removes usage of Object#in? from the code base (the method remains defined by Active Support)

Selecting which key extensions to include in active_support/rails
made apparent the systematic usage of Object#in? in the code base.
After some discussion in

    https://github.com/rails/rails/commit/5ea6b0df9a36d033f21b52049426257a4637028d

we decided to remove it and use plain Ruby, which seems enough
for this particular idiom.

In this commit the refactor has been made case by case. Sometimes
include? is the natural alternative, others a simple || is the
way you actually spell the condition in your head, others a case
statement seems more appropriate. I have chosen the one I liked
the most in each case.

32 files changed, 53 insertions, 66 deletions

diff --git a/actionpack/lib/action_controller/metal/mime_responds.rb b/actionpack/lib/action_controller/metal/mime_responds.rb
index 64461c73e0..18ae2c3bfc 100644
--- a/actionpack/lib/action_controller/metal/mime_responds.rb
+++ b/actionpack/lib/action_controller/metal/mime_responds.rb
@@ -341,9 +341,9 @@ module ActionController #:nodoc:
         config = self.class.mimes_for_respond_to[mime]
 
         if config[:except]
-          !action.in?(config[:except])
+          !config[:except].include?(action)
         elsif config[:only]
-          action.in?(config[:only])
+          config[:only].include?(action)
         else
           true
         end
diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index 2b3095a234..ab584abf68 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -345,7 +345,7 @@ module ActionDispatch
         define_method(method) do |*args|
           reset! unless integration_session
           # reset the html_document variable, but only for new get/post calls
-          @html_document = nil unless method.in?(["cookies", "assigns"])
+          @html_document = nil unless method == 'cookies' || method == 'assigns'
           integration_session.__send__(method, *args).tap do
             copy_session_variables!
           end
diff --git a/actionpack/test/controller/mime_responds_test.rb b/actionpack/test/controller/mime_responds_test.rb
index 6f9dd44e21..b21d35c846 100644
--- a/actionpack/test/controller/mime_responds_test.rb
+++ b/actionpack/test/controller/mime_responds_test.rb
@@ -151,10 +151,11 @@ class RespondToController < ActionController::Base
 
   protected
     def set_layout
-      if action_name.in?(["all_types_with_layout", "iphone_with_html_response_type"])
-        "respond_to/layouts/standard"
-      elsif action_name == "iphone_with_html_response_type_without_layout"
-        "respond_to/layouts/missing"
+      case action_name
+        when "all_types_with_layout", "iphone_with_html_response_type"
+          "respond_to/layouts/standard"
+        when "iphone_with_html_response_type_without_layout"
+          "respond_to/layouts/missing"
       end
     end
 end
diff --git a/actionpack/test/controller/resources_test.rb b/actionpack/test/controller/resources_test.rb
index c7c367f18a..236e16c68e 100644
--- a/actionpack/test/controller/resources_test.rb
+++ b/actionpack/test/controller/resources_test.rb
@@ -1307,7 +1307,7 @@ class ResourcesTest < ActionController::TestCase
     def assert_resource_methods(expected, resource, action_method, method)
       assert_equal expected.length, resource.send("#{action_method}_methods")[method].size, "#{resource.send("#{action_method}_methods")[method].inspect}"
       expected.each do |action|
-        assert action.in?(resource.send("#{action_method}_methods")[method])
+        assert resource.send("#{action_method}_methods")[method].include?(action)
           "#{method} not in #{action_method} methods: #{resource.send("#{action_method}_methods")[method].inspect}"
       end
     end
@@ -1344,9 +1344,9 @@ class ResourcesTest < ActionController::TestCase
       options = options.merge(:action => action.to_s)
       path_options = { :path => path, :method => method }
 
-      if action.in?(Array(allowed))
+      if Array(allowed).include?(action)
         assert_recognizes options, path_options
-      elsif action.in?(Array(not_allowed))
+      elsif Array(not_allowed).include?(action)
         assert_not_recognizes options, path_options
       end
     end
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index d0308b0e74..b029131ad8 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -511,7 +511,7 @@ class TestRoutingMapper < ActionDispatch::IntegrationTest
         resources :todos, :id => /\d+/
       end
 
-      scope '/countries/:country', :constraints => lambda { |params, req| params[:country].in?(["all", "France"]) } do
+      scope '/countries/:country', :constraints => lambda { |params, req| %w(all France).include?(params[:country]) } do
         get '/',       :to => 'countries#index'
         get '/cities', :to => 'countries#cities'
       end
diff --git a/actionpack/test/template/erb_util_test.rb b/actionpack/test/template/erb_util_test.rb
index 4132c8ca04..f1cb920963 100644
--- a/actionpack/test/template/erb_util_test.rb
+++ b/actionpack/test/template/erb_util_test.rb
@@ -39,7 +39,7 @@ class ErbUtilTest < ActiveSupport::TestCase
 
   def test_rest_in_ascii
     (0..127).to_a.map {|int| int.chr }.each do |chr|
-      next if chr.in?('&"<>\'')
+      next if %('"&<>).include?(chr)
       assert_equal chr, html_escape(chr)
     end
   end
diff --git a/actionpack/test/template/form_helper_test.rb b/actionpack/test/template/form_helper_test.rb
index ab22dbfa44..a20a68c1b2 100644
--- a/actionpack/test/template/form_helper_test.rb
+++ b/actionpack/test/template/form_helper_test.rb
@@ -2659,7 +2659,7 @@ class FormHelperTest < ActionView::TestCase
   def hidden_fields(method = nil)
     txt =  %{<div style="margin:0;padding:0;display:inline">}
     txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
-    if method && !method.to_s.in?(['get', 'post'])
+    if method && !%w(get post).include?(method.to_s)
       txt << %{<input name="_method" type="hidden" value="#{method}" />}
     end
     txt << %{</div>}
diff --git a/actionpack/test/template/form_options_helper_test.rb b/actionpack/test/template/form_options_helper_test.rb
index 66a572e719..682ffdcc18 100644
--- a/actionpack/test/template/form_options_helper_test.rb
+++ b/actionpack/test/template/form_options_helper_test.rb
@@ -82,7 +82,7 @@ class FormOptionsHelperTest < ActionView::TestCase
   def test_collection_options_with_proc_for_disabled
     assert_dom_equal(
       "<option value=\"&lt;Abe&gt;\">&lt;Abe&gt; went home</option>\n<option value=\"Babe\" disabled=\"disabled\">Babe went home</option>\n<option value=\"Cabe\" disabled=\"disabled\">Cabe went home</option>",
-      options_from_collection_for_select(dummy_posts, "author_name", "title", :disabled => lambda{|p| p.author_name.in?(["Babe", "Cabe"]) })
+      options_from_collection_for_select(dummy_posts, "author_name", "title", :disabled => lambda {|p| %w(Babe Cabe).include?(p.author_name)})
     )
   end
 
diff --git a/actionpack/test/template/form_tag_helper_test.rb b/actionpack/test/template/form_tag_helper_test.rb
index dcae5b2352..9a85b1b553 100644
--- a/actionpack/test/template/form_tag_helper_test.rb
+++ b/actionpack/test/template/form_tag_helper_test.rb
@@ -15,7 +15,7 @@ class FormTagHelperTest < ActionView::TestCase
 
     txt =  %{<div style="margin:0;padding:0;display:inline">}
     txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
-    if method && !method.to_s.in?(['get','post'])
+    if method && !%w(get post).include?(method.to_s)
       txt << %{<input name="_method" type="hidden" value="#{method}" />}
     end
     txt << %{</div>}
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index 87e4319421..85aec00f25 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -65,7 +65,7 @@ module ActiveModel
   #
   #   class TitleValidator < ActiveModel::EachValidator
   #     def validate_each(record, attribute, value)
-  #       record.errors.add attribute, 'must be Mr. Mrs. or Dr.' unless value.in?(['Mr.', 'Mrs.', 'Dr.'])
+  #       record.errors.add attribute, 'must be Mr., Mrs., or Dr.' unless %w(Mr. Mrs. Dr.).include?(value)
   #     end
   #   end
   #
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 4db7038d2e..9f47e7e631 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -176,7 +176,7 @@ module ActiveRecord
         def creation_attributes
           attributes = {}
 
-          if reflection.macro.in?([:has_one, :has_many]) && !options[:through]
+          if (reflection.macro == :has_one || reflection.macro == :has_many) && !options[:through]
             attributes[reflection.foreign_key] = owner[reflection.active_record_primary_key]
 
             if reflection.options[:as]
diff --git a/activerecord/lib/active_record/associations/has_one_association.rb b/activerecord/lib/active_record/associations/has_one_association.rb
index c5aed6e26a..191c4e8e39 100644
--- a/activerecord/lib/active_record/associations/has_one_association.rb
+++ b/activerecord/lib/active_record/associations/has_one_association.rb
@@ -51,16 +51,19 @@ module ActiveRecord
         end
 
         def remove_target!(method)
-          if method.in?([:delete, :destroy])
-            target.send(method)
-          else
-            nullify_owner_attributes(target)
+          case method
+            when :delete
+              target.delete
+            when :destroy
+              target.destroy
+            else
+              nullify_owner_attributes(target)
 
-            if target.persisted? && owner.persisted? && !target.save
-              set_owner_attributes(target)
-              raise RecordNotSaved, "Failed to remove the existing associated #{reflection.name}. " +
-                                    "The record failed to save when after its foreign key was set to nil."
-            end
+              if target.persisted? && owner.persisted? && !target.save
+                set_owner_attributes(target)
+                raise RecordNotSaved, "Failed to remove the existing associated #{reflection.name}. " +
+                                      "The record failed to save when after its foreign key was set to nil."
+              end
           end
         end
 
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index 7d759c1048..04fff99a6e 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -55,7 +55,7 @@ module ActiveRecord
         end
 
         sup = active_record_super
-        if sup.in?([Base, Model]) || sup.abstract_class?
+        if sup == Base || sup == Model || sup.abstract_class?
           self
         else
           sup.base_class
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index 6bb0c39b79..e0659700b6 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -1,4 +1,3 @@
-require 'active_support/core_ext/object/inclusion'
 require 'active_record'
 
 db_namespace = namespace :db do
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index fb3dfc2730..b41cc68b6a 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -115,7 +115,7 @@ module ActiveRecord
       end
 
       def local_database?(configuration)
-        configuration['host'].in?(LOCAL_HOSTS) || configuration['host'].blank?
+        configuration['host'].blank? || LOCAL_HOSTS.include?(configuration['host'])
       end
     end
   end
diff --git a/activerecord/lib/rails/generators/active_record/session_migration/session_migration_generator.rb b/activerecord/lib/rails/generators/active_record/session_migration/session_migration_generator.rb
index a976571dee..75aee4f408 100644
--- a/activerecord/lib/rails/generators/active_record/session_migration/session_migration_generator.rb
+++ b/activerecord/lib/rails/generators/active_record/session_migration/session_migration_generator.rb
@@ -13,8 +13,8 @@ module ActiveRecord
 
         def session_table_name
           current_table_name = ActiveRecord::SessionStore::Session.table_name
-          if current_table_name.in?(["sessions", "session"])
-            current_table_name = (ActiveRecord::Base.pluralize_table_names ? 'session'.pluralize : 'session')
+          if current_table_name == 'session' || current_table_name == 'sessions'
+            current_table_name = ActiveRecord::Base.pluralize_table_names ? 'sessions' : 'session'
           end
           current_table_name
         end
diff --git a/activerecord/test/cases/associations/join_model_test.rb b/activerecord/test/cases/associations/join_model_test.rb
index d4b7960047..3cea20527e 100644
--- a/activerecord/test/cases/associations/join_model_test.rb
+++ b/activerecord/test/cases/associations/join_model_test.rb
@@ -453,7 +453,7 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
     assert saved_post.tags.include?(new_tag)
 
     assert new_tag.persisted?
-    assert new_tag.in?(saved_post.reload.tags(true))
+    assert saved_post.reload.tags(true).include?(new_tag)
 
 
     new_post = Post.new(:title => "Association replacmenet works!", :body => "You best believe it.")
@@ -466,7 +466,7 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase
 
     new_post.save!
     assert new_post.persisted?
-    assert saved_tag.in?(new_post.reload.tags(true))
+    assert new_post.reload.tags(true).include?(saved_tag)
 
     assert !posts(:thinking).tags.build.persisted?
     assert !posts(:thinking).tags.new.persisted?
diff --git a/activerecord/test/cases/attribute_methods/read_test.rb b/activerecord/test/cases/attribute_methods/read_test.rb
index 55d45d9d93..da5d9d8c2a 100644
--- a/activerecord/test/cases/attribute_methods/read_test.rb
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -47,13 +47,13 @@ module ActiveRecord
         instance = @klass.new
 
         @klass.column_names.each do |name|
-          assert !name.in?(instance.methods.map(&:to_s))
+          assert !instance.methods.map(&:to_s).include?(name)
         end
 
         @klass.define_attribute_methods
 
         @klass.column_names.each do |name|
-          assert name.in?(instance.methods.map(&:to_s)), "#{name} is not defined"
+          assert instance.methods.map(&:to_s).include?(name), "#{name} is not defined"
         end
       end
 
diff --git a/activerecord/test/cases/defaults_test.rb b/activerecord/test/cases/defaults_test.rb
index 81c5850a47..deaf5252db 100644
--- a/activerecord/test/cases/defaults_test.rb
+++ b/activerecord/test/cases/defaults_test.rb
@@ -94,7 +94,7 @@ if current_adapter?(:MysqlAdapter) or current_adapter?(:Mysql2Adapter)
       assert_equal 0, klass.columns_hash['zero'].default
       assert !klass.columns_hash['zero'].null
       # 0 in MySQL 4, nil in 5.
-      assert klass.columns_hash['omit'].default.in?([0, nil])
+      assert [0, nil].include?(klass.columns_hash['omit'].default)
       assert !klass.columns_hash['omit'].null
 
       assert_raise(ActiveRecord::StatementInvalid) { klass.create! }
diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
index 5be63af342..2c1ad60d44 100644
--- a/activesupport/lib/active_support/cache/file_store.rb
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -1,6 +1,5 @@
 require 'active_support/core_ext/file/atomic'
 require 'active_support/core_ext/string/conversions'
-require 'active_support/core_ext/object/inclusion'
 require 'uri/common'
 
 module ActiveSupport
@@ -23,7 +22,7 @@ module ActiveSupport
       end
 
       def clear(options = nil)
-        root_dirs = Dir.entries(cache_path).reject{|f| f.in?(EXCLUDED_DIRS + [".gitkeep"])}
+        root_dirs = Dir.entries(cache_path).reject {|f| (EXCLUDED_DIRS + [".gitkeep"]).include?(f)}
         FileUtils.rm_r(root_dirs.collect{|f| File.join(cache_path, f)})
       end
 
@@ -151,7 +150,7 @@ module ActiveSupport
         # Delete empty directories in the cache.
         def delete_empty_directories(dir)
           return if dir == cache_path
-          if Dir.entries(dir).reject{|f| f.in?(EXCLUDED_DIRS)}.empty?
+          if Dir.entries(dir).reject {|f| EXCLUDED_DIRS.include?(f)}.empty?
             File.delete(dir) rescue nil
             delete_empty_directories(File.dirname(dir))
           end
@@ -165,7 +164,7 @@ module ActiveSupport
         def search_dir(dir, &callback)
           return if !File.exist?(dir)
           Dir.foreach(dir) do |d|
-            next if d.in?(EXCLUDED_DIRS)
+            next if EXCLUDED_DIRS.include?(d)
             name = File.join(dir, d)
             if File.directory?(name)
               search_dir(name, &callback)
diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
index 8f79334159..3f7d0e401a 100644
--- a/activesupport/lib/active_support/callbacks.rb
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -3,7 +3,6 @@ require 'active_support/descendants_tracker'
 require 'active_support/core_ext/class/attribute'
 require 'active_support/core_ext/kernel/reporting'
 require 'active_support/core_ext/kernel/singleton_class'
-require 'active_support/core_ext/object/inclusion'
 
 module ActiveSupport
   # \Callbacks are code hooks that are run at key points in an object's lifecycle.
@@ -353,7 +352,7 @@ module ActiveSupport
       # CallbackChain.
       #
       def __update_callbacks(name, filters = [], block = nil) #:nodoc:
-        type = filters.first.in?([:before, :after, :around]) ? filters.shift : :before
+        type = [:before, :after, :around].include?(filters.first) ? filters.shift : :before
         options = filters.last.is_a?(Hash) ? filters.pop : {}
         filters.unshift(block) if block
 
diff --git a/activesupport/lib/active_support/rails.rb b/activesupport/lib/active_support/rails.rb
index 933c6e6136..b05c3ff126 100644
--- a/activesupport/lib/active_support/rails.rb
+++ b/activesupport/lib/active_support/rails.rb
@@ -11,9 +11,6 @@
 # Defines Object#blank? and Object#present?.
 require 'active_support/core_ext/object/blank'
 
-# Defines Object#in?.
-require 'active_support/core_ext/object/inclusion'
-
 # Rails own autoload, eager_load, etc.
 require 'active_support/dependencies/autoload'
 
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index 451520ac5c..93c2d614f5 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -1,6 +1,5 @@
 require 'active_support/values/time_zone'
 require 'active_support/core_ext/object/acts_like'
-require 'active_support/core_ext/object/inclusion'
 
 module ActiveSupport
   # A Time-like class that can represent a time in any time zone. Necessary because standard Ruby Time instances are
@@ -339,7 +338,7 @@ module ActiveSupport
       end
 
       def duration_of_variable_length?(obj)
-        ActiveSupport::Duration === obj && obj.parts.any? {|p| p[0].in?([:years, :months, :days]) }
+        ActiveSupport::Duration === obj && obj.parts.any? {|p| [:years, :months, :days].include?(p[0]) }
       end
 
       def wrap_with_time_zone(time)
diff --git a/activesupport/test/transliterate_test.rb b/activesupport/test/transliterate_test.rb
index b7076e9e58..b5d8142458 100644
--- a/activesupport/test/transliterate_test.rb
+++ b/activesupport/test/transliterate_test.rb
@@ -1,7 +1,6 @@
 # encoding: utf-8
 require 'abstract_unit'
 require 'active_support/inflector/transliterate'
-require 'active_support/core_ext/object/inclusion'
 
 class TransliterateTest < ActiveSupport::TestCase
 
@@ -16,7 +15,7 @@ class TransliterateTest < ActiveSupport::TestCase
     # create string with range of Unicode"s western characters with
     # diacritics, excluding the division and multiplication signs which for
     # some reason or other are floating in the middle of all the letters.
-    string = (0xC0..0x17E).to_a.reject {|c| c.in?([0xD7, 0xF7])}.pack("U*")
+    string = (0xC0..0x17E).to_a.reject {|c| [0xD7, 0xF7].include?(c)}.pack("U*")
     string.each_char do |char|
       assert_match %r{^[a-zA-Z']*$}, ActiveSupport::Inflector.transliterate(string)
     end
diff --git a/guides/rails_guides/textile_extensions.rb b/guides/rails_guides/textile_extensions.rb
index 0a002a785f..1faddd4ca0 100644
--- a/guides/rails_guides/textile_extensions.rb
+++ b/guides/rails_guides/textile_extensions.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/object/inclusion'
-
 module RedCloth::Formatters::HTML
   def emdash(opts)
     "--"
diff --git a/guides/source/asset_pipeline.textile b/guides/source/asset_pipeline.textile
index 42b5d102e7..8fec109951 100644
--- a/guides/source/asset_pipeline.textile
+++ b/guides/source/asset_pipeline.textile
@@ -432,7 +432,7 @@ NOTE. If you are precompiling your assets locally, you can use +bundle install -
 The default matcher for compiling files includes +application.js+, +application.css+ and all non-JS/CSS files (this will include all image assets automatically):
 
 <ruby>
-[ Proc.new{ |path| !File.extname(path).in?(['.js', '.css']) }, /application.(css|js)$/ ]
+[ Proc.new{ |path| !%w(.js .css).include?(File.extname(path)) }, /application.(css|js)$/ ]
 </ruby>
 
 NOTE. The matcher (and other members of the precompile array; see below) is applied to final compiled file names. This means that anything that compiles to JS/CSS is excluded, as well as raw JS/CSS files; for example, +.coffee+ and +.scss+ files are *not* automatically included as they compile to JS/CSS.
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 9521805778..2b36cc9d0d 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -49,7 +49,7 @@ module Rails
         @assets = ActiveSupport::OrderedOptions.new
         @assets.enabled                  = false
         @assets.paths                    = []
-        @assets.precompile               = [ Proc.new{ |path| !File.extname(path).in?(['.js', '.css']) },
+        @assets.precompile               = [ Proc.new { |path| !%w(.js .css).include?(File.extname(path)) },
                                              /(?:\/|\\|\A)application\.(css|js)$/ ]
         @assets.prefix                   = "/assets"
         @assets.version                  = ''
diff --git a/railties/lib/rails/commands.rb b/railties/lib/rails/commands.rb
index 8816387d34..9c5dc8f188 100644
--- a/railties/lib/rails/commands.rb
+++ b/railties/lib/rails/commands.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/object/inclusion'
-
 ARGV << '--help' if ARGV.empty?
 
 aliases = {
@@ -71,7 +69,7 @@ when 'application', 'runner'
   require "rails/commands/#{command}"
 
 when 'new'
-  if ARGV.first.in?(['-h', '--help'])
+  if %w(-h --help).include?(ARGV.first)
     require 'rails/commands/application'
   else
     puts "Can't initialize a new Rails application within the directory of another, please change to a non-Rails directory first.\n"
@@ -84,7 +82,7 @@ when '--version', '-v'
   require 'rails/commands/application'
 
 else
-  puts "Error: Command not recognized" unless command.in?(['-h', '--help'])
+  puts "Error: Command not recognized" unless %w(-h --help).include?(command)
   puts <<-EOT
 Usage: rails COMMAND [ARGS]
 
diff --git a/railties/lib/rails/commands/destroy.rb b/railties/lib/rails/commands/destroy.rb
index ae354eca97..9023c61bf2 100644
--- a/railties/lib/rails/commands/destroy.rb
+++ b/railties/lib/rails/commands/destroy.rb
@@ -1,7 +1,6 @@
 require 'rails/generators'
-require 'active_support/core_ext/object/inclusion'
 
-if ARGV.first.in?([nil, "-h", "--help"])
+if [nil, "-h", "--help"].include?(ARGV.first)
   Rails::Generators.help 'destroy'
   exit
 end
diff --git a/railties/lib/rails/commands/generate.rb b/railties/lib/rails/commands/generate.rb
index 1fb2d98834..9f13cb0513 100644
--- a/railties/lib/rails/commands/generate.rb
+++ b/railties/lib/rails/commands/generate.rb
@@ -1,7 +1,6 @@
 require 'rails/generators'
-require 'active_support/core_ext/object/inclusion'
 
-if ARGV.first.in?([nil, "-h", "--help"])
+if [nil, "-h", "--help"].include?(ARGV.first)
   Rails::Generators.help 'generate'
   exit
 end
diff --git a/railties/lib/rails/engine/commands.rb b/railties/lib/rails/engine/commands.rb
index ffbc0b4bd6..072d16291b 100644
--- a/railties/lib/rails/engine/commands.rb
+++ b/railties/lib/rails/engine/commands.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/object/inclusion'
-
 ARGV << '--help' if ARGV.empty?
 
 aliases = {
@@ -25,7 +23,7 @@ when '--version', '-v'
   require 'rails/commands/application'
 
 else
-  puts "Error: Command not recognized" unless command.in?(['-h', '--help'])
+  puts "Error: Command not recognized" unless %w(-h --help).include?(command)
   puts <<-EOT
 Usage: rails COMMAND [ARGS]
 
diff --git a/railties/lib/rails/generators/base.rb b/railties/lib/rails/generators/base.rb
index a49a1724c5..a3f8ebf476 100644
--- a/railties/lib/rails/generators/base.rb
+++ b/railties/lib/rails/generators/base.rb
@@ -8,7 +8,6 @@ rescue LoadError
 end
 
 require 'rails/generators/actions'
-require 'active_support/core_ext/object/inclusion'
 
 module Rails
   module Generators
@@ -171,7 +170,7 @@ module Rails
         names.each do |name|
           defaults = if options[:type] == :boolean
             { }
-          elsif default_value_for_option(name, options).in?([true, false])
+          elsif [true, false].include?(default_value_for_option(name, options))
             { :banner => "" }
           else
             { :desc => "#{name.to_s.humanize} to be invoked", :banner => "NAME" }