Fix inlay hint file source

analysis/bin/main.ml

@@ -161,10 +161,14 @@ let main () =
         (match allowForConstructorPayloads with
         | "true" -> true
         | _ -> false)
+  | [_; "inlayHint"; path; line_start; line_end; maxLength; currentFile] ->
+    Commands.inlayhint ~path
+      ~pos:(int_of_string line_start, int_of_string line_end)
+      ~maxLength ~currentFile:(Some currentFile) ~debug
   | [_; "inlayHint"; path; line_start; line_end; maxLength] ->
     Commands.inlayhint ~path
       ~pos:(int_of_string line_start, int_of_string line_end)
-      ~maxLength ~debug
+      ~maxLength ~currentFile:None ~debug
   | [_; "codeLens"; path] -> Commands.codeLens ~path ~debug
   | [_; "codeAction"; path; startLine; startCol; endLine; endCol; currentFile]
     ->

analysis/src/Commands.ml

@@ -41,9 +41,9 @@ let completionResolve ~path ~modulePath =
   in
   print_endline docstring
 
-let inlayhint ~path ~pos ~maxLength ~debug =
+let inlayhint ~path ~pos ~maxLength ~currentFile ~debug =
   let result =
-    match Hint.inlay ~path ~pos ~maxLength ~debug with
+    match Hint.inlay ~path ~pos ~maxLength ~currentFile ~debug with
     | Some hints -> hints |> Protocol.array
     | None -> Protocol.null
   in
@@ -491,7 +491,7 @@ let test ~path =
               ("Inlay Hint " ^ path ^ " " ^ string_of_int line_start ^ ":"
              ^ string_of_int line_end);
             inlayhint ~path ~pos:(line_start, line_end) ~maxLength:"25"
-              ~debug:false
+              ~currentFile:None ~debug:false
           | "cle" ->
             print_endline ("Code Lens " ^ path);
             codeLens ~path ~debug:false

analysis/src/Hint.ml

@@ -31,7 +31,7 @@ let locItemToTypeHint ~full:{file; package} locItem =
         | `Field -> fromType t))
   | _ -> None
 
-let inlay ~path ~pos ~maxLength ~debug =
+let inlay ~path ~pos ~maxLength ~currentFile ~debug =
   let maxlen = try Some (int_of_string maxLength) with Failure _ -> None in
   let hints = ref [] in
   let start_line, end_line = pos in
@@ -70,11 +70,16 @@ let inlay ~path ~pos ~maxLength ~debug =
     Ast_iterator.default_iterator.value_binding iterator vb
   in
   let iterator = {Ast_iterator.default_iterator with value_binding} in
+  let sourceFile =
+    match currentFile with
+    | Some f -> f
+    | None -> path
+  in
   (if Files.classifySourceFile path = Res then
      let parser =
        Res_driver.parsing_engine.parse_implementation ~for_printer:false
      in
-     let {Res_driver.parsetree = structure} = parser ~filename:path in
+     let {Res_driver.parsetree = structure} = parser ~filename:sourceFile in
      iterator.structure iterator structure |> ignore);
   match Cmt.loadFullCmtFromPath ~path with
   | None -> None

server/src/server.ts

@@ -572,6 +572,7 @@ let closedFile = async (fileUri: utils.FileURI) => {
   }
 };
 
+let refreshTimeout: ReturnType<typeof setTimeout> | null = null;
 let updateOpenedFile = (fileUri: utils.FileURI, fileContent: string) => {
   getLogger().info(
     `Updating opened file ${fileUri}, incremental TC enabled: ${config.extensionConfiguration.incrementalTypechecking?.enable}`,
@@ -581,12 +582,18 @@ let updateOpenedFile = (fileUri: utils.FileURI, fileContent: string) => {
   stupidFileContentCache.set(filePath, fileContent);
   if (config.extensionConfiguration.incrementalTypechecking?.enable) {
     ic.handleUpdateOpenedFile(filePath, fileContent, send, () => {
-      if (config.extensionConfiguration.codeLens) {
-        sendCodeLensRefresh();
-      }
-      if (config.extensionConfiguration.inlayHints) {
-        sendInlayHintsRefresh();
+      if (refreshTimeout != null) {
+        clearTimeout(refreshTimeout);
       }
+      refreshTimeout = setTimeout(() => {
+        refreshTimeout = null;
+        if (config.extensionConfiguration.codeLens) {
+          sendCodeLensRefresh();
+        }
+        if (config.extensionConfiguration.inlayHints) {
+          sendInlayHintsRefresh();
+        }
+      }, 200);
     });
   }
 };
@@ -646,18 +653,37 @@ async function inlayHint(msg: p.RequestMessage) {
   const filePath = utils.uriToNormalizedPath(
     params.textDocument.uri as utils.FileURI,
   );
-
-  const response = await utils.runAnalysisCommand(
+  let args: Array<any> = [
+    "inlayHint",
     filePath,
-    [
-      "inlayHint",
-      filePath,
-      params.range.start.line,
-      params.range.end.line,
-      config.extensionConfiguration.inlayHints?.maxLength,
-    ],
-    msg,
-  );
+    params.range.start.line,
+    params.range.end.line,
+    config.extensionConfiguration.inlayHints?.maxLength,
+  ];
+  let tmpname: string | null = null;
+  let projectRootPath = utils.findProjectRootOfFile(filePath);
+  let rescriptVersion = projectRootPath
+    ? projectsFiles.get(projectRootPath)?.rescriptVersion
+    : null;
+  let supportsCurrentFile =
+    rescriptVersion != null &&
+    semver.valid(rescriptVersion) != null &&
+    semver.gte(rescriptVersion, "12.0.0-alpha.5");
+  // The currentFile argument (passing unsaved buffer content via a temp file)
+  // is only supported by the analysis binary that ships with the compiler
+  // starting from 12.0.0-alpha.5. Older versions don't recognize the extra
+  // argument and would fail to match the CLI pattern.
+  if (supportsCurrentFile) {
+    let code = getOpenedFileContent(params.textDocument.uri as utils.FileURI);
+    let extension = path.extname(params.textDocument.uri);
+    tmpname = utils.createFileInTempDir(extension);
+    fs.writeFileSync(tmpname, code, { encoding: "utf-8" });
+    args.push(tmpname);
+  }
+  const response = await utils.runAnalysisCommand(filePath, args, msg);
+  if (tmpname != null) {
+    fs.unlink(tmpname, () => null);
+  }
   return response;
 }