3 files changed, 16 insertions, 17 deletions
diff --git a/src/library/scala/collection/immutable/NumericRange.scala b/src/library/scala/collection/immutable/NumericRange.scala
index 65bd9ab6f2..0966fa035f 100644
--- a/src/library/scala/collection/immutable/NumericRange.scala
+++ b/src/library/scala/collection/immutable/NumericRange.scala
@@ -172,6 +172,13 @@ extends AbstractSeq[T] with IndexedSeq[T] with Serializable {
     try containsTyped(x.asInstanceOf[T])
     catch { case _: ClassCastException => false }
 
+  final override def sum[B >: T](implicit num: Numeric[B]): B = {
+    import num.Ops
+    if (isEmpty) this.num fromInt 0
+    else if (numRangeElements == 1) head
+    else ((this.num fromInt numRangeElements) * (head + last) / (this.num fromInt 2))
+  }
+
   override lazy val hashCode = super.hashCode()
   override def equals(other: Any) = other match {
     case x: NumericRange[_] =>
diff --git a/test/files/run/t4658.check b/test/files/run/t4658.check
index 743b0faee3..bb6405175e 100644
--- a/test/files/run/t4658.check
+++ b/test/files/run/t4658.check
@@ -19,8 +19,8 @@ Ranges:
 -30
 -10
 IntRanges:
-Disabled #1
-Disabled #2
+-1073741824
+-1073741824
 0
 0
 55
@@ -39,8 +39,8 @@ Disabled #2
 -30
 -10
 LongRanges:
-Disabled #1
-Disabled #2
+2305843008139952128
+-2305843008139952128
 0
 0
 55
@@ -59,8 +59,8 @@ Disabled #2
 -30
 -10
 BigIntRanges:
-Disabled #1
-Disabled #2
+2305843008139952128
+-2305843008139952128
 0
 0
 55
diff --git a/test/files/run/t4658.scala b/test/files/run/t4658.scala
index e1799fae9b..8c07c50694 100644
--- a/test/files/run/t4658.scala
+++ b/test/files/run/t4658.scala
@@ -20,22 +20,14 @@ object Test {
   def numericBigIntRanges = rangeData.map(r => if (r.inclusive) NumericRange.inclusive(BigInt(r.start), BigInt(r.end), BigInt(r.step)) else NumericRange(BigInt(r.start), BigInt(r.end), BigInt(r.step)))
 
   def main(args: Array[String]) {
-    // We drop the first two tests for all ranges which don't have a decent sum implementation,
-    // because it is just too slow.
     println("Ranges:")
     ranges.foreach{range => println(range.sum)}
     println("IntRanges:")
-    println("Disabled #1")
-    println("Disabled #2")
-    numericIntRanges.drop(2).foreach{range => println(range.sum)}
+    numericIntRanges.foreach{range => println(range.sum)}
     println("LongRanges:")
-    println("Disabled #1")
-    println("Disabled #2")
-    numericLongRanges.drop(2).foreach{range => println(range.sum)}
+    numericLongRanges.foreach{range => println(range.sum)}
     println("BigIntRanges:")
-    println("Disabled #1")
-    println("Disabled #2")
-    numericBigIntRanges.drop(2).foreach{range => println(range.sum)}
+    numericBigIntRanges.foreach{range => println(range.sum)}
   }
 
 }
 \ No newline at end of file