remove unused rec flag

Author: zth

compiler/ext/warnings.ml

@@ -397,9 +397,7 @@ let message = function
       tc1 tc2
   | Unused_value_declaration v -> "unused value " ^ v ^ "."
   | Unused_open s -> "unused open " ^ s ^ "."
-  | Unused_type_declaration s ->
-    (* TODO(actions) Remove type declaration *)
-    "unused type " ^ s ^ "."
+  | Unused_type_declaration s -> "unused type " ^ s ^ "."
   | Unused_for_index s -> "unused for-loop index " ^ s ^ "."
   | Unused_constructor (s, false, false) ->
     (* TODO(actions) Remove constructor *)
@@ -424,9 +422,7 @@ let message = function
       name
       ^ " is never used to build values.\n\
          It is exported or rebound as a private extension.")
-  | Unused_rec_flag ->
-    (* TODO(actions) Remove rec flag *)
-    "unused rec flag."
+  | Unused_rec_flag -> "unused rec flag."
   | Ambiguous_name ([s], tl, false) ->
     s ^ " belongs to several types: " ^ String.concat " " tl
     ^ "\nThe first one was selected. Please disambiguate if this is wrong."

compiler/ml/cmt_utils.ml

@@ -15,6 +15,7 @@ type action_type =
   | RemoveUnusedVariable
   | RemoveUnusedType
   | RemoveUnusedModule
+  | RemoveRecFlag
 
 (* TODO: 
 - Unused var in patterns (and aliases )*)
@@ -49,6 +50,7 @@ let action_to_string = function
   | RewriteIdent {new_ident} ->
     Printf.sprintf "RewriteIdent(%s)"
       (Longident.flatten new_ident |> String.concat ".")
+  | RemoveRecFlag -> "RemoveRecFlag"
 
 let _add_possible_action : (cmt_action -> unit) ref = ref (fun _ -> ())
 let add_possible_action action = !_add_possible_action action
@@ -82,7 +84,9 @@ let emit_possible_actions_from_warning loc w =
   | Unused_pat -> (* TODO: Remove full pattern. *) ()
   | Unused_argument ->
     (* TODO(actions) Remove unused argument or prefix with underscore *) ()
-  | Unused_rec_flag -> (* TODO(actions) Remove unused rec flag *) ()
+  | Unused_rec_flag ->
+    add_possible_action
+      {loc; action = RemoveRecFlag; description = "Remove rec flag"}
   | _ -> ()
 
 let _ =

tests/build_tests/actions/expected/Actions_RemoveRecFlag_applied.res

@@ -0,0 +1,10 @@
+// actionFilter=RemoveRecFlag
+let f = 12
+let fn = () => {
+  let x = 12
+}
+
+/* === AVAILABLE ACTIONS:
+- RemoveRecFlag - Remove rec flag
+- RemoveRecFlag - Remove rec flag
+*/

tests/build_tests/actions/fixtures/Actions_RemoveRecFlag.res

@@ -0,0 +1,5 @@
+// actionFilter=RemoveRecFlag
+let rec f = 12
+let fn = () => {
+    let rec x = 12
+}

tools/src/tools.ml

@@ -1298,6 +1298,24 @@ module Actions = struct
     let mapper =
       {
         Ast_mapper.default_mapper with
+        structure_item =
+          (fun mapper str_item ->
+            let remove_rec_flag_action_locs =
+              List.filter_map
+                (fun (action : Cmt_utils.cmt_action) ->
+                  match action.action with
+                  | RemoveRecFlag -> Some action.loc
+                  | _ -> None)
+                actions
+            in
+            match str_item.pstr_desc with
+            | Pstr_value (Recursive, ({pvb_pat = {ppat_loc}} :: _ as bindings))
+              when List.mem ppat_loc remove_rec_flag_action_locs ->
+              let str_item =
+                Ast_mapper.default_mapper.structure_item mapper str_item
+              in
+              {str_item with pstr_desc = Pstr_value (Nonrecursive, bindings)}
+            | _ -> Ast_mapper.default_mapper.structure_item mapper str_item);
         structure =
           (fun mapper items ->
             let items =
@@ -1518,6 +1536,17 @@ module Actions = struct
                      else
                        (* Other cases when the loc is on something else in the expr *)
                        match (expr.pexp_desc, action.action) with
+                       | ( Pexp_let
+                             ( Recursive,
+                               ({pvb_pat = {ppat_loc}} :: _ as bindings),
+                               cont ),
+                           RemoveRecFlag )
+                         when action.loc = ppat_loc ->
+                         Some
+                           {
+                             expr with
+                             pexp_desc = Pexp_let (Nonrecursive, bindings, cont);
+                           }
                        | ( Pexp_field
                              ( {pexp_desc = Pexp_ident e},
                                {txt = Lident inner; loc} ),
@@ -1633,7 +1662,8 @@ module Actions = struct
                  | RemoveUnusedVariable ->
                    List.mem "RemoveUnusedVariable" filter
                  | RemoveUnusedType -> List.mem "RemoveUnusedType" filter
-                 | RemoveUnusedModule -> List.mem "RemoveUnusedModule" filter)
+                 | RemoveUnusedModule -> List.mem "RemoveUnusedModule" filter
+                 | RemoveRecFlag -> List.mem "RemoveRecFlag" filter)
       in
       match applyActionsToFile path possible_actions with
       | Ok applied ->