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, 3 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 7e7adb12be..be2109c9f8 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -929,9 +929,10 @@ abstract class RefChecks extends InfoTransform {
     /** Similar to deprecation: check if the symbol is marked with @migration
      *  indicating it has changed semantics between versions.
      */
-    private def checkMigration(sym: Symbol, pos: Position) =
+    private def checkMigration(sym: Symbol, pos: Position) = {
       for (msg <- sym.migrationMessage)
-        unit.warning(pos, "%s%s has changed semantics:\n %s".format(sym, sym.locationString, msg))
+        unit.warning(pos, "%s%s has changed semantics:\n%s".format(sym, sym.locationString, msg))
+    }
 
     /** Check that a deprecated val or def does not override a
       * concrete, non-deprecated method.  If it does, then