diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
index 606abb7e24..5ac1e0c001 100644
--- a/activerecord/lib/active_record/coders/yaml_column.rb
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -1,4 +1,5 @@
 require 'yaml'
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   module Coders # :nodoc:
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 0a98a8e9c1..25e3939b62 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -9,6 +9,7 @@ require 'active_record/connection_adapters/mysql/schema_dumper'
 require 'active_record/connection_adapters/mysql/type_metadata'
 
 require 'active_support/core_ext/string/strip'
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   module ConnectionAdapters
diff --git a/activerecord/lib/active_record/dynamic_matchers.rb b/activerecord/lib/active_record/dynamic_matchers.rb
index 88cb66d977..0bdebb3989 100644
--- a/activerecord/lib/active_record/dynamic_matchers.rb
+++ b/activerecord/lib/active_record/dynamic_matchers.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/regexp'
+
 module ActiveRecord
   module DynamicMatchers #:nodoc:
     def respond_to?(name, include_private = false)
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 1ad209cbbf..1bb4688717 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/module/attribute_accessors"
 require 'set'
+require "active_support/core_ext/module/attribute_accessors"
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   class MigrationError < ActiveRecordError#:nodoc:
diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
index 13f80270a4..ad74659cba 100644
--- a/activerecord/lib/active_record/relation/delegation.rb
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -1,4 +1,5 @@
 require 'active_support/concern'
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   module Delegation # :nodoc:
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 62821cacc9..0749bb30b5 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -4,6 +4,7 @@ require "active_record/relation/where_clause"
 require "active_record/relation/where_clause_factory"
 require 'active_model/forbidden_attributes_protection'
 require 'active_support/core_ext/string/filters'
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   module QueryMethods
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
index 6ecb9ce3a7..f007e9e733 100644
--- a/activerecord/lib/active_record/sanitization.rb
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/regexp'
+
 module ActiveRecord
   module Sanitization
     extend ActiveSupport::Concern
diff --git a/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
index 54c958e30b..de03550ec2 100644
--- a/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
+++ b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
@@ -1,4 +1,5 @@
 require 'rails/generators/active_record'
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   module Generators # :nodoc:
diff --git a/activerecord/test/cases/associations/left_outer_join_association_test.rb b/activerecord/test/cases/associations/left_outer_join_association_test.rb
index fcf1e0b040..e3b257efb2 100644
--- a/activerecord/test/cases/associations/left_outer_join_association_test.rb
+++ b/activerecord/test/cases/associations/left_outer_join_association_test.rb
@@ -5,6 +5,7 @@ require 'models/author'
 require 'models/essay'
 require 'models/categorization'
 require 'models/person'
+require 'active_support/core_ext/regexp'
 
 class LeftOuterJoinAssociationTest < ActiveRecord::TestCase
   fixtures :authors, :essays, :posts, :comments, :categorizations, :people
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
index 30d342ac70..6679f9415b 100644
--- a/activerecord/test/cases/scoping/default_scoping_test.rb
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -5,6 +5,7 @@ require 'models/developer'
 require 'models/computer'
 require 'models/vehicle'
 require 'models/cat'
+require 'active_support/core_ext/regexp'
 
 class DefaultScopingTest < ActiveRecord::TestCase
   fixtures :developers, :posts, :comments
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
index cde5488315..fcb6552e5b 100644
--- a/activerecord/test/cases/test_case.rb
+++ b/activerecord/test/cases/test_case.rb
@@ -1,5 +1,6 @@
 require 'active_support/test_case'
 require 'active_support/testing/stream'
+require 'active_support/core_ext/regexp'
 
 module ActiveRecord
   # = Active Record Test Case