nimble file should not use #head

[c-blake]

Maybe it will even go away in the not too distant future (as measured in units of 2020-2016 =~ 4 years...). ;-)

Anyway, docopt has had quite a few releases since you probably worked on this. One of them almost surely "just works".

[c-blake]

In case you didn't read the linked-to comment, the basic issue is that once installed the @#head version is never updated again. So, on some end nimble-user's pkgs/ directory it is easy (likely even) to have very stale versions, conceivably even versions that pre-date your package entirely meaning you have no idea if it will even compile. If you want just the most recent version of docopt then you can just remove all version stuff after the dependency.