diff --git a/packages/runtime-core/src/warning.ts b/packages/runtime-core/src/warning.ts
index 09cf34e5..7ea32b7c 100644
--- a/packages/runtime-core/src/warning.ts
+++ b/packages/runtime-core/src/warning.ts
@@ -7,7 +7,7 @@ type ComponentVNode = VNode & {
   type: Component
 }
 
-let stack: VNode[] = []
+const stack: VNode[] = []
 
 type TraceEntry = {
   vnode: ComponentVNode