gistfile1.diff

diff --git a/kernel/common/array.rb b/kernel/common/array.rb
index 39bfde2..a66ac71 100644
--- a/kernel/common/array.rb
+++ b/kernel/common/array.rb
@@ -743,8 +743,11 @@ class Array
     hash_val = size
     return size if Thread.detect_outermost_recursion self do
       i = to_iter
+      mask = Fixnum::MAX >> 1 
       while i.next
-        hash_val ^= i.item.hash
+        hash_val  &= mask
+        hash_val <<= 1
+        hash_val  ^= i.item.hash
       end
     end