merge revision(s) 58660e943488778563b9e41005a601e9660ce21f: [Backport #17519]

	Skip refined method when exporting methods with changed visibility

	Previously, attempting to change the visibility of a method in a
	singleton class for a class/module that is prepended to and refined
	would raise a NoMethodError.

	Fixes [Bug #17519]
	---
	 test/ruby/test_module.rb | 23 +++++++++++++++++++++++
	 vm_method.c              | 14 +++++++++++---
	 2 files changed, 34 insertions(+), 3 deletions(-)

1 files changed, 23 insertions, 0 deletions

diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index 43f0c51753..254dc51b9b 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -2237,6 +2237,29 @@ class TestModule < Test::Unit::TestCase
     assert_equal(0, 1 / 2)
   end
 
+  def test_visibility_after_refine_and_visibility_change
+    m = Module.new
+    c = Class.new do
+      def x; :x end
+    end
+    c.prepend(m)
+    Module.new do
+      refine c do
+        def x; :y end
+      end
+    end
+
+    o1 = c.new
+    o2 = c.new
+    assert_equal(:x, o1.public_send(:x))
+    assert_equal(:x, o2.public_send(:x))
+    o1.singleton_class.send(:private, :x)
+    o2.singleton_class.send(:public, :x)
+
+    assert_raise(NoMethodError) { o1.public_send(:x) }
+    assert_equal(:x, o2.public_send(:x))
+  end
+
   def test_prepend_visibility
     bug8005 = '[ruby-core:53106] [Bug #8005]'
     c = Class.new do