merge revision(s) 57362: [Backport #13096]

	vm_method.c: resolve refined method to undef

	* vm_method.c (rb_undef): resolve the method entry which refines a
	  prepended method entry.  [ruby-core:78944] [Bug #13096]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@57862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 19 insertions, 0 deletions

diff --git a/test/ruby/test_refinement.rb b/test/ruby/test_refinement.rb
index 8af9945080..66202cda11 100644
--- a/test/ruby/test_refinement.rb
+++ b/test/ruby/test_refinement.rb
@@ -1474,6 +1474,25 @@ class TestRefinement < Test::Unit::TestCase
     INPUT
   end
 
+  def test_undef_prepended_method
+    bug13096 = '[ruby-core:78944] [Bug #13096]'
+    klass = EnvUtil.labeled_class("X") do
+      def foo; end
+    end
+    klass.prepend(Module.new)
+    ext = EnvUtil.labeled_module("Ext") do
+      refine klass do
+        def foo
+        end
+      end
+    end
+    assert_nothing_raised(NameError, bug13096) do
+      klass.class_eval do
+        undef :foo
+      end
+    end
+  end
+
   def test_call_refined_method_in_duplicate_module
     bug10885 = '[ruby-dev:48878]'
     assert_in_out_err([], <<-INPUT, [], [], bug10885)