type 'a t
include sig ... end
val sexp_of_t : ('a ‑> Base.Sexp.t) ‑> 'a t ‑> Base.Sexp.t
val value_exn : 'a t ‑> 'a
value_exn t returns the value in the heap controlled by this token if the value is still in the heap, and raises otherwise.
value_exn t