2 files changed, 2 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index dd44bd8d51..cf4594ad7f 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -8,7 +8,7 @@ module ActiveRecord
       include AttributeMethods::Write
 
       included do
-        if self < Timestamp
+        if self < ::ActiveRecord::Timestamp
           raise "You cannot include Dirty after Timestamp"
         end
 
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 411330dda2..82d94b848a 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -6,7 +6,7 @@ module ActiveRecord
       # Returns this record's primary key value wrapped in an Array
       # or nil if the record is a new_record?
       def to_key
-        new_record? ? nil : [ send(self.class.primary_key) ]
+        new_record? ? nil : [ id ]
       end
 
       module ClassMethods