class.c: suppress wrong warning

* class.c (HAVE_METACLASS_P): should check FL_SINGLTON flag before get
  instance variable to get rid of wrong warning about __attached__.
  [ruby-core:53839] [Bug #8188]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40013 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 0 deletions

diff --git a/test/ruby/test_eval.rb b/test/ruby/test_eval.rb
index 580d3e88b1..a97b982246 100644
--- a/test/ruby/test_eval.rb
+++ b/test/ruby/test_eval.rb
@@ -215,6 +215,13 @@ class TestEval < Test::Unit::TestCase
     end
   end
 
+  def test_instance_eval_on_argf_singleton_class
+    bug8188 = '[ruby-core:53839] [Bug #8188]'
+    assert_warning('', bug8188) do
+      ARGF.singleton_class.instance_eval{}
+    end
+  end
+
   class Foo
     Bar = 2
   end