Simplify types in 0install one bit further

Signed-off-by: Ambre Austen Suhamy <ambre@tarides.com>

src/0install-solver/src/solver/s.ml

@@ -58,9 +58,6 @@ module type CORE_MODEL = sig
       dep_importance : [ `Essential | `Recommended | `Restricts ]
     }
 
-  (* The top-level requirements from the user. *)
-  type requirements = { role : Role.t }
-
   (** Get an implementation's dependencies.
 
       The dependencies should be ordered with the most important first.
@@ -145,7 +142,7 @@ module type SELECTIONS = sig
 
   val to_map : t -> impl RoleMap.t
   val get_selected : Role.t -> t -> impl option
-  val requirements : t -> requirements
+  val requirements : t -> Role.t
 end
 
 module type SOLVER_RESULT = sig
@@ -160,7 +157,6 @@ module type SOLVER_RESULT = sig
     with module Role = Input.Role
      and type dependency = Input.dependency
      and type dep_info = Input.dep_info
-     and type requirements = Input.requirements
 
   val unwrap : impl -> Input.impl
 

src/0install-solver/src/solver/solver_core.ml

@@ -345,8 +345,7 @@ struct
     in
     let+ () =
       (* This recursively builds the whole problem up. *)
-      (let { Model.role } = root_req in
-       let+ impl = lookup_impl role in
+      (let+ impl = lookup_impl root_req in
        impl#get_vars)
       >>| S.at_least_one sat ~reason:"need root" (* Must get what we came for! *)
     in
@@ -370,7 +369,7 @@ struct
       ; dep_importance : [ `Essential | `Recommended | `Restricts ]
       }
 
-    type requirements = Model.requirements = { role : Role.t }
+    type requirements = Role.t
 
     let dep_info = Model.dep_info
     let requires role impl = Model.requires role impl.impl
@@ -412,7 +411,7 @@ struct
     let sat = S.create () in
     let dummy_impl = if closest_match then Some Model.dummy_impl else None in
     let+ impl_clauses = build_problem root_req sat ~dummy_impl in
-    let lookup { Model.role } = (ImplCache.get_exn role impl_clauses :> candidates) in
+    let lookup role = (ImplCache.get_exn role impl_clauses :> candidates) in
     (* Run the solve *)
     let decider () =
       (* Walk the current solution, depth-first, looking for the first undecided interface.
@@ -438,7 +437,7 @@ struct
                    we'll handle it when we get to them.
                    If noone wants it, it will be set to unselected at the end. *)
                 None
-              else find_undecided { Model.role = dep_role }
+              else find_undecided dep_role
             in
             List.find_map check_dep deps)
       in

src/0install-solver/src/solver/zeroinstall_solver.mli

@@ -18,7 +18,7 @@ module Make
         every interface, so we can always select something. Useful for diagnostics.
         Note: always try without [closest_match] first, or it may miss a valid solution.
       @return None if the solve fails (only happens if [closest_match] is false). *)
-  val do_solve : closest_match:bool -> Input.requirements -> Output.t option Monad.t
+  val do_solve : closest_match:bool -> Input.Role.t -> Output.t option Monad.t
 end
 
 (** Explaining why a solve failed or gave an unexpected answer. *)

src/opam-0install/lib/model.ml

@@ -102,8 +102,6 @@ struct
     ; dep_importance : [ `Essential | `Recommended | `Restricts ]
     }
 
-  type requirements = { role : Role.t }
-
   let dummy_impl = Dummy
 
   (* Turn an opam dependency formula into a 0install list of dependencies. *)

src/opam-0install/lib/solver.ml

@@ -18,15 +18,15 @@ struct
         let impl = Input.virtual_impl ~context ~depends:pkgs () in
         Input.virtual_role [ impl ]
     in
-    { Input.role }
+    role
   ;;
 
   module Solver = Zeroinstall_solver.Make (Monad) (Input)
   module Diagnostics = Zeroinstall_solver.Diagnostics (Monad) (Solver.Output)
 
   type t = Context.t
   type selections = Solver.Output.t
-  type diagnostics = Input.requirements (* So we can run another solve *)
+  type diagnostics = Input.Role.t (* So we can run another solve *)
 
   let solve context pkgs =
     let req = requirements ~context pkgs in