diff --git a/actionpack/lib/action_controller/testing/process.rb b/actionpack/lib/action_controller/testing/process.rb
index 7634290ea1cf70d538bd57dce4a5416ebad15110..e7c64d09427bf8941b16f7c6ad146ed67733cadd 100644
--- a/actionpack/lib/action_controller/testing/process.rb
+++ b/actionpack/lib/action_controller/testing/process.rb
@@ -1,3 +1,4 @@
+require 'action_dispatch'
 require 'rack/session/abstract/id'
 require 'active_support/core_ext/object/conversions'
 
diff --git a/actionpack/lib/action_view.rb b/actionpack/lib/action_view.rb
index 27a06db5bb49c8c6f9eee9e03ef8dd116163f63a..2a17faf99afa0fafff0b9178085c335d048bc254 100644
--- a/actionpack/lib/action_view.rb
+++ b/actionpack/lib/action_view.rb
@@ -36,6 +36,7 @@ def self.load_all!
   autoload :Base,              'action_view/base'
   autoload :Helpers,           'action_view/helpers'
   autoload :InlineTemplate,    'action_view/template/inline'
+  autoload :MissingTemplate,   'action_view/base'
   autoload :Partials,          'action_view/render/partials'
   autoload :Resolver,          'action_view/template/resolver'
   autoload :PathSet,           'action_view/paths'
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 5223cea135953276dfba8561c88852afbc500dc7..54a869396dd6ac7160dc2883c50368961fc83700 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -1,5 +1,7 @@
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/hash/keys'
+require 'active_support/concern'
+require 'active_support/callbacks'
 
 module ActiveModel
   module Validations