RC8 candidate for the first 2.8.0 beta

package foo {
package bar {
}
object baz {
implicit val bar = 0
}

import baz._
class test {
implicitly[Int] // Compiles under RC5, fails with RC8 "error:
could not find implicit value for parameter e: Int"
// bar + 1 // Fails under RC5 and RC8 with "value + is not a
member of package foo.bar"
}
}

The code about compiles under RC5, but not under RC8. This is most
likely related to https://lampsvn.epfl.ch/trac/scala/changeset/20486.
I think its a feature, not a bug, but I'm not sure.

-jason

On Mon, Jan 18, 2010 at 10:08 PM, Antonio Cunei wrote:
> All,
>
> A new release candidate for 2.8.0.Beta1 is available for testing. You can
> obtain the new candidate from the links below, as well as from the
> scala-tools.org Maven repository:
>
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.tgz
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.zip
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala.library_2.8.0.Be...
>
> This is a candidate for the first, preliminary beta release of 2.8.0: it is
> only intended to help developers port their code onto the new 2.8 codebase,
> and it is not production-quality code.
>
> Developers: this version includes the very latest fixes and updates to the
> Scala 2.8 codebase. Kindly test this last RC as well, and let us know if you
> detect anything unusual.
>
> Thanks!
> Toni
>
>

On Jan 18, 2010, at 1:08 PM, Antonio Cunei wrote:

> All,
>
> A new release candidate for 2.8.0.Beta1 is available for testing. You can
> obtain the new candidate from the links below, as well as from the
> scala-tools.org Maven repository:
>
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.tgz
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.zip
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala.library_2.8.0.Be...

Hi Antonio,

I don't see an RC8 tag here:

http://lampsvn.epfl.ch/svn-repos/scala/scala/tags/

Regards,
Blair

On Tue, January 19, 2010 8:16 am, Blair Zajac wrote:
> Hi Antonio,
> I don't see an RC8 tag here:
>
> http://lampsvn.epfl.ch/svn-repos/scala/scala/tags/
>
> Regards,
> Blair
>

Done now :)
Toni

On Tue, Jan 19, 2010 at 8:03 AM, Jason Zaugg wrote:
> package foo {
>   package bar {
>   }
>   object baz {
>      implicit val bar = 0
>   }
>
>   import baz._
>   class test {
>     implicitly[Int] // Compiles under RC5, fails with RC8 "error:
> could not find implicit value for parameter e: Int"
>     // bar + 1      // Fails under RC5 and RC8 with "value + is not a
> member of package foo.bar"
>   }
> }
>
> The code about compiles under RC5, but not under RC8. This is most
> likely  related to https://lampsvn.epfl.ch/trac/scala/changeset/20486.
> I think its a feature, not a bug, but I'm not sure.
>
Yes, definitely feature. The implicit bar is hidden by the package bar.

Cheers

When updating from RC7 to RC8 we observe the following compiler error:
[ERROR] .../lift-mapper/src/main/scala/net/liftweb/mapper/MetaMapper.scala:1262: error: type arguments [net.liftweb.mapper.IndexItem[A]] do not conform to method sameElements's type parameter bounds [B >: net.liftweb.mapper.IndexItem[Any]] [INFO] case class Index[A <: Mapper[A]](indexColumns : IndexItem[A]*) extends BaseIndex[A](indexColumns : _*)
Any ideas what could be going wrong here?
Attached you will find the full source file.
Heiko
2010/1/18 Antonio Cunei <antonio.cunei@epfl.ch>

All,

A new release candidate for 2.8.0.Beta1 is available for testing. You can
obtain the new candidate from the links below, as well as from the
scala-tools.org Maven repository:

http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.tgz
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.zip
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-installer.jar
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-devel-docs.tgz
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-sources.tgz
http://www.scala-lang.org/downloads/distrib/files/scala.library_2.8.0.Beta1-RC8.jar

This is a candidate for the first, preliminary beta release of 2.8.0: it is
only intended to help developers port their code onto the new 2.8 codebase,
and it is not production-quality code.

Developers: this version includes the very latest fixes and updates to the Scala 2.8 codebase. Kindly test this last RC as well, and let us know if you detect anything unusual.

Thanks!
Toni

--
Heiko Seeberger

Work: weiglewilczek.com
Blog: heikoseeberger.name
Follow me: twitter.com/hseeberger
OSGi on Scala: scalamodules.org
Lift, the simply functional web framework: liftweb.net

Okay... it looks like the VarArg stuff is messing with the compiler:

case class Index[A <: Mapper[A]](columns: Seq[IndexItem[A]])

works just fine, but:

case class Index[A <: Mapper[A]](columns: IndexItem[A] *)

Fails.

On Thu, Jan 21, 2010 at 10:51 AM, Heiko Seeberger <heiko.seeberger@googlemail.com> wrote:

When updating from RC7 to RC8 we observe the following compiler error:
[ERROR] .../lift-mapper/src/main/scala/net/liftweb/mapper/MetaMapper.scala:1262: error: type arguments [net.liftweb.mapper.IndexItem[A]] do not conform to method sameElements's type parameter bounds [B >: net.liftweb.mapper.IndexItem[Any]] [INFO] case class Index[A <: Mapper[A]](indexColumns : IndexItem[A]*) extends BaseIndex[A](indexColumns : _*)
Any ideas what could be going wrong here?
Attached you will find the full source file.
Heiko
2010/1/18 Antonio Cunei <antonio.cunei@epfl.ch>

All,

A new release candidate for 2.8.0.Beta1 is available for testing. You can
obtain the new candidate from the links below, as well as from the
scala-tools.org Maven repository:

http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.tgz
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.zip
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-installer.jar
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-devel-docs.tgz
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-sources.tgz
http://www.scala-lang.org/downloads/distrib/files/scala.library_2.8.0.Beta1-RC8.jar

This is a candidate for the first, preliminary beta release of 2.8.0: it is
only intended to help developers port their code onto the new 2.8 codebase,
and it is not production-quality code.

Developers: this version includes the very latest fixes and updates to the Scala 2.8 codebase. Kindly test this last RC as well, and let us know if you detect anything unusual.

Thanks!
Toni

--
Heiko Seeberger

Work: weiglewilczek.com
Blog: heikoseeberger.name
Follow me: twitter.com/hseeberger
OSGi on Scala: scalamodules.org
Lift, the simply functional web framework: liftweb.net

--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Surf the harmonics

I've written a work-around and am currently testing the code.... more in a few minutes.

On Thu, Jan 21, 2010 at 11:20 AM, David Pollak <feeder.of.the.bears@gmail.com> wrote:

Okay... it looks like the VarArg stuff is messing with the compiler:

case class Index[A <: Mapper[A]](columns: Seq[IndexItem[A]])

works just fine, but:

case class Index[A <: Mapper[A]](columns: IndexItem[A] *)

Fails.

On Thu, Jan 21, 2010 at 10:51 AM, Heiko Seeberger <heiko.seeberger@googlemail.com> wrote:

When updating from RC7 to RC8 we observe the following compiler error:
[ERROR] .../lift-mapper/src/main/scala/net/liftweb/mapper/MetaMapper.scala:1262: error: type arguments [net.liftweb.mapper.IndexItem[A]] do not conform to method sameElements's type parameter bounds [B >: net.liftweb.mapper.IndexItem[Any]] [INFO] case class Index[A <: Mapper[A]](indexColumns : IndexItem[A]*) extends BaseIndex[A](indexColumns : _*)
Any ideas what could be going wrong here?
Attached you will find the full source file.
Heiko
2010/1/18 Antonio Cunei <antonio.cunei@epfl.ch>

All,

A new release candidate for 2.8.0.Beta1 is available for testing. You can
obtain the new candidate from the links below, as well as from the
scala-tools.org Maven repository:

http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.tgz
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.zip
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-installer.jar
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-devel-docs.tgz
http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-sources.tgz
http://www.scala-lang.org/downloads/distrib/files/scala.library_2.8.0.Beta1-RC8.jar

This is a candidate for the first, preliminary beta release of 2.8.0: it is
only intended to help developers port their code onto the new 2.8 codebase,
and it is not production-quality code.

Developers: this version includes the very latest fixes and updates to the Scala 2.8 codebase. Kindly test this last RC as well, and let us know if you detect anything unusual.

Thanks!
Toni

--
Heiko Seeberger

Work: weiglewilczek.com
Blog: heikoseeberger.name
Follow me: twitter.com/hseeberger
OSGi on Scala: scalamodules.org
Lift, the simply functional web framework: liftweb.net

--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Surf the harmonics

--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Surf the harmonics

On Thu, Jan 21, 2010 at 8:31 PM, David Pollak
wrote:
> I've written a work-around and am currently testing the code.... more in a
> few minutes.
>
If you can make it work, so much the better. To give some info: The
original ticket had a vararg parameter of the form List[_]* in a case
class. This caused type inference for the synthetic equals method
(which uses sameElements for varargs) to fail, because the existential
in List[_] made the problem underconstrained. The patch passed the
argument type explicitly as the type parameter. In the lift case, it
seems that this explicit type parameter violated some type bound, so
the type inferencer should have chosen a more general type which would
not violate the bound. The easiest fix is probably to just roll back
and leave ticket #2867 open until we find a better solution. That's
what I have done.

Cheers

(Un)fortunately I have an idea what the problem is. It's probably my
fix for #2867. I have now rolled back that fix in r20629. Can you
check again whether it works with that revision (should be in the
nightly tomorrow)? If it does we might be able to make an exception to
our RC = final rule, because this one just rolls back a non-critical
patch, so I fail to see how this could affect anything but the
original ticket.

Cheers

Okay... the work-around is checked into the Lift repo.

I say, "Ship RC8 as the beta" and we'll work through this (and likely other) issues during the beta period.

On Thu, Jan 21, 2010 at 11:36 AM, martin odersky <martin.odersky@epfl.ch> wrote:

On Thu, Jan 21, 2010 at 8:31 PM, David Pollak
<feeder.of.the.bears@gmail.com> wrote:
> I've written a work-around and am currently testing the code.... more in a
> few minutes.
>
If you can make it work, so much the better. To give some info: The
original ticket had a vararg parameter of the form List[_]* in a case
class. This caused type inference for the synthetic equals method
(which uses sameElements for varargs) to fail, because the existential
in List[_] made the problem underconstrained. The patch passed the
argument type explicitly as the type parameter. In the lift case, it
seems that this explicit type parameter violated some type bound, so
the type inferencer should have chosen a more general type which would
not violate the bound. The easiest fix is probably to just roll back
and leave ticket #2867 open until we find a better solution. That's
what I have done.

Cheers

On Mon, Jan 18, 2010 at 1:08 PM, Antonio Cunei wrote:
> All,
>
> A new release candidate for 2.8.0.Beta1 is available for testing. You can
> obtain the new candidate from the links below, as well as from the
> scala-tools.org Maven repository:
>
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.tgz
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8.zip
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala-2.8.0.Beta1-RC8-...
> http://www.scala-lang.org/downloads/distrib/files/scala.library_2.8.0.Be...
>
> This is a candidate for the first, preliminary beta release of 2.8.0: it is
> only intended to help developers port their code onto the new 2.8 codebase,
> and it is not production-quality code.
>
> Developers: this version includes the very latest fixes and updates to the
> Scala 2.8 codebase. Kindly test this last RC as well, and let us know if you
> detect anything unusual.

My stuff basically works. With -optimize I'm occasionally getting errors for ->
Exception in thread "main" java.lang.NoSuchMethodError:
scala.Predef$ArrowAssoc.x()Ljava/lang/Object;

I'll isolate something to report in the next day or so.

I don't think is a show stopper, though. (Either optimize or don't use
-> for a while...)