traits, generics, java interop + @specialized

This is indeed a bug, but has nothing to do with @specialized (or if it does, please be more specific).
Mixed in methods seem to lack their Java signature. I updated the ticket, thanks for reporting!
iulian

On Wed, May 26, 2010 at 7:03 PM, Vladimir Kirichenko <vladimir.kirichenko@gmail.com> wrote:

Here the thing I've found during exploration of Java complaining on
generics in methods generated for specialization.
The problem also found with method generaited for trait implementation.

An example:

Scala:

trait Test[A] {
       def m( a: A ): A
       def specified(a:A):A = a
}

abstract class T2[A] extends Test[A]

Java:

public class JTest<A> extends T2<A> {
       public A m( A a ) {
               return a;
       }
}

java compiler (-Xlint:unckecked) complains about:

specified(java.lang.Object) in T2 implements specified(A) in Test;
return type requires unchecked conversion
found   : java.lang.Object
required: A


JD Java Decompiler shows that generated method is not generic:

public abstract interface Test<A> extends ScalaObject
{
 public abstract A m(A paramA);

 public abstract A specified(A paramA);
}


public abstract class T2<A>
 implements Test<A>, ScalaObject
{
 public Object specified(Object a)
 {
   return Test.class.specified(this, a); }
 public T2() { Test.class.$init$(this); }

}

public class JTest<A> extends T2<A>
{
 public A m(A a)
 {
   return a;
 }
}

> scalac -version
Scala compiler version 2.8.0.r22036-b20100526020129 -- Copyright
2002-2010, LAMP/EPFL

Ticket: https://lampsvn.epfl.ch/trac/scala/ticket/3486

--
Best Regards,
Vladimir Kirichenko

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