Guix,

I just encountered the following:

  foo.scm:4:2: error: url-fetch: unbound variable
  hint: Did you forget `(use-modules (guix build download))'?

Actually importing that module, instead of (guix download), will 
cause some other very hard-to-debug error that I can't remember 
but coincidentally helped someone fix on #guix the other day.

Now I understand how they got to that bad place.

Kind regards,

T G-R