This *is* currently possible, it's even built into the damn thing, they just refuse to enable it in the public API because of philosophical reasons. They call them transformers and projects exist and have existed (e.g. https://github.com/nonara/ts-patch https://github.com/cevek/ttypescript) for a long time, but they are not well known because the TS team doesn't want them around.

I wrote a compile time IoC container that worked totally fine using `ttsc` four or five years ago. It's possible, has always been possible, and the only reason it's not more widely used is the API is intentionally unfriendly and will likely never be allowed to be public.