Rails if statement syntax
Try this :
<% if user_signed_in? %> <%= render 'form' %><% end %>If you do <%= ... %>, it will try to output the thing you put between the tags. But, if you do <% ... %>, then no output is processed, just the code is evaluated. If this is not working, then there is probably something wrong with your user_signed_in? helper method.
<%= will try to output your user_signed_in? helper, so try:
<% if user_signed_in? %> <%= render 'form' %><% end %>or even better (and less confusing):
<%= render 'form' if user_signed_in? %>