@kcsrk.info torn between being lazy and strict

Strava

Thanks for sharing. Congratulations on the paper. I’ll have a look.

You can:

# let f : 'a @ unique once -> 'a @ unique once = fun x -> x;;
val f : 'a @ once unique -> 'a @ once unique = <fun>

Nice, we can’t get two aliases for physical equality check; if we did the reference is not unique.

I know that Daan Leijen and others worked on uniqueness and reuse, and have published a few papers on this.

I think the compiler will not be able to infer the magic there because we're switching the phantom type argument. Compiler can't see that, I think.

Indeed. This would work

```
let write r v =
{ contents = v }
```

Then, perhaps explain that the magic is safe since the protocol is encoded in the phantom type argument.

I believe this is one of the design goals of the modes system. For Jane Street, it brings the ability to erase modes and release open source libs compatible with upstream OCaml. However, I don’t know the modes system enough to see whether this is possible in all the cases.