1 files changed, 1 insertions, 1 deletions
diff --git a/util/async.ts b/util/async.ts
index 15edb1b42..b737c4cc8 100644
--- a/util/async.ts
+++ b/util/async.ts
@@ -25,7 +25,7 @@ export function deferred<T>(): Deferred<T> {
       methods = { resolve, reject };
     }
   );
-  return Object.assign(promise, methods) as Deferred<T>;
+  return Object.assign(promise, methods)! as Deferred<T>;
 }
 
 interface TaggedYieldedValue<T> {