Issue I am having with 'additionalProperties' and TypeSpec

Hi there,

So I recently found out about https://typespec.io/ and was interested in giving it ago, and so far has been pretty interesting as well as a nice difference to writing it in yaml.

However I just found my first problem since using it, and that is that they don't allow you a way to generate additionalProperties with a yes meaning I am currently unable to use my APIError object as I previously was, and that is due to the EmptyObject that is applied, which essentially forces me to do as any every time I wish to output any metadata.

export type t_APIError = {
  error: string
  message?: string
  metadata?: {
    [key: string]: EmptyObject
  }
  suggested?: string
}

Is there a way to nicely work around this or will I need to wait for some update/change for it? For now I will just override the type checking with as any until a better solution is found.

No repository file or test is named. Start by tracing how the t_APIError example and its metadata additionalProperties are represented in generated TypeScript, especially where EmptyObject is introduced; done means generated metadata accepts arbitrary values without requiring as any, with a regression test if the project has a relevant test entry point.