ambiguous error when `fetchInfo = "path:."`

[DavHau]

After executing floco translat -ptj, the pdef.json file contained the following entry for the top-level package:

[...]
  "fetchInfo": "path:.",
[...]

On a nix build this leads to the following error:

error: string '<unknown-file>/.' doesn't represent an absolute path

This error isn't very helpful as it doesn't describe the problem or how to fix it.

I'd expect something along these lines:

Cannot find the source for package XXX, please define via override:
    [example for a source override]