Simplify naming of reason ast files

We don't need to preserve the .ml/.mli extension anymore.

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>

src/module.ml

@@ -28,23 +28,6 @@ module File = struct
     { name : string
     ; syntax : Syntax.t
     }
-
-  let to_ocaml t =
-    match t.syntax with
-    | OCaml -> Exn.code_error "to_ocaml: can only convert reason Files"
-                 ["t.name", Sexp.To_sexp.string t.name]
-    | Reason ->
-      { syntax = OCaml
-      ; name =
-          let base, ext = Filename.split_extension t.name in
-          base ^ ".re" ^
-          (match Filename.extension t.name with
-           | ".re" -> ".ml"
-           | ".rei" -> ".mli"
-           | _ -> Exn.code_error "to_ocaml: unrecognized extension"
-                    [ "name", Sexp.To_sexp.string t.name
-                    ; "ext", Sexp.To_sexp.string ext ])
-      }
 end
 
 type t =

src/module.mli

@@ -28,8 +28,6 @@ module File : sig
     { name : string
     ; syntax: Syntax.t
     }
-
-  val to_ocaml : t -> t
 end
 
 (** Representation of a module. It is guaranteed that at least one of

src/preprocessing.ml

@@ -422,7 +422,12 @@ let setup_reason_rules sctx ~dir (m : Module.t) =
     match f.syntax with
     | OCaml  -> f
     | Reason ->
-      let ml = Module.File.to_ocaml f in
+      let ml =
+        { Module.File.
+          syntax = OCaml
+        ; name   = f.name ^ ".ast"
+        }
+      in
       SC.add_rule sctx (rule f.name ml.name);
       ml)