ActiveAdmin -- How to access instance variables from partials?

I can't seem to access instance objects in partials. Example:

In controller I have:

ActiveAdmin.register Store do
  sidebar "Aliases", :only => :edit do
    @aliases = Alias.where("store_id = ?", params[:id])
    render :partial => "store_aliases"
  end
end

Then in the _store_aliases.html.erb partial I have:

<% @aliases.each do |alias| %>
  <li><%= alias.name %></li>
<% end %>

This doesn't work. The only thing that does work (which is horrible to do as I'm putting logic in a view is this:

  <% @aliases = Alias.where("store_id = ?", params[:id]) %> 
  <% @aliases.each do |alias| %>
     <li><%= alias.name %></li>
  <% end %>