`panic: field lacking {function | object | value}` doesn't contain the field that causes the error

[Makeshift]

I'm currently trying to understand how to implement docsonnet into a library I'm building, but am having a lot of trouble troubleshooting it as pretty much every failure results in a very opaque error:

 ± docsonnet lib/main.libsonnet
Extracting from Jsonnet
Transforming to docsonnet model
panic: field  lacking {function | object | value}

goroutine 1 [running]:
github.com/jsonnet-libs/docsonnet/pkg/docsonnet.loadField({0xa8bf58, 0x0}, 0xc000502e70, 0xc000502e40)
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/pkg/docsonnet/fast.go:93 +0x17d
github.com/jsonnet-libs/docsonnet/pkg/docsonnet.loadNested({0xc0004e6df0, 0xa}, 0xc000502e40)
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/pkg/docsonnet/fast.go:67 +0x1c6
github.com/jsonnet-libs/docsonnet/pkg/docsonnet.loadNested({0xc0004e6e80, 0x9}, 0xc000502e10)
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/pkg/docsonnet/fast.go:72 +0x267
github.com/jsonnet-libs/docsonnet/pkg/docsonnet.fastLoad(0xc000502db0)
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/pkg/docsonnet/fast.go:42 +0x3e7
github.com/jsonnet-libs/docsonnet/pkg/docsonnet.Transform({0xc000510a00, 0x4e7, 0x500})
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/pkg/docsonnet/load.go:70 +0xbe
main.main.func1(0xc0000f0600?, {0xc000030f10?, 0x1?, 0x1?})
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/main.go:43 +0x247
github.com/go-clix/cli.(*Command).execute(0xc0000cae60, {0xc000016050, 0x1, 0x1})
        /home/connor/go/pkg/mod/github.com/go-clix/cli@v0.1.2-0.20200502172020-b8f4629e879a/command.go:120 +0x451
github.com/go-clix/cli.(*Command).Execute(0xc0000cae60)
        /home/connor/go/pkg/mod/github.com/go-clix/cli@v0.1.2-0.20200502172020-b8f4629e879a/command.go:76 +0xbb
main.main()
        /home/connor/go/pkg/mod/github.com/jsonnet-libs/docsonnet@v0.0.7-0.20231214125531-6ac6c69685b8/main.go:68 +0x385

This error doesn't tell me what actually caused the error. It's obviously receiving an empty field somewhere, but as someone new to doscsonnet, I haven't got a clue how or why. docsonnet --raw outputs something that looks pretty sane to me, but I'm not familiar enough with the tool yet to know valid from invalid.

In this case I have two files:

main.libsonnet:

local d = import 'github.com/jsonnet-libs/docsonnet/doc-util/main.libsonnet';

{
  '#':: d.pkg(
    name='mypkg',
    url='',
    help='Opinionated templates'
  ),
  templates: {
    webservice: import 'templates/webservicetest.libsonnet'
  }
}

templates/webservicetest.libsonnet:

local d = import 'github.com/jsonnet-libs/docsonnet/doc-util/main.libsonnet';

{
  '#':: d.pkg(
    name='webservice',
    url='',
    help='foo'
  ),
  '#new':: d.fn(help=|||
    `new` returns a new instance of the webservice template
  |||, args=[
    d.arg('name', 'string', 'The name of the webservice'),
    d.arg('image', 'string', 'The Docker image to run in the webservice'),
  ]),
  new(name, image): {
    name: name,
    image: image
  }
}

With docsonnet --raw main.libsonnet I get:

{
   "#": {
      "help": "Opinionated templates",
      "import": "",
      "name": "mypkg"
   },
   "templates": {
      "webservice": {
         "#": {
            "help": "foo",
            "import": "",
            "name": "webservice"
         },
         "#new": {
            "function": {
               "args": [
                  {
                     "default": "The name of the webservice",
                     "name": "name",
                     "type": "string"
                  },
                  {
                     "default": "The Docker image to run in the webservice",
                     "name": "image",
                     "type": "string"
                  }
               ],
               "help": "`new` returns a new instance of the webservice template\n"
            }
         }
      }
   }
}

I'm assuming that to someone that knows what they're doing it must be pretty obvious what's wrong there, but a bit more detail in the error messages would be greatly appreciated.