A 64-bit sum type can't magically combine an i64, f64, and several raw pointers, each of which carry a full 64 bits themselves. You have to change the semantics of the code. Some semantics could be expressed more easily with compiler improvements, allowing eg `Aligned<T>` like `NonNull<T>`, or `FiniteF64` like `NonZeroU64`, or even `#[range(0..1<<60)] u64`, but you still couldn't overlap two `Aligned`s in one enum, because only one can be stored unchanged, the others need masking off before usage. Even if the enum semantics allowed this, I'm not sure the compiler should do this kind of compute/memory tradeoff automagically. Which doesn't mean you can't write nice abstractions over it, there's a few tagged ptr crates which aim to do it for you