immutable.Map keySet returns immutable.Set.

5 files changed, 10 insertions, 6 deletions

diff --git a/src/library/scala/collection/immutable/MapLike.scala b/src/library/scala/collection/immutable/MapLike.scala
index bbad195687..0e2723cf2b 100644
--- a/src/library/scala/collection/immutable/MapLike.scala
+++ b/src/library/scala/collection/immutable/MapLike.scala
@@ -50,8 +50,6 @@ trait MapLike[A, +B, +This <: MapLike[A, B, This] with Map[A, B]]
   extends scala.collection.MapLike[A, B, This]
 { self =>
 
-  import scala.collection.Traversable
-
   /** A new immutable map containing updating this map with a given key/value mapping.
    *  @param    key the key
    *  @param    value the value
@@ -110,6 +108,11 @@ trait MapLike[A, +B, +This <: MapLike[A, B, This] with Map[A, B]]
     def get(key: A) = self.get(key).map(f)
   }
 
+  /** Collects all keys of this map in a set.
+   *  @return  a set containing all keys of this map.
+   */
+  override def keySet: immutable.Set[A] = immutable.Set.empty ++ (this map (_._1))
+
   /** This function transforms all the values of mappings contained
    *  in this map with function `f`.
    *
diff --git a/src/library/scala/collection/immutable/MapProxy.scala b/src/library/scala/collection/immutable/MapProxy.scala
index fa0b097070..8313e4d143 100644
--- a/src/library/scala/collection/immutable/MapProxy.scala
+++ b/src/library/scala/collection/immutable/MapProxy.scala
@@ -35,6 +35,7 @@ trait MapProxy[A, +B] extends Map[A, B] with MapProxyLike[A, B, Map[A, B]] {
   override def + [B1 >: B](elem1: (A, B1), elem2: (A, B1), elems: (A, B1) *) = newProxy(self.+(elem1, elem2, elems: _*))
   override def ++[B1 >: B](xs: TraversableOnce[(A, B1)]) = newProxy(self ++ xs)
 
+  override def keySet: immutable.Set[A] = new SetProxy[A] { val self = MapProxy.this.self.keySet }
   override def filterKeys(p: A => Boolean) = self.filterKeys(p)
   override def mapValues[C](f: B => C) = self.mapValues(f)
 }
diff --git a/src/library/scala/collection/immutable/SortedMap.scala b/src/library/scala/collection/immutable/SortedMap.scala
index f49c4a9986..aa30932bb7 100644
--- a/src/library/scala/collection/immutable/SortedMap.scala
+++ b/src/library/scala/collection/immutable/SortedMap.scala
@@ -36,8 +36,8 @@ trait SortedMap[A, +B] extends Map[A, B]
     SortedMap.newBuilder[A, B]
 
   override def empty: SortedMap[A, B] = SortedMap.empty
-
   override def updated [B1 >: B](key: A, value: B1): SortedMap[A, B1] = this + ((key, value))
+  override def keySet: immutable.SortedSet[A] = SortedSet.empty ++ (this map (_._1))
 
   /** Add a key/value pair to this map.
    *  @param    kv the key/value pair
diff --git a/test/files/neg/type-diagnostics.check b/test/files/neg/type-diagnostics.check
index 0ed9f4631b..c5e6dec3f8 100644
--- a/test/files/neg/type-diagnostics.check
+++ b/test/files/neg/type-diagnostics.check
@@ -1,8 +1,8 @@
 type-diagnostics.scala:4: error: type mismatch;
  found   : scala.collection.Set[String]
  required: scala.collection.immutable.Set[String]
-  def f = Calculator("Hello",binding.keySet)
-                                     ^
+  def f = Calculator("Hello", binding.keySet: collection.Set[String])
+                                            ^
 type-diagnostics.scala:13: error: type mismatch;
  found   : List[a(in method f2)]
  required: List[a(in method f1)]
diff --git a/test/files/neg/type-diagnostics.scala b/test/files/neg/type-diagnostics.scala
index fcc49812f4..c4171328de 100644
--- a/test/files/neg/type-diagnostics.scala
+++ b/test/files/neg/type-diagnostics.scala
@@ -1,7 +1,7 @@
 object SetVsSet {
   case class Calculator[+T](name: String, parameters: Set[String])
   val binding = Map.empty[String, String]
-  def f = Calculator("Hello",binding.keySet)
+  def f = Calculator("Hello", binding.keySet: collection.Set[String])
 }
 
 object TParamConfusion {