diff --git a/.rubocop_basic.yml b/.rubocop_basic.yml
index 6bbcb18c9..e6578c2d3 100644
--- a/.rubocop_basic.yml
+++ b/.rubocop_basic.yml
@@ -120,6 +120,9 @@ Layout/TrailingWhitespace:
 Lint/LiteralAsCondition:
   Enabled: true
 
+Lint/ShadowingOuterLocalVariable:
+  Enabled: true
+
 Lint/UselessAssignment:
   Enabled: true
 
diff --git a/app/controllers/tracking/budget_investments_controller.rb b/app/controllers/tracking/budget_investments_controller.rb
index 83a4f28d0..88315685c 100644
--- a/app/controllers/tracking/budget_investments_controller.rb
+++ b/app/controllers/tracking/budget_investments_controller.rb
@@ -58,14 +58,13 @@ class Tracking::BudgetInvestmentsController < Tracking::BaseController
                               }
                             ]
 
-      filters = investment_headings.inject(all_headings_filter) do |filters, heading|
+      investment_headings.inject(all_headings_filter) do |filters, heading|
         filters << {
           name: heading.name,
           id: heading.id,
           count: investments.select { |i| i.heading_id == heading.id }.size
         }
-      end
-      filters.uniq
+      end.uniq
     end
 
     def restrict_access_to_assigned_items
diff --git a/db/dev_seeds/polls.rb b/db/dev_seeds/polls.rb
index 75ee07871..d284e93ae 100644
--- a/db/dev_seeds/polls.rb
+++ b/db/dev_seeds/polls.rb
@@ -222,10 +222,10 @@ section "Creating Poll Questions from Proposals" do
     poll = Poll.current.first
     question = Poll::Question.new(poll: poll)
     question.copy_attributes_from_proposal(proposal)
-    title = question.title
+    question_title = question.title
     I18n.available_locales.map do |locale|
       Globalize.with_locale(locale) do
-        question.title = "#{title} (#{locale})"
+        question.title = "#{question_title} (#{locale})"
       end
     end
     question.save!
@@ -252,10 +252,10 @@ section "Creating Successful Proposals" do
     poll = Poll.current.first
     question = Poll::Question.new(poll: poll)
     question.copy_attributes_from_proposal(proposal)
-    title = question.title
+    question_title = question.title
     I18n.available_locales.map do |locale|
       Globalize.with_locale(locale) do
-        question.title = "#{title} (#{locale})"
+        question.title = "#{question_title} (#{locale})"
       end
     end
     question.save!
diff --git a/spec/features/admin/budget_investments_spec.rb b/spec/features/admin/budget_investments_spec.rb
index 2ed59f9ee..86c8b8c4b 100644
--- a/spec/features/admin/budget_investments_spec.rb
+++ b/spec/features/admin/budget_investments_spec.rb
@@ -1773,8 +1773,8 @@ describe "Admin budget investments" do
       visit admin_budget_budget_investments_path(budget)
 
       cookies = page.driver.browser.manage.all_cookies
-      cookie = cookies.find { |cookie| cookie[:name] == "investments-columns" }
-      cookie_value = cookie[:value]
+      columns_cookie = cookies.find { |cookie| cookie[:name] == "investments-columns" }
+      cookie_value = columns_cookie[:value]
 
       expect(cookie_value).to eq("id,title,supports,admin,valuator,geozone," +
         "feasibility,price,valuation_finished,visible_to_valuators,selected,incompatible")
@@ -1827,8 +1827,8 @@ describe "Admin budget investments" do
       end
 
       cookies = page.driver.browser.manage.all_cookies
-      cookie = cookies.find { |cookie| cookie[:name] == "investments-columns" }
-      cookie_value = cookie[:value]
+      columns_cookie = cookies.find { |cookie| cookie[:name] == "investments-columns" }
+      cookie_value = columns_cookie[:value]
 
       expect(cookie_value).to eq("id,supports,admin,geozone," +
         "feasibility,valuation_finished,visible_to_valuators,selected,incompatible,author")
@@ -1836,8 +1836,8 @@ describe "Admin budget investments" do
       visit admin_budget_budget_investments_path(budget)
 
       cookies = page.driver.browser.manage.all_cookies
-      cookie = cookies.find { |cookie| cookie[:name] == "investments-columns" }
-      cookie_value = cookie[:value]
+      columns_cookie = cookies.find { |cookie| cookie[:name] == "investments-columns" }
+      cookie_value = columns_cookie[:value]
 
       expect(cookie_value).to eq("id,supports,admin,geozone,feasibility,valuation_finished," +
         "visible_to_valuators,selected,incompatible,author")