Pick up TS 5.9-beta for built-in support

extensions/package-lock.json

@@ -10,7 +10,7 @@
       "hasInstallScript": true,
       "license": "MIT",
       "dependencies": {
-        "typescript": "^5.8.3"
+        "typescript": "^5.9.0-beta"
       },
       "devDependencies": {
         "@parcel/watcher": "2.5.1",
@@ -940,9 +940,9 @@
       }
     },
     "node_modules/typescript": {
-      "version": "5.8.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.8.3.tgz",
-      "integrity": "sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==",
+      "version": "5.9.0-beta",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.0-beta.tgz",
+      "integrity": "sha512-p91qoTdwWKj9YEBYavmGiBn0DF4OBElzw4pW4oPbK4HeCfr/SDz9+yviVWshZXGvGvFCJ3AVQ+J7F1UZXc23QQ==",
       "license": "Apache-2.0",
       "bin": {
         "tsc": "bin/tsc",

extensions/package.json

@@ -4,7 +4,7 @@
   "license": "MIT",
   "description": "Dependencies shared by all extensions",
   "dependencies": {
-    "typescript": "^5.8.3"
+    "typescript": "^5.9.0-beta"
   },
   "scripts": {
     "postinstall": "node ./postinstall.mjs"

extensions/typescript-language-features/src/languageFeatures/fileConfigurationManager.ts

@@ -208,7 +208,6 @@ export default class FileConfigurationManager extends Disposable {
 			includeCompletionsForModuleExports: config.get<boolean>('suggest.autoImports'),
 			...getInlayHintsPreferences(config),
 			...this.getOrganizeImportsPreferences(preferencesConfig),
-			// @ts-expect-error until TS 5.9
 			maximumHoverLength: this.getMaximumHoverLength(document),
 		};