input is self closing and should not have content

Looks like you've got content inside your input tags. In HTML, input tags can't have content,
therefore you should delete any whitespace or characters following input tags in your jade file.
Ex:
input(type="text",name="whatever") something
should be
input(type="text",name="whatever",value="something")

Sometimes the answer is a little tricker than just some content after the tag on the same line (such as a few spaces). Watch out for the line following the input tag being indented by mistake!

After running into the same error I was checking the line of jade template marked in error report. It was actually containing input definition, but that definition was fine for there wasn't any whitespace and printable content succeeding it. The following line was even less indented (two levels up for starting another row of form) and thus there was definitely no content to input element defined in marked line.

However there was another input succeeding this marked one a few lines down the template. And that input element indeed was having some subordinated content. Removing content there was fixing somewhat false positive "here".