---
- name: Invalid tabs as indendation in a mapping
  from: https://github.com/nodeca/js-yaml/issues/80
  tags: error mapping whitespace
  fail: true
  yaml: |
    ---
    a:
    ———»b:
    ———»———»c: value
  tree: |
    +STR
     +DOC ---
      +MAP
       =VAL :a