[Fix #9766] Fix a clobbering error for Style/ClassAndModuleChildren with compact style

changelog/fix_clobbering_error_in_class_and_module_children_cop.md

@@ -0,0 +1 @@
+* [#9766](https://github.com/rubocop/rubocop/pull/9766): Fix a clobbering error for `Style/ClassAndModuleChildren` cop with compact style. ([@tejasbubane][])

lib/rubocop/cop/style/class_and_module_children.rb

@@ -132,6 +132,9 @@ def check_nested_style(node)
         end
 
         def check_compact_style(node, body)
+          parent = node.parent
+          return if parent&.class_type? || parent&.module_type?
+
           return unless needs_compacting?(body)
 
           add_offense(node.loc.name, message: COMPACT_MSG) do |corrector|

spec/rubocop/cop/style/class_and_module_children_spec.rb

@@ -227,6 +227,23 @@ class Foo::Bar::Baz
       RUBY
     end
 
+    it 'registers and offense for deeply nested children' do
+      expect_offense(<<~RUBY)
+        class Foo
+              ^^^ Use compact module/class definition instead of nested style.
+          class Bar
+            class Baz
+            end
+          end
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        class Foo::Bar::Baz
+        end
+      RUBY
+    end
+
     it 'registers an offense for modules with partially nested children' do
       expect_offense(<<~RUBY)
         module Foo::Bar