precondition for owned access; access is owned if it evaluates to true

`type t````=`

`|` `Conjunction of InferStdlib.IntSet.t` | (** Conjunction of "formal index must be owned" predicates. true if empty *)
`|` `False`

``
`include InferStdlib.PrettyPrintable.PrintableOrderedType with type PrintableOrderedType.t := t`
`include InferStdlib.IStd.Caml.Set.OrderedType`
`type t`````
`val compare : t ‑> t ‑> int`
`val pp : InferStdlib.PrettyPrintable.F.formatter ‑> t ‑> unit`
`val is_true : t ‑> bool`

return `true` if the precondition evaluates to true