Feedback: polymorphic_path and single resources

With single resources:

map.resource :profile

polymorphic_path(@profile) generates profile_path but fails because of the
remaining @profile object, I guess:

NoMethodError: You have a nil object when you didn't expect it!
The error occurred while evaluating nil.to_sym
from /usr/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/routing/route.rb:145:in
`extra_keys'
from /usr/lib/ruby/gems/1.8/gems/actionpack-2.1.0/lib/action_controller/routing/route.rb:145:in
`map'
[...]

Would be interesting to have this working?