handle top level

Author: zth

compiler/ext/warnings.ml

@@ -502,8 +502,6 @@ let message = function
     "Integer literal exceeds the range of representable integers of type int"
   | Bs_uninterpreted_delimiters s -> "Uninterpreted delimiters " ^ s
   | Bs_toplevel_expression_unit help ->
-    (* TODO(actions) Assign to `let _ =` *)
-    (* TODO(actions) Ignore *)
     Printf.sprintf
       "This%sis at the top level and is expected to return `unit`. But it's \
        returning %s.\n\n\

compiler/ml/cmt_utils.ml

@@ -18,6 +18,8 @@ type action_type =
   | RemoveRecFlag
   | RemoveRecordSpread
   | ForceOpen
+  | AssignToUnderscore
+  | PipeToIgnore
 
 (* TODO: 
 - Unused var in patterns (and aliases )*)
@@ -55,6 +57,8 @@ let action_to_string = function
   | RemoveRecFlag -> "RemoveRecFlag"
   | ForceOpen -> "ForceOpen"
   | RemoveRecordSpread -> "RemoveRecordSpread"
+  | AssignToUnderscore -> "AssignToUnderscore"
+  | PipeToIgnore -> "PipeToIgnore"
 
 let _add_possible_action : (cmt_action -> unit) ref = ref (fun _ -> ())
 let add_possible_action action = !_add_possible_action action
@@ -102,7 +106,10 @@ let emit_possible_actions_from_warning loc w =
   | Unused_argument -> (* Remove unused argument or prefix with underscore *) ()
   | Nonoptional_label _ -> (* Add `?` to make argument optional *) ()
   | Bs_toplevel_expression_unit _ ->
-    (* Assign to let _ = or pipe to ignore() *) ()
+    add_possible_action
+      {loc; action = PipeToIgnore; description = "Pipe to ignore()"};
+    add_possible_action
+      {loc; action = AssignToUnderscore; description = "Assign to let _ ="}
   | _ -> ()
 
 let _ =

tests/build_tests/actions/expected/Actions_AssignToUnderscore_applied.res

@@ -0,0 +1,8 @@
+let _ = // actionFilter=AssignToUnderscore
+switch 1 {
+| _ => "one"
+}
+
+/* === AVAILABLE ACTIONS:
+- AssignToUnderscore - Assign to let _ =
+*/

tests/build_tests/actions/expected/Actions_PipeToIgnore_applied.res

@@ -0,0 +1,8 @@
+// actionFilter=PipeToIgnore
+switch 1 {
+| _ => "one"
+}->ignore
+
+/* === AVAILABLE ACTIONS:
+- PipeToIgnore - Pipe to ignore()
+*/

tests/build_tests/actions/fixtures/Actions_AssignToUnderscore.res

@@ -0,0 +1,4 @@
+// actionFilter=AssignToUnderscore
+switch 1 {
+| _ => "one"
+}

tests/build_tests/actions/fixtures/Actions_PipeToIgnore.res

@@ -0,0 +1,4 @@
+// actionFilter=PipeToIgnore
+switch 1 {
+| _ => "one"
+}

tools/src/tools.ml

@@ -1316,7 +1316,32 @@ module Actions = struct
                   | _ -> None)
                 actions
             in
+            let assign_to_underscore_action_locs =
+              List.filter_map
+                (fun (action : Cmt_utils.cmt_action) ->
+                  match action.action with
+                  | AssignToUnderscore -> Some action.loc
+                  | _ -> None)
+                actions
+            in
             match str_item.pstr_desc with
+            | Pstr_eval (({pexp_loc} as e), attrs)
+              when List.mem pexp_loc assign_to_underscore_action_locs ->
+              let str_item =
+                Ast_mapper.default_mapper.structure_item mapper str_item
+              in
+              let loc = str_item.pstr_loc in
+              {
+                str_item with
+                pstr_desc =
+                  Pstr_value
+                    ( Nonrecursive,
+                      [
+                        Ast_helper.Vb.mk ~loc ~attrs
+                          (Ast_helper.Pat.var ~loc (Location.mkloc "_" loc))
+                          e;
+                      ] );
+              }
             | Pstr_open ({popen_override = Fresh} as open_desc)
               when List.mem str_item.pstr_loc force_open_action_locs ->
               let str_item =
@@ -1457,6 +1482,28 @@ module Actions = struct
                      if action.loc = expr.pexp_loc then
                        let expr = Ast_mapper.default_mapper.expr mapper expr in
                        match action.action with
+                       | PipeToIgnore ->
+                         Some
+                           {
+                             expr with
+                             pexp_desc =
+                               Pexp_apply
+                                 {
+                                   funct =
+                                     Ast_helper.Exp.ident
+                                       (Location.mknoloc (Longident.Lident "->"));
+                                   partial = false;
+                                   transformed_jsx = false;
+                                   args =
+                                     [
+                                       (Nolabel, expr);
+                                       ( Nolabel,
+                                         Ast_helper.Exp.ident
+                                           (Location.mknoloc
+                                              (Longident.Lident "ignore")) );
+                                     ];
+                                 };
+                           }
                        | RemoveRecordSpread -> (
                          match expr with
                          | {pexp_desc = Pexp_record (fields, Some _)} ->
@@ -1688,7 +1735,9 @@ module Actions = struct
                  | RemoveUnusedModule -> List.mem "RemoveUnusedModule" filter
                  | RemoveRecFlag -> List.mem "RemoveRecFlag" filter
                  | ForceOpen -> List.mem "ForceOpen" filter
-                 | RemoveRecordSpread -> List.mem "RemoveRecordSpread" filter)
+                 | RemoveRecordSpread -> List.mem "RemoveRecordSpread" filter
+                 | AssignToUnderscore -> List.mem "AssignToUnderscore" filter
+                 | PipeToIgnore -> List.mem "PipeToIgnore" filter)
       in
       match applyActionsToFile path possible_actions with
       | Ok applied ->