[Misc #19304] Pretend global methods to be in Object

Show global methods, which are defined as public in `Kernel`, like as
defined in `Object`.

lib/rdoc/context.rb

@@ -1259,6 +1259,10 @@ def upgrade_to_class mod, class_type, enclosing
     klass
   end
 
+  def pretend_object? # :nodoc:
+    false
+  end
+
   autoload :Section, "#{__dir__}/context/section"
 
 end

lib/rdoc/normal_module.rb

@@ -15,6 +15,11 @@ def inspect # :nodoc:
     ]
   end
 
+  def initialize(name, *args) # :nodoc:
+    super
+    @pretend_object = name == "Kernel"
+  end
+
   ##
   # The definition of this module, <tt>module MyModuleName</tt>
 
@@ -29,6 +34,16 @@ def module?
     true
   end
 
+  ##
+  # Show public methods in Object class?
+
+  def pretend_object?
+    if @pretend_object
+      (@current_line_visibility || @visibility) == :public
+    end
+  end
+
+  ##
   def pretty_print q # :nodoc:
     q.group 2, "[module #{full_name}:", "]" do
       q.breakable

lib/rdoc/parser/ruby.rb

@@ -219,7 +219,7 @@ def get_visibility_information tk, single # :nodoc:
         :public
       when 'module_function' then
         singleton = true
-        :public
+        :module_function
       else
         raise RDoc::Error, "Invalid visibility: #{tk.name}"
       end
@@ -1462,6 +1462,9 @@ def parse_method(container, single, tk, comment)
     meth.add_tokens [token, newline, indent]
     meth.add_tokens @token_stream
 
+    if !meth.singleton and container.pretend_object?
+      container = @top_level.object_class
+    end
     parse_method_params_and_body container, single, meth, added_container
 
     comment.normalize
@@ -1500,6 +1503,9 @@ def parse_method_params_and_body container, single, meth, added_container
           meth.visibility = :public
         end
       end
+      if meth.visibility == :module_function
+        meth.visibility = :public
+      end
 
       parse_statements container, single, meth
     end
@@ -2339,7 +2345,14 @@ def update_visibility container, vis_type, vis, singleton # :nodoc:
       container.set_visibility_for args, vis, singleton
     end
 
+    # Move public methods from Kernel to Object
+    if container.pretend_object?
+      old_methods = container.methods_hash
+      container = @top_level.object_class
+    end
+
     new_methods.each do |method|
+      old_methods&.delete(method.pretty_name)
       case method
       when RDoc::AnyMethod then
         container.add_method method

test/rdoc/test_rdoc_parser_ruby.rb

@@ -2747,7 +2747,7 @@ def test_parse_statements_identifier_module_function
     assert_equal false,    foo.singleton,  'instance method singleton'
 
     assert_equal 'foo',   s_foo.name,       'module function name'
-    assert_equal :public, s_foo.visibility, 'module function visibility'
+    assert_equal :module_function, s_foo.visibility, 'module function visibility'
     assert_equal true,    s_foo.singleton,  'module function singleton'
   end