basic PoC of doing a sort of incremental typechecking

Author: zth

analysis/src/Cmt.ml

@@ -16,13 +16,21 @@ let fullFromUri ~uri =
     let moduleName =
       BuildSystem.namespacedName package.namespace (FindFiles.getName path)
     in
-    match Hashtbl.find_opt package.pathsForModule moduleName with
-    | Some paths ->
-      let cmt = getCmtPath ~uri paths in
-      fullForCmt ~moduleName ~package ~uri cmt
-    | None ->
-      prerr_endline ("can't find module " ^ moduleName);
-      None)
+    let incrementalCmtPath =
+      package.rootPath ^ "/lib/bs/___incremental" ^ "/" ^ moduleName ^ ".cmt"
+    in
+    match fullForCmt ~moduleName ~package ~uri incrementalCmtPath with
+    | Some cmtInfo ->
+      if Debug.verbose () then Printf.printf "[cmt] Found incremental cmt\n";
+      Some cmtInfo
+    | None -> (
+      match Hashtbl.find_opt package.pathsForModule moduleName with
+      | Some paths ->
+        let cmt = getCmtPath ~uri paths in
+        fullForCmt ~moduleName ~package ~uri cmt
+      | None ->
+        prerr_endline ("can't find module " ^ moduleName);
+        None))
 
 let fullsFromModule ~package ~moduleName =
   if Hashtbl.mem package.pathsForModule moduleName then

client/src/extension.ts

@@ -294,7 +294,8 @@ export function activate(context: ExtensionContext) {
       if (
         affectsConfiguration("rescript.settings.inlayHints") ||
         affectsConfiguration("rescript.settings.codeLens") ||
-        affectsConfiguration("rescript.settings.signatureHelp")
+        affectsConfiguration("rescript.settings.signatureHelp") ||
+        affectsConfiguration("rescript.settings.incrementalTypechecking")
       ) {
         commands.executeCommand("rescript-vscode.restart_language_server");
       } else {

package-lock.json

@@ -4,7 +4,7 @@
 	"description": "ReScript language support (official)",
 	"author": "ReScript Team",
 	"license": "MIT",
-	"version": "1.42.0",
+	"version": "1.44.0",
 	"repository": {
 		"type": "git",
 		"url": "https://github.com/rescript-lang/rescript-vscode"
@@ -176,6 +176,11 @@
 					"default": true,
 					"description": "Enable signature help for function calls."
 				},
+				"rescript.settings.incrementalTypechecking": {
+					"type": "boolean",
+					"default": true,
+					"description": "Enable incremental type checking."
+				},
 				"rescript.settings.binaryPath": {
 					"type": [
 						"string",

package.json

@@ -1,7 +1,7 @@
 {
 	"name": "@rescript/language-server",
 	"description": "LSP server for ReScript",
-	"version": "1.42.0",
+	"version": "1.44.0",
 	"author": "ReScript Team",
 	"license": "MIT",
 	"bin": {