--- Rakefile~	2021-03-17 23:49:38.000000000 +0000

+++ Rakefile	2021-10-06 18:35:20.948000000 +0000

@@ -19,7 +19,7 @@ begin

   class RDoc::RDoc

-    alias old_parse_files parse_files

+    alias_method :old_parse_files, :parse_files if !instance_methods.include?(:old_parse_files)

     def parse_files(options)

       file_info = old_parse_files(options)