Dropped about 1.5 Mb off scala-library.jar.

This commit and the two subsequent commits were contributed by:

  Todd Vierling <tv@duh.org>.

I combined some commits and mangled his commit messages, but all the
credit is his. This pursues the same approach to classfile reduction
seen in r19989 when AbstractFunctionN was introduced, but applies it to
the collections. Thanks to -Xlint it's easy to verify that the private
types don't escape.

Design considerations as articulated by Todd:

* Don't necessarily create concrete types for _everything_. Where a
subtrait only provides a few additional methods, don't bother; instead,
use the supertrait's concrete class and retain the "with". For example,
"extends AbstractSeq[A] with LinearSeq[A]".

* Examine all classes with .class file size greater than 10k. Named
classes and class names ending in $$anon$<num> are candidates for
analysis.

* If a return type is currently inferred where an anon subclass would be
returned, make the return type explicit. Don't allow the library-private
abstract classes to leak into the public namespace [and scaladoc].

1 files changed, 2 insertions, 1 deletions

diff --git a/src/library/scala/collection/immutable/List.scala b/src/library/scala/collection/immutable/List.scala
index fb7808bc41..d5e5f2aee0 100644
--- a/src/library/scala/collection/immutable/List.scala
+++ b/src/library/scala/collection/immutable/List.scala
@@ -74,7 +74,8 @@ import annotation.tailrec
  *  @define mayNotTerminateInf
  *  @define willNotTerminateInf
  */
-sealed abstract class List[+A] extends LinearSeq[A]
+sealed abstract class List[+A] extends AbstractSeq[A]
+                                  with LinearSeq[A]
                                   with Product
                                   with GenericTraversableTemplate[A, List]
                                   with LinearSeqOptimized[A, List[A]] {