hash.c: rb_hash_reject without dup

* hash.c (rb_hash_reject): copy unrejected elements only to new hash,
  so that the change on the original receiver can affect.
  [ruby-core:58914] [Bug #9223]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44047 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 3 deletions

diff --git a/test/ruby/test_enumerator.rb b/test/ruby/test_enumerator.rb
index e08edd512c..1d583e4fee 100644
--- a/test/ruby/test_enumerator.rb
+++ b/test/ruby/test_enumerator.rb
@@ -501,9 +501,13 @@ class TestEnumerator < Test::Unit::TestCase
 
   def test_size_for_enum_created_from_hash
     h = {a: 1, b: 2, c: 3}
-    %i[delete_if reject! select select! keep_if each each_key each_pair].each do |method|
-      assert_equal 3, h.send(method).size
-    end
+    methods = %i[delete_if reject reject! select select! keep_if each each_key each_pair]
+    enums = methods.map {|method| h.send(method)}
+    s = enums.group_by(&:size)
+    assert_equal([3], s.keys, ->{s.reject!{|k| k==3}.inspect})
+    h[:d] = 4
+    s = enums.group_by(&:size)
+    assert_equal([4], s.keys, ->{s.reject!{|k| k==4}.inspect})
   end
 
   def test_size_for_enum_created_from_env