Enable Lint/DuplicateMethods rubocop rule

.rubocop.yml

@@ -208,6 +208,9 @@ Lint/AmbiguousRegexpLiteral:
 Lint/DuplicateRequire:
   Enabled: true
 
+Lint/DuplicateMethods:
+  Enabled: true
+
 Lint/ErbNewArguments:
   Enabled: true
 

actionpack/test/controller/routing_test.rb

@@ -1917,8 +1917,6 @@ class RouteSetTest < ActiveSupport::TestCase
 
   include ActionDispatch::RoutingVerbs
 
-  alias :routes :set
-
   def test_generate_with_optional_params_recalls_last_request
     @set = make_set false
 

activesupport/lib/active_support/core_ext/time/calculations.rb

@@ -305,7 +305,7 @@ class Time
     other.is_a?(DateTime) ? to_f - other.to_f : minus_without_coercion(other)
   end
   alias_method :minus_without_coercion, :-
-  alias_method :-, :minus_with_coercion
+  alias_method :-, :minus_with_coercion # rubocop:disable Lint/DuplicateMethods
 
   # Layers additional behavior on Time#<=> so that DateTime and ActiveSupport::TimeWithZone instances
   # can be chronologically compared with a Time

activesupport/lib/active_support/notifications/instrumenter.rb

@@ -153,7 +153,7 @@ module ActiveSupport
             Process.clock_gettime(Process::CLOCK_THREAD_CPUTIME_ID, :float_millisecond)
           end
         rescue
-          def now_cpu
+          def now_cpu # rubocop:disable Lint/DuplicateMethods
             0.0
           end
         end
@@ -165,7 +165,7 @@ module ActiveSupport
             0
           end
         else
-          def now_allocations
+          def now_allocations  # rubocop:disable Lint/DuplicateMethods
             GC.stat(:total_allocated_objects)
           end
         end

activesupport/test/array_inquirer_test.rb

@@ -55,7 +55,7 @@ class ArrayInquirerTest < ActiveSupport::TestCase
   ensure
     Array.class_eval do
       undef_method :respond_to_missing?
-      def respond_to_missing?(name, include_private = false)
+      def respond_to_missing?(name, include_private = false) # rubocop:disable Lint/DuplicateMethods
         super
       end
     end

activesupport/test/string_inquirer_test.rb

@@ -38,7 +38,7 @@ class StringInquirerTest < ActiveSupport::TestCase
   ensure
     String.class_eval do
       undef_method :respond_to_missing?
-      def respond_to_missing?(name, include_private = false)
+      def respond_to_missing?(name, include_private = false) # rubocop:disable Lint/DuplicateMethods
         super
       end
     end

activesupport/test/subscriber_test.rb

@@ -34,7 +34,7 @@ end
 # Monkey patch subscriber to test that only one subscriber per method is added.
 class TestSubscriber
   remove_method :open_party
-  def open_party(event)
+  def open_party(event) # rubocop:disable Lint/DuplicateMethods
     events << event
   end
 end