## single slash => silent comment
#foo
  :color black
  / comment

----------------------

#foo { color: black; }

## single slash for commenting out nested attributes => FAIL
#foo
  :font
    / :weight bold
    :size 11px

----------------------

ERROR: Illegal nesting: Only attributes may be nested beneath attributes.

## single slash with nested stuff is not even a comment
#foo
  / comment
    :font-size 11px

----------------------

#foo / comment { font-size: 11px; }