Comment by throwaway17_17
1 year ago
In this case (i.e. Rust specifically) what do unboxed generics mean. Without actually knowing Rust I don’t think I can analogize to either type theory or another language. I assume if I can figure out what they are I infer why they are difficult to compile.
It means ABI-stable interfaces (i.e. interfaces between separately-compiled "crates"/libraries, including dylibs and shared objects) can involve arbitrarily complex types with possibly nested generics, and these are implemented behind a single pointer dereference at most. This requires something a lot like dyn trait object vtables in Rust ("witness tables") except quite a bit more complex.