diff --git a/src/core/observer/scheduler.ts b/src/core/observer/scheduler.ts
index 8fc82b48cf4..fb301baf577 100644
--- a/src/core/observer/scheduler.ts
+++ b/src/core/observer/scheduler.ts
@@ -152,7 +152,7 @@ export function queueActivatedComponent(vm: Component) {
   activatedChildren.push(vm)
 }
 
-function callActivatedHooks(queue) {
+function callActivatedHooks(queue: Component[]) {
   for (let i = 0; i < queue.length; i++) {
     queue[i]._inactive = true
     activateChildComponent(queue[i], true /* true */)