Thank you for your patience in explaining all this. Runtime tagging seems to make a lot of sense for this approach! Is this based on any previous work? It's been about ten years since I was last up to date with compile-time garbage collection techniques.

> What about compiling to low-level targets, like LLVM IR, which don't really have a 'runtime' and rather specify the manual layout of structs and references?

If you want to support dynamic memory allocation/deallocation, you will have to provide a runtime anyway. Even if it's "just" LLVM IR or C code or whatever for a simple allocator.

I think I'll have at least one more question about how the "tying of references to the stack" works, but I need to think things through a bit more.