Unhelpful error message when schema JSON is invalid

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$ref": "#/definitions/foo",
  "definitions": {
    "foo": {
      "type": "object",
      "properties": {
        "bar": {
          "$ref": "bar.json#"
        },
      },
      "required": [
        "bar"
      ],
    },
    "title": "foo"
  }
}

Running quicktype CLI with this Schema produces

Error: Internal error: Defined value expected, but got undefined.