2 files changed, 10 insertions, 4 deletions
diff --git a/activerecord/lib/active_record/type/serialized.rb b/activerecord/lib/active_record/type/serialized.rb
index 732029c723..ea3e0d6a45 100644
--- a/activerecord/lib/active_record/type/serialized.rb
+++ b/activerecord/lib/active_record/type/serialized.rb
@@ -26,9 +26,15 @@ module ActiveRecord
         end
       end
 
+      def inspect
+        Kernel.instance_method(:inspect).bind(self).call
+      end
+
       def changed_in_place?(raw_old_value, value)
         return false if value.nil?
-        subtype.changed_in_place?(raw_old_value, serialize(value))
+        raw_new_value = serialize(value)
+        raw_old_value.nil? != raw_new_value.nil? ||
+          subtype.changed_in_place?(raw_old_value, raw_new_value)
       end
 
       def accessor
diff --git a/activerecord/lib/active_record/type/value.rb b/activerecord/lib/active_record/type/value.rb
index fc3ef5e83b..6b9d147ecc 100644
--- a/activerecord/lib/active_record/type/value.rb
+++ b/activerecord/lib/active_record/type/value.rb
@@ -12,7 +12,7 @@ module ActiveRecord
       def type # :nodoc:
       end
 
-      # Convert a value from database input to the appropriate ruby type. The
+      # Converts a value from database input to the appropriate ruby type. The
       # return value of this method will be returned from
       # ActiveRecord::AttributeMethods::Read#read_attribute. The default
       # implementation just calls Value#cast.
@@ -36,7 +36,7 @@ module ActiveRecord
         cast_value(value) unless value.nil?
       end
 
-      # Cast a value from the ruby type to a type that the database knows how
+      # Casts a value from the ruby type to a type that the database knows how
       # to understand. The returned value from this method should be a
       # +String+, +Numeric+, +Date+, +Time+, +Symbol+, +true+, +false+, or
       # +nil+.
@@ -44,7 +44,7 @@ module ActiveRecord
         value
       end
 
-      # Type cast a value for schema dumping. This method is private, as we are
+      # Type casts a value for schema dumping. This method is private, as we are
       # hoping to remove it entirely.
       def type_cast_for_schema(value) # :nodoc:
         value.inspect