Module Substitution.Head

type t =
  1. | None of {
    1. location : Syncom.Location.t;
    }
  2. | Identity of {
    1. location : Syncom.Location.t;
    }
  3. | Substitution_variable of {
    1. location : Syncom.Location.t;
    2. identifier : Syncom.Identifier.t;
    3. closure : t Support.Option.t;
    }