Inherited Resources

As of 1.4, the load_and_authorize_resource call will automatically detect if you are using Inherited Resources and load the resource through that. The load part in CanCan is still necessary since Inherited Resources does lazy loading. This will also ensure the behavior is identical to normal loading.

class ProjectsController < InheritedResources::Base
  load_and_authorize_resource
end

if you are doing nesting you will need to mention it in both Inherited Resources and CanCan.

class TasksController < InheritedResources::Base
  belongs_to :project
  load_and_authorize_resource :project
  load_and_authorize_resource :task, :through => :project
end

Please note that even for a has_many :tasks association, the load_and_authorize_resource needs the singular name of the associated model...

Warning: when overwriting the collection method in a controller the load part of a load_and_authorize_resource call will not work correctly. See https://github.com/ryanb/cancan/issues/274 for the discussions.

In this case you can override collection like

skip_load_and_authorize_resource :only => :index

def collection
  @products ||= end_of_association_chain.accessible_by(current_ability).paginate(:page => params[:page], :per_page => 10)
end

Mongoid

With mongoid it is necessary to reference :project_id instead of just :project

class TasksController < InheritedResources::Base
  ...
  load_and_authorize_resource :task, :through => :project_id
end