closes #3112. no review.

3 files changed, 32 insertions, 12 deletions

diff --git a/src/library/scala/collection/immutable/Vector.scala b/src/library/scala/collection/immutable/Vector.scala
index 1326768090..6fb2aee054 100644
--- a/src/library/scala/collection/immutable/Vector.scala
+++ b/src/library/scala/collection/immutable/Vector.scala
@@ -108,34 +108,38 @@ override def companion: GenericCompanion[Vector] = Vector
   }
 
   override def take(n: Int): Vector[A] = {
-    if (n < 0) throw new IllegalArgumentException(n.toString)
-    if (startIndex + n < endIndex) {
+    if (n <= 0)
+      Vector.empty
+    else if (startIndex + n < endIndex)
       dropBack0(startIndex + n)
-    } else
+    else
       this
   }
 
   override def drop(n: Int): Vector[A] = {
-    if (n < 0) throw new IllegalArgumentException(n.toString)
-    if (startIndex + n < endIndex) {
+    if (n <= 0)
+      this
+    else if (startIndex + n < endIndex)
       dropFront0(startIndex + n)
-    } else
+    else
       Vector.empty
   }
 
   override def takeRight(n: Int): Vector[A] = {
-    if (n < 0) throw new IllegalArgumentException(n.toString)
-    if (endIndex - n > startIndex) {
+    if (n <= 0)
+      Vector.empty
+    else if (endIndex - n > startIndex)
       dropFront0(endIndex - n)
-    } else
+    else
       this
   }
 
   override def dropRight(n: Int): Vector[A] = {
-    if (n < 0) throw new IllegalArgumentException(n.toString)
-    if (endIndex - n > startIndex) {
+    if (n <= 0)
+      this
+    else if (endIndex - n > startIndex)
       dropBack0(endIndex - n)
-    } else
+    else
       Vector.empty
   }
 
@@ -843,6 +847,7 @@ private[immutable] trait VectorPointer[T] {
 
      final def copyOf(a: Array[AnyRef]) = {
       //println("copy")
+      if (a eq null) println ("NULL")
       val b = new Array[AnyRef](a.length)
       Platform.arraycopy(a, 0, b, 0, a.length)
       b
diff --git a/test/files/run/t3112.check b/test/files/run/t3112.check
new file mode 100644
index 0000000000..a95644c82c
--- /dev/null
+++ b/test/files/run/t3112.check
@@ -0,0 +1,4 @@
+Vector()
+Vector()
+Vector()
+Vector()
\ No newline at end of file
diff --git a/test/files/run/t3112.scala b/test/files/run/t3112.scala
new file mode 100644
index 0000000000..eb8eec6327
--- /dev/null
+++ b/test/files/run/t3112.scala
@@ -0,0 +1,11 @@
+// #3112
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    println((Vector() ++ (0 until 32)) take 0) // works
+    println((Vector() ++ (0 until 33)) take 0) // error
+    println((Vector() ++ (0 until 32)) takeRight 0) // works
+    println((Vector() ++ (0 until 33)) takeRight 0) // error
+  }
+
+}
\ No newline at end of file