remove the check for needs_type_condition? because ensure_proper_type will pick up the type column

activerecord/lib/active_record/base.rb

@@ -1916,8 +1916,9 @@ MSG
       # do Reply.new without having to set <tt>Reply[Reply.inheritance_column] = "Reply"</tt> yourself.
       # No such attribute would be set for objects of the Message class in that example.
       def ensure_proper_type
-        unless self.class.descends_from_active_record?
-          write_attribute(self.class.inheritance_column, self.class.sti_name)
+        klass = self.class
+        if klass.finder_needs_type_condition?
+          write_attribute(klass.inheritance_column, klass.sti_name)
         end
       end
 

activerecord/lib/active_record/named_scope.rb

@@ -48,7 +48,7 @@ module ActiveRecord
           current_scope.scope_for_create
         else
           # Return an empty hash in the simple case
-          return {} unless finder_needs_type_condition? || default_scopes.any?
+          return {} unless default_scopes.any?
 
           scope = relation.clone
           scope.default_scoped = true