closes #3241 and improves serialization of hash...

closes #3241 and improves serialization of hash tries. review by
community.

3 files changed, 27 insertions, 3 deletions

diff --git a/test/files/jvm/t1600.scala b/test/files/jvm/t1600.scala
index 1cdcee8547..79391b7e76 100644
--- a/test/files/jvm/t1600.scala
+++ b/test/files/jvm/t1600.scala
@@ -12,11 +12,11 @@ object Test {
       def elements = entries.map(_._1)
 
       val maps = Seq[Map[Foo, Int]](new mutable.HashMap, new mutable.LinkedHashMap,
-          new immutable.HashMap).map(_ ++ entries)
+          immutable.HashMap.empty).map(_ ++ entries)
       test[Map[Foo, Int]](maps, entries.size, assertMap _)
 
       val sets = Seq[Set[Foo]](new mutable.HashSet, new mutable.LinkedHashSet,
-          new immutable.HashSet).map(_ ++ elements)
+          immutable.HashSet.empty).map(_ ++ elements)
       test[Set[Foo]](sets, entries.size, assertSet _)
     }
   }
@@ -31,7 +31,7 @@ object Test {
 
       assertFunction(deserializedCollection, expectedSize)
       assert(deserializedCollection.getClass == collection.getClass,
-          "collection class should remain the same after deserialization")
+          "collection class should remain the same after deserialization ("+deserializedCollection.getClass+" != "+collection.getClass+")")
       Foo.hashCodeModifier = 0
     }
   }
diff --git a/test/files/run/t3241.check b/test/files/run/t3241.check
new file mode 100644
index 0000000000..348ebd9491
--- /dev/null
+++ b/test/files/run/t3241.check
@@ -0,0 +1 @@
+done
\ No newline at end of file
diff --git a/test/files/run/t3241.scala b/test/files/run/t3241.scala
new file mode 100644
index 0000000000..40097a046f
--- /dev/null
+++ b/test/files/run/t3241.scala
@@ -0,0 +1,23 @@
+object Test {
+
+  def main(args : Array[String]) : Unit = {
+    recurse(Map(1->1, 2->2, 3->3, 4->4, 5->5, 6->6, 7->7))
+    recurse(Set(1,2,3,4,5,6,7))
+    println("done")
+  }
+
+  def recurse(map: collection.immutable.Map[Int, Int]): Unit = {
+    if (!map.isEmpty) {
+      val x = map.keys.head
+      recurse(map - x)
+    }
+  }
+
+  def recurse(set: collection.immutable.Set[Int]): Unit = {
+    if (!set.isEmpty) {
+      val x = set.toStream.head
+      recurse(set - x)
+    }
+  }
+
+}