pandoc/test/command/indented-fences.md

`````
% pandoc -t native
  ```haskell
  let x = y
in y
   ```
^D
[ CodeBlock ( "" , [ "haskell" ] , [] ) "let x = y\nin y" ]
`````
`````
% pandoc -t native
 ~~~ {.haskell}
  let x = y
 in y +
y +
 y
~~~
^D
[ CodeBlock
    ( "" , [ "haskell" ] , [] ) " let x = y\nin y +\ny +\ny"
]
`````