Altered GenericRange contains to do something l...

Altered GenericRange contains to do something less useless when trying
to cast the parameter to T. And check contains properly when step != 1.

2 files changed, 20 insertions, 7 deletions

diff --git a/src/library/scala/Range.scala b/src/library/scala/Range.scala
index 4f21bc36dc..4cf8bac950 100644
--- a/src/library/scala/Range.scala
+++ b/src/library/scala/Range.scala
@@ -12,6 +12,7 @@ package scala
 
 import collection.immutable.Vector
 import collection.generic.VectorView
+import util.control.Exception.catching
 
 /** <p>
  *    <code>GenericRange</code> is a generified version of the
@@ -90,14 +91,26 @@ extends VectorView[T, Vector[T]] with RangeToString[T] {
     start + idx * step
   }
 
+  // The contains situation makes for some interesting code.
+  // This attempts to check containerhood in a range-sensible way, but
+  // falls back on super.contains if the cast ends up failing.
   override def contains(_x: Any): Boolean = {
-    // XXX - can we avoid this cast and still have a contains method?
-    val x =
-      try   { _x.asInstanceOf[T] }
-      catch { case _: ClassCastException => return false }
+    def doContains = {
+      // checking for Int is important so for instance BigIntRange from
+      // 1 to Googlefinity can see if 5 is in there without calling super.
+      val x = _x match {
+        case i: Int => fromInt(i)
+        case _      => _x.asInstanceOf[T]
+      }
+      def matchesStep = (x - start) % step == zero
+      def withinRange =
+        if (step > zero) start <= x && x < trueEnd
+        else start >= x && x > trueEnd
+
+      withinRange && matchesStep
+    }
 
-    if (step > zero) start <= x && x < trueEnd
-    else start >= x && x > trueEnd
+    catching(classOf[ClassCastException]) opt doContains getOrElse super.contains(_x)
   }
 }
 
diff --git a/src/library/scala/util/control/Exception.scala b/src/library/scala/util/control/Exception.scala
index 49dad8cf9f..769be2fef8 100644
--- a/src/library/scala/util/control/Exception.scala
+++ b/src/library/scala/util/control/Exception.scala
@@ -194,7 +194,7 @@ object Exception
   }
 
   /** Private **/
-  private def wouldMatch(x: AnyRef, classes: collection.Sequence[Class[_]]): Boolean =
+  private def wouldMatch(x: Throwable, classes: collection.Sequence[Class[_]]): Boolean =
     classes exists (_ isAssignableFrom x.getClass)
 
   private def pfFromExceptions(exceptions: Class[_]*) =