Add Rails/I18nLocaleTexts match for redirect_back

Author: bensheldon

changelog/change_add_i18nlocaletext_match_for_redirect_back.md

@@ -0,0 +1 @@
+* [#880](https://github.com/rubocop/rubocop-rails/pull/880): Add Rails/I18nLocaleTexts match for redirect_back. ([@bensheldon][])

lib/rubocop/cop/rails/i18n_locale_texts.rb

@@ -69,7 +69,7 @@ module Rails
       class I18nLocaleTexts < Base
         MSG = 'Move locale texts to the locale files in the `config/locales` directory.'
 
-        RESTRICT_ON_SEND = %i[validates redirect_to []= mail].freeze
+        RESTRICT_ON_SEND = %i[validates redirect_to redirect_back []= mail].freeze
 
         def_node_search :validation_message, <<~PATTERN
           (pair (sym :message) $str)
@@ -94,7 +94,7 @@ def on_send(node)
               add_offense(text_node)
             end
             return
-          when :redirect_to
+          when :redirect_to, :redirect_back
             text_node = redirect_to_flash(node).to_a.last
           when :[]=
             text_node = flash_assignment?(node)

spec/rubocop/cop/rails/i18n_locale_texts_spec.rb

@@ -26,6 +26,13 @@
     RUBY
   end
 
+  it 'registers an offense when using `redirect_back` with text flash messages' do
+    expect_offense(<<~RUBY)
+      redirect_back fallback_location: root_path, notice: "Post created!"
+                                                          ^^^^^^^^^^^^^^^ Move locale texts to the locale files in the `config/locales` directory.
+    RUBY
+  end
+
   it 'does not register an offense when using `redirect_to` with localized flash messages' do
     expect_no_offenses(<<~RUBY)
       redirect_to root_path, notice: t(".success")