AR simple cleanup patch

Hi

Looking for some people to check/comment on a simple cleanup patch I have for AR:
http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1728-accessor-methods-for-association-instances

Basically code like the following:
ivar = "@#{reflection.name}"

# for reading
association = instance_variable_get(ivar) if instance_variable_defined?(ivar)
if association.respond_to?(:loaded?)
   # ...
end

# and for writing
instance_variable_set(ivar, association)
Is replaced with code like:

# for reading

if association = association_instance_get(reflection.name)
   # ...
end

# and for writing
association_instance_set(reflection.name, association)
- Eloy