link_attributes vs. reference-links vs. markdown writer

[sebogh]

$ pandoc -v
pandoc 1.19.2.1
Compiled with pandoc-types 1.17.0.4, texmath 0.9, skylighting 0.1.1.4
...

When converting from markdown to markdown a space seems to be missing before the attributes in the reference:

$ pandoc -f markdown -t markdown --reference-links
![foo](bar.png){#id:1}
^D
![foo]

    [foo]: bar.png{#id:1}

If this is (again) sent through Pandoc, the former attributes become part of the image name as in:

 $ pandoc -f markdown -t markdown --reference-links | pandoc -f markdown -t html
 ![foo](bar.png){#id:1}
 ^D
 <div class="figure">
 <embed src="bar.png%7B#id:1%7D" />
 <p class="caption">foo</p>
 </div>