[Fix rubocop#11168] Fix an incorrect autocorrect for `Style/ClassEqua…

…lityComparison`

Fixes rubocop#11168.

This PR fixes an incorrect autocorrect for `Style/ClassEqualityComparison`
when using instance variable comparison in module.

changelog/fix_an_incorrect_autocorrect_for_style_class_equality_comparison.md

@@ -0,0 +1 @@
+* [#11168](https://github.com/rubocop/rubocop/issues/11168): Fix an incorrect autocorrect for `Style/ClassEqualityComparison` when using instance variable comparison in module. ([@koic][])

lib/rubocop/cop/style/class_equality_comparison.rb

@@ -97,12 +97,14 @@ def class_name(class_node, node)
           if node.children.first.method?(:name)
             return class_node.receiver.source if class_node.receiver
 
-            value = class_node.source.delete('"').delete("'")
-            value.prepend('::') if class_node.each_ancestor(:class, :module).any?
-            value
-          else
-            class_node.source
+            if class_node.str_type?
+              value = class_node.source.delete('"').delete("'")
+              value.prepend('::') if class_node.each_ancestor(:class, :module).any?
+              return value
+            end
           end
+
+          class_node.source
         end
 
         def offense_range(receiver_node, node)

spec/rubocop/cop/style/class_equality_comparison_spec.rb

@@ -127,4 +127,25 @@ class Bar
       RUBY
     end
   end
+
+  context 'with instance variable comparison in module' do
+    it 'registers and corrects an offense' do
+      expect_offense(<<~RUBY)
+        module Foo
+          def bar?(value)
+            bar.class.name == @class_name
+                ^^^^^^^^^^^^^^^^^^^^^^^^^ Use `instance_of?(@class_name)` instead of comparing classes.
+          end
+        end
+      RUBY
+
+      expect_correction(<<~RUBY)
+        module Foo
+          def bar?(value)
+            bar.instance_of?(@class_name)
+          end
+        end
+      RUBY
+    end
+  end
 end