6 files changed, 8 insertions, 6 deletions
diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index db5759ada9..6d11c0fbdc 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -436,7 +436,7 @@ module ActiveModel
     # attribute_missing is like method_missing, but for attributes. When method_missing is
     # called we check to see if there is a matching attribute method. If so, we call
     # attribute_missing to dispatch the attribute. This method can be overloaded to
-    # customise the behaviour.
+    # customize the behavior.
     def attribute_missing(match, *args, &block)
       __send__(match.target, match.attr_name, *args, &block)
     end
diff --git a/activemodel/lib/active_model/callbacks.rb b/activemodel/lib/active_model/callbacks.rb
index c52e4947ae..b5562dda2e 100644
--- a/activemodel/lib/active_model/callbacks.rb
+++ b/activemodel/lib/active_model/callbacks.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/array/extract_options'
+
 module ActiveModel
   # == Active \Model \Callbacks
   #
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
index ecb7a9e9b1..6e67cd2285 100644
--- a/activemodel/lib/active_model/dirty.rb
+++ b/activemodel/lib/active_model/dirty.rb
@@ -119,7 +119,7 @@ module ActiveModel
     #   person.name = 'bob'
     #   person.changes # => { "name" => ["bill", "bob"] }
     def changes
-      HashWithIndifferentAccess[changed.map { |attr| [attr, attribute_change(attr)] }]
+      ActiveSupport::HashWithIndifferentAccess[changed.map { |attr| [attr, attribute_change(attr)] }]
     end
 
     # Returns a hash of attributes that were changed before the model was saved.
diff --git a/activemodel/lib/active_model/validations/clusivity.rb b/activemodel/lib/active_model/validations/clusivity.rb
index 3d7067fbcb..49df98d6c1 100644
--- a/activemodel/lib/active_model/validations/clusivity.rb
+++ b/activemodel/lib/active_model/validations/clusivity.rb
@@ -3,7 +3,7 @@ require 'active_support/core_ext/range'
 module ActiveModel
   module Validations
     module Clusivity #:nodoc:
-      ERROR_MESSAGE = "An object with the method #include? or a proc, lambda or symbol is required, " <<
+      ERROR_MESSAGE = "An object with the method #include? or a proc, lambda or symbol is required, " \
                       "and must be supplied as the :in (or :within) option of the configuration hash"
 
       def check_validity!
diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
index 744c196d30..085532c35b 100644
--- a/activemodel/lib/active_model/validations/numericality.rb
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -17,9 +17,9 @@ module ActiveModel
       end
 
       def validate_each(record, attr_name, value)
-        before_type_cast = "#{attr_name}_before_type_cast"
+        before_type_cast = :"#{attr_name}_before_type_cast"
 
-        raw_value = record.send(before_type_cast) if record.respond_to?(before_type_cast.to_sym)
+        raw_value = record.send(before_type_cast) if record.respond_to?(before_type_cast)
         raw_value ||= value
 
         return if options[:allow_nil] && raw_value.nil?
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index d51f4d1936..f989b21140 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -103,7 +103,7 @@ module ActiveModel
     end
 
     # Accepts options that will be made available through the +options+ reader.
-    def initialize(options)
+    def initialize(options = {})
       @options = options.freeze
     end