :-(
This minimal test case fails to compile with javac5,6,7 and elicits nearly identical message: // --------------------------8<------------------------ interface AnInterface { } abstract class Task<Input> { } public class X<T extends AnInterface> { public class ExecutionContext { public class SubTask extends Task<String> { } public <Input> void doSomething( Class<? extends Task<Input>> method) { } public void start() { doSomething(SubTask.class); } } } // --------------------------8<------------------------ What do you think is the bug here ?
I found the bug in my source code. In the minimal test case provided by Srikanth, the subclass SubTask is indirectly parameterized by T of class X. Thus the compiler is unable to know exactly what is SubTask.class. Having this subclass static or removing the generic parameterization on X will correct the bug. Now the main question is : why was this working fine in eclipse 3.6 ? The compilation, and more importantly, the execution were fine.
(In reply to comment #7) > I found the bug in my source code. In the minimal test case provided by > Srikanth, the subclass SubTask is indirectly parameterized by T of class X. > Thus the compiler is unable to know exactly what is SubTask.class. Having this > subclass static or removing the generic parameterization on X will correct the > bug. Thanks for confirming this. > Now the main question is : why was this working fine in eclipse 3.6 ? It is called a bug ? :) >The > compilation, and more importantly, the execution were fine. Type unsafe code may not always produce visible problems. It is just that there is some set of constraints under which it could produce problems.
Verified for 3.8M4 using build I20111202-0800.
