Imported From: https://issues.scala-lang.org/browse/SI-3575?orig=1
Reporter: @rossjudson

@rossjudson said:
Output looks something like this, showing the selection of the specialized type for the third print.

solo.Two
solo.Two
solo.Two$$mcII$$sp

@dragos said:
It is specced like that, but it seems more people complained about it, so it may change in the next version of Scala.

@adriaanm said:
(In r22802) closes #3575. stricter override checking for java members with default access: can only override such a member from the same package
cloneSymbol now preserves privateWithin -- need to reset it explicitly now when before it was assumed to be not to be carried over

rewrote accessibility in overriding checks so they're more readable, but hopefully with same semantics

review by odersky

@ijuma said:
I think Adriaan meant #3757 as can be seen in the follow-up commit r22803. Reopening.

@non said:
Interestingly, now that [@Specialize A] includes AnyRef, I would have expected this bug to be fixed.

But it seems that AnyRef specialization isn't working properly in this case at least. I see synthetic classes like Two$mcLI$sp being generated but not used. This may actually be a recently introduced bug breaking @SPEC(AnyRef) though; in which case, this bug might actually be fixed.

@non said:
I have opened #5488 to deal with the bugs with AnyRef specialization. When that bug is fixed, this bug might be fixed as well!

@non said (edited on Feb 17, 2012 11:38:44 PM UTC):
When AnyRef specialization is used explicitly (e.g. @specialized(Int, AnyRef)), this bug is fixed.

There's another bug, which is that as things stand [@specialized A] creates AnyRef specializations, but fails to use them. I'll look in this more closely.

@non said:
Now that #5500 is fixed, I have submitted a pull request which correctly interprets [@specialized A] as specializing on all types, including AnyRef. The only thing needed was to fix specializedOn to return a List of all the specialized types when the annotation didn't include any.

@non said:
This bug is fixed.

@magarciaEPFL said:

Now the specialized version is constructed in each case (ie the bug is fixed, closing it):

Welcome to Scala version 2.10.0-20120503-215615-f146d5826f (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_29).
Type in expressions to have them evaluated.
Type :help for more information.

scala> case class Two[@specialized A, @specialized B](v: A, w: B);
defined class Two

scala> println(Two("Hello", 12).getClass().getName());
$line3.$read$$iw$$iw$Two$mcLI$sp

scala> println(Two("Hello", "World").getClass().getName())
$line3.$read$$iw$$iw$Two

scala> println(Two(12,12).getClass().getName())
$line3.$read$$iw$$iw$Two$mcII$sp

scala>