hash.c: reject shoult infect

* hash.c (rb_hash_reject): result should be infected by the
  receiver.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44074 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

hash.c

@@ -1119,6 +1119,7 @@ rb_hash_reject(VALUE hash)
 
     RETURN_SIZED_ENUMERATOR(hash, 0, 0, hash_enum_size);
     ret = hash_alloc(rb_obj_class(hash));
+    OBJ_INFECT(ret, hash);
     if (!RHASH_EMPTY_P(hash)) {
 	rb_hash_foreach(hash, reject_i, ret);
     }

test/ruby/test_hash.rb

@@ -555,6 +555,8 @@ class TestHash < Test::Unit::TestCase
 
     assert_equal(h3, h.reject {|k,v| v })
     assert_equal(base, h)
+
+    assert_predicate(h.taint.reject {true}, :tainted?)
   end
 
   def test_reject!