Fix SI-5846 and SI-4027.

1 files changed, 17 insertions, 13 deletions

diff --git a/src/library/scala/collection/MapLike.scala b/src/library/scala/collection/MapLike.scala
index b9b8f62574..55d482f6c8 100644
--- a/src/library/scala/collection/MapLike.scala
+++ b/src/library/scala/collection/MapLike.scala
@@ -226,31 +226,35 @@ self =>
    */
   def default(key: A): B =
     throw new NoSuchElementException("key not found: " + key)
-
-  /** Filters this map by retaining only keys satisfying a predicate.
-   *  @param  p   the predicate used to test keys
-   *  @return an immutable map consisting only of those key value pairs of this map where the key satisfies
-   *          the predicate `p`. The resulting map wraps the original map without copying any elements.
-   */
-  def filterKeys(p: A => Boolean): Map[A, B] = new AbstractMap[A, B] with DefaultMap[A, B] {
+  
+  protected class FilteredKeys(p: A => Boolean) extends AbstractMap[A, B] with DefaultMap[A, B] {
     override def foreach[C](f: ((A, B)) => C): Unit = for (kv <- self) if (p(kv._1)) f(kv)
     def iterator = self.iterator.filter(kv => p(kv._1))
     override def contains(key: A) = self.contains(key) && p(key)
     def get(key: A) = if (!p(key)) None else self.get(key)
   }
-
-  /** Transforms this map by applying a function to every retrieved value.
-   *  @param  f   the function used to transform values of this map.
-   *  @return a map view which maps every key of this map
-   *          to `f(this(key))`. The resulting map wraps the original map without copying any elements.
+  
+  /** Filters this map by retaining only keys satisfying a predicate.
+   *  @param  p   the predicate used to test keys
+   *  @return an immutable map consisting only of those key value pairs of this map where the key satisfies
+   *          the predicate `p`. The resulting map wraps the original map without copying any elements.
    */
-  def mapValues[C](f: B => C): Map[A, C] = new AbstractMap[A, C] with DefaultMap[A, C] {
+  def filterKeys(p: A => Boolean): Map[A, B] = new FilteredKeys(p)
+  
+  protected class MappedValues[C](f: B => C) extends AbstractMap[A, C] with DefaultMap[A, C] {
     override def foreach[D](g: ((A, C)) => D): Unit = for ((k, v) <- self) g((k, f(v)))
     def iterator = for ((k, v) <- self.iterator) yield (k, f(v))
     override def size = self.size
     override def contains(key: A) = self.contains(key)
     def get(key: A) = self.get(key).map(f)
   }
+  
+  /** Transforms this map by applying a function to every retrieved value.
+   *  @param  f   the function used to transform values of this map.
+   *  @return a map view which maps every key of this map
+   *          to `f(this(key))`. The resulting map wraps the original map without copying any elements.
+   */
+  def mapValues[C](f: B => C): Map[A, C] = new MappedValues(f)
 
   // The following 5 operations (updated, two times +, two times ++) should really be
   // generic, returning This[B]. We need better covariance support to express that though.