Ran into this error when testing out eco (Embedded Coffee Script) templates.
1 2 3 <% if 7 > 3 %> teststring <% end %>
1 2 3 <% if 7 > 3: %> teststring <% end %>
Notice the colon, this is telling coffeescript that the next line is indented. It’s document here: https://github.com/sstephenson/eco it had just slipped my mind.