Fix method caching bug when including/prepend module A that prepends module B

Fix by always adding the generated iclass to the subclasses list,
otherwise the method cache for the iclass is not cleared when
the method in the module is overwritten.

Fixes [Bug #20716]

1 files changed, 29 insertions, 0 deletions

diff --git a/test/ruby/test_super.rb b/test/ruby/test_super.rb
index aa09f9e1b9..418f293f66 100644
--- a/test/ruby/test_super.rb
+++ b/test/ruby/test_super.rb
@@ -633,6 +633,35 @@ class TestSuper < Test::Unit::TestCase
     }
   end
 
+  def test_super_with_included_prepended_module_method_caching_bug_20716
+    a = Module.new do
+      def test(*args)
+        super
+      end
+    end
+
+    b = Module.new do
+      def test(a)
+        a
+      end
+    end
+
+    c = Class.new
+
+    b.prepend(a)
+    c.include(b)
+
+    assert_equal(1, c.new.test(1))
+
+    b.class_eval do
+      def test
+        :test
+      end
+    end
+
+    assert_equal(:test, c.new.test)
+  end
+
   class TestFor_super_with_modified_rest_parameter_base
     def foo *args
       args