Not in the type system itself, but you could write a lint to forbid heap allocation. This way, you could annotate a function (with e.g. `#[forbid(allocations)]`

Not in the type system itself, but you could write a lint to forbid heap allocation. This way, you could annotate a function (with e.g. `#[forbid(allocations)]`) to get a compile error when your function (or code your function calls) tries to allocate. This might not be easy, though :)