diff --git a/src/services/codefixes/fixCannotFindModule.ts b/src/services/codefixes/fixCannotFindModule.ts
index a5d44c887b9a2..482480d84205d 100644
--- a/src/services/codefixes/fixCannotFindModule.ts
+++ b/src/services/codefixes/fixCannotFindModule.ts
@@ -52,6 +52,6 @@ namespace ts.codefix {
     function getTypesPackageNameToInstall(packageName: string, host: LanguageServiceHost, diagCode: number): string | undefined {
         return diagCode === errorCodeCannotFindModule
             ? (JsTyping.nodeCoreModules.has(packageName) ? "@types/node" : undefined)
-            : (host.isKnownTypesPackageName!(packageName) ? getTypesPackageName(packageName) : undefined); // TODO: GH#18217
+            : (host.isKnownTypesPackageName?.(packageName) ? getTypesPackageName(packageName) : undefined);
     }
 }