module Reason:Datatype.S_with_collections
with type t = PdgTypes.Node.t * PdgTypes.Node.t * reason_type
Reasons for impact are expressed as sets (n', n, reason)
include Datatype.S
module Set:Datatype.Set
with type elt = t
module Map:Datatype.Map
with type key = t
module Hashtbl:Datatype.Hashtbl
with type key = t