module Elt:sig..end
type 'a t
val value_exn : 'a t -> 'avalue_exn t return the value in the heap controlled by this token if the value
is still in the heap. Raise otherwise.val sexp_of_t : ('a -> Sexplib.Sexp.t) -> 'a t -> Sexplib.Sexp.tvalue_exn t return the value in the heap controlled by this token if the value
is still in the heap. Raise otherwise.