Fix an incorrect autocorrect for Layout/ClassStructure when definit…

…ions that need to be sorted are defined alternately

This PR is fix an incorrect autocorrect for `Layout/ClassStructure`
when definitions that need to be sorted are defined alternately.

## Code to reproduce

```ruby
class A
  private def foo; end

  def bar; end

  private def baz; end

  def qux; end
end
```

## Expected behavior

Automatically corrected as follows:

```ruby
class A
  def bar; end

  def qux; end

  private def foo; end

  private def baz; end
end
```

## Actual behavior

Automatically corrected as follows:

```ruby
class A
  def qux; end

  def bar; end

  def qux; end # <------ Duplicate

  private def foo; end

  private def baz; end
end
```

changelog/fix_an_incorrect_autocorrect_for_layout_class_structure.md

@@ -0,0 +1 @@
+* [#11529](https://github.com/rubocop/rubocop/pull/11529): Fix an incorrect autocorrect for `Layout/ClassStructure` when definitions that need to be sorted are defined alternately. ([@ydah][])

lib/rubocop/cop/layout/class_structure.rb

@@ -134,6 +134,7 @@ module Layout
       #
       class ClassStructure < Base
         include VisibilityHelp
+        include CommentsHelp
         extend AutoCorrector
 
         HUMANIZED_NODE_TYPE = {
@@ -163,7 +164,7 @@ def on_class(class_node)
 
         # Autocorrect by swapping between two nodes autocorrecting them
         def autocorrect(corrector, node)
-          previous = node.left_siblings.find do |sibling|
+          previous = node.left_siblings.reverse.find do |sibling|
             !ignore_for_autocorrect?(node, sibling)
           end
           return unless previous
@@ -283,21 +284,6 @@ def marked_as_private_constant?(node, name)
           node.arguments.any? { |arg| (arg.sym_type? || arg.str_type?) && arg.value == name }
         end
 
-        def source_range_with_comment(node)
-          begin_pos, end_pos =
-            if (node.def_type? && !node.method?(:initialize)) ||
-               (node.send_type? && node.def_modifier?)
-              start_node = find_visibility_start(node) || node
-              end_node = find_visibility_end(node) || node
-              [begin_pos_with_comment(start_node),
-               end_position_for(end_node) + 1]
-            else
-              [begin_pos_with_comment(node), end_position_for(node)]
-            end
-
-          Parser::Source::Range.new(buffer, begin_pos, end_pos)
-        end
-
         def end_position_for(node)
           heredoc = find_heredoc(node)
           return heredoc.location.heredoc_end.end_pos + 1 if heredoc

spec/rubocop/cop/layout/class_structure_spec.rb

@@ -404,9 +404,9 @@ class A
         class A
           public def bar
           end
-
           private def foo
           end
+
         end
       RUBY
     end
@@ -427,9 +427,37 @@ def bar
         class A
           def bar
           end
-
           private def foo
           end
+
+        end
+      RUBY
+    end
+
+    it 'registers an offense and corrects when definitions that need to be sorted are defined alternately' do
+      expect_offense(<<~RUBY)
+        class A
+          private def foo; end
+
+          def bar; end
+          ^^^^^^^^^^^^ `public_methods` is supposed to appear before `private_methods`.
+
+          private def baz; end
+
+          def qux; end
+          ^^^^^^^^^^^^ `public_methods` is supposed to appear before `private_methods`.
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        class A
+          def bar; end
+          def qux; end
+          private def foo; end
+
+
+          private def baz; end
+
         end
       RUBY
     end
@@ -451,10 +479,10 @@ def bar
         class A
           def bar
           end
-
           def foo
           end
           private :foo
+
         end
       RUBY
     end