module type S1_phantom = sig .. end
type ('a, +'phantom) t
val mem : ?equal:('a -> 'a -> bool) -> ('a, 'b) t -> 'a -> bool
val length : ('a, 'b) t -> int
val is_empty : ('a, 'b) t -> bool
val iter : ('a, 'b) t -> f:('a -> unit) -> unit
val fold : ('a, 'b) t ->
init:'accum -> f:('accum -> 'a -> 'accum) -> 'accum
val exists : ('a, 'b) t -> f:('a -> bool) -> bool
val for_all : ('a, 'b) t -> f:('a -> bool) -> bool
val count : ('a, 'b) t -> f:('a -> bool) -> int
val find : ('a, 'b) t -> f:('a -> bool) -> 'a option
val find_map : ('a, 'c) t -> f:('a -> 'b option) -> 'b option
val to_list : ('a, 'b) t -> 'a list
val to_array : ('a, 'b) t -> 'a array