Fix autocorrection error with nested index offenses

Author: lovro-bikic

changelog/fix_index_with_nested_offenses.md

@@ -0,0 +1 @@
+* [#1483](https://github.com/rubocop/rubocop-rails/pull/1483): Fix autocorrection error when `Rails/IndexWith` has nested offenses. ([@lovro-bikic][])

lib/rubocop/cop/mixin/index_method.rb

@@ -132,9 +132,13 @@ def handle_possible_offense(node, match, match_desc)
         add_offense(
           node, message: "Prefer `#{new_method_name}` over `#{match_desc}`."
         ) do |corrector|
+          next if part_of_ignored_node?(node)
+
           correction = prepare_correction(node)
           execute_correction(corrector, node, correction)
         end
+
+        ignore_node(node)
       end
 
       def extract_captures(match)

spec/rubocop/cop/rails/index_with_spec.rb

@@ -325,6 +325,28 @@
         end
       end
     end
+
+    context 'with nested offenses' do
+      it 'registers offenses and autocorrects' do
+        expect_offense(<<~RUBY)
+          x.each_with_object({}) do |el, h|
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Prefer `index_with` over `each_with_object`.
+            h[el] = el.each_with_object({}) do |inner_el, inner_h|
+                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Prefer `index_with` over `each_with_object`.
+              inner_h[inner_el] = foo(inner_el)
+            end
+          end
+        RUBY
+
+        expect_correction(<<~RUBY)
+          x.index_with do |el|
+            el.each_with_object({}) do |inner_el, inner_h|
+              inner_h[inner_el] = foo(inner_el)
+            end
+          end
+        RUBY
+      end
+    end
   end
 
   context 'when using Rails 5.2 or older', :rails52 do