Fix merlin-lib 4.18 compatibility for OCaml 4.14

- inlay_hints.ml: Disable hint_function_params (not available in merlin-lib 4.18)
- rename.ml: Use `Buffer scope instead of `Renaming (project-wide renaming not available in merlin-lib 4.18)

Author: davesnx

ocaml-lsp-server/src/inlay_hints.ml

@@ -29,11 +29,6 @@ let compute (state : State.t) { InlayHintParams.range; textDocument = { uri }; _
           c.hint_pattern_variables)
         |> Option.value ~default:false
       in
-      let hint_function_params =
-        Option.map state.configuration.data.inlay_hints ~f:(fun c ->
-          c.hint_function_params)
-        |> Option.value ~default:false
-      in
       Document.Merlin.with_pipeline_exn ~name:"inlay-hints" doc (fun pipeline ->
         let start = range.start |> Position.logical
         and stop = range.end_ |> Position.logical in
@@ -43,7 +38,6 @@ let compute (state : State.t) { InlayHintParams.range; textDocument = { uri }; _
             , stop
             , hint_let_bindings
             , hint_pattern_variables
-            , hint_function_params
             , not inside_test )
         in
         let hints = Query_commands.dispatch pipeline command in

ocaml-lsp-server/src/rename.ml

@@ -8,7 +8,7 @@ let rename (state : State.t) { RenameParams.textDocument = { uri }; position; ne
   | `Other -> Fiber.return (WorkspaceEdit.create ())
   | `Merlin merlin ->
     let command =
-      Query_protocol.Occurrences (`Ident_at (Position.logical position), `Renaming)
+      Query_protocol.Occurrences (`Ident_at (Position.logical position), `Buffer)
     in
     let+ locs, _status = Document.Merlin.dispatch_exn ~name:"rename" merlin command in
     let version = Document.version doc in
@@ -22,7 +22,11 @@ let rename (state : State.t) { RenameParams.textDocument = { uri }; position; ne
           | "" -> uri
           | path -> Uri.of_path path
         in
-        Uri.Map.add_to_list uri edit acc)
+        let add_to_list key value map =
+          let existing = Option.value ~default:[] (Uri.Map.find_opt key map) in
+          Uri.Map.add key (value :: existing) map
+        in
+        add_to_list uri edit acc)
     in
     let edits =
       Uri.Map.mapi
@@ -71,7 +75,7 @@ let rename (state : State.t) { RenameParams.textDocument = { uri }; position; ne
       if documentChanges
       then (
         let documentChanges =
-          Uri.Map.to_list edits
+          Uri.Map.bindings edits
           |> List.map ~f:(fun (uri, edits) ->
             let textDocument =
               OptionalVersionedTextDocumentIdentifier.create ~uri ~version ()
@@ -81,7 +85,7 @@ let rename (state : State.t) { RenameParams.textDocument = { uri }; position; ne
         in
         WorkspaceEdit.create ~documentChanges ())
       else (
-        let changes = Uri.Map.to_list edits in
+        let changes = Uri.Map.bindings edits in
         WorkspaceEdit.create ~changes ())
     in
     workspace_edits