merges r23191 from trunk into ruby_1_9_1.

--
* array.c (rb_ary_flatten): flatten(0) works as Array#dup.
  [ruby-core:23168]

* test/ruby/test_array.rb: add a test for above.

git-svn-id: http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_1@23339 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 5 insertions, 0 deletions

diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 1cd018be8..36abe0996 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -719,6 +719,11 @@ class TestArray < Test::Unit::TestCase
     a7 = a6.flatten
     assert_equal(true, a7.tainted?)
     assert_equal(true, a7.untrusted?)
+
+    a8 = @cls[[1, 2], 3]
+    a9 = a8.flatten(0)
+    assert_equal(a8, a9)
+    assert_not_same(a8, a9)
   end
 
   def test_flatten!