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, 1 insertions, 1 deletions

diff --git a/test/files/neg/migration28.check b/test/files/neg/migration28.check
index 19aba2c31d..4c8c58e0fd 100644
--- a/test/files/neg/migration28.check
+++ b/test/files/neg/migration28.check
@@ -2,7 +2,7 @@ migration28.scala:5: error: method ++= in class Stack is deprecated: use pushAll
   s ++= List(1,2,3)
   ^
 migration28.scala:7: error: method foreach in class Stack has changed semantics:
- Stack iterator and foreach now traverse in FIFO order.
+Stack iterator and foreach now traverse in FIFO order.
   s foreach (_ => ())
   ^
 two errors found