8 files changed, 13 insertions, 12 deletions
diff --git a/sources/scala/Predef.scala b/sources/scala/Predef.scala
index ebe450a42b..218b5d926e 100644
--- a/sources/scala/Predef.scala
+++ b/sources/scala/Predef.scala
@@ -15,7 +15,8 @@ object Predef {
     def List[A](x: A*): List[A] = x as List[A];
     val List = scala.List;
 
-    def Set[A](es: A*): MutableSet[A] = {
+/*
+    def Set[A](es: A*): scala.Set[A] = {
         val set = new HashSet[A];
         set.addSet(es);
         set;
@@ -26,6 +27,7 @@ object Predef {
         map.putMap(mappings);
         map;
     }
+*/
 
     def error(x: String): All = new java.lang.RuntimeException(x).throw;
 
diff --git a/sources/scala/collection/mutable/Buffer.scala b/sources/scala/collection/mutable/Buffer.scala
index 654a4560fb..13ec8aa6eb 100644
--- a/sources/scala/collection/mutable/Buffer.scala
+++ b/sources/scala/collection/mutable/Buffer.scala
@@ -18,7 +18,7 @@ package scala.collection.mutable;
  *  @author  Matthias Zenger
  *  @version 1.0, 08/07/2003
  */
-class Buffer[A] with scala.collection.mutable.List[A] {
+class Buffer[A] with MutableList[A] {
 
     def prepend(elem: A) = prependElem(elem);
 
@@ -55,9 +55,7 @@ class Buffer[A] with scala.collection.mutable.List[A] {
                 i = i - 1;
             }
             val old = elem.next;
-            elem.next = new LinkedList[A];
-            elem.next.elem = newelem;
-            elem.next.next = old;
+            elem.next = new LinkedList[A](newelem, old);
         }
     }
 
diff --git a/sources/scala/collection/mutable/List.scala b/sources/scala/collection/mutable/MutableList.scala
index 1c8634c751..5e9b3d917d 100644
--- a/sources/scala/collection/mutable/List.scala
+++ b/sources/scala/collection/mutable/MutableList.scala
@@ -9,6 +9,7 @@
 
 package scala.collection.mutable;
 
+
 /** This class is used internally to represent mutable lists. It is the
  *  basis for the implementation of the classes <code>Buffer</code>,
  *  <code>Stack</code>, and <code>Queue</code>.
@@ -16,7 +17,7 @@ package scala.collection.mutable;
  *  @author  Matthias Zenger
  *  @version 1.0, 08/07/2003
  */
-class List[A] with Seq[A] with PartialFunction[Int, A] {
+class MutableList[A] with Seq[A] with PartialFunction[Int, A] {
 
     protected var first: LinkedList[A] = null;
     protected var last: LinkedList[A] = null;
diff --git a/sources/scala/collection/mutable/Queue.scala b/sources/scala/collection/mutable/Queue.scala
index 91c6d8b3c7..b25b4cdf72 100644
--- a/sources/scala/collection/mutable/Queue.scala
+++ b/sources/scala/collection/mutable/Queue.scala
@@ -15,7 +15,7 @@ package scala.collection.mutable;
  *  @author  Matthias Zenger
  *  @version 1.0, 08/07/2003
  */
-class Queue[A] with scala.collection.mutable.List[A] {
+class Queue[A] with MutableList[A] {
 
     /** Checks if the queue is empty.
      *
@@ -63,7 +63,7 @@ class Queue[A] with scala.collection.mutable.List[A] {
      *
      *  @returns the first element.
      */
-    def first: A = first.elem;
+    def front: A = first.elem;
 
     /** Removes all elements from the queue. After this operation is completed,
      *  the queue will be empty.
diff --git a/sources/scala/collection/mutable/Set.scala b/sources/scala/collection/mutable/Set.scala
index 688130b156..5c0e1bb6da 100644
--- a/sources/scala/collection/mutable/Set.scala
+++ b/sources/scala/collection/mutable/Set.scala
@@ -37,7 +37,7 @@ trait Set[A] with scala.collection.Set[A] {
     def removeSet(that: Iterable[A]): Unit =
         that.elements.foreach(elem => remove(elem));
 
-    def intersect(that: scala.collection.Set[A]): Unit = filter(that.contains);
+    def intersect(that: Set[A]): Unit = filter(that.contains);
 
     def clear: Unit;
 
diff --git a/sources/scala/collection/mutable/SingleLinkedList.scala b/sources/scala/collection/mutable/SingleLinkedList.scala
index edeb0db261..c7926a28e4 100644
--- a/sources/scala/collection/mutable/SingleLinkedList.scala
+++ b/sources/scala/collection/mutable/SingleLinkedList.scala
@@ -36,7 +36,7 @@ abstract class SingleLinkedList[A, This <: SingleLinkedList[A, This]]: This with
 
     def apply(n: Int): A = {
         if (n == 0) elem
-        else if (next == null) null
+        else if (next == null) error("unknown element")
         else next.apply(n - 1);
     }
 
diff --git a/sources/scala/collection/mutable/Stack.scala b/sources/scala/collection/mutable/Stack.scala
index 6b19a3dd3c..dca34693ce 100644
--- a/sources/scala/collection/mutable/Stack.scala
+++ b/sources/scala/collection/mutable/Stack.scala
@@ -16,7 +16,7 @@ package scala.collection.mutable;
  *  @author  Matthias Zenger
  *  @version 1.0, 08/07/2003
  */
-class Stack[A] with scala.collection.mutable.List[A] with Iterable[A] {
+class Stack[A] with MutableList[A] {
 
     /** Checks if the stack is empty.
      *
diff --git a/sources/scala/collection/mutable/SynchronizedSet.scala b/sources/scala/collection/mutable/SynchronizedSet.scala
index a13f6ec288..ce38dcc38d 100644
--- a/sources/scala/collection/mutable/SynchronizedSet.scala
+++ b/sources/scala/collection/mutable/SynchronizedSet.scala
@@ -62,7 +62,7 @@ trait SynchronizedSet[A] extends scala.collection.mutable.Set[A] with Monitor {
         super.clear;
     }
 
-    override def subsetOf(that: Set[A]) = synchronized {
+    override def subsetOf(that: scala.collection.Set[A]) = synchronized {
         super.subsetOf(that);
     }