lib/cancan/ability.rb
def aliases_for_action(action)
      results = [action]
      aliased_actions.each do |aliased_action, actions|
        results += aliases_for_action(aliased_action) if actions.include? action
      end
      results
    end
def aliases_for_action(action)
      results = [action]
      aliased_actions.each do |aliased_action, actions|
        results += aliases_for_action(aliased_action) if actions.include? action
      end
      results
    end
Given an action, it will try to find all of the actions which are aliased to it.
 This does the opposite kind of lookup as expand_actions.