diff --git a/src/server/project.ts b/src/server/project.ts
index 13bd6e1246e..1c9e985c83c 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -1663,7 +1663,7 @@ export abstract class Project implements LanguageServiceHost, ModuleResolutionHo
         }
     }
 
-    private addMissingFileWatcher(missingFilePath: Path) {
+    private addMissingFileWatcher(missingFilePath: Path): FileWatcher {
         if (isConfiguredProject(this)) {
             // If this file is referenced config file, we are already watching it, no need to watch again
             const configFileExistenceInfo = this.projectService.configFileExistenceInfoCache.get(missingFilePath as string as NormalizedPath);