Leveraged -Xmigration to burn off some warts wh...

Leveraged -Xmigration to burn off some warts which arose in the new
collections. Warnings put in place for behavioral changes, allowing the
following. 1) Buffers: create new collections on

++ and -- like all the other collections.  2) Maps: eliminated
never-shipped redundant method valuesIterable and supplied these
return types:

  def keys: Iterable[A]
  def keysIterator: Iterator[A]
  def values: Iterable[B]
  def valuesIterator: Iterator[B]
  def keySet: Set[A]

I concluded that keys should return Iterable because keySet also exists
on Map, and is not solely in the province of Maps even if we wanted to
change it: it's defined on Sorted and also appears in some Sets. So it
seems sensible to have keySet return a Set and keys return the more
general type.

Closes #3089, #3145.  Review by odersky.

1 files changed, 6 insertions, 11 deletions

diff --git a/src/library/scala/collection/MapLike.scala b/src/library/scala/collection/MapLike.scala
index 8806098aa4..ac3c675c14 100644
--- a/src/library/scala/collection/MapLike.scala
+++ b/src/library/scala/collection/MapLike.scala
@@ -12,6 +12,7 @@ package scala.collection
 
 import generic._
 import mutable.{Builder, StringBuilder, MapBuilder}
+import annotation.migration
 import PartialFunction._
 
 /** A template trait for maps of type `Map[A, B]` which associate keys of type `A`
@@ -181,15 +182,16 @@ self =>
    *
    *  @return an iterator over all keys.
    */
-  @deprecated("use `keysIterator' instead")
-  def keys: Iterator[A] = keysIterator
+  @migration(2, 8, "As of 2.8, keys returns Iterable[A] rather than Iterator[A].")
+  def keys: Iterable[A] = keySet
 
   /** Collects all values of this map in an iterable collection.
    * @return the values of this map as an iterable.
    */
-  def valuesIterable: Iterable[B] = new DefaultValuesIterable
+  @migration(2, 8, "As of 2.8, values returns Iterable[B] rather than Iterator[B].")
+  def values: Iterable[B] = new DefaultValuesIterable
 
-  /** The implementation class of the iterable returned by `valuesIterable`.
+  /** The implementation class of the iterable returned by `values`.
    */
   protected class DefaultValuesIterable extends Iterable[B] {
     def iterator = valuesIterator
@@ -207,13 +209,6 @@ self =>
     def next = iter.next._2
   }
 
-  /** Creates an iterator for all contained values.
-   *
-   *  @return an iterator over all values.
-   */
-  @deprecated("use `valuesIterator' instead")
-  def values: Iterator[B] = valuesIterator
-
   /** Defines the default value computation for the map,
    *  returned when a key is not found
    *  The method implemented here throws an exception,